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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.
221

The technology and economics of water-borne transportation systems in Roman Britain

Millar, Roderick J. O. 05 1900 (has links)
The thesis examines a number of questions concerning the design, construction, costs and use of Romano-British seagoing and inland waters shipping. In the first part the reasons for the methods of construction for seagoing and coastal vessels, such as the Blackfriars Ship 1, the St. Peter Port Ship and the Barland's Farm Boat, have been investigated. The constructional characteristics of the two ships are massive floors and frames, with the planking fastened only to the floors and frames with heavy clenched iron nails. There is no edge to edge fastening of the planks, with tenons inserted into mortises cut into the edges of the planks, as is normal in the Mediterranean tradition of ship construction in the Roman period. The Romano-British ships also differ from the Scandinavian tradition of clinker building with overlapping planks nailed to each other along their length. It has been concluded that a natural phenomenon, the large tidal range around the British Isles and the northern coasts of Gaul and Germany, had a dominant effect on the design of seagoing vessels. Deep water harbours, such as Portus, Caesar ea Maritima and Alexandria in the Mediterranean, where ships could lie afloat at all times, were neither practicable nor economic with the technology available. At the British ports, such as Dover, London and Chichester, ships had to come in with the high tide, moor to simple wharves at the high tide level, and then settle on the ground as the tide dropped. At the numerous small havens, inlets and estuaries around the British coasts, ships would come in with the tide, settle on a natural or man-made 'hard' as the tide fell, and discharge cargo over the side to carts, pack animals or people. This mode of operation required sturdy ships that could take the ground without damage, and also withstand a certain amount of 'bumping' on the bottom in the transition period from fully afloat to fully aground. The second part of the thesis investigates the cost of building, maintaining and operating various types of vessels. To do this, a new mode for measuring cost, the Basic Economic Unit, or BEU, has been developed. The probable volume of the various types of cargoes carried has been examined. It appears that grain was the dominant cargo in both coastal and overseas traffic. The total cost of building, maintaining and operating the seagoing and inland water shipping was less than one percent of the gross product of Britain, a small cost for an essential service.
222

Massively parallel time- and frequency-domain Navier-Stokes Computational Fluid Dynamics analysis of wind turbine and oscillating wing unsteady flows

Drofelnik, Jernej January 2017 (has links)
Increasing interest in renewable energy sources for electricity production complying with stricter environmental policies has greatly contributed to further optimisation of existing devices and the development of novel renewable energy generation systems. The research and development of these advanced systems is tightly bound to the use of reliable design methods, which enable accurate and efficient design. Reynolds-averaged Navier-Stokes Computational Fluid Dynamics is one of the design methods that may be used to accurately analyse complex flows past current and forthcoming renewable energy fluid machinery such as wind turbines and oscillating wings for marine power generation. The use of this simulation technology offers a deeper insight into the complex flow physics of renewable energy machines than the lower-fidelity methods widely used in industry. The complex flows past these devices, which are characterised by highly unsteady and, often, predominantly periodic behaviour, can significantly affect power production and structural loads. Therefore, such flows need to be accurately predicted. The research work presented in this thesis deals with the development of a novel, accurate, scalable, massively parallel CFD research code COSA for general fluid-based renewable energy applications. The research work also demonstrates the capabilities of newly developed solvers of COSA by investigating complex three-dimensional unsteady periodic flows past oscillating wings and horizontal-axis wind turbines. Oscillating wings for the extraction of energy from an oncoming water or air stream, feature highly unsteady hydrodynamics. The flow past oscillating wings may feature dynamic stall and leading edge vortex shedding, and is significantly three-dimensional due to finite-wing effects. Detailed understanding of these phenomena is essential for maximising the power generation efficiency. Most of the knowledge on oscillating wing hydrodynamics is based on two-dimensional low-Reynolds number computational fluid dynamics studies and experimental testing. However, real installations are expected to feature Reynolds numbers of the order of 1 million and strong finite-wing-induced losses. This research investigates the impact of finite wing effects on the hydrodynamics of a realistic aspect ratio 10 oscillating wing device in a stream with Reynolds number of 1.5 million, for two high-energy extraction operating regimes. The benefits of using endplates in order to reduce finite-wing-induced losses are also analyzed. Three-dimensional time-accurate Reynolds-averaged Navier-Stokes simulations using Menter's shear stress transport turbulence model and a 30-million-cell grid are performed. Detailed comparative hydrodynamic analyses of the finite and infinite wings highlight that the power generation efficiency of the finite wing with sharp tips for the considered high energy-extraction regimes decreases by up to 20 %, whereas the maximum power drop is 15 % at most when using the endplates. Horizontal-axis wind turbines may experience strong unsteady periodic flow regimes, such as those associated with the yawed wind condition. Reynolds-averaged Navier-Stokes CFD has been demonstrated to predict horizontal-axis wind turbine unsteady flows with accuracy suitable for reliable turbine design. The major drawback of conventional Reynolds-averaged Navier-Stokes CFD is its high computational cost. A time-step-independent time-domain simulation of horizontal-axis wind turbine periodic flows requires long runtimes, as several rotor revolutions have to be simulated before the periodic state is achieved. Runtimes can be significantly reduced by using the frequency-domain harmonic balance method for solving the unsteady Reynolds-averaged Navier-Stokes equations. This research has demonstrated that this promising technology can be efficiently used for the analyses of complex three-dimensional horizontal-axis wind turbine periodic flows, and has a vast potential for rapid wind turbine design. The three-dimensional simulations of the periodic flow past the blade of the NREL 5-MW baseline horizontal-axis wind turbine in yawed wind have been selected for the demonstration of the effectiveness of the developed technology. The comparative assessment is based on thorough parametric time-domain and harmonic balance analyses. Presented results highlight that horizontal-axis wind turbine periodic flows can be computed by the harmonic balance solver about fifty times more rapidly than by the conventional time-domain analysis, with accuracy comparable to that of the time-domain solver.
223

