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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.
421

Pavages de l'espace affine / Tilings of the affine space

Smilga, Ilia 12 November 2014 (has links)
Pour tout entier naturel impair d, on construit un domaine fondamental pour l'action sur l'espace affine de dimension 2d+1 de certains groupes de transformations affines libres non abéliens, discrets, agissant proprement et de partie linéaire Zariski-dense dans SO(d+1, d). Pour tout groupe de Lie semisimple réel non compact G, on construit ensuite un groupe de transformations affines de son algèbre de Lie g qui est libre non abélien, discret, agit proprement sur g et a sa partie linéaire Zariski-dense dans Ad G. Enfin, on donne quelques résultats sur le comportement local des fonctions harmoniques sur le triangle de Sierpinski, plus précisément de leur restriction à un bord du triangle. / For every odd positive integer d, we construct a fundamental domain for the action on the 2d+1-dimensional space of certain groups of affine transformations which are free, nonabelian, act properly discontinuously and have linear part Zariski-dense in SO(d+1,d). Next for every semisimple noncompact real Lie group G, we construct a group of affine transformations of its Lie algebra g which is free, nonabelian, acts properly discontinuously and has linear part Zariski-dense in Ad G. Finally, we give some results about the local behavior of harmonic functions on the Sierpinski triangle restricted to a side of the triangle.
422

Die Taiwan-Frage im Kontext der US-Strategie für Ostasien-Pazifik nach dem Ende des Ost-West-Konfliktes

Lee, Yuh-Feng 11 December 2003 (has links)
Die Taiwan-Frage war ein Dauerproblem der internationalen Politik im Zeitalter des Kalten Krieges. Auch nach dem Ende des Ost-West-Konflikts ist die Taiwan-Frage immer noch ein gefährlicher Konfliktherd in Ostasien und das schwierigste Problem in den Beziehungen zwischen China und den USA. Die Taiwan-Frage ist deshalb ein ausgesprochen wichtiges Thema in der US-Strategie für Ostasien-Pazifik nach dem Ende des Ost-West-Konfliktes. Der Aufstieg Chinas wird die Taiwan-Frage in Zukunft unumgänglich wieder aufwerfen und könnte irgendwann einmal eine direkte Konfrontation zwischen China und den USA heraufbeschwören. In Hinblick darauf, dass das Modell des Dreiecks Washington-Taipeh-Beijing besonders gut für die strategische Analyse der Interaktion innerhalb diesen Beziehungsdreiecks ist, will die vorliegende Arbeit auf der systemischen Ebene das Modell des "Taiwan-Straßen-Dreiecks" auch anwenden, um die Taiwan-Frage aus der strategischen Perspektive zu untersuchen. Die vorliegende Untersuchung will auf den Zeitraum von 1990-2000. Dazu sind eine eingehende Darstellung und Analyse der strategischen Strukturen der Taiwan-Frage ebenso notwendig wie eine Auseinandersetzung mit theoretischen Ansätzen und deren Untersuchung in Hinblick auf die ostasiatisch-pazifische Strategie der Vereinigten Staaten. Durch theoretische Untersuchung und empirische Analyse soll diese Forschungsarbeit ein in der politischen Praxis operationalisierbares Modell der strategischen Interaktion in der Taiwan-Frage entwickeln, von dem aus die optimale strategische Option für Taiwan gewählt und somit Lösungsmöglichkeiten diskutiert werden können. / The Taiwan issue was a constant problem for international politics during the Cold War era and it has remained a dangerous source of conflict in East Asia ever since. It is the most complicated aspect of Sino-American relations. Therefore the Taiwan issue has been a decisive factor in US East Asian strategy. China s rise to power will inevitably raise the issue again in the future and this could one day lead to direct confrontation between China and the USA. So it follows that the term, strategic triangle, which was used to describe the relationship between Washington, Moscow and Beijing has now also been applied to the interconnections between Washington, Taipei and Beijing. Seeing that the above-mentioned triangular model is extremely useful for a strategic analysis of the interactions within this group, the study presented here attempts to use the model of the "Taiwan Strait Triangle" to examine the Taiwan issue in the changing international system from a strategic perspective. The study presented here concentrates on the time period between 1990 and 2000. Its fundamental prerequisites are a thorough presentation and analysis of the strategic structures pertinent to the Taiwan issue, as well as a discussion of the theories that have been considered and applied in US strategy for East Asia and the Pacific. Moreover, there is great need for further thorough examination of the developments in the Taiwan issue and the strategic configuration in the East Asian and Pacific region in terms of the fundamentally changed strategic circumstances brought about by the changes in the global system after the end of the East - West conflict.
423

