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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.
1

Ice distribution in the Gulf of St. Lawrence during the breakup season

Forward, Charles Nelson January 1952 (has links)
The Gulf of St. Lawrence Is closed to commercial navigation for nearly five months each year due to ice conditions. In order to lengthen the shipping season, greater knowledge of the behaviour of the ice is necessary. A step in this direction was the inauguration in 1940 of aerial ice surveys in the gulf during the breakup season. The surveys have continued annually for the past thirteen years. Based primarily on the data provided by these surveys, maps were drawn showing the limits of the main ice areas in each breakup season. Although the maps enabled the isolation of several distinct patterns and rates of breakup, they revealed that the behaviour of the ice was extremely variable. The factors influencing ice conditions, including tides, ocean currents, temperature, and wind, were examined with the aim of discovering the causes of the breakup patterns. A number of factors were found to be important in determining the fundamental behaviour of the ice, bat the meteorological factors of temperature and wind appeared to be the chief agents in causing the variable behaviour from year to year. In spite of these variations, it was possible to trace average conditions throughout the Ice season. The chief characteristics of the ice season may be stated briefly. The Gulf of St. Lawrence is never completely covered with ice, but rather, it is partly covered with fields of shifting pack ice between which lie broad stretches of open water. The southern part of the gulf is an area of accumulation where ice conditions are most serious. The clearing of ice from the gulf begins slowly in January and February and becomes accelerated in March and April. The bulk of the ice moves through Cabot Strait to the open Atlantic rather than remaining inside the gulf until it melts. Generally, the ice either withdraws from west to east, passing through Cabot Strait directly, or it stagnates in the southern part of the gulf toward the end of the season. By the first of May the gulf is usually clear of ice which constitutes a hinderance to navigation. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
2

The Wabash, priorities in conflict

Lines, Scott Alan January 1978 (has links)
This creative project has taken the form of a 16 millimeter color documentary film that analyzed the proposed alteration of a major natural resource in Indiana; i.e., the Wabash River. The agency responsible for studying the proposed alteration was the U.S. Army, Corps of Engineers, which was acting in response to Congressional authorization.The film analyzed the proposed alteration, known as Wabash Navigation, from the perspectives of history, ecology, economics, and philosophy; differing world views inherent in the global ecological crisis were found to exist in the values of waterway advocates and opponents.The Corps of Engineers found this particular project to be non-feasible. However, the historical and philosophical point is made that non-feasibility does not mean that efforts to promote the waterway would necessarily be dropped. Viewers are asked to analyze the issue from the various perspectives represented in the film and formulate their own opinions.
3

Análise de transporte multimodal na região da hidrovia Tietê-Paraná

Bravin, Luís Fernando Nicolosi [UNESP] 24 July 2001 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2001-07-24Bitstream added on 2014-06-13T20:32:01Z : No. of bitstreams: 1 bravin_lfn_me_botfca.pdf: 437731 bytes, checksum: 76e60ecd78bce56040361c1fa6425214 (MD5) / A hidrovia Tietê-Paraná foi aqui analisada sob o ponto de vista de seu aproveitamento para a navegação comercial, servindo para o escoamento dos produtos da rica região centro-oeste brasileira com destino ao porto de Santos (SP), com o objetivo de mostrar a vantagem competitiva de se utilizar a multimodalidade de transporte no escoamento de grãos. Considerando que o custo de transporte ou custo logístico chega, em alguns casos, a representar até 30% do valor final de vários produtos agrícolas, verificou-se que a navegação fluvial tornou-se um grande fator de redução no custo dos produtos, que necessitam de transporte em longa distância e, ao mesmo tempo, mantém um fluxo de carga muito elevado. Esta economia no custo de frete pode chegar a valores acima de 30%, quando se utiliza embarcações fluviais de terceiros e uma economia de mais de 40% ao se utilizar embarcações próprias, na fase do transporte hidroviário. Pela metodologia utilizada no trabalho foram identificadas duas regiões distintas: a consumidora e a produtora. Esta condição permitiu que fosse apresentado um estudo logístico específico, com maior detalhamento de rota e melhor especificação de equipamentos a serem utilizados, os quais permitiram obter resultados que possibilitaram otimizar o frete. Comparou-se os resultados desta análise de transporte com finalidade de obter relações entre custos e benefícios observados em outras modalidades de transporte utilizados nesta região, potencialmente rica e carente de transportes eficientes. / The Tietê-Paraná's waterway was analyzed here under the point of view of its use for the commercial sailing; being good for the canal of the products of the rich center-west region of Brazil to Santos' harbour, with objective to show the advance multimodal transporting in grains drainage. Considering that the cost of transporting or logistic's cost reach thirty per cent of the final value of several agricultural products. The fluvial sailing is seen today as a great reduction factor in the costs of products, that need transport of long distance and at the same time it maintains a very high load flow. This reduction of freight may get thirty per cent if used undertaking boat, but forty per cent or more will be get if used self-boat. The work has a sequence that will begin with the general characterization of the area consumer, as well as the location of the producing areas, presenting a specific study where it will consist a larger route specially and the equipments to be it used. This source will show a series of calculations that they will have later as objective to arrive to a freight optimized in this project, which intends to offer the analysis of transport alternative comparable with the costs and benefits of the other modalities of this area, potentially rich and poor of efficient transports.
4