Propriedades mecânicas de juntas soldadas com diferença de espessura pelo processo de soldagem por atrito linear com mistura em ligas de Al-Mg para aplicação na construção naval

Feistauer, Eduardo Etzberger 21 March 2014 (has links)
The shipbuilding sector, as well as all modern transportation industries, is faced with demands for greater productivity while at the same time ensuring the manufacture of consistently high quality products, reducing levels of re-working, saving energy, and minimizing operational costs. Furthermore, it is imperative that new designs and all the stages of production comply with stringent environmental regulation. Within this context, the application of Friction Stir Welding (FSW) as a manufacturing process to weld Tailor Welded Blanks (TWB) for Al structures can contribute to the development of high speed craft and lightweight ships that are more fuel efficient, based on a high energetic efficient and environmental friendly welding process. In this work, the heterogeneous mechanical behavior of TWB joints welded by FSW was evaluated using quasi-static and cyclic loading, and the observed microstructural features were analyzed. The TWB joints were manufactured using dissimilar alloys and thicknesses (6 and 8mm) of particular interest in the shipbuilding sector (AA5083, AA5059 and AA6082). An evaluation of local constitutive properties in different regions through the TWB joint was performed by digital image correlation linked to the tensile test system. From the DIC data processing were generated stress concentrations diagrams and true stress-strain curves for several TWB subzones. The DIC methodology used as well as the accuracy of the proposed method are described in detail. The joints exhibited excellent mechanical properties approximately the same as those of the base metal for the joints manufactured with work hardened alloys (AA5059/AA5083) and 76% mechanical efficiency to those manufactured with the heat-treatable alloy (AA6082). The fatigue strength of the TWB joints were higher than the IIW references for welded structures in aluminum and the fracture mechanisms were characterized using SEM. / O setor de construção naval, bem como a indústria moderna, é continuamente sobrecarregada por demandas de aumento de produtividade e ao mesmo tempo precisa garantir a fabricação de produtos com alta qualidade, reduzindo os níveis de retrabalhos, economizando energia e diminuindo os custos operacionais. Adicionalmente a este paradoxo, é imperativo que os novos designs de produtos e todos os estágios de produção sejam compatibilizados com as rígidas exigências ambientais. Neste contexto, a concepção de projetos de estruturas leves soldadas por SALM em configurações sob medidas (Tailor Welded Blanks - TWB) em Al podem contribuir para produção de embarcações com eficiente consumo de combustível e redução dos níveis de eliminação de CO2 através da redução do peso de suas estruturas. Além de utilizar um processo de soldagem eficiente energeticamente e amigável ao meio ambiente. Neste trabalho as características heterogêneas de juntas em TWB soldadas por SALM foram avaliadas através de ensaios mecânicos com carregamentos quasi-estáticos e dinâmicos e, foram criadas relações entre as propriedades mecânicas das juntas e alterações microestruturas resultantes do processo de soldagem. As juntas em TWB foram produzidas com três diferentes ligas de alumínio de particular interesse da construção naval, (AA5083, AA5059 e AA6082) em configurações similares e dissimilar, com combinações de espessuras de 6 e 8mm. Acoplado ao ensaio de tração um sistema de correlação digital de imagens (DIC) foi instalado e o perfil de deformação local das juntas foram investigados durante o carregamento. A partir do processamento dos dados obtidos por DIC, diagramas de concentração de tensão e curvas de tensão-deformação locais foram computados para diferentes subzonas das juntas. O procedimento utilizado, bem como os dados obtidos e a precisão da metodologia proposta foram descritos detalhadamente. As juntas apresentaram excelentes propriedades mecânicas, equivalentes às do metal base para a junta dissimilar produzida com as ligas endurecidas por trabalho mecânico (AA5059/AA5083) e 76% de eficiência para as juntas similares produzidas com a liga tratável termicamente (AA6082). A resistência a fadiga das juntas foram superiores às referências do IIW para juntas soldadas em alumínio e os mecanismos de fratura foram caracterizados por MEV.
224