Where do beginner readers read in the English, mainstream primary school and where could they read?

Dyer, Emma January 2018 (has links)
Where do beginner readers read in the English, mainstream primary school and where could they read? Emma Jane Dyer This thesis explores design for the beginner reader in Year One by evaluating existing spaces in the English primary school and imagining new ones. Three significant gaps identified in the literature of reading, the teaching of reading and school design are addressed: the impact of reading pedagogies, practices and routines on spatial arrangements for beginner readers inside and beyond the classroom; a theoretical understanding of the physical, bodily and sensory experience of the beginner reader; and the design of reading spaces by teaching staff. The study uses a design-oriented research methodology and framework proposed by Fällman. A designed artefact is a required outcome of the research: in this case, a child-sized, semi-enclosed book corner known as a nook. The research was organized in three phases. First, an initial design for the nook was created, based on multi-disciplinary, theoretical research about reading, school design and architecture. Secondly, empirical research using observation, pupil-led tours and interviews was undertaken in seven primary schools to determine the types of spaces where readers read: spaces that were often unsuitable for their needs. Thirdly, as a response to the findings of phases one and two, the nook was reconceived to offer a practical solution to poorly-designed furniture for reading in schools and to provoke further research about the ideal qualities of spaces for the beginner reader. The study demonstrates how the experience of the individual reader is affected by choices made about the national curriculum; by the size of schools and the spaces within them where readers can learn; by the design of classrooms by teachers; and by regulatory standards for teaching and non-teaching spaces. In developing a methodology that can stimulate and facilitate communication between architects, educators, policy-makers and readers, this thesis offers a valuable contribution to the ongoing challenge of improving school design for practitioners and pupils.
424

As maras e pandillas no Triângulo Norte da América Central e a atuação dos Estados Unidos em seu combate

