Waste production and management problems have increased in this century. Population growth and consumption patterns in developing societies are associated with this growth. During the last decades, some world organisations have contributed to a global discussion and common resolutions. Concerns about the environment and sustainable development have been soundly highlighted. The European Union through its five Environment and Development Programmes as well the Directives and other special Regulations have responded that Agenda 21. The complexity and historical context of integrated and sustainable waste management is studied within the context of the construction industry in Portugal. International experience and knowledge were also drawn upon to add to the local knowledge. The study classifies the debris trail. The deconstruction process is studied in order to illuminate the relationship with the nature of the debris trail. This is the core of the research which seeks to make a contribution to the understanding of this relationship and forms the basis for the development of a dynamic construction and demolition estimating and assessment model. The work is based on case studies derived by observation from five complex and holistic case studies in Lisbon, cases studies reported from other countries and from work by others undertaken in France. Soft Systems Methodologies are used to illuminate the qualitative concerns. The quantitative information from practice is placed along side the qualitative data to give further insight into the issues being studied. The difficulties of insufficient actor involvement and participation in the process are also discussed. Systems Dynamics methodologies are used to define a dynamic model using data from the sources referred. The model is intended to assist the assessment and estimation of the characteristics of the debris trail. The output of the dynamic model will contribute to a national strategy and plan for the construction and demolition waste stream in Portugal within the context of European Union strategies and guidelines.

Thesis (M.Arch.) - Carleton University, 2007. / Includes bibliographical references (p. 124). Also available in electronic format on the Internet.

The Fabriconda wave energy converter is a submerged tube lying perpendicular to incoming wave fronts. The tubeconsists of a series of smaller fabric tubes, called cells, joined together longitudinally to form a larger central tube. The cells and central tube are flooded with water. Cross-sectional area changes with pressure due to the cells changing shape. The Fabriconda is therefore distensible, enabling it to extract energy from external waves. Waves induce a series of travelling bulges, and an internal oscillatory flow, in both the central tube and cells. If the speed of these bulges is close to the phase speed of the external wave, energy is progressively transferred to this flow. A power take-off system terminates the tube at the stern. A 1D mathematical model has been developed to predict the power captured by the Fabriconda, based on the application of the conservation of momentum and mass to the flow in both the central tube and cells. An analytical solution of this model has been found using an assumption of harmonic behaviour. A time-stepping finite difference solution was also derived and found to agree with the analytical solution. The results from these models have been compared with measurements. The cross sectional shape of the Fabriconda depends on the ratio between cell and central tube pressure, while the free bulge speed is dependent on the sum of the central tube and cell distensibilities. Both �ndings were supported by measurements. Measurements found that power generally peaked closer to the resonance frequency than predicted and was dependent on initial pressure. The effect of tube length on the frequency dependency of power capture and the presence of secondary peaks led to the conclusion that normal mode effects are significant to the Fabriconda's performance. This work has determined the operating principles of the Fabriconda and demonstrated that it can extract energy from waves. Predictions of full scale performance and commercial viability are not considered.

This thesis is concerned with Dynamic Economic Dispatch (DED) problems, in particular in the context of the current and future needs of the electrical power system in the State of Kuwait. General Economic Dispatch (ED) issues are addressed, under both static and dynamic conditions, with valve-point effects accounted for. Improvements have been achieved in terms of lower fuel costs, but also more efficient and reliable simulation algorithms. The existing ED/DED models have been improved in various ways and enhanced by developing and incorporating two renewable energy sources; namely wind energy and solar energy. These two have been identified as most relevant to the power system investigated. The models developed are general and can be adjusted to represent many practical systems. The Economic Dispatch problem had been formulated and solved as a constrained optimisation and a particular technique selected for this purpose – not explored before – was a Pattern Search (PS) algorithm. For illustrative purposes, the proposed PS technique had been applied to various test systems to validate its effectiveness. Furthermore, convergence characteristics and robustness of the method had been assessed through comparison with results reported in literature. The PS technique was found to be very competitive in terms of its overall performance. Variations of the technique have also been explored, in particular a hybrid formulation exploiting Genetic Algorithm (GA), Pattern Search (PS) and Sequential Quadratic Programming, and advantages of such a combined technique reported. A DED model for the West Doha Power Station (WDPS) in Kuwait has been developed and the penetration of renewable energy resources to this model has been discussed. The DED model was then solved using the PS method developed in this thesis to achieve the optimal dispatch with the aim to minimise fuel costs in WDPS. Considerable potential savings in electric power production of WDPS have been identified and thus the benefits of deploying renewable energy in Kuwaiti electric system demonstrated.