Trabalhadores de SUAPE : estudo sobre a diversidade de experiências operárias / Workers of SUAPE

Queiroz, Pedro Henrique Santos, 1990- 11 June 2014 (has links)
Orientador: Fernando Antonio Lourenço / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Filosofia e Ciências Humanas / Made available in DSpace on 2018-08-26T09:10:51Z (GMT). No. of bitstreams: 1 Queiroz_PedroHenriqueSantos_M.pdf: 5241057 bytes, checksum: deaf3ce7c197b1ddee0a5a63aff86c00 (MD5) Previous issue date: 2014 / Resumo: Neste estudo, proponho a investigação e análise de um conjunto amplo e diverso de experiências vividas por um grupo operário específico a partir da consideração de sua posição relativa no processo produtivo e em um contexto marcado por grandes transformações regionais. O grupo operário enfocado é composto por duas categorias: os trabalhadores da construção civil pesada e os trabalhadores da construção naval, ambas circunscritas ao Complexo Industrial Portuário de Suape ¿ Governador Eraldo Gueiros, localizado entre os municípios do Cabo de Santo Agostinho e Ipojuca no estado de Pernambuco. A possibilidade de uma análise comparativa entre as duas categorias se dá pela existência de uma série de semelhanças entre elas quanto aos aspectos: perfil socioeconômico de sua composição, perfil de conflitos trabalhistas e natureza específica do processo de trabalho. São analisadas as experiências de trabalho, de não-trabalho e de ação política, com uma ênfase maior nesse último tipo de experiência. Foram analisados mais detidamente os conflitos ocorridos no período 2008 a 2012, momento em que houve uma quantidade excepcional de paralisações e greves em ambas as categorias. É constatada a ocorrência de situações em comum vividas pelo movimento de trabalhadores de ambas as categorias, quais sejam: mercado de trabalho local aquecido, com consequências para o poder de barganha da classe trabalhadora; alto grau de ativismo independente das "bases"; dificuldade de legitimação e representatividade enfrentadas pelas lideranças sindicais e membros de comissão de base; emprego por parte das empresas de práticas antissindicais. A abordagem assumida segue por uma via de valorização das várias formas pelas quais os trabalhadores percebem e explicam sua experiência vivida. Ao empregar como principal suporte teórico a categoria thompsoniana de experiência, busco investigar as formas extremamente diversas pelas quais os trabalhadores de Suape sentem, percebem, explicam, se organizam, resistem, se adaptam e lutam em um contexto marcado pela implantação de "grandes projetos". A fim de concretizar tais objetivos, foi empregada uma série de técnicas de pesquisa, porém com maior destaque para as entrevistas e conversas com trabalhadores, sindicalistas, militantes e demais informantes privilegiados. Isso porque o momento de encontro, escuta e diálogo é concebido aqui como momento privilegiado para a compreensão das formas como a experiência vivida é elaborada pela consciência dos sujeitos. De forma acessória, a fim de recolher informações adicionais que servissem de complemento e contraponto às falas dos entrevistados, fiz análise de documentos oficiais (convenções coletivas, atas de audiências, acórdãos), monitoramento de notícias veiculadas pela imprensa (em formato impresso e online) e pesquisas de campo de caráter etnográfico em espaços relevantes para a compreensão das experiências de não-trabalho (espaços de circulação, entretenimento, comércio e religião) / Abstract: In this study, I propose the investigation and analysis of a broad and diverse set of experiences liven by a specific group of workers from the consideration of its relative position in the productive process and in a context characterized by major local transformations. The group of workers focused here is composed by two professional categories: the heavy construction workers and naval construction workers, both located in Suape Industrial Dock Complex, between the cities Cabo de Santo Agostinho and Ipojuca in the state of Pernambuco. The possibility of a comparative analsys between the two categories is given by the existence of a series of similarities between then on behalf of the following aspects: socioeconomic profile, conflicts profile and specifc nature of the labour process. Were analysed the experiences of work, non-work, and of political action, giving particular emphasis to this last category of experience. Were analysed more closely the conflicts occurred in the period 2008-2012, when there has been a exceptional amount of outages and strikes in both professional categories. It was found the occurrence of a series of situations in common that were faced by the workers movement of both professional categories, such as: heated labour market, with consequences for the bargaining power of the working class, high degree of independent activism, difficulties of legitimacy and representativeness faced by union leaders and members of base commissions; use of anti-union practices by the companies. The approach followed in this research aimed the valorization of the various forms by which the workers feels and explains their experiences. By using the thompsonian category of experience as the main theoretical support, I seek to investigate the extremely diverse forms by which the workers of Suape feel, perceive, explain, organize themselves, resist, adapt and fight in a context marked by the implantation of "big projects". In order to achieve such goals, it was deployed several research techniques, giving more emphasis to the interviews and conversations with workers, union leaders, militants and other informants. This choice is based on the conception of the moments of meeting, hearing and dialogue as a privileged space for the understanding of how the experiences is elaborated by the subjects consciousness. In an ancillary basis and aiming to collect further information that could serve as complement and counterpoint, I did official document analysis, news monitoring and ethnographic field research in relevant spaces for the comprehension of non-work experiences (spaces of circulation, entertainment, commerce and religion) / Mestrado / Sociologia / Mestre em Sociologia
225