Correa, Paulo Mortari Araujo 23 April 2015 (has links)
Made available in DSpace on 2016-04-29T13:48:37Z (GMT). No. of bitstreams: 1 Paulo Mortari Araujo Correa.pdf: 1838397 bytes, checksum: 6861111ef03c826f74df72c0ab83180d (MD5) Previous issue date: 2015-04-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Maras and pandillas are terms usually employed in El Salvador, Guatemala and Honduras which jointly comprise the so-called Central America Northern Triangle with regard to street gangs, whose members are traditionally youngsters (and mostly men) and share a common identity, which can range from the use of specific forms of communication and cultural expression (including slangs, body gestures, tattoos, graffiti on walls and musical rhythms) to the enforcement of rigorous standards of conduct. The expansion of these groups throughout the region, and its accountability for the growth of violence in big cities have been prompting the adoption of not only domestic measures, but also international ones, which consequently involves both Central American authorities and institutions from other countries, such as the United States. Based on this finding, it is questioned, in this research, what the interest of the United States is in combating street gangs out of its borders, considering that this is commonly seen as a public security problem concerning the state in which territory such groups operate. Through the hypothetical-deductive method, and by the consultation with official reports and other American governmental sources besides the specific literature on gangs in the Northern Triangle and on the recent history and current context of the region , at least four hypothesis are tested, which refer to the United States possible perception that the gangs I) are (or are willing to be) tied to groups seen as terrorists; II) have a significant participation on the international illicit drug trade, even in collaboration with great cartels of the region; III) are transnational organized crime groups, capable of coordinating crimes on American soil with their peers established there; and that IV) the violence concerning gangs in El Salvador, Guatemala and Honduras feeds migratory fluxes (including the migration of mareros and pandilleros) from these countries towards the United States, something which would not be desired by the latter. Discussions on new and newest wars, in the context of the expansion of the International Security Studies, are adopted as the theoretical framework, especially in reference to the performance of states in the combat of non-traditional threats / Maras e pandillas são termos usualmente empregados em El Salvador, Guatemala e Honduras que, juntos, compõem o chamado Triângulo Norte da América Central em referência a gangues de rua, cujos membros são tradicionalmente jovens (e, em sua maioria, do sexo masculino) e compartilham de uma identidade comum, o que pode incluir desde o uso de formas de comunicação e expressão cultural específicas (entre gírias, gestos corporais, tatuagens, grafites em muros e ritmos musicais) até a aplicação de rigorosas normas de conduta. A expansão desses grupos pela região e sua responsabilização pela escalada da violência nas grandes cidades têm incitado a adoção de medidas não só domésticas, mas, também, internacionais, envolvendo, por conseguinte, tanto autoridades centro-americanas como instituições de outros países, como os Estados Unidos. Com base nessa constatação, questiona-se, nesta pesquisa, qual é o interesse dos Estados Unidos em atuar no combate a gangues de rua fora de suas fronteiras, considerando que isso é comumente visto como um problema de segurança pública do Estado em cujo território tais grupos operam. Através do método hipotético-dedutivo e a partir da consulta a relatórios oficiais e outras fontes do governo estadunidense além da literatura específica sobre as gangues no Triângulo Norte e sobre a história recente e contexto atual da região , testam-se ao menos quatro hipóteses, que se referem à possível percepção dos Estados Unidos de que as gangues I) têm ou almejam ter vínculos com grupos tidos como terroristas; II) atuam de forma expressiva no tráfico internacional de drogas, inclusive em cooperação com grandes cartéis da região; III) são grupos transnacionais do crime organizado, capazes de coordenar delitos em solo estadunidense com seus pares lá estabelecidos; e que IV) a violência concernente às gangues em El Salvador, Guatemala e Honduras fomenta fluxos migratórios (inclusive de mareros e pandilleros) desses países em direção aos Estados Unidos, algo indesejado pelos últimos. Adotam-se como matriz teórica as discussões acerca das novas e novíssimas guerras, dentro do contexto de expansão dos Estudos de Segurança Internacional, em referência especialmente à atuação de Estados no combate a ameaças não tradicionais
425

越戰對美、蘇、中共三角關係之影響(1964-1973年)

吳家新, Jia-shin Wu Unknown Date (has links)
426

俄羅斯亞太政策形成之研究 (1992-1998) / The Formation of Russia's Asia-Pacific Policy (1992-98)

