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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

Análise de sistemas de propulsão e manobra alternativos para aumento da manobrabilidade de comboios fluviais. / Analysis of pusher-barge system with different maneuvering and propulsion devices.

Yuba, Douglas Gustavo Takashi 24 March 2014 (has links)
O presente trabalho aborda análises de sistemas de propulsão e manobra para comboios fluviais, e seus efeitos na manobrabilidade dos comboios. Analisam-se o sistema de propulsão convencional (propulsor mais leme), o sistema azimutal e o equipamento de proa auxiliar combinado com cada um destes sistemas de propulsão. Apresenta-se a modelagem matemática dos sistemas de propulsão e manobra citados, os quais serviram de base para implementação de um simulador computacional utilizado para obtenção dos resultados desta dissertação. As forças e momentos hidrodinâmicos são obtidos através do método das derivadas hidrodinâmicas para as simulações próximas à velocidade de serviço do comboio, enquanto para simulações em baixa velocidade utilizou um método semi-empírico baseado no princípio de cross-flow. Inicialmente, efetuou-se a validação do simulador com resultados da literatura para o caso do comboio com propulsão convencional. Em seguida, o modelo foi adaptado para os demais tipos de sistemas de propulsão e manobra propostos. Os resultados obtidos mostram que há uma maior eficiência do sistema de propulsão azimutal e do equipamento na proa para manobras em baixas velocidades, o que se torna adequado sua aplicação em comboios fluvial, pois essas embarcações navegam em velocidades menores se comparadas a outros tipos de embarcações. / The present work deal with analysis of propulsion and maneuvering systems for pusher-barge system, and results on the maneuverability of convoys. It analyzes the conventional propulsion system (rudder plus propeller), the azimuth system and combined auxiliary equipment bow with each of these propulsion systems. Presents the mathematical modeling of propulsion and maneuvering systems mentioned, which served as the basis for implementation of a computational simulator used to obtain the results of this dissertation. The hydrodynamic forces and moments are obtained by the method of hydrodynamic derivatives for simulations about service speed, while for simulations at low speed used a semi - empirical method based on the principle of cross-flow. Initially, performed the validation of the simulation results with the literature for the case of pusher-barge system with conventional propulsion. Then the model was adapted to other types of propulsion and maneuvering systems proposed. The results show that there is a greater efficiency of azimuth propulsion system and equipment in the bow to maneuver at low speeds, which makes it suitable for application in river transport, because these vessels navigate slower speeds compared to other types of vessels.
12

Essays on the Upper Mississippi River and Illinois Waterway and U.S. grain market

Yu, Tun-Hsiang 29 August 2005 (has links)
This dissertation examines several issues regarding the congestion on the Upper Mississippi River and Illinois Waterway. Chapter II identifies and measures the impact of lock congestion on grain barge rates on these waterways. Results indicate grain barge rates on both rivers are not affected by lagged lock congestion. In present time, however, lock congestion in the lower reaches of the upper Mississippi and Illinois Rivers are found to increase barge rates that link the north central United States to the lower Mississippi Gulf port area. The findings suggest the impact of lock congestion on grain barge rates is moderate. Chapter III explores the interaction between grain prices in export and domestic markets and transportation rates linking these markets over time. Three model frameworks were evaluated and some consistent results are observed. In general, shocks in transportation rates (barge, rail, and ocean) explain a great proportion of the variation in corn and soybean market prices in the long run, suggesting the importance of transportation in grain price determination. The volatile ocean freight rates are the mostimportant transportation rates contributing to the variation in grain prices, while shocks in barge rates on the Upper Mississippi River and Illinois Waterway generally explain less than 15 percent of the variation in grain prices. The dynamic interrelationships among the six evaluated transportation rates are also found. In addition, the north central corn markets likely have the most influence over other markets while soybean export price dominates the soybean market in the long run. Chapter IV estimates the structural demand for grain barge transportation on both the upper Mississippi and Illinois Rivers. Results suggest foreign grain demand is the most influential force affecting grain barge demand on both rivers. Also, results indicate an inelastic demand for grain barge transportation on the Upper Mississippi in the short run; demand is price elastic in the long run. The price elasticity for grain barge demand on the Illinois River is consistently inelastic. Additionally, the winter season and floods affect demand on the Upper Mississippi negatively, while barge demand increases on the Illinois River in winter.
13

Análise de sistemas de propulsão e manobra alternativos para aumento da manobrabilidade de comboios fluviais. / Analysis of pusher-barge system with different maneuvering and propulsion devices.