The technology and economics of water-borne transportation systems in Roman Britain

Millar, Roderick J. O. 05 1900 (has links)
The thesis examines a number of questions concerning the design, construction, costs and use of Romano-British seagoing and inland waters shipping. In the first part the reasons for the methods of construction for seagoing and coastal vessels, such as the Blackfriars Ship 1, the St. Peter Port Ship and the Barland's Farm Boat, have been investigated. The constructional characteristics of the two ships are massive floors and frames, with the planking fastened only to the floors and frames with heavy clenched iron nails. There is no edge to edge fastening of the planks, with tenons inserted into mortises cut into the edges of the planks, as is normal in the Mediterranean tradition of ship construction in the Roman period. The Romano-British ships also differ from the Scandinavian tradition of clinker building with overlapping planks nailed to each other along their length. It has been concluded that a natural phenomenon, the large tidal range around the British Isles and the northern coasts of Gaul and Germany, had a dominant effect on the design of seagoing vessels. Deep water harbours, such as Portus, Caesar ea Maritima and Alexandria in the Mediterranean, where ships could lie afloat at all times, were neither practicable nor economic with the technology available. At the British ports, such as Dover, London and Chichester, ships had to come in with the high tide, moor to simple wharves at the high tide level, and then settle on the ground as the tide dropped. At the numerous small havens, inlets and estuaries around the British coasts, ships would come in with the tide, settle on a natural or man-made 'hard' as the tide fell, and discharge cargo over the side to carts, pack animals or people. This mode of operation required sturdy ships that could take the ground without damage, and also withstand a certain amount of 'bumping' on the bottom in the transition period from fully afloat to fully aground. The second part of the thesis investigates the cost of building, maintaining and operating various types of vessels. To do this, a new mode for measuring cost, the Basic Economic Unit, or BEU, has been developed. The probable volume of the various types of cargoes carried has been examined. It appears that grain was the dominant cargo in both coastal and overseas traffic. The total cost of building, maintaining and operating the seagoing and inland water shipping was less than one percent of the gross product of Britain, a small cost for an essential service. / Arts, Faculty of / Classical, Near Eastern and Religious Studies, Department of / Graduate
226

Impact of marine sound pollution from merchant ships / Impacto de la contaminación acústica marina de los buques mercantes