劉蕭翔, Liou, Shiau-Shyang Unknown Date (has links)
俄羅斯獨立之初,其對外政策路線為「向西方一面倒」,亞太政策並未能與其對西方政策相提並論。但在短短數年間,俄羅斯與亞太區域大國—中共的關係急遽加溫,雙方建立了戰略夥伴關係。這足以說明俄羅斯的亞太政策在其對外政策中的比重已然提升。俄羅斯現行的對外政策走的是「東西平衡」路線;從而,俄羅斯的亞太政策也有重大的調整。本論文將探討1992至1998年間,俄羅斯的亞太政策如何形成。 本論文認為:1992年俄羅斯獨立之後,俄羅斯的亞太政策乃是在國內經濟發展的需求以及戰略三角的互動等環節關聯上,受到克里姆林宮政治生態互動而形成。此一命題可再引申為下列邏輯相關的子命題:(一)由於美國主導北約的東進使俄羅斯感受威脅,加上中共與美國的戰略衝突,引起美俄中戰略三角的互動,促使俄羅斯意圖聯合中共以制衡美國,因而造成俄羅斯亞太政策的重大調整。(二)在俄羅斯國內經濟凋敝的情況下,俄屬遠東的開發為其自力救濟的唯一途徑。為加速俄屬遠東的開發,俄羅斯勢必要開創有利的國際環境,從而必須調整其亞太政策。(三)俄羅斯亞太政策的形成與其國內政治生態的互動有密切的關聯:克里姆林宮政治生態互動,造成俄羅斯的對外政策路線從原來的「向西方一面倒」徹底轉為東西平衡的「雙頭鷹」,而亞太政策就是其重要環節之一。 上述的三個成因,構成本論文的核心論點;而對應於此三個論點,本論文將分六章探討。第一章為緒論,說明研究動機與範圍、文獻述評與研究途徑。第二章:俄羅斯的亞太政策。本章將略述俄羅斯獨立後,其亞太政策的實際運作。當中以俄羅斯對中共、日本與南北韓的政策,做為重點加以描述,其次再論及俄羅斯對東南亞地區國家的政策。第三章:戰略三角互動對俄羅斯亞太政策的影響。本章將闡述戰略三角互動對俄羅斯亞太政策形成的影響。第四章:俄羅斯遠東經濟開發對其亞太政策的影響。本章將檢視俄屬遠東經濟開發對俄羅斯亞太政策的影響。第五章:俄羅斯政治生態互動對其亞太政策的影響。本章將探討克里姆林宮政治生態互動對俄羅斯亞太政策的影響。第六章:結論。 目錄-----------------------------------------------------------I 圖表目錄------------------------------------------------------VI 縮寫表------------------------------------------------------VIII 第一章 緒論---------------------------------------------------1 第一節 研究動機與目的-----------------------------------------1 第二節 研究範圍-----------------------------------------------4 第三節 文獻述評-----------------------------------------------6 第四節 研究途徑與架構----------------------------------------13 第二章 俄羅斯的亞太政策--------------------------------------24 第一節 俄羅斯對東亞政策--------------------------------------26 一、俄羅斯對中共政策------------------------------------------26 (一)俄中夥伴關係層次的提升—由「睦鄰友好」到「戰略夥伴」----26 (二)俄中夥伴關係的具體表現----------------------------------30 二、俄羅斯對台灣政策------------------------------------------36 (一)俄台關係—中斷四十年後的交流----------------------------36 (二)俄台經貿往來成果----------------------------------------37 第二節 俄羅斯對東北亞政策------------------------------------39 一、俄羅斯對日政策--------------------------------------------40 (一)俄日零和關係的轉變—「東京宣言」------------------------40 (二)俄羅斯對日政策推行的障礙—北方四島問題------------------41 二、俄羅斯對朝鮮半島政策--------------------------------------44 (一)俄羅斯對南韓政策—漸行漸遠的雙邊關係--------------------45 (二)俄羅斯對北韓政策—由疏而近的調整------------------------47 第三節 俄羅斯對東南亞政策------------------------------------49 (一)俄羅斯與東協「對話夥伴關係」的建立----------------------49 (二)俄羅斯東南亞政策的具體成就------------------------------52 第三章 戰略三角互動對俄羅斯亞太政策的影響--------------------54 第一節 俄美的戰略衝突----------------------------------------56 (一)俄美「成熟戰略夥伴關係」的建立--------------------------56 (二)俄美之間日漸浮現的衝突----------------------------------58 (三)俄美衝突的激化—美國主導北約東擴------------------------66 第二節 美中的戰略衝突----------------------------------------77 (一)「圍堵」與「反圍堵」------------------------------------77 (二)美國干涉1996年台海飛彈危機------------------------------84 (三)貌合神離的美中「建設性夥伴關係」------------------------87 第三節 俄中的戰略匯合----------------------------------------91 (一)俄羅斯對中共的軍售與技術轉移----------------------------91 (二)俄中邊界裁軍與互信措施的建立----------------------------97 (三)俄中對外戰略的互補--------------------------------------99 第四節 戰略三角互動對俄羅斯亞太政策的影響-------------------110 第四章 俄屬遠東開發對俄羅斯亞太政策的影響-------------------112 第一節 俄屬遠東的開發現況與困境-----------------------------113 (一)俄屬遠東開發的歷史回顧---------------------------------114 (二)俄屬遠東的開發現況-------------------------------------119 (三)俄屬遠東開發所面臨的困境-------------------------------123 第二節 東北亞區域經濟合作對俄屬遠東開發的必要性-------------130 (一)東北亞區域經濟合作的源起—圖們江開發計劃---------------130 (二)東北亞區域經濟合作—圖們江開發計劃的推行現況-----------133 (三)東北亞區域經濟合作對俄屬遠東開發的必要性---------------137 第三節 俄羅斯國內對俄屬遠東開發的歧見-----------------------140 (一)俄羅斯的遠東開發政策-----------------------------------140 (二)遠東地區對開發當地的看法-------------------------------146 第四節 俄羅斯為其遠東開發所做的政策調整---------------------150 (一)裡應外合的前置調整-------------------------------------150 (二)俄屬遠東開發與俄羅斯亞太政策之間的聯繫-----------------152 (三)俄羅斯亞太政策因應俄屬遠東開發的調整-------------------153 第五節 俄屬遠東開發對俄羅斯亞太政策的影響-------------------164 第五章 俄羅斯政治生態互動對其亞太政策的影響-----------------166 第一節 俄羅斯亞太政策的決策機制-----------------------------168 (一)總統府-------------------------------------------------168 (二)外交部-------------------------------------------------176 (三)國會---------------------------------------------------178 