Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 12 of 12 for “"pipe model"”.
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Modelling the Viability of Heat Recovery from Underground Pipes. Deterministic modelling of wastewater temperatures in a 3000 sewer pipe network
Modelling wastewater temperature variations in a network of 3048 sewer pipes was achieved in this project. Recovering heat from sewers presents attractive options for producing clean energy. However, heat recovery from sewerage may result in wastewater temperature drops which may reduce the …
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Flow routing in the parallel pipes of a combined sewer system
A parallel pipe model has been constructed and successfully applied to a twin pipe sewer system. The model predicts flow and level for each of the parallel pipes and deals with the complex behaviour which occurs at cross-connections.<br/><br/>The model DUPPERS is an enhancement of the single pipe …
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Coherent structures in incompressible fluid flows
… related to the transition to turbulence in pipe at intermediate Reynolds numbers and includes a discussion of two classes of structures observed during the transition to turbulence: numerically-extracted solutions of the Navier-Stokes equations (the "exact'') and localized/patterned …
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ANALYSIS AND SIMULATION OF THE PNEUMATIC BRAKING SYSTEM OF FREIGHT TRAINS
… valves of the cars are connected by a brake pipe which serves the dual purpose of conducting pneumatic power and transmitting the control signal (brake signal) from the locomotive to each car of the train. The development of the air brake system has been largely empirical and experimental, …
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On Model Libraries for Thermo-hydraulic Applications
Mathematical modelling and simulation are important tools when dealing with engineering systems that today are becoming increasingly more complex. Tightly integrated production and process optimization are trends that give rise to heterogeneous systems, which are difficult to handle without …
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Ground vibration from underground railways: how simplifying assumptions limit prediction accuracy
… track, tunnel and soil resulting in numerical models which can predict ground-borne vibration around the tunnels and at the soil surface. However, all such numerical models rely on simplifying assumptions to make the problems trackable: soil is assumed homogenous, tunnels are assumed long and …
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The effect of viscoelastic deformation in pipe cracks on leakage response to variations in pressure
… affecting the pressure-leakage relationship is pipe material behaviour (Van Zyl & Clayton 2007; Greyvenstein & Van Zyl 2007). The pressure – leakage relationship has been described by several relationships such as the Torricelli equation, the Fixed and Variable Area Discharge (FAVAD) concept and …
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Investigation of Linear and Nonlinear Torsional Guided Waves in Hollow Circular Cylinders for Damage Detection
… detection in engineering applications, such as pipeline and truss system. Common types of damage in the structures include cracks and corrosion. Guided wave is sensitive to cracks up to micro scale. Long range inspection is the other benefit of using guided wave. The overall aim of this thesis …
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Optimization of stationary expansion planning and transient network control by mixed-integer nonlinear programming
… of size and complexity encountered in practice. Model formulations of both problems are located in the field of Mixed-Integer Nonlinear Programming (MINLP). However, global state-of-the-art MINLP solvers are not mature enough to solve or even find primal solutions on large-scale real-world …
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Tropical transport and the seasonal variability of the subtropical "edges" in the stratosphere
… using three very different tools: a simple model of stratospheric transport, which allows us to investigate the role of tropical transport in determining global transport timescales, satellite observations of long-lived tracers, which allow us to diagnose the seasonal variability of the …
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Examination of model uncertainty and parameter sensitivity in correlated systems using covariance structure analysis
Correlated parameters are often expected when modeling a natural system. However, correlation among the variables often blurs the model uncertainty and makes it difficult to determine parameter sensitivity. In simple systems, model structure and uncertainty can be explained directly; however, …
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Ammonia emission from fertiliser application : quantification techniques and mitigation strategies
… a estos resultados experimentales, se creó un modelo conceptual con el objetivo de definir y describir los principales factores que determinan las emisiones de NH3 debidas a la fertilización con urea en un suelo semiárido; así como el efecto de distintas estrategias de mitigación sobre dichas …