Marco-Franco, Julio Emilio 27 September 2022 (has links)
This thesis deals with the study and normative proposal for a regulation of noise pollution generated by merchant ships, which is the main cause of underwater noise pollution. It is divided into three chapters. In the first chapter, the aspects of marine acoustics are reviewed, including a revisit of hydrophones, the analysis of the distances at which sound intensities are maintained above a baseline level, and a self designed study, which leads to the conclusion that the differences in incremental trends in underwater sound intensity in previous studies are due to differences in maritime traffic. This is confirmed by highly significant statistical data obtained by binary logistic regression between hydrophonic records that have detected an increase and those that have not (p<0.0001). A compilation and bibliometric analysis has made it possible to study specifically the negative impact of ship-generated noise on marine species. In 87% of the publications consulted, including experimental data, a high or moderately high negative impact of sound on marine species was evident; only 5% of the articles reported no effects of noise pollution. The study covered a wide variety of seas and oceans, although most of the studies (31%) were conducted using cages or similar. The research was mainly conducted on fish (43%) and mammals (38%). Behavioural changes were recorded in 59% of cases, physical changes in 11%, masking in 11% and combined changes in 14%. Four levels of underwater sound intensity are proposed: Environmental zone 0 (no appreciable anthropogenic pollution), from baseline level (30 dB) to 80 dB. Zone A of acceptable (low) pollution, from 81 dB to 175 dB (threshold of potential damage). Zone B of tolerable, but potentially harmful sound intensities (between 176 dB and 195 dB) and a Zone C of risk of permanent injury (above 195 dB, permanent injury threshold); vessels generating intensities at this level should be penalised or even banned. A way forward for the future regulation of underwater noise pollution is suggested, through a concerted effort via a global track derived from the UN in collaboration with specialised global and EU organisations, including the Baltic Sea registers, and legal support from the experts of the World Commission on Environmental Law. Its implementation should be carried out through the International Maritime Organization IMO).
227

Cost Effectiveness and Complexity Assessment in Ship Design within a Concurrent Engineering and "Design for X" Framework