第二節 對外政策路線論爭的影響-------------------------------180 (一)俄羅斯對外政策路線的轉折-------------------------------180 (二)大西洋學派、歐亞大陸學派與大俄羅斯帝國學派-------------183 (三)對外政策路線的論戰-------------------------------------186 (四)「俄羅斯對外政策概念」與「俄羅斯的戰略」之比較---------191 第三節 府會之間對立的影響-----------------------------------197 (一)府會政爭的前夕-----------------------------------------197 (二)府會衝突的激化-----------------------------------------200 (三)府會之間對立對俄羅斯外交路線的影響---------------------209 第四節 國會政治生態的影響-----------------------------------211 (一)93國會大選後的政治生態---------------------------------212 (二)95國會改選的衝擊---------------------------------------217 (三)國會政治生態對俄羅斯外交路線的影響---------------------224 第五節 總統大選的衝擊---------------------------------------226 (一)96外長易人後國內的政治生態-----------------------------226 (二)車臣戰事的糾葛-----------------------------------------231 (三)總統大選對俄羅斯外交路線的影響-------------------------238 第六節 俄羅斯政治生態互動對其亞太政策的影響-----------------240 第六章 結論-------------------------------------------------242 參考書目-----------------------------------------------------245 / In the initial stage immediately after its dependence, Russia’s foreign policy was following the line of “inclining to the West” therefore, the gravity of Russia’s Asia-Pacific Policy was disproportional comparing with that of its Policy toward the West. Nevertheless, during recent years, the Russo-Chinese relation has developed rapidly, and both sides have established the “strategic partnership”. This means that Russia’s Asia-Pacific Policy has become more and more significant since Russia is seeking an equilibrium between the East and the West in its current foreign policy. Against this background, this thesis will survey the factors that exert impact on the formation of Russia’s Asia-Pacific Policy during the period from 1992 to 1998. This thesis is taking the position that Russia’s Asia-Pacific policy has been shaped by the Kremlin politics within the context of its domestic imperative of economic development and the interaction of “Strategic Triangle” politics since the collapse of the former Soviet Union. This hypothesis can be further developed into the following three logically intertwined propositions: (1) Due to the US led NATO expansion eastward, which has created threats Russia’s security and the strategic conflict between the U.S.A. and the PRC. Russia intends to search the support from the PRC in order to check the US hegemonism. Under this consideration, Russia adjusts its Asia-Pacific Policy. (2) With the difficulties in its domestic economic development, the development of Russia’s Far East is the only way to release Russia from such a predicament. In order to accelerate the development of Russia’s Far East, Russia, it is necessary to search for a stable international condition. This consideration also demands that Russia adjust its Asia-Pacific Policy. (3) The formulation of Russia’s Asia-Pacific Policy is driven by its domestic political struggle: Kremlin politics makes the thoroughgoing change of Russia’s foreign policy line. Now Russia is seeking an equilibrium between the East and the West, which demands an adjustment in its Asia-Pacific policy in turn. These three factors above constitute the core points of this thesis. In accordance with these points, this thesis will be discussed in six chapters. Chapter one is introduction, it will explain the purpose, scope and approaches of this study. Chapter two will survey the development of Russia’s Asia-Pacific Policy during the period defined. This chapter will sketch the implementation of Russia’s Asia-Pacific Policy, with emphasis on Russia’s policies toward the PRC, Japan and the Korean Peninsula, and the Southeast Asia. Chapter three will explore the influence of the Strategic Triangle politics. Chapter four will examine the influence of the development of Russia’s Far East on Russia’s Asia-Pacific Policy. Chapter five will discuss how the Kremlin politics influences Russia’s Asia-Pacific Policy. Chapter six is conclusion.
427

