126 research outputs found

    Stirring by swimming bodies

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    We consider the stirring of an inviscid fluid caused by the locomotion of bodies through it. The swimmers are approximated by non-interacting cylinders or spheres moving steadily along straight lines. We find the displacement of fluid particles caused by the nearby passage of a swimmer as a function of an impact parameter. We use this to compute the effective diffusion coefficient from the random walk of a fluid particle under the influence of a distribution of swimming bodies. We compare with the results of simulations. For typical sizes, densities and swimming velocities of schools of krill, the effective diffusivity in this model is five times the thermal diffusivity. However, we estimate that viscosity increases this value by two orders of magnitude.Comment: 5 pages, 5 figures. PDFLaTeX with RevTeX 4 macros. Final versio

    From Revolution To Ruin: A Preliminary Look at Rwanda’s First Two Presidents, Grégoire Kayibanda and Juvénal Habyarimana, and Their Administrations

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    Title from PDF of title page, viewed on November 24, 2015Dissertation advisor: Stephen DilksVitaIncludes bibliographical references (page 565-593)Thesis (Ph.D.)--Department of English Language and Literature and The Social Science Consortium. University of Missouri--Kansas City, 2015This paper brings together primary and secondary materials from a vast number of sources related to the first two presidents of Rwanda, Grégoire Kayibanda and Juvénal Habyarimana, in a preliminary look at the men and their administrations. Using a critical realist methodology, a rounded picture of the two presidents results, and the following findings, in particular are presented: the genocide was not an inevitable aspect of Habyarimana’s policies, and would not have occurred without the RPF invasion; the effect of literacy on the illiterate Rwandan society, from its introduction at the start of the twentieth century, had a profound impact on the socio-political and economic system, and the culture—an impact that has not been adequately recognized per se; the rhizomic nature of the Rwandan social and cultural matrix carried through even the dramatic shift from a chiefdom to independence and a constitutional republic; the questionable nature of Rwanda as a legitimate nation-state under the First and Second Republics; the reason why the single-party government system was chosen and why it failed both presidencies; and the impossible demands on the first presidencies to build an entire State infrastructure from the ground up in the period of a few years.Chapter 1. Introduction -- Chapter 2. Research method -- Chapter 3. Disclaimer -- Chapter 4. Underpinnings of Rwandan Identity: ‘Tutsi’ and ‘Hutu’ Populations / Socio-Psychological Effects Of The Hutu-Tutsi ‘Divide’ / Socio-Political Structure From Habyarimana’s Grandfather’s Time / No Village Pattern / Northwest Region Semi-Autonomous -- Chapter 5. Habyarimana’s Grandfather / Father / Habyarimana’s Early Years -- Chapter 6. Kayibanda’s Early Years / Léon Classe Institute / Catholic Action and the Start of the “Hutu Movement / Office of School Inspection”/ Kinyamateka as Political Platform -- Chapter 7. The Bahutu Manifesto / Beginnings of PARMEHUTU Party / New Parties and the 1959 Elections / The Peasant Revolt (The Muyaga) and the Violence of Toussaint Rwandaise) / Communal Elections -- Chapter 8. Habyarimana: University / Officer’s School -- Chapter 9. Independence / Kayibanda’s Presidency and the First Republic / The Constitution Of 1962 / Municipal Elections / The 1963 Inyenzi Attacks / The One-Party State -- Chapter 10. Habyarimana and Kayibanda / Kayibanda’s Failure and Decline / The Coup d’État of 1973 -- Chapter 11. Following the Coup d’État: the CPUN -- Chapter 12. The MRND Party / Umuganda / Animations/ Jurisprudence Chapter 13. Economic Ills and the Growth of an Inegalitarian Society—the Urban- Rural Dichotomy -- Chapter 14. Challenges to Habyarimana and the One-Party State / The Akazu / Mobutu’s Influence / La Baule / Aggiornamento / The Structural Adjustment Program (SAP) -- Chapter 15. Brief Look at the RPF and Why They Invaded / The Hutu Ten Commandments / The 1991 Constitution / Multipartyism / ID cards -- Chapter 16. Youth Militias and the Fomentation of Violence / The Church at the End of 1991 / Opposition Parties Form Coalition -- Chapter 17. RPF Violates Cease-Fire Agreement / RTLM / New Coalition -- Chapter 18. Arusha Accords / Burundian President Assassinated / Habyarimana Sworn in as President of BBTG / The Failure to Install the Transition Government / The Dar es Salaam Summit and Habyarimana Assassinated -- Appendix A. Kayibanda’s Presidential Address (Excerpt) 1961 -- Appendix B. The 1962 Rwandan Constitution -- Appendix C. Kayibanda’s Address to The Country, 10 April 1964: “Democracy Is Incompatible With Violence” -- Appendix D. Message to the Nation from the President of the Committee for Peace and National Unity on the Occasion of the July 1973 Coup d’État -- Appendix E. Communiqué Issued at the End of a Regional Summit Meeting in Dar Es Salaam on 6th April 1994 -- Appendix F. Habyarimana Through the Eyes of His Wife, Agathe Kanziga -- Appendix G. A Comment on the 1962 Constitutio