Caprace, Jean-David 26 February 2010 (has links)
Decisions taken during the initial design stage determine 60% to 95% of the total cost of a product. So there is a significant need to concurrently consider performance, cost, production and design complexity issues at the early stages of the design process. The main obstacle to this approach is the lack of convenient and reliable cost and performance models that can be integrated into a complex design process as is used in the shipbuilding industry. Traditional models and analysis methods frequently do not provide the required sensitivity to consider all the important variables impacting performance, cost, production and ships life cycle. Our challenge is that achieving this sensitivity at the early design stage almost requires data available during the detail design analysis. The traditional design methods do not adequately include, early enough, production and life cycle engineering to have a positive impact on the design. Taking an integrated approach throughout the life cycle of the ship and using concurrent engineering analysis tools can improve these traditional design process weaknesses. Innovation is required in structural design and cost assessment. The use of design for X, and particular design for production and cost schemes, during the design is the solution: to reduce failure during a ships life caused by design misconception, to reduce the overall design time and to shorten the build cycle of ships, to enlarge the number of design alternatives during the design process. The author has developed some assessment methods for cost effectiveness and complexity measurements intended to be used by ship designers for the real time control of cost process. The outcome is that corrective actions can be taken by management in a rather short time to actually improve or overcome predicted unfavourable performance. Fundamentally, these methods will provide design engineers with objective and quantifiable cost and complexity measures making it possible to take rational design decisions throughout the design stages. The measures proposed in this PhD are based on several techniques like decision analysis, data mining, neural network, fuzzy logic. They are objective facts, which are not dependent on the engineers interpretation of information, but rather on a model generated to represent the ship design. The objectivity aspect is essential when using the complexity and cost measures in a design automation system. Finally, with these tools, the designers should obtain well-defined and unambiguous metrics for measurement of the different types of cost effectiveness and complexities in engineered artefacts. Such metrics help the designers and design automation tools to be objective and perform quantitative comparisons of alternative design solutions, cost estimation, as well as design optimization. In this PhD, these metrics have been applied and validated with success in real industrial conditions on the design of passenger ships. Les décisions prises au cours de la phase initiale de conception déterminent 60% à 95% du coût total dun produit. Il y a donc un besoin important denvisager simultanément des aspects de performance, de coût, de production, de complexité au stade précoce du processus de conception. Le principal obstacle à cette approche est le manque de commodité et de fiabilité des modèles de coûts et des modèles danalyse de performance qui peuvent être intégrés dans un processus de conception aussi complexe que celui utilisé dans lindustrie de la construction navale. Les modèles traditionnels et les méthodes danalyse les plus fréquemment utilisés ne fournissent pas la sensibilité nécessaire pour examiner toutes les variables de conception importantes qui ont une influence sur la performance, le coût, la production et le cycle de vie des navires. Notre défi est quatteindre cette sensibilité au niveau de la conception initiale demande presque toujours des données uniquement disponibles lors de la conception détaillée. Les méthodes de conception traditionnelles ne prennent pas suffisamment en compte, suffisamment tôt, la production et lingénierie du cycle de vie afin davoir un impact positif sur la conception. Adopter une approche intégrée sur lensemble du cycle de vie des navires et utiliser lingénierie simultanée peuvent améliorer les faiblesses des processus de conception traditionnels. Linnovation est nécessaire dans la conception structurelle et lévaluation des coûts. Lutilisation du concept de "design for X", et en particulier le design en pensant à la production et à la réduction des coûts lors de la conception est la solution : pour réduire les dysfonctionnements qui peuvent apparaître pendant la vie du navire causés par des erreurs de conception, de réduire le temps total de conception et de raccourcir le cycle de la construction de navires, délargir le nombre dalternatives de conception évaluées au cours du processus de conception. Lauteur a développé quelques méthodes dévaluation des coûts et des techniques de mesure de la complexité destinées à être utilisés par les concepteurs de navire pour le contrôle en temps réel de la conception. Le résultat est que les actions correctives peuvent être prises par la direction dans un temps assez court pour améliorer réellement ou surmonter les prévisions de performance défavorables. Fondamentalement, ces méthodes offrent aux ingénieurs de conception des mesures quantifiables des coûts et de la complexité qui rend possible la prise de décisions rationnelles tout au long des étapes de conception. Les mesures proposées dans cette thèse sont basées sur plusieurs techniques telles que lanalyse à la décision, lanalyse de données, les réseaux de neurones ou encore la logique floue. Ce sont des faits objectifs, qui ne dépendent pas de linterprétation de linformation par lingénieur, mais plutôt dun modèle généré pour représenter le design du navire. Laspect de lobjectivité est essentiel pour lutilisation de la complexité et la mesure des coûts dans un système dautomatisation de la conception. Finalement, avec ces outils, les concepteurs obtiennent des mesures bien définies et non ambigües des paramètres de mesure de coûts, defficacité et de complexité des artefacts dingénierie. De telles mesures aident les concepteurs et les outils dautomatisation de la conception, à être objectifs et à comparer de manière quantitative les différentes alternatives lors de la conception, de lestimation des coûts, ainsi que de loptimisation. Dans cette thèse, ces paramètres ont été appliqués et validés avec succès et dans des conditions industrielles réelles sur la conception de navires à passagers. Las decisiones tomadas en la etapa inicial de un diseño determinan el 60% al 95% del total del costo de un producto. Por esta razón, es necesario considerar al mismo tiempo rendimiento, costo, producción y la complejidad en el proceso de la fase inicial del diseño. El principal obstáculo de este enfoque es la falta de práctica y fiabilidad de costos y de modelos de análisis de rendimiento, que puedan ser integrados en un proceso complejo de concepción utilizado en la industria de la construcción naval. Los modelos tradicionales y los métodos de análisis frecuentemente no tienen la sensibilidad necesaria para examinar todas las variables importantes que influyen en el rendimiento, costo, producción y la vida útil del buque. Nuestro reto es el que logrando de que ésta sensibilidad en la fase inicial de diseño casi siempre requiera de datos únicamente disponibles durante un análisis de diseño require detallado. Los métodos tradicionales de diseño no incluyen temprana y adecuadamente, la producción y la ingeniería del ciclo de vida para tener un impacto positivo en el diseño. Adoptando un enfoque integrado a lo largo del ciclo de vida de la nave usando la ingeniería concurrente y herramientas de análisis se pueden mejorar estas debilidades del proceso tradicional de diseño. Se requiere innovación en el diseño estructural y la evaluación de los costos. La utilización del concepto diseño para X, y en particular el diseño pensando en la producción y en la reducción de costos durante la concepción es la solución: para reducir errores durante la vida útil de los buques causados en la concepción del mismo, para reducir el tiempo total de diseño y acortando el ciclo constructivo del buque, para ampliar el número de alternativas durante el proceso de diseño. El autor ha desarrollado algunos métodos de evaluación de costos y de técnicas de medida de la complejidad destinadas a ser utilizadas por los diseñadores de barcos para el control en tiempo real del proceso de costos. El resultado es que las acciones correctivas pueden ser adoptadas por la dirección en un tiempo suficientemente corto para realmente mejorar o superar el rendimiento desfavorable proyectado. Fundamentalmente, estos métodos ofrecerán a los ingenieros diseñadores con medidas objetivas y cuantificables de costos y complejidad haciendo posible tomar decisiones racionales a lo largo de todas las etapas de diseño. Las medidas propuestas en esta tesis doctoral se basan en varias técnicas tales como análisis de decisión, análisis de datos, redes neuronales y lógica difusa. Son objetivos hechos, que no dependen de la interpretación que el ingeniero realice sobre la información, sino más bien en un modelo generado para representar el diseño de los buques. El aspecto de la objetividad es esencial cuando se usa las medidas de complejidad y costos en un sistema de automatización del diseño. Finalmente con estas herramientas, los diseñadores podrían obtener medidas bien definidas y no parámetros de medición ambiguos de costos, de eficacidad y de complejidad en los artefactos de ingeniería. Estas medidas ayudan a los diseñadores y a las herramientas automatizadas de diseño, a ser objetivos y a comparar de manera cuantitativa las diferentes alternativas de solución del diseño, estimación de costos, así como también la optimización del diseño. En este doctorado, estos parámetros han sido aplicados y validados con éxito sobre el diseño de buques de pasajeros en condiciones industriales reales. In der Anfangsphase einer Produktentwicklung getroffene Entscheidungen definieren 60% bis 90% der Gesamtkosten eines Produktes. Daher ist es absolut notwendig Performance, Kosten, Produktion, Designkomplexität in der Entstehungsphase eines Produktes zu betrachten. Das Haupthindernis hierbei ist das Fehlen von praktikablen und zuverlässigen Kosten- und Performancemodellen, welche sich in den komplexen Designprozess wie in der Schiffbauindustrie integrieren lassen. Konventionelle Modelle und Analysemethoden berücksichtigen oft nicht all die wichtigen Performance-, kosten-, produktion-, und Lebenszyklus-relevanten Variablen. Unsere Herausforderung, dass das Erreichen dieser Sensibilität in der Anfangsphase der Produktentwicklung, benötigt fast immer Daten, die erst in der Phase der Detailkonstruktion zur Verfügung stehen. Die konventionelle Entwurfsmethoden berücksichtigen nicht angemessen und früh genug die Produktion und das Lebenszyklen-Engineering, welche eine positive Auswirkung auf das Design haben. Ein integrierter Ansatz entlang des Lebenszyklus eines Schiffes und das Praktizieren von Concurrent Engineering können die Schwäche des konventionellen Entwurfsprozesses beseitigen. Innovation ist notwendig im Strukturentwurf und in der Kostenanalyse. Die Anwendung von Design for X und besonders Design for Production and Cost Scheme während der Entwurfsphase ist die Lösung: Um die Fehlerquote verursacht durch Missverständnisse und die Entwurfs- und Produktionszeit zu reduzieren, sowie um eine höhere Anzahl von Entwurfsvarianten zu ermöglichen. Der Autor hat einige Analysemethoden für Kosteneffektivität und Komplexitätsmaßnahmen für die Anwendung durch Schiffsentwerfer für die Echtzeit-Steuerung von Kostenprozess entwickelt. Das Ergebnis ist, dass das Management korrigierende Maßnahmen in kurzer Zeit treffen kann, um eine ungünstige Performance zu verbessern bzw. zu vermeiden. Im Grunde beschaffen diese Methoden den Entwurfsingenieuren mit objektiven und quantifizierten Kosten- und Komplexitätsmaßnahmen. Dies vereinfacht das Treffen von vernünftigen Entwurfsentscheidungen über die gesamte Entstehungsphase eines Schiffes. Die in dieser Arbeit vorgestellten Maßnahmen basieren auf Techniken wie die Entscheidungsanalyse, das Data-Mining, neurale Netze und die Fuzzy-Logik. Es sind objektive Fakten, welche nicht von der Interpretation des Ingenieurs abhängen, sondern von einem generierten Model, um den Schiffsentwurf darzustellen. Der objektive Aspekt ist essenziell bei der Anwendung von Komplexitäts- und Kostenmaßnahmen in einem automatisierten Entwurfssystem. Mit diesen Werkzeugen sollte der Entwerfer gut-definierte und eindeutige Werte für Maßnahmen von unterschiedlicher Natur von Kosteneffektivität und -komplexität erhalten. Diese Werte helfen dem Entwerfer und automatisierten Entwurfssystemen, objektive zu sein. Ferner, ermöglichen diese Werte quantitative Vergleiche von Entwurfsvarianten, Kostenabschätzung und Entwurfsoptimierung. Diese Werte wurden im Rahmen eines Studienfalles mit realen Voraussetzungen (Entwurf von Passagierschiffen) erfolgreich angewendet und validiert.
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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.
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Les grands navires construits à clin en Europe septentrionale et occidentale du milieu du 14ème au milieu du 16ème siècle / The large clinker ships in Northern and Western Europe from the mid-14th to the mid-16th century