台灣、中國與中美洲國家三邊關係之分析(2000年至2008年) / Trilateral Relations between Taiwan, China and Central America (2000-2008)

陳翰民, Chen, Han Ming Unknown Date (has links)
2007年6月,與我建交長達60年以上之中美洲國家哥斯大黎加(Costa Rica)驟然宣佈與中國大陸建交,當時各界開始擔憂,台灣過去在中美洲頗為自豪之完整外交版圖在缺少了一角後,是否將發生骨牌效應?雖然事後證明此種疑慮並未成真,但已引起各界對我國維繫邦交成效之討論,也成為筆者之研究動機。 本文研究方法係針對傳統戰略三角分析途徑之侷限,提出改良式三邊關係分析模型,用以研究2000年至2008年期間台灣、中國大陸及中美洲友邦三邊關係。本研究目的有三,第一、界定台灣在此時期三邊關係中之地位優劣及導因,分析台灣在維繫邦交之優勢、劣勢、機會與挑戰。第二、藉由分析我國在三邊關係中之優勢及劣勢,進而提出提升地位及鞏固邦交之策略建議。第三、在研究方法層次,嘗試建構一套合理之三角關係分析途徑,設計出更合理且適用性更高之研究途徑。
428

Trigonometry: Applications of Laws of Sines and Cosines

Su, Yen-hao 02 July 2010 (has links)
Chapter 1 presents the definitions and basic properties of trigonometric functions including: Sum Identities, Difference Identities, Product-Sum Identities and Sum-Product Identities. These formulas provide effective tools to solve the problems in trigonometry. Chapter 2 handles the most important two theorems in trigonometry: The laws of sines and cosines and show how they can be applied to derive many well known theorems including: Ptolemy¡¦s theorem, Euler Triangle Formula, Ceva¡¦s theorem, Menelaus¡¦s Theorem, Parallelogram Law, Stewart¡¦s theorem and Brahmagupta¡¦s Formula. Moreover, the formulas of computing a triangle area like Heron¡¦s formula and Pick¡¦s theorem are also discussed. Chapter 3 deals with the method of superposition, inverse trigonometric functions, polar forms and De Moivre¡¦s Theorem.
429

Application en métrologie électrique de dispositifs monoélectroniques : vers une fermeture du triangle métrologique