Douglas Gustavo Takashi Yuba 24 March 2014 (has links)
O presente trabalho aborda análises de sistemas de propulsão e manobra para comboios fluviais, e seus efeitos na manobrabilidade dos comboios. Analisam-se o sistema de propulsão convencional (propulsor mais leme), o sistema azimutal e o equipamento de proa auxiliar combinado com cada um destes sistemas de propulsão. Apresenta-se a modelagem matemática dos sistemas de propulsão e manobra citados, os quais serviram de base para implementação de um simulador computacional utilizado para obtenção dos resultados desta dissertação. As forças e momentos hidrodinâmicos são obtidos através do método das derivadas hidrodinâmicas para as simulações próximas à velocidade de serviço do comboio, enquanto para simulações em baixa velocidade utilizou um método semi-empírico baseado no princípio de cross-flow. Inicialmente, efetuou-se a validação do simulador com resultados da literatura para o caso do comboio com propulsão convencional. Em seguida, o modelo foi adaptado para os demais tipos de sistemas de propulsão e manobra propostos. Os resultados obtidos mostram que há uma maior eficiência do sistema de propulsão azimutal e do equipamento na proa para manobras em baixas velocidades, o que se torna adequado sua aplicação em comboios fluvial, pois essas embarcações navegam em velocidades menores se comparadas a outros tipos de embarcações. / The present work deal with analysis of propulsion and maneuvering systems for pusher-barge system, and results on the maneuverability of convoys. It analyzes the conventional propulsion system (rudder plus propeller), the azimuth system and combined auxiliary equipment bow with each of these propulsion systems. Presents the mathematical modeling of propulsion and maneuvering systems mentioned, which served as the basis for implementation of a computational simulator used to obtain the results of this dissertation. The hydrodynamic forces and moments are obtained by the method of hydrodynamic derivatives for simulations about service speed, while for simulations at low speed used a semi - empirical method based on the principle of cross-flow. Initially, performed the validation of the simulation results with the literature for the case of pusher-barge system with conventional propulsion. Then the model was adapted to other types of propulsion and maneuvering systems proposed. The results show that there is a greater efficiency of azimuth propulsion system and equipment in the bow to maneuver at low speeds, which makes it suitable for application in river transport, because these vessels navigate slower speeds compared to other types of vessels.
14

Structural Vulnerability Assessment of Bridge Piers in the Event of Barge Collision

Ribbans, David A 18 March 2015 (has links)
The inland waterway system in the United States is fundamental to the transportation system as a whole and the success of the nation’s economy. Barge transportation in these waterways levitates congestion on the highway system and is beneficial when comparing barge transportation to other modes of freight transportation in measures of capacity, congestion, emissions, and safety. Unavoidably, the highway system intersects with the waterways, resulting in the risk of vessels collision into bridge structures. Particularly for barge impact, the literature is questioning the accuracy and oversimplification of the current design specifications. The impact problem was investigated in this research using three-dimensional finite-element analyses. To investigate the collision of a barge into a bridge pier, a range of material models are first investigated through simulating a drop-hammer impact onto a reinforced concrete beam. A detailed model of a jumbo hopper barge is then developed, with particular detail in the bow. The barge model is examined for its response to impact into rigid piers of different size and shape. RC piers, having different shape and boundary conditions, are impacted by the barge model and assessed using selected metrics. The final part of the research examines the response of an existing bridge pier subject to an impact by a chemical transporter barge that frequently travels in the waterway.
15

Transportation Route Optimization for the State of Ohio’s Inland Waterway System: A Case Study for Mid-Ohio River Valley Region