Grille, Alexandra 05 July 2016 (has links)
Depuis les années 1980, des épaves de grands navires construits à clin de la fin du Moyen-Age ont été découvertes sur les littoraux des mers septentrionales et occidentales. Elles ont régulièrement suscité individuellement un intérêt de la communauté scientifique en regard de leur architecture, puisque la fin du Moyen-Age correspond historiquement à l’apparition puis à la diffusion et à l’adaptation de la construction navale à franc-bord d’origine méditerranéenne en Europe du Nord et de l’Ouest. Pourtant, la comparaison des différentes épaves entre elles pour étudier les développements de la construction navale à clin de cette période est très récente et généralement rattachée à l’analyse des épaves nouvellement trouvées.Cette thèse étudie l’ensemble des navires de plus de 20 m de long susceptibles, par leur architecture, d’avoir évolué en haute mer sur les routes du commerce lointain. En regard du contexte technique et historique, cette étude est limitée géographiquement aux mers nordiques et chronologiquement au Moyen-Age tardif et au début de la période moderne.Le navire résulte à la fois des technique de construction navale et de la demande de ses commanditaires. Durant la période d’étude envisagée dans la thèse, les marchands, qui sont également les affréteurs, constituent les principaux armateurs avec les gens de mer, marins et capitaines, qui régulièrement sont propriétaires en totalité ou en partie des grands bâtiments.De ce fait, le contexte historique, affectant les activités de commerce et de transport, contribue à expliquer les développements de la construction navale. De plus, l’analyse technique des épaves permet de comprendre comment les charpentiers de marine ont pu répondre à la demande de ces propriétaires. Pour cela, la reconstitution des épaves, comme celle de l’Aber Wrac’h 1(France), est essentielle, car les données relatives à la construction, la conception et la forme des navires fournissent des éléments de comparaison scientifique fiables en regard des typologies chronologiques et régionales et permettent de replacer le navire dans son contexte historique et socio-économique. / Since the 1980s, several wrecks of large clinker ships adting from the late Middle Ages were found on the coasts of Northern and Atlantic seas. The scientific community was regularly interested in the architecture of each site as the late Middle Ages historically corresponds to the appearance, dissemination and adaptation of the carvel shipbuilding from the Mediterranean in Northern and Western Europe. Yet the comparison of the different wrecks themselves to study the development of the clinker shipbuilding of this period is recent and usually linked to the analysis of newly found wrecks.This thesis explores all vessels over a length of 20 meters, which were able, according to their architecture, to sail on open seas for long-distance trade. Due to the technical and historical context, this study is limited geographically to the nordic seas and chronologically to the Late Middle Ages and early modern period.The ship results from the shipbuilding technology and the demand of its owners. During the late Middle Ages, the merchant class, which was the principal user, was also the main shipowner with the seafarers, sailors and captains, who regularly owned all or part of large vessels.Therefore, the historical context, affecting trade and transport activities, helps to explain the developments in shipbuilding. Therefore, technical analysis of wrecks allows understanding how the shipwrights and carpenters could meet the demand of those owners. Hence, there construction of the wreck, such as Aber Wrac’h 1 (France), is essential because the data about the building, design and shape of the vessels provide reliable scientific information for comparison in terms of chronological and regional typologies and help to place the ship in its historical, environmental and socio-economic context.
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L'internationalisation des chaînes de valeur dans l'industrie de défense : le cas du naval / Value chains internationalization in the defense industry : focus on the naval industry