Steck, Barthélémy 28 November 2007 (has links) (PDF)
Dans l'optique d'une modification du système international d'unités (SI), le LNE développe l'expérience du triangle métrologique (ETM). Cette expérience consiste à appliquer la loi d'Ohm à l'aide des effets Hall quantique pour la résistance, Josephson pour la tension et tunnel à un électron (SET) pour le courant. L'objectif est d'augmenter notre connaissance de la cohérence des constantes impliquées dans ces phénomènes.<br />Dans ce cadre, nous nous somme intéressés dans cette thèse à la possibilité d'utiliser les pompes à électrons de type R à 3 jonctions de façon métrologique autour de 10 pA. Notre montage expérimental est conçu afin de mesurer le courant quantifié généré par le dispositif en utilisant un comparateur cryogénique de courants (CCC).<br />Les principaux résultats ont été obtenus avec une pompe fabriquée par la PTB couplée à un CCC connecté en contre-réaction interne, i.e. utilisé comme un amplificateur de courant et ne donnant qu'une valeur relative du courant. Ces expériences ont permis de montrer l'existence de marches de courant jusqu'à environ 16 pA et une stabilité du courant généré par le dispositif sur des temps longs, indépendamment de la fréquence de pompage jusqu'à 100 MHz. Le niveau de bruit blanc est de 10-15 fA/Hz^(1/2) et, après 7 heures de mesure à une fréquence de 100 MHz, une incertitude relative de type A de 4.10^(-6) a été atteinte.<br />La dernière partie de ce travail présente la première réalisation directe de l'ETM. Dans ce cas, le courant généré par la pompe traverse une résistance étalonnée et la tension aux bornes de celle-ci est comparée à la tension délivrée par un réseau Josephson. Les premiers résultats qui sont présentés semblent prometteurs.
430

Rheo-NMR studies of viscoelastic secondary flows in ducts of non-circular cross-section

Schroeder, Christian Berthold Karl 07 May 2012 (has links)
The existence of hydrodynamically developed, laminar Viscoelastic Secondary Flows (VSFs) of non-Newtonian fluids in straight ducts of non-circular cross-section was proposed in the 1950's. VSFs have since been observed sporadically, and only once with a velocimetric technique. Using axial and transverse full flow-field velocity-position raster maps made with Rheological Nuclear Magnetic Resonance (Rheo-NMR), Newtonian and non-Newtonian fluid flows were quantified in Hagen-Poiseuille and Power Law contexts, over more than two orders of magnitude of flow rate, in ducts of circle, square, triangle, and pentagon cross-section. VSF was reliably and repeatedly observed to occur at between one part in 130 and one part in 600 of the primary axial flow velocity. Velocity measurements ranged from <10 µm/s to approximately 30 cm/s, suggesting a velocity dynamic range >3E4 without optimization. To obtain VSF flow direction information, a novel flow directional phantom was developed and characterized. Aqueous solutions of Polyethylene Oxide (PEO), Viscarin GP-109NF, Viscarin GP-209NF (V209), Hyaluronan (HA) in a Phosphate-Buffered Saline-like solvent, and an aqueous Polyethylene Glycol/PEO-based Boger fluid were investigated. Axial data was corroborated with related data gathered by an independent method. Basic simulations corroborated the VSF observations. Duct hydraulic diameters (>= 1.6 mm) approached the micro-channel regime. VSF detections in HA --- synovial fluid's principal component --- and V209 were novel, as were observations of some artifacts which were subsequently characterized and corrected. The detection of VSF in HA represents the first experimental evidence suggesting that its second normal stress (N_2) is comparable to that of better-characterized fluids. In the first application of a new VSF-based method, a particular Boger fluid's constant viscosity and, in the square duct, its lack of VSF were used with established criteria to suggest that the fluid's N_2 approached zero. The development of a rudimentary, but versatile and inexpensive home-built velocimetric spectrometer is detailed, as are several new components. An exhaustive VSF literature review is included. The remarkable transverse velocimetric ability of Rheo-NMR in both optically opaque and transparent system is highlighted, suggesting that perhaps the technique might represent, in both micro-channels and conventional ducts, the gold-standard in flow velocimetry.

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