Análise de transporte multimodal na região da hidrovia Tietê-Paraná /

Bravin, Luís Fernando Nicolosi, 1969- January 2001 (has links)
Resumo: A hidrovia Tietê-Paraná foi aqui analisada sob o ponto de vista de seu aproveitamento para a navegação comercial, servindo para o escoamento dos produtos da rica região centro-oeste brasileira com destino ao porto de Santos (SP), com o objetivo de mostrar a vantagem competitiva de se utilizar a multimodalidade de transporte no escoamento de grãos. Considerando que o custo de transporte ou custo logístico chega, em alguns casos, a representar até 30% do valor final de vários produtos agrícolas, verificou-se que a navegação fluvial tornou-se um grande fator de redução no custo dos produtos, que necessitam de transporte em longa distância e, ao mesmo tempo, mantém um fluxo de carga muito elevado. Esta economia no custo de frete pode chegar a valores acima de 30%, quando se utiliza embarcações fluviais de terceiros e uma economia de mais de 40% ao se utilizar embarcações próprias, na fase do transporte hidroviário. Pela metodologia utilizada no trabalho foram identificadas duas regiões distintas: a consumidora e a produtora. Esta condição permitiu que fosse apresentado um estudo logístico específico, com maior detalhamento de rota e melhor especificação de equipamentos a serem utilizados, os quais permitiram obter resultados que possibilitaram otimizar o frete. Comparou-se os resultados desta análise de transporte com finalidade de obter relações entre custos e benefícios observados em outras modalidades de transporte utilizados nesta região, potencialmente rica e carente de transportes eficientes. / Abstract: The Tietê-Paraná's waterway was analyzed here under the point of view of its use for the commercial sailing; being good for the canal of the products of the rich center-west region of Brazil to Santos' harbour, with objective to show the advance multimodal transporting in grains drainage. Considering that the cost of transporting or logistic's cost reach thirty per cent of the final value of several agricultural products. The fluvial sailing is seen today as a great reduction factor in the costs of products, that need transport of long distance and at the same time it maintains a very high load flow. This reduction of freight may get thirty per cent if used undertaking boat, but forty per cent or more will be get if used self-boat. The work has a sequence that will begin with the general characterization of the area consumer, as well as the location of the producing areas, presenting a specific study where it will consist a larger route specially and the equipments to be it used. This source will show a series of calculations that they will have later as objective to arrive to a freight optimized in this project, which intends to offer the analysis of transport alternative comparable with the costs and benefits of the other modalities of this area, potentially rich and poor of efficient transports. / Orientador: Widsney Alves Ferreira / Coorientador: Marco Antônio Martin Biaggioni / Banca: Elias José Simon / Banca: Adilio F. de Lacerda Filho / Mestre
5

A viagem do comandante dos Estados Unidos, Thomas Jefferson Page (U.S. Navy), ao estuário do Prata (1853-1860) / The expedition of the U.S navy commander, Thomas Jefferson Page, through the river La Plata, the Argentine Confederation and Paraguay (1853-1860)