Celikbilek, Can January 2015 (has links)
No description available.
16

A case study approach of the transformation of Brown Barge Elementary School and the closing of A. A. Dixon School following Augustus versus Escambia County School Board

Juneau, Gayle Ann Alexandra. January 2007 (has links)
Thesis (Ed.D.)--University of West Florida, 2007. / Title from title page of source document. Document formatted into pages; contains 194 pages. Includes bibliographical references.
17

De brignatium à gesoriacum : les amers, les navires et les ports en mare externum sous l'empire Romain / From Brigantium to Gesoriacum : the Landmarks, the Boats and the Harbours in Mare Externum under the Roman Empire

Delacroix, Barbara 08 December 2016 (has links)
La navigation sur l’arc atlantique à l’époque romaine est un sujet immense qui pâtit encore trop souvent de l’avis sceptique de chercheurs obnubilés par la Méditerranée. Il a donc fallu détricoter le mythe de l’océan infranchissable par l’étude approfondie des éléments interdépendants constitutifs de la navigation fluvio-maritime et moteurs de l’économie de l’arc atlantique, à savoir : l’amer, le navire et le port. Aussi l’étude de l’organisation du commerce atlantique sur les voies fluviales et maritimes, de La Corogne à Boulogne-sur-Mer, a-t-elle abouti à l’établissement d’une typologie « atlantique » tripartite. / Navigation in the Atlantic arc – enlarged to the English Channel and the North Sea – in Roman period, is a vast topic that, too often, still suffers from the sceptical opinion of researchers obsessed with the Mediterranean. It has been necessary to unravel the myth of the impassable Ocean, by means of a deep study of the mutually dependent elements forming the maritime and fluvial navigation and driving force of the Atlantic arc economy: the landmark, the vessel and the harbour. Moreover, the study of the organization of the Atlantic trade through the maritime and fluvial routes, from A Coruña to Boulogne-sur-Mer, have result in the establishment of a three-party ‘Atlantic’ typology.
18

Un système réactif d'aide à la décision pour le transport intermodal de marchandises / A reactive decision support system for intermodal freight transportation

Wang, Yunfei 02 March 2017 (has links)
Le transport fluvial de conteneurs constitue une activité économique importante qui suscite un intérêt grandissant de la part de scientifiques. Considéré comme durable et économique, le transport par barge a été identifié comme étant une alternative compétitive pour le transport de marchandises, en complément des modes traditionnels de transport, routier et ferroviaire. Néanmoins, les travaux de recherche en rapport avec la planification et le management du transport par barge, en particulier dans le contexte du transport intermodal, sont encore peu abondants. Le but de cette thèse est d’apporter une contribution dans ce domaine, par la proposition de modèles et de méthodes de planification et gestion avancées, dans le cadre d’un système d’aide à la décision pour le transport de conteneurs par barge développé pour accompagner les opérateurs de transport. La méthodologie proposée fait appel à des concepts et principes de gestion du revenu, des ressources et des services de transport pour la conception de plans de services réguliers avec horaires, au niveau tactique. Les opérateurs de transport peuvent ainsi offrir des plans de transport avec des services plus flexibles pour leurs clients, tout en assurant un meilleur niveau de fiabilité. Plus de demandes de transport pourront ainsi être satisfaites, avec globalement une plus grande satisfaction des chargeurs. Une originalité importante proposée par notre approche est l’utilisation de principes et techniques de gestion du revenu (segmentation du marché, classes tarifaires...) aussi bien au niveau opérationnel de la modélisation qu’au niveau tactique. Les problèmes d’optimisation sont formalisés sous forme de modèles de programmation linéaire mixte en nombres entiers (PLNE), implémentés et testés sous différentes configurations de réseaux de transport et différents scénarios de demandes, et ce pour chaque niveau de décision. Au niveau tactique, une nouvelle approche de résolution, combinant la recherche adaptative à voisinage large (ALNS) et la recherche taboue, est proposée pour résoudre des problèmes PLNE de grande taille. Une plateforme de simulation, qui intègre les niveaux tactique et opérationnel de prise de décision, est proposée pour la validation du système d’aide à la décision sous différentes configurations : différentes topologies du réseau physique, différents paramètres pour la gestion du revenu, différents degrés de précision caractérisant les prévisions de demande. Pour l’analyse des résultats numériques ainsi obtenus, plusieurs types d’indicateurs de performance sont proposés et utilisés. / Barge transportation is an important research topic that started to draw increasing scientific attention in the recent decade. Considered as sustainable, environment-friendly and economical, barge transportation has been identified as a competitive alternative for freight transportation, complementing the traditional road and rail modes. However, contributions related to barge transportation, especially in the context of intermodal transportation, are still scarce. The objective of this thesis is to contribute to fill this gap by proposing a reactive decision support system for freight intermodal barge transportation from the perspective of the carriers. The proposed system incorporates resource and revenue management concepts and principles to build the optimal set of scheduled services plans at the tactical level. Carriers may thus benefit from transportation plans offering increased flexibility and reliability. They could thus serve more demands and better satisfy customers. One novelty of the approach is the application of revenue management considerations (e.g., market segmentation and price differentiation) at both operational and tactical planning levels. The optimization problems are mathematically formalized and mixed integer linear programming (MILP) models are proposed, implemented and tested against various network settings and demand scenarios, for each decision level. At the tactical level, a new solution approach, combining adaptive large neighborhood search (ALNS) and Tabu search is designed to solve large scale MILP problems. An integrated simulation framework, including the tactical and the operational levels jointly, is proposed to validate the decision support system in different settings, in terms of physical network topology, revenue management parameters and accuracy degree of demand forecasts. To analyze the numerical results corresponding to the solutions of the optimization problems, several categories of performance indicators are proposed and used.
19

