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Since the distribution system is often the major investment of a municipal waterworks, it is important that any design satisfy system requirements at a minimum cost. Present design procedures usually employ a trial-and-error process which can be time consuming and lead to non-optimal designs. Although several authors have introduced various mathematical techniques to be used in the solution of this problem, most of the methods are rather limited in their practical application. A general computer program was developed to be used in the optimal design of hydraulic networks. The computer program can be used to optimize three basic system variables; input hydraulic head, pump head, and discrete pipe diameter sizes. Since the basic network equations describing the system are nonlinear, the problem is to optimize a nonlinear objective function subject to linear and nonlinear inequality variable constraints and nonlinear inequality system constraints. A modified Box Complex optimization technique is used to minimize the nonlinear objective function while the linear method of hydraulic analysis is used in the evaluation of the system constraints. The optimization program was applied to three example networks. The general results of this study show that the new method is very efficient and has tendency toward finding the globally optimal solution. / M.S.

A municipal water distribution system is a network of underground pipes, usually mirroring the city street network, that connects water supply sources such as reservoirs and water towers with demand points such as residential homes, industrial sites and fire hydrants. These systems are extremely expensive to install, with costs typically in the tens of millions of dollars. Existing pipes wear out, leak and break due to various factors including corrosion and cold weather ruptures, each requiring inconvenient and expensive repairs. Therefore, over time, these pipes need to be considered for replacement. Meanwhile, increasing urban development and water use rates dictate the need for larger and larger pipes to handle increased flow rates, while keeping water pressure within an acceptable range. However, larger pipes cost considerably more to install and maintain, causing the pipe sizing decision to be a critical task. We develop an optimal network design and replacement strategy that meets hydraulic requirements under all likely demand and failure scenarios. Two submodels are used in a hierarchical fashion to integrate the reliability and cost analysis, and the network optimization process, within the overall network design process. The pipe reliability and cost submodel uses statistical methodologies based on historical records of pipe breaks to estimate future maintenance costs, and to recommend replacing relatively expensive-to-maintain or undercapacitated pipes. The pipe network optimization submodel provides a least cost construction and replacement plan along with optimal flows and energy heads for each fixed network configuration and demand pattern. Traditional approaches isolate the above two types of models, assuming away the required interaction of inputs and outputs between them. We use a hierarchical design approach that integrates the foregoing two submodels by designing the network in a sequential fashion over a number of stages. The models are tied in a feedback loop that reprocesses the information until a stable design is attained. The result is a comprehensive reduced cost network design that meets all pressure and flow requirements for realistic problems, even under a wide variety of pipe failure modes. For the optimization model, we develop two new algorithms that exploit the special network structure of the problem. In the first approach, the problem is restructured in a manner that facilitates its decomposition into a master control program, and an easy-to-solve convex cost network flow programming subproblem. The master program operates in the space of the structural design variables, while the subproblem determines flows as well as heads via its primal and dual optimal solutions. The coordination between the master program and the subproblems is effected via a suitable penalty term. The theoretical validity of the decomposition scheme is established, and efficient algorithmic implementation strategies are developed. On a standard popular test problem in the literature, this procedure is shown to recover a solution that significantly improves upon a previously best known solution. The second optimization approach is one that guarantees a global optimal solution, and contrasts with previous approaches that at best produce local optimal solutions. This procedure is based on a Reformulation-Linearization Technique that constructs tight linear programming relaxations for the nonlinear problem, and embeds these in a branch-and-bound algorithm. A suitable partitioning strategy is coordinated with this scheme to provably ensure infinite convergence to a global optimum. When this method is applied to the aforementioned test problem, a further improved solution is obtained. It is hoped that with additional enhancements and refinements, our proposed methodologies will serve to provide a useful tool for practitioners to design reliable pipe network water distribution systems. / Ph. D.

published_or_final_version / Architecture / Master / Master of Science in Interdisciplinary Design and Management

Main subject of the diploma thesis is an evaluation of waterworks sludge dewatering using the CST method. The CST or capillary suction time is method developed to evaluate specific resistance to filtration in an indirect way. In principle it is based on the use of filtration paper to measure willingness of sludge to release water or its filterability. Results are measured as time needed for the water to overcome a defined trajectory and expressed in seconds. The shorter the CST time the more filterable is the sludge sample. The CST method has been critically evaluated and it was assessed as a great method for selecting the ideal polymer used for the sludge dewatering and for defining its optimal dose. Measurements have been made on sludge from two waterworks plants Želivka and Kozičín. Polymer products from company Sokoflok and products Praestol and Magnafloc have been tested on both of them. The best polymers for dewatering have been selected. It was Sokoflok 104 for sludge Želivka 1, 55CN for sludge Želivka 2, Magnafloc for sludge Kozičín 1 and 55CN for sludge Kozičín 2. Second subject of the thesis was to evaluate a sludge sensibility to the shear rate. Havlík (2003) and Bache et al.(2003) are describing sludge as a substance very sensitive to higher shear rate which causes that the aggregates...

