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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

A Framework to Protect Water Distribution Systems Against Potential Intrusions

Lindley, Trevor Ray 11 October 2001 (has links)
No description available.
2

Calibration Of Water Distribution Networks

Ar, Kerem 01 January 2012 (has links) (PDF)
Water distribution network models are used for different purposes. In this study, a model, used for daily operational issues is concerned. Models results should be consistent with actual conditions for sound decisions during operational studies. Adjusting model parameters according to site measurements in order to fit the model to obtain realistic results is known as calibration. Researchers have carried out numerous studies on calibration and developed various methods. In this study, an actual network (N8.3 Pressure Zone, Ankara) has been calibrated by two classical methods developed by Walski (1983) and Bhave (1988). The network parameter calibrated in this study is Hazen-Williams roughness coefficient, C-factor, and other parameters have been lumped in the C-factor. Results of the analysis showed that, C-factors have been found in a wide range.
3

Load measurement error influence on friction factor calibration of pipe water distribution networks through do reverse transient method and genetic algorithm / A InfluÃncia de erros de mediÃÃo de carga na calibraÃÃo de fator de atrito em tubulaÃÃes de redes de distribuiÃÃo de Ãgua atravÃs do mÃtodo transiente inverso e algoritmo genÃtico

BÃrbara Cristina Alves da Costa 10 November 2014 (has links)
O estudo de redes hidrÃulicas para fins de operaÃÃo ou anÃlise de viabilidade para ampliaÃÃo ou recuperaÃÃo das mesmas à iniciado pela calibraÃÃo, neste contexto, entendida como identificaÃÃo de parÃmetros tais como: fator de atrito, rugosidade e diÃmetro. O MÃtodo Transiente Inverso em conjunto com Algoritmo genÃtico se mostra eficiente nessa tarefa. O referido mÃtodo emprega o MÃtodo das CaracterÃsticas na soluÃÃo das equaÃÃes de movimento para escoamento transiente em tubos de redes e a otimizaÃÃo das soluÃÃes à baseada na Teoria Evolutiva e avaliada por uma funÃÃo objetivo, que neste estudo à o somatÃrio do mÃdulo da diferenÃa entre as cargas medidas e calculadas pelo modelo para cada conjunto de soluÃÃes. Considerando que o objetivo do desenvolvimento de modelos matemÃticos para a calibraÃÃo de redes hipotÃticas à a utilizaÃÃo dos mesmos em redes reais, e que nessas, a coleta de dados de carga està sujeita a erros de mediÃÃo, seja devido a defeitos nos equipamentos seja por condiÃÃes ambiente desfavorÃveis ou outros efeitos aleatÃrios e tendo em vista a relevÃncia dos fatores de atrito nas tubulaÃÃes, pela sua relaÃÃo com perdas de carga que devem ser controladas para um Ãtimo funcionamento de redes, garantindo um abastecimento contÃnuo em quantidade e condiÃÃes de funcionamento adequados, este trabalho propÃe-se a verificar a interferÃncia da presenÃa de erros de mediÃÃo de carga transiente na identificaÃÃo dos fatores de atrito em duas redes hidrÃulicas hipotÃticas. As mesmas sÃo de portes diferentes com relaÃÃo ao nÃmero de anÃis, nÃs e tubos. Ambas sÃo alimentadas por um reservatÃrio cada. As condiÃÃes transientes sÃo atribuÃdas a uma manobra de vÃlvula instalada em um dos nÃs de cada rede. A coleta de dados de carga à restrita a 20% dos nÃs de cada rede, sendo que um deles à o nà onde se encontra a vÃlvula. O tempo de observaÃÃo do transiente hidrÃulico à restrito ao tempo da manobra de vÃlvula, 20s, e ocorre em intervalos de 0,1s, resultando em 200 registros de carga. A condiÃÃo permanente das redes à inicialmente desconhecida o conhecimento acerca da mesma à restrito a carga nos reservatÃrios e demandas nos nÃs, bem como diÃmetros dos tubos, os fatores de atrito sÃo inicialmente estipulados. A determinaÃÃo das condiÃÃes permanente e transiente bem como a identificaÃÃo dos fatores de atrito à realizada com a utilizaÃÃo de um modelo hidrÃulico e geram cargas transientes que sÃo consideradas convencionalmente verdadeiras, essas entÃo recebem incrementos de diversos erros sistemÃticos e aleatÃrios, que geram novas cargas e essas sÃo consideradas coletadas com erros de mediÃÃo. A partir dessas novas cargas sÃo realizadas identificaÃÃes de fatores de atrito, os quais sÃo comparados com os que foram obtidos considerando um caso ideal de cargas sem erros de mediÃÃo. A referida comparaÃÃo à realizada atravÃs do Erro MÃdio Relativo e da FunÃÃo Objetivo Ãtima. Os resultados encontrados demonstram que os erros de mediÃÃo interferem na identificaÃÃo dos fatores de atrito apesar de nÃo ser possÃvel delinear uma relaÃÃo entre os mesmos. / The study of hydraulic networks for operation purposes or viability analysis for extension or renovation of the same is started the calibration in this context understood as identification parameters, such as friction coefficient, surface roughness and diameter. The Transient Inverse Method in conjunction with genetic algorithm is efficient in this task shows. This method employs the method of characteristics in the solution of the equations of motion for transient flow in networks of pipes and the optimization of solutions is based on Evolutionary Theory and evaluated by an objective function, which in this study is the sum of the difference between the module loads measured and calculated by the model for each set of solutions. Whereas the objective of the development of mathematical models for calibration hypothetical networks is their use in real networks, and that these, the collection of payload data is subject to measurement errors, is due to defects in the equipment or by conditions unfavorable environment or other random effects and taking into account the relevance of friction factors in pipelines, by their relationship to head losses that must be controlled to a great operation of networks, ensuring a continuous supply in quantity and appropriate operating conditions, this work is proposed to verify the influence of the presence of transient load measurement errors in the identification of friction factors in two hypothetical hydraulic networks. They are of different sizes with the number of rings, knots and tubes. Both are each fed by a reservoir. The transient conditions are assigned to a valve maneuver installed in one of the nodes of each network. The load data collection is restricted to 20% of the nodes in each network, one of which is the node where the valve is located. The hydraulic transient observation time is restricted to the valve maneuver time, 20s, and occurs at intervals of 0.1s, resulting in 200 charge records. The permanent condition of networks is initially unknown knowledge about the same is restricted to load in the reservoirs and demands on us as well as pipe diameter, the friction factors are initially stipulated. The determination of the permanent and transient conditions and the identification of the friction factors is performed using a hydraulic model and generate transient loads which are conventionally considered true, then these various steps of receiving systematic and random errors, which generate new burdens and these are considered collected with measurement errors. From these new loads are carried IDs friction factors, which are compared with those obtained considering an ideal case with no measurement errors loads. This comparison is performed using the mean relative error and function great goal. The results show that measurement errors in the identification of interfering friction factors although not possible to draw a relationship between them.
4