Dynamique de la distribution, sélection de l’habitat et stratégie d’alimentation chez la barge à queue noire limosa limosa à l’échelle des sites d’hivernage français / Distribution, habitat selection and feeding strategies of the black-tailed godwit limosa limosa at the French wintering site scale

Robin, Frédéric 24 February 2011 (has links)
La Barge à queue noire Limosa limosa est un oiseau limicole communément rencontré tout au long de l’année sur le territoire Français. Les individus présents sur la partie ouest de l’Europe sont représentés par deux sous-espèces : la sous-espèce L. l. limosa, dite barge à queue noire « continentale », est principalement observée pendant les phases de migration et en très faibles effectifs reproducteurs sur les marais ouest Atlantique; la sous-espèce L. l. islandica, dite « islandaise », est quant à elle, exclusivement présente en hivernage le long des côtes atlantiques et de la Manche. L’étude menée au cours de ces travaux de thèse porte principalement sur la barge « islandaise » en dehors de la période de reproduction sur les sites d’hivernage le long de la façade atlantique Française. Contrairement à L. l. limosa, la population de L. l. islandica connaît sur l’ensemble de son aire de répartition, une expansion aussi bien en termes d’effectif qu’en nombre de sites fréquentés. La synthèse des effectifs nationaux hivernants montre que la population hivernante en France suit cette même tendance, avec une progression de 1350 à 27000 individus au cours des vingt dernières années. Actuellement, la France accueille environ 30 % de la population sur un nombre de sites grandissant mais néanmoins restreint, principalement représentés par les Réserves Naturelles littorales abritant des vasières intertidales utilisés comme zone d’alimentation. À partir de données biométriques, génétiques ou encore des historiques de vie des oiseaux équipés de bagues couleurs, les périodes de présence des deux populations sur le territoire Français ont pu être mis à jour. De plus, au sein de la sous-espèce islandaise, plusieurs durées d’hivernage en France ont été avancées, pouvant varier de 2 à 8 mois selon les individus. La phénologie des effectifs étudiée sur chacun des sites suggère une utilisation très variée des sites ainsi que de nombreux échanges entre ces sites au cours d’un même hiver. Couramment utilisée dans la compréhension de la distribution des populations d’oiseaux, la disponibilité de la ressource trophique a également été étudiée au regard du régime alimentaire de la Barge queue noire à partir d’échantillonnages de macrofaune, de collecte de fèces mais aussi d’analyses d’isotopes stables. Au cours de l’hiver, à l’échelle des Pertuis Charentais, les barges montrent deux régimes distincts mais néanmoins monospécifiques. Elles s’alimentent de rhizomes de zostères (Zostera noltii) sur les herbiers des vasières de l’Ile de Ré et de bivalves (Macoma balthica) sur les vasières nues. Au cours de l’hiver, il est supposé que la déplétion de ces ressources conduit à une redistribution des effectifs de barges sur de nouvelles zones d’alimentation voire de nouveaux reposoirs. Les deux régimes alimentaires sont majoritairement retrouvés à l’échelle de la distribution nationale des barges. Néanmoins, leurs distributions au sein des sites français dépend des caractéristiques sédimentaires, des interactions intra et interspécifiques, de la disponibilité de reposoirs de marée haute et des dérangements tels que la chasse. Ce travail a permis d’établir de solides connaissances et aboutit à la collecte de données détaillées et complémentaires qui vont permettre de tester les modèles théoriques de distribution spatiale des organismes à l’échelle d’une région de leur aire de distribution. / The