Moreira, Marília Arantes Silva 11 October 2013 (has links)
O artigo discute os interesses principalmente dos sulistas dos Estados Unidos na América do Sul, através do estudo da expedição do navio a vapor Water Witch realizada pelo comandante da U.S. Navy, Thomas Jefferson Page, pelo rio da Prata e adjacentes. Com poderes para realizar trabalhos científicos na região e diplomáticos para negociar em favor da livre navegação dos rios da região, além de estabelecer tratados comerciais, Page obteve consentimentos para a navegação, principalmente por parte do Império do Brasil e da Confederação Argentina. Contudo, entrou em conflito com o governo do Paraguai, originando uma contenda com o presidente do país, Carlos Antonio López, durante a qual o navio de Page foi bombardeado. Em resposta, os Estados Unidos aprovaram uma intervenção ao Paraguai em 1858, enviando para lá uma esquadra. Tal realização movimentou navios e canhões para restituir acordos comerciais e viabilizar a segunda -- e conclusiva -- etapa da expedição de Page, entre 1858-60. O artigo pretende mostrar que parte dos objetivos dos norte-americanos foram alcançados na região, ainda que tenham usado a força para fazer valer as suas intenções, principalmente, no Paraguai. / The article discusses the interests involved in the expedition made by commander Thomas Jefferson Page through river de La Plata and adjacent rivers. Having diplomatic powers to persuade the free navigation of rivers in South America, T.J. Page obtained consent for his transit and cartographic work, especially on the part of the Empire of Brazil and the Argentine Confederation. However, he a conflict with the government of Paraguay, resulted in a feud with the country\'s president, Carlos Antonio López. Thus, an intervention, approved by the U.S. Congress, in 1858, stirred ships and cannons to repay commercial agreements and enabling the second - and conclusive - part of the expedition (1859-60). The official narrative reveals horizons of the North-American Southern elite next to the imminent U.S. Civil War (1861-65). In the South of the continent, the regional conflicts were developing into the Paraguayan War (1864-70).
6

A viagem do comandante dos Estados Unidos, Thomas Jefferson Page (U.S. Navy), ao estuário do Prata (1853-1860) / The expedition of the U.S navy commander, Thomas Jefferson Page, through the river La Plata, the Argentine Confederation and Paraguay (1853-1860)

Marília Arantes Silva Moreira 11 October 2013 (has links)
O artigo discute os interesses principalmente dos sulistas dos Estados Unidos na América do Sul, através do estudo da expedição do navio a vapor Water Witch realizada pelo comandante da U.S. Navy, Thomas Jefferson Page, pelo rio da Prata e adjacentes. Com poderes para realizar trabalhos científicos na região e diplomáticos para negociar em favor da livre navegação dos rios da região, além de estabelecer tratados comerciais, Page obteve consentimentos para a navegação, principalmente por parte do Império do Brasil e da Confederação Argentina. Contudo, entrou em conflito com o governo do Paraguai, originando uma contenda com o presidente do país, Carlos Antonio López, durante a qual o navio de Page foi bombardeado. Em resposta, os Estados Unidos aprovaram uma intervenção ao Paraguai em 1858, enviando para lá uma esquadra. Tal realização movimentou navios e canhões para restituir acordos comerciais e viabilizar a segunda -- e conclusiva -- etapa da expedição de Page, entre 1858-60. O artigo pretende mostrar que parte dos objetivos dos norte-americanos foram alcançados na região, ainda que tenham usado a força para fazer valer as suas intenções, principalmente, no Paraguai. / The article discusses the interests involved in the expedition made by commander Thomas Jefferson Page through river de La Plata and adjacent rivers. Having diplomatic powers to persuade the free navigation of rivers in South America, T.J. Page obtained consent for his transit and cartographic work, especially on the part of the Empire of Brazil and the Argentine Confederation. However, he a conflict with the government of Paraguay, resulted in a feud with the country\'s president, Carlos Antonio López. Thus, an intervention, approved by the U.S. Congress, in 1858, stirred ships and cannons to repay commercial agreements and enabling the second - and conclusive - part of the expedition (1859-60). The official narrative reveals horizons of the North-American Southern elite next to the imminent U.S. Civil War (1861-65). In the South of the continent, the regional conflicts were developing into the Paraguayan War (1864-70).
7

Étude expérimentale des effets de hauteur d'eau finie, de confinement latéral et de courant sur les sillages et la résistance à l'avancement des navires / An experimental study of the effects of finite water depth, lateral confinement and current on ships wakes and drag