Automated Calibration Of Water Distribution Networks

Apaydin, Oncu 01 February 2013 (has links) (PDF)
Water distribution network models are widely used for various purposes such as long-range planning, design, operation and water quality management. Before these models are used for a specific study, they should be calibrated by adjusting model parameters such as pipe roughness values and nodal demands so that models can yield compatible results with site observations (basically, pressure readings). Many methods have been developed to calibrate water distribution networks. In this study, Darwin Calibrator, a computer software that uses genetic algorithm, is used to calibrate N8.3 pressure zone model of Ankara water distribution network / in this case study the network is calibrated on the basis of roughness parameter, Hazen Williams coefficient for the sake of simplicity. It is understood that there are various parameters that contribute to the uncertainties in water distribution network modelling and the calibration process. Besides, computer software&rsquo / s are valuable tools to solve water distribution network problems and to calibrate network models in an accurate and fast way using automated calibration technique. Furthermore, there are many important aspects that should be considered during automated calibration such as pipe roughness grouping. In this study, influence of flow velocity on pipe roughness grouping is examined. Roughness coefficients of pipes have been estimated in the range of 70-140.
5

Les fontaines monumentales en Afrique romaine / Monumental Fountains in Roman North Africa

Lamare, Nicolas 13 March 2014 (has links)
Cette étude porte sur les fontaines monumentales ou nymphées dans les provinces de l’Afrique du Nord à l’époque romaine, sur une période allant du Ier au IVe siècle ap. J.‑C. Nous avons constitué un catalogue des monuments et un corpus épigraphique, à partir de sources bibliographiques et archéologiques recueillies par un travail de terrain. Après avoir rappelé l’histoire des recherches sur l’hydraulique de l’Afrique antique, nous étudions en détail les aspects techniques et architecturaux des fontaines monumentales. Nous proposons une synthèse sur les techniques de construction et le fonctionnement hydraulique, mais également sur la restitution architecturale et du décor sculpté, à l’aide de sources littéraires et iconographiques. Sans proposer de typologie, nous étudions les fontaines dans leur contexte, au sein de la ville et du réseau hydraulique. Nous mettons ainsi en avant l’insertion des fontaines dans la ville et le lien qu’elles entretiennent avec la mise en place des adductions et les programmes urbanistiques. Ces observations rendent possible une étude de la répartition des fontaines dans l’espace urbain et de son impact, décoratif et fonctionnel. L’étude des inscriptions nous permet de mieux envisager le fonctionnement de l’évergétisme, le comportement de la cité et des notables face à ces édifices. Elle est aussi l’occasion de revenir sur les problèmes de vocabulaire qui impliquent une réflexion sur l’appellation des édifices et leur fonction religieuse. / This thesis deals with monumental fountains or nymphaea in the Roman North Africa provinces from the 1st to the 4th century CE. We have made up a catalogue of the monuments and inscriptions, composed from bibliographical and archaeological sources compiled on-site. We first sum up the history of research on hydraulics in ancient North Africa and then we study in detail the technical and architectural aspects of monumental fountains. We offer a synthesis on building techniques and hydraulic system as well as architectural and ornamental reconstruction with the help of literary and iconographic sources. Avoiding to establish a typology, we contextualise the fountains both within the city and the hydraulic network. Thus we put forward the insertion of fountains in the city and their link with the founding of a new water supply or town-planning programmes. These observations make possible a study of how the fountains were spread out in the urban space and to what extent it had a decorative and functional impact. By studying inscriptions, we may better understand how euergetism worked, just as the behaviour of cities and notables faced with these monuments. We may also go back to questions of vocabulary which imply to think about the appellation of fountains and their religious function.

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