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In two-dimensional flow, the point of flow separation from the surface coincides with the point at which the skin friction vanishes. However, in three-dimensional flow, the situation is much more complex and the flow separation is rarely associated with the vanishing of the wall shear stress except in a few special cases. Though the effects of cross-plane separation are substantial and have been recognized for some time, the phenomenon of flow separation over three-dimensional bodies is still far from being completely understood. The flow is so complex that no completely satisfactory analytical tools are available at the moment. In an attempt to logically identify the various effects and parametric dependence while simultaneously minimizing configuration dependent issue, the flow over a 6 to 1 prolate spheroid, which is a generic three-dimensional body, is investigated. For the identification of the general flow pattern and better understanding of the flow field, surface-oil-flow visualization tests and force and moment tests were performed. The angle of attack effect and Reynolds number effect on the separation location are studied with natural transition. Forces and moments tests, surface pressure distribution measurements as well as the surface pressure fluctuations, and mini-tuft flow visualization tests were made to document the flow characteristics on the surface of the body with an artificial boundary layer trip. / Ph. D.

The theoretical part of the thesis focuses on the characteristics of water as the basic structural element of the life on the Earth. It also mentions regulations related to critical infrastructure, water protection and water management. It describes water management system of the Czech Republic and the South Bohemian Region. It similarly characterizes the most probable chemical, biological or radiological water contaminants that might be abused by a man in the case of trespassing into waterworks system objects. The aim of the thesis was to map possible threats to the waterworks system and to propose follow-up measures preventing the South Bohemian Waterworks System from abuse. Upon identification of possible threats in the territory of South Bohemia and from the point of view of the extent of the thesis the text then focuses on intentional threat of waterworks object by a man. The research part first deals with more detailed description of the South Bohemia Waterworks System, from drinking water via its pumping, treatment, storage to its supply to final consumers. The system of drinking water supply to inhabitants of South Bohemia is divided into sectors by means of AKIS method here. A questionnaire to employees working in the water management sphere was based on this division and particularly vulnerability and the level of security measures in the individual South Bohemian Waterworks System sectors was evaluated from the information based on their answers. In the second plan the research part of the thesis focuses on description of security elements used in South Bohemian Waterworks System objects accompanied by my own photo documentation of objects and areas administered by the South Bohemian Waterworks Union. The elements of passive and active protection used by the South Bohemian Waterworks Union are documented and described here. Application of two operation analysis methods relates to this part. Quantitative research of security of waterworks objects based on evaluation of the best secured object of the South Bohemian Waterworks System was first performed. The obtained results enable us to determine which of the South Bohemian Waterworks System premises has the best active and passive security against trespass of unauthorized persons. To assess relevancy of the quantitative security research the method of relative comparison of waterworks objects security and its consequent interpretation by the security index is also used. The security index describes object protection against possible trespass within the whole area of the object. Application of this method brings numeric interpretation and identification of the overall security of the South Bohemian Waterworks System with regard to preference of the monitored parameters. The same result is achieved by both the methods. The applied operation analysis methods have revealed that the heart of the South Bohemian Waterworks System, the Plav drinking water treatment plant, the only drinking water treatment plant of South Bohemia supplying majority of South Bohemia inhabitants with drinking water, is the best protected object. Pumping stations and water towers are further well secured objects. There are also completely unsecured object in the South Bohemian Waterworks System. The conclusion contains some measures that should prevent unauthorized persons from trespassing into all waterworks objects and thus protect drinking water against contamination. As the observation has revealed the protection of waterworks objects should be improved with regard to the worsening safety situation in the world. This also involves the costs the South Bohemian Waterworks Union should invest in security to introduce the most up-to-date security elements into practice. We may conclude that the major part of waterworks objects are secured against abuse both passively and actively.

This dissertation focuses on the interdependency between causality, context and history in selected novels by E.L. Doctorow: The Book of Daniel (1971), Ragtime (1974), Loon Lake (1980), World's Fair (1985) and The Waterworks (1995). Doctorow' s fiction is marked by an apparent paradox: while it underscores fictionalization and sometimes distorts late nineteenth and twentieth century American history, it simultaneously purports to be a valid representation of the past. The novelist's implementation of causality which is a significant component of "the power of freedom", constitutes fiction's ability to convey truth without relying on factuality or "the power of the regime". According to Doctorow, the documented fact is already an interpretation which induces the perception that all documentation is subjective. The author composes fictional contexts that disregard the pretence of reliability in non-fictional texts. Doctorow focuses on how contexts are formed: the contexts are usually defined through the experience of characters who have been exposed to an event or events that were generated by motivations, for example, emotions of fear, racism, conviction, desire and greed, i.e., the catalysts that form history. Each of the novels discussed focuses on various aspects of society and the fate of specific individuals. The Book of Daniel proposes that a human being can only survive physically and spiritually by remaining a social entity. Ragtime focuses on the persistent illusion in history that society is fragmented. The various "faces" of society encountered by the main character in Loon Lake, mirror one another and reflect spiritual poverty. Consequently, Loon Lake demonstrates that the search for personal fulfilment does not require a physical journey, but an inner or spiritual exploration. World's Fair postulates that reality is never exclusively defined by either fortune or misfortune alone. The Waterworks offers perhaps one of the most significant evaluations of history as it perceives that the world in which we live is essentially unknown to us. We have neither the practical means to obtain a total perspective of what occurs in society (especially among politicians and the financially powerful) nor do we have sufficient skills to distinguish what the motivations of individuals' actions really entail. / Thesis (M.A.) Potchefstroom University for Christian Higher Education, 2000.