Hérault, Paul 13 February 2018 (has links)
L’internationalisation des chaînes de valeur fait l’objet de nombreuses recherches macroéconomiques ou ciblées sur des secteurs majoritairement civils. En se concentrant sur l’industrie de défense, cette thèse évalue comment ce processus de fragmentation fonctionnelle et géographique peut s’appliquer à un secteur hautement régulé par les Etats et dont les échanges internationaux sont très strictement encadrés.Cette recherche apporte plusieurs estimations du niveau d’internationalisation de l’industrie navale de défense française, à partir de données originales de Naval Group. Si les programmes relatifs à la dissuasion nucléaire sont très peu internationalisés, de nombreux facteurs concourent à l’internationalisation de la filière : exigences de contenu local et transferts de technologie des clients étrangers, intégration de technologies civiles ou duales, stratégies d’internationalisation. Enfin, le recours au concept de modularité permet de montrer que l’évolution du processus productif s’accompagne souvent d’une évolution de l’architecture des produits. / Many research works have already been dedicated to the internationalization of value chains. Whereas this research is often performed through macroeconomics or focused on civilian sectors, this thesis examines how the process of functional and geographic unbundling can apply to such a regulated sector as the defense industry, where exports are strictly controlled by states.Based on original data provided by Naval Group, this dissertation set out several estimates of the internationalization level of French navy programs. Although programs related to nuclear deterrence remain almost exclusively « made in France », many factors contribute to the internationalization of value chains in the naval industry: transfer of technology, local content requirements, integration of commercial or dual-use technologies, internationalization corporate strategies. Referring to the concept of modularity, this thesis reveals that changes in production process can foster innovation in product architecture.

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