Caplier, Clément 15 December 2015 (has links)
Ce mémoire présente une étude expérimentale des effets de confinement de la voie d'eau et de courant sur les sillages et la résistance à l'avancement des navires. Deux formes de carènes génériques et représentatives de navires maritimes et fluviaux ont fait l'objet de mesures dans le bassin des carènes de l'Institut Pprime dans différentes configurations bathymétriques. Des méthodes de mesure de déformée de surface libre par moyens optiques stéréoscopiques ont été mises en place pour caractériser les sillages générés. L'étendue spatiale et la résolution des mesures optiques permet de mener une analyse fine du sillage dans l'espace spectral, afin de le décomposer en une composante hydrodynamique dans le champ proche de la carène et une composante ondulatoire dans le champ lointain. Les résultats obtenus dans une configuration de voie d'eau profonde mettent en évidence la non-linéarité des sillages. Les résultats obtenus dans une configuration de voie d'eau peu profonde mettent en avant une modification de la forme des sillages et une répartition différente de l'énergie entre les différents systèmes de vagues. L'influence de la forme et de la vitesse des navires sur l'amplitude de la réponse hydrodynamique et du courant de retour est mise en avant. Des mesures en présence de contre-courant montrent une augmentation de l'amplitude des vagues du sillage et un élargissement de la zone de réflexion au niveau des parois du canal. Des mesures de forces de traînée avec un dynamomètre donnent accès aux courbes de résistance dans chaque configuration. L'augmentation de la résistance à l'avancement en eau peu profonde est mise en parallèle avec l'augmentation de l'amplitude et de la longueur d'onde des ondes transverses. / This thesis presents an experimental study of the effects of the waterway confinement and the current on ships wakes and drag. Two generic hulls representative of maritime and river ships have been studied in several bathymetric configurations in the towing tank of the Institut Pprime. Optical measurement methods based on a stereovision principle have been set up to measure the free surface deformations. The spatial extent and the resolution permits to lead a fine analysis of the wakes in the spectral space in order to decompose them into a hydrodynamic component and an undulatory component, respectively in the near-field and the far-field of the ship hull. The results obtained in a deep waterway configuration highlight the non-linearity of the ship wakes, which results in a modification of the shape of the envelop of the wave field in the real space. The results obtained in a shallow waterway configuration show a modification of the shape of the ship wakes and a different distribution of the energy between the wave systems. The influence of the shape and the speed of the ships on the amplitude of the hydrodynamic response and the return current is also identified. The comparison of the measurements in the presence of a counter-current with the results in calm water show an increase of the amplitude of the waves and an enlargement of the wash zone on the walls of the canal. Drag forces measurements with a multicomponent dynamometer give access to resistance curves for each configuration. The increase of the ship resistance in shallow water is put in parallel with the increase of the amplitude and the wavelength of the transverse waves.
8

EXPANDING THE AUTONOMOUS SURFACE VEHICLE NAVIGATION PARADIGM THROUGH INLAND WATERWAY ROBOTIC DEPLOYMENT

Reeve David Lambert (13113279) 19 July 2022 (has links)
<p>This thesis presents solutions to some of the problems facing Autonomous Surface Vehicle (ASV) deployments in inland waterways through the development of navigational and control systems. Fluvial systems are one of the hardest inland waterways to navigate and are thus used as a use-case for system development. The systems are built to reduce the reliance on a-prioris during ASV operation. This is crucial for exceptionally dynamic environments such as fluvial bodies of water that have poorly defined routes and edges, can change course in short time spans, carry away and deposit obstacles, and expose or cover shoals and man-made structures as their water level changes. While navigation of fluvial systems is exceptionally difficult potential autonomous data collection can aid in important scientific missions in under studied environments.</p> <p><br></p> <p>The work has four contributions targeting solutions to four fundamental problems present in fluvial system navigation and control. To sense the course of fluvial systems for navigable path determination a fluvial segmentation study is done and a novel dataset detailed. To enable rapid path computations and augmentations in a fast moving environment a Dubins path generator and augmentation algorithm is presented ans is used in conjunction with an Integral Line-Of-Sight (ILOS) path following method. To rapidly avoid unseen/undetected obstacles present in fluvial environments a Deep Reinforcement Learning (DRL) agent is built and tested across domains to create dynamic local paths that can be rapidly affixed to for collision avoidance. Finally, a custom low-cost and deployable ASV, BREAM (Boat for Robotic Engineering and Applied Machine-Learning), capable of operating in fluvial environments is presented along with an autonomy package used in providing base level sensing and autonomy processing capability to varying platforms.</p> <p><br></p> <p>Each of these contributions form a part of a larger documented Fluvial Navigation Control Architecture (FNCA) that is proposed as a way to aid in a-priori free navigation of fluvial waterways. The architecture relates the navigational structures into high, mid, and low-level controller Guidance and Navigational Control (GNC) layers that are designed to increase cross vehicle and domain deployments. Each component of the architecture is documented, tested, and its application to the control architecture as a whole is reported.</p>

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