O presente trabalho tem por objetivo disponibilizar metodologia para o projeto de tratamento de esgoto sanitário através de disposição oceânica com utilização de emissário submarino, para localidades de pequeno porte. Também apresenta metodologia simplificada para obtenção de alguns dados oceanográficos necessários, na perspectiva de atender aos administradores dessas pequenas prefeituras envolvidas nas questões de atendimento de sua população quanto aos serviços de tratamento dos esgotos sanitários. Esses municípios, por serem pequenos e em país em desenvolvimento, carecem de recursos financeiros para as soluções convencionais de tratamento de esgotos sanitários. O trabalho contém uma revisão da bibliografia técnica relativa ao processo objeto deste estudo, não só referente ao projeto hidráulico como também à estabilidade física da tubulação do emissário assentada no leito do mar. Julgou-se necessário a realização, deste trabalho depois que se verificou que a implantação de emissários submarinos com diâmetros até da ordem de 300 mm, em geral tem seus custos inferiores aos dos sistemas convencionais. / This paper aims to provide a simplified methodology for the treatment design of sewage disposal through the use of oceanic outfall locations for small towns. It also features simplified methodology for obtaining oceanographic data needed for those small municipalities management. As these cities are usually on a development phase and have restricted resources to invest on its needs, the designed system becomes very attractive due to its low capital requirement. This work includes a technical review on the subject of this case study, not only regarding the water issues but also related to its physical stability of the outfall pipe at the bottom of the sea.It was felt necessary to organize this work after it was found that the introduction of submarine outfalls with diameters up to around 300 mm, has its costs below those of conventional systems. The most important result from this work is the competitiveness conclusion of the required implementation investment of submarine outfalls, with diameters up to 300 mm.

Multiphase flow is the simultaneous flow of two or more phases, in direct contact, and is important in the oil industry, e.g. in production wells, in sub-sea pipelines and during the drilling of wells. The behaviour of the flow will depend on the properties of the constituent phases, the flow velocities and volume fractions of the phases and the geometry of the system. In solids-in-liquid flows, measurement of the local solids volume fraction distribution and the local axial solids velocity distribution in the flow cross section is important for many reasons including health and safety and economic reasons, particularly in oil well drilling operations. However upward inclined solidsliquid flows which are frequently encountered during oil well drilling operations are not well understood. Inclined solids-liquid flows result in non- uniform profiles of the solids volume fraction and axial solids velocity in the flow cross- section. In order to measure the solids volumetric flow rate in these situations it is necessary to measure the distributions of the local solids volume fraction and the local axial solids velocity and then to integrate the product of these local properties in the flow cross section. This thesis describes the development of a non-intrusive Impedance Cross-Correlation (ICC) device to measure the local solids volume fraction distribution and the local solids axial solids velocity distribution in upward inclined solids-water flows in which these distributions are highly non-uniform. The ICC device comprises a non-conductive pipe section of 80mm internal diameter fitted with two arrays of electrodes, denoted „array A‟ and „array B‟, separated by an axial distance of 50mm. At each array, eight electrodes are equispaced over the internal circumference of the pipe. A control system consisting of a microcontroller and analogue switches is used such that, for arrays A and B, any of the eight electrodes can be configured as an "excitation electrode" (V+), a "virtual earth measurement electrode" (Ve) or an "earth electrode" (E) thus enabling the local mixture conductance in different regions of the flow cross-section to be measured and thereby allowing the local solids volume fraction in each region to be deduced. The conductance signals from arrays A and B are also cross-correlated to yield the local solids axial velocity in the regions of flow under interrogation. A number of experiments were carried out in solids-in-water flows in a flow loop with an 80 mm inner diameter, 1.68m long Perspex test section which was inclined at three different inclination angle to the vertical ( o 0 , o 15 and o 30 ). The obtained results show good quantitative agreement with previous work carried out using intrusive local probes. Integration of the flow profiles in the cross section also yielded excellent quantitative agreement with reference measurements of the mean solids volume fraction, the mean solids velocity and the solids volumetric flow rate. Furthermore, this study also showed good qualitative agreement with high speed film of the flow. It is believed that the method of velocity and volume fraction profile measurement described in this thesis is much simpler to implement, more accurate and less expensive than the currently very popular technique of dual-plane Electrical Resistance Tomography (ERT). Finally, the thesis describes a mathematical model for predicting the axial velocity distribution of inclined solids-water flows using the solids volume fraction profiles measured by the ICC device. Good agreement was obtained between the predicted velocity profiles and the velocity profiles measured using the ICC device.

No description available.