Black-tailed godwit Limosa limosa is a shorebird species commonly observed in France throughout the year. Two sub-species are dissociated in West European. The so called “continental” Godwit L. l. limosa is observed in France during migration cycles and some pairs breed in marshes on the Atlantic coast; the so called “Icelandic” Godwit winters exclusively along coast of the Western Europe. This present work mainly investigates the wintering ecology of Icelandic–godwit in coastal mudflats of France. Contrarily to the continental sub-species, the whole Icelandic-godwit L. l. islandica population increased quantitatively as long as the number of sites used. In France, national counts pointed out that wintering population follows this trend and have increased from 1350 to 27000 individuals during the last twenty years. This population represents now around 30% of the whole islandica population but individuals stage in large flocks in a very limited number of sites, mainly included in Nature Reserves. From standard biometrics, molecular analyses and resighting data, phenologies of the both sub-species can then be specified for France. Furthermore, this study allowed to define how long the wintering period lasts in France for Icelandic-Godwits, between 2 and 8 months depending on individuals. Phenology at site scale suggested that godwits used several sites throughout the winter. As currently used for understanding the distribution of bird populations, trophic resource availability was studied in regard to the diet of the Black-tailed godwit from macrofauna sampling, droppings collection and stable isotope analyses. At the Pertuis Charentais scale, two feeding behaviors were clearly distinguished: seagrass grazing (Zostera notlii) or bivalve probing (Macoma balthica). Food depletion along the winter is expected to lead to the decrease of local populations, and to the selection of new feeding area or roost. Considering the distribution of the species at the national level, the diets were recorded depending on the mudflats’ characteristics. Even if food distribution is commonly used to understand at first the bird population distribution, our observations point out that, here at a local level, more parameters may influence the wintering distribution such as sediment characteristics, intra and inter-specific interactions, high tide roosts availability and human disturbances as the hunt. This work allowed to establish a solid knowledge and to collect many complementary data to test the distribution theories on the Black-tailed Godwit population wintering in France.
20

Grounds For Healing : Tales of Toxic Terrain

Ingebrigtsen, Anna January 2014 (has links)
This project proposes the restoration of Vinterviken’s contaminated grounds, a legacy of Nobel’s dynamite production. How can we live with toxicity? The design sows phytoremediating meadows, extracts toxins, harvests, decomposes, burns, and grows new crops. Elevated pathways offer a procession through the site, to green roofs, mountain paths, an open kitchen & hearth, a floating barge with biopools & a sauna. As the fields are healed, the structures move into the barge and sail to other polluted sites. / Projektet är ett förslag till återställandet av Vintervikens förorenade marker, ett arv från Nobels dynamitproduktion. Hur kan vi leva med toxicitet? Modellen sår fytoremedierande ängar, skiljer ut gifter, skördar, bryter ned, bränner, och odlar nya grödor. Förhöjda stigar erbjuder en gångväg genom området, till gröna tak, bergsstigar, ett öppet kök och härd, en flytande pråm med biopooler och en bastu. När områdena har läkts, flyttar strukturerna in i pråmen och seglar till andra förorenade platser.

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