    Hovering of a passive body in an oscillating airflow

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    International audienceSmall flexible bodies are observed to hover in an oscillating air column. The air is driven by a large speaker at frequencies in the range 10–65 Hz at amplitudes 1–5 cm. The bodies are made of stiffened tissue paper, bent to form an array of four wings, symmetric about a vertical axis. The flapping of the wings, driven by the oscillating flow, leads to stable hovering. The hovering position of the body is unstable under free fall in the absence of the airflow. Measurements of the minimum flow amplitude as a function of flow frequency were performed for a range of self-similar bodies of the same material. The optimal frequency for hovering is found to vary inversely with the size. We suggest, on the basis of flow visualization, that hovering of such bodies in an oscillating flow depends upon a process of vortex shedding closely analogous to that of an active flapper in otherwise still air. A simple inviscid model is developed illustrating some of the observed properties of flexible passive hoverers at high Reynolds number

    On unidirectional flight of a free flapping wing

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    International audienceWe study the dynamics of a rigid, symmetric wing that is flapped vertically in a fluid. The motion of the wing in the horizontal direction is not constrained. Above a critical flapping frequency, forward flight arises as the wing accelerates to a terminal state of constant speed. We describe a number of measurements which supplement our previous work. These include (a) a study of the initial transition to forward flight near the onset of the instability, (b) the separate effects of flapping amplitude and frequency, (c) the effect of wing thickness, (d) the effect of asymmetry of the wing planform, and (e) the response of the wing to an added resistance. Our results emphasize the robustness of the mechanisms determining the forward flight speed as observed in our previous study

    Day trippin' treasures

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    This travel article from the South Carolina Department of Parks, Recreation and Tourism gives a list of some of South Carolina’s undiscovered gems that are in close proximity to other popular destinations

    South Carolina’s west coast

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    This travel article from the South Carolina Department of Parks, Recreation and Tourism describes the areas known as South Carolina's west coast. Included are descriptions of J. Strom Thurmond Lake, Hickory Knob State Resort Park, Hamilton Branch State Recreation Area and Sumter National Forest

    The Big Mo

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    This travel article from the South Carolina Department of Parks, Recreation and Tourism describes the Big Mo drive-in located on Monetta. When Richard and Lisa Boaz opened the Big Mo March 26, 1999, they saved a cultural icon from junkyard duty. Now they’re open each year from March to around November. They've even started to expand. Since 1999, they’ve added a second screen as well as a children’s Ferris wheel and train ride

    The old guard

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    This travel article from the South Carolina Department of Parks, Recreation and Tourism highlights lighthouses of South Carolina. Described are the Hunting Island Lighthouse, the Georgetown Lighthouse and the two Cape Romain lighthouses
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