Accurate modeling of contaminant transport and sorption processes in the soil and landfill liners is a prerequisite for realistic model simulations of contaminant fate and transport in the environment. These studies are also important for the remediation of soil and groundwater contamination. Modeling of contaminant transport through soils and landfill liners consists of either solving the direct/forward problem or the inverse problem. In this thesis, an automated time-stepping implicit procedure is developed from the convergence and error studies of explicit and implicit finite-difference solutions for the advection-dispersion transport of contaminants through soil with different sorption mechanisms. This study is further extended for transient through-diffusion (TTD) transport of contaminant in landfills by considering linear sorption mechanism. To validate the numerical solution and also to study the behavior of finite-difference numerical solutions for TTD transport problem, closed-form analytical solution is derived. Further, a new interface condition is proposed based on the finite-volume procedure for stratified soil or landfill liner system. Solvers are developed for the parameter estimation of inverse problem by integrating the developed procedures for the above forward problem with different optimization procedures. Solvers based on Simulated Annealing (SA) and Genetic Algorithm (GA) are developed for TTD transport in the landfill liners and verified with the existing methods of parameter estimation. Novel swarm intelligence based solver is developed for the first time for parameter estimation in contaminant transport inverse problem to overcome some of the limitations of the classical optimization methods and evolutionary methods such as GA. Additionally, the proposed swarm intelligence based algorithms and a new variant is applied to solve ill-posed problem of contaminant source characterization. The presented work in this dissertation can be unswervingly applied for modeling the contaminant transport in laboratory through-diffusion tests and contaminant transport through landfill liners where the transport is usually considered to be one-dimensional and also diffusion-dominated. Similarly, the advection-dispersion transport through laboratory soil columns can also be modeled with the developed, fast, automated, implicit numerical procedure with very good accuracy. The present study can be applied further for contaminant transport through stratified soil/liner system using fast converging numerical algorithms. Finally, the problems of design parameter estimation and source characterization can be handled accurately by the use of developed automated nature-inspired solvers.

Optimal cut plans for cutter suction dredgers aim to maximize operational efficiency. Maximizing operational efficiency involves minimization of stoppage time resulting from non-productive dredger movements. To automate a systematic search for optimal twodimensional cut plans for cutter suction dredgers two models with an adaptive simulated annealing-based solution approach were developed. The first model, the dredge cut nesting model, optimizes irregular stock cutting problems where stencils represent dredge cuts and sheets represent dredging areas. Stencils are collections of unit dredge cuts with dimensions related to an effective cutting width which can be achieved with the cutter suction dredger considered. The objectives of the dredge cut nesting model are to maximize sheet coverage and to minimize stencil overlap. Centroids of unit dredge cuts of final nest layouts are extracted and used as grid nodes in the second model. The second model, the dredger routing model, optimizes asymmetric travelling salesperson problems with turning costs. The objectives of the dredger routing model are to minimize total route length and sum of turning angles, and to maximize average link length. A link consists of two or more route edges which are aligned with each other to within specified limits. A significant result of this research is that an engineering application of both models showed that two-dimensional cut plans for cutter suction dredgers can be systematically optimized and that dredger routes with minimum turning costs can be found. However, results also showed that the dredger routing model is not yet sophisticated enough to find cut plans for cutter suction dredgers for which overall project execution time is minimal.

Gravel filters are potentially a low cost, low maintenance water treatment solution. They require no mechanical or electrical parts and can operate without the addition of chemicals or the need for close supervision. As such, they are an appropriate technology for treating road runoff as a component of Sustainable urban Drainage Systems (SuDS) and as an initial stage of drinking water treatment in rural areas. However, the processes by which pollutant particles are removed in gravel filters are poorly understood and practical experience shows that many filters fail long before their expected design life is reached. For this reason gravel filters are little used for drinking water treatment and, when they are incorporated into SuDS, their removal efficiency and maintenance requirements are unpredictable. The aim of this thesis was to better understand particle removal processes and the implications for gravel filter design. This was achieved through a combination of lab-based experiments and numerical modelling. • The change in conservative tracer transport characteristics with pollutant particle accumulation was assessed through column experiments. • The spatial heterogeneity of particle accumulation was measured by collecting 3D data with magnetic resonance imaging (MRI). Multiple scans of filters allowed the temporal evolution of particle accumulation to be assessed. A method for processing the raw MRI data to yield the change in 3D pore geometry was developed, assessed and applied. • A simple method for extracting and comparing pore network characteristics at different stages of particle accumulation was applied to the MRI derived geometry. • Direct modelling of the 3D MRI pore geometry with the open source software OpenFOAM allowed correlation of flow velocities with particle accumulation at each point in the pore network. Lagrangian particle tracking was used to simulate the transport of a conservative tracer through the filter. Key findings were that spatial heterogeneity in particle accumulation was influenced by both initial pore geometry and the temporal evolution of the pore network with accumulation. This was attributed to the formation of high velocity preferential flow paths that were evident in both the 3D MRI data and the numerical model of that data. Pore networks exhibited a decrease in connectivity with accumulation and this was mirrored by a decrease in the volume of the filter that was accessible to a conservative tracer. Conclusions of this thesis are that MRI is a useful tool for non-invasively assessing the spatial variability of clogging in gravel filters and, when combined with numerical modelling of the pore geometry, for establishing the link between pore velocity and particle removal. The formation of preferential flow paths is detrimental to the pollutant removal efficiency of a filter and could explain why many filters fail to produce good quality effluent well before their physical pollutant storage capacity is reached.