Long Term Evolution (LTE) is one of the latest mobile communication technologies being commercially deployed worldwide. It has emerged as a promising technology for new applications such as mobile video surveillance (IPVS) due to its higher data throughputs as well as the quality of the service management capabilities. This work focuses on the performance evaluation of a mobile and real-time IPVS system over a LTE network in both operation modes, namely FDD and TDD. The QoS Requirements for the IPVS were defined and two simulation analyses were performed in OPNET Modeler in order to compare them to the QoS Delivered. The first analysis studied the performance of the IPVS service from a capacity point of view in a single cell scenario while the second analysis looked at the performance of the IPVS service in a sample network configuration including several cells. In light of the analysed results it was evidenced the flexibility of TDD operation mode in terms of capacity as well as its higher delay and packet delay behaviours in comparison with FDD operation mode. Additionally it was shown that TDD index 6 does not comply with the QoS performance required for an IPVS service in a multi cell network. 

During the last decades there has been an increase in the generation of solid wastes in the world, in developing countries the situation has been specifically critical since in many cases there is no adequate treatment for the solid waste due to the scarcity of the resources and to the poor conscience of the real situation and possible consequences. This document presents the composting method as a suitable alternative for the treatment of solid waste in developing countries considering that its costs are not so high and that the composition of the solid waste is mainly organic. The analysis was based on a current literature review and on the study of some cases of composting projects, according to the results an operational guideline for the development of composting projects in developing countries was proposed. The guideline is composed of two main cores: the planning system and the evaluation system. The planning system supports the development of a composting project and the evaluation system is a base for the comparison of performance between different future cases.

Engineered barriers are used in the containment of hazardous materials and are usually a composite of compacted clayey soil and a synthetic membrane. Containment elements such as landfill liners should be designed to control or prevent leachate migration or groundwater ingress. Engineering specifications for a compacted clay liner are based mainly in a hydraulic conductivity less than 10-9 m/s and the need for stability during construction and operation of the landfill. Sandbentonite mixtures are often used as a barrier material. The addition of relatively small amounts of bentonite (5-15%) can improve the performance of a granular material providing both a low permeability and an enhanced mechanical stability. However not all the possible compaction conditions produce a low permeability and mechanically stable material. Changes in water content after compaction can cause swelling or collapse depending on the stress and suction conditions before the water content change occurs. A laboratory investigation of the swelling-collapse behaviour of compacted mixtures of Sand-bentonite has been undertaken. Compaction and suction characteristics were established. The suction and volume change characteristics were investigated through a series of oedometer tests. The central part of the experimental programme focused on the detailed investigation of the processes of swelling and collapse during controlled wetting.To do this, a significant number of modifications were required to the existing apparatus. Fabric studies including Environmental Scanning Electron Microscopy and Mercury Intrusion Porosimetry were also undertaken. Intrinsic behaviour and the relationship between suction and water content were comprehensively studied. A parametric study of the influence of bentonite content and sand grading was also undertaken. The results are presented and analysed. Recommendations for future research are made.

Carbon Capture and Storage (CCS) is an emerging technology designed to tackle climate change by making processes more sustainable. This work gives a technical review of the current status of this process in order to compare it with the production of biochar. The latter is a carbon-rich material obtained when biomass is heated in the absence of oxygen. Although this production technique, which is called pyrolysis, has been known for centuries, there is little information regarding its process at an industrial level. As a result, this dissertation presents a study of the feasibility of biochar production as a means of carbon capture and storage. In other words, this research generates an approach to provide a preliminary estimate of the potential of large-scale biochar production to reduce atmospheric CO2. In this context, it is important to consider that pyrolysis-based biochar could be valuable in terms of soil improvement, crop yield increase, bioenergy generation and greenhouse gas (GHG) offsets. In this perspective, there are two categories of pyrolysis: fast and slow. Fast pyrolysis produces biochar in a matter of seconds, whereas slow pyrolysis produces a higher conversion to biochar but in a matter of hours. Generally speaking, the pyrolysis-based process is considered to be carbon-negative, because biochar production could reduce the amount of carbon in the atmosphere. In terms of the data analysis, several factors were considered and some assumptions were made. These assumptions are based on the literature because biochar production is not yet available at a commercial scale. According to the results, the cost to capture a tonne of carbon dioxide is $6.47 and $32.49 for fast and slow pyrolysis respectively. Therefore, although it is not a profitable technology, it could be cost competitive compared with CCS projects.

En este texto se encuentran datos sobre construcción de líneas eléctricas aéreas, los conductores, los aisladores y sus diferencias, las campanas del aislador, soportes de líneas y postes de madera y de concreto.

A technological and environmental alternative has been studied for about a decade to reduce the consumption of coal. It consists of substitute one part of the coal by biomass (neutral generated of CO2) in a co-_ring process. The co-_ring process consists of the controlled combustion of two or more fuels in the same burner. According to research performed in the US and Europe this process has economic and technical viability. And depending on the characteristics of the fuel, this process can contribute reducing the greenhouse gases (GHG). This thesis presents a methodological proposal to analyze and evaluate a thermoelectric power plant from the exergoenviromental point of view, operating in co-_ring process and using coal and biomass. The boundary of the problem is composed by the power plant and the technological paths to obtain and manipulate the fuels. Exergy is used in the thermodynamic analysis and the life cycle assessment method is proposed to quantify the environmental impact. The climate change category was used following the global warming potential index. Two scenarios were evaluated: scenario A corresponds to the power plant operating with 100% coal and scenario B corresponds to the power plant operating in co-_ring with 90% of coal and 10% of biomass. The technological route used for the coal is established between the southern mineral region of the state of Santa Catarina and the Jorge Lacerda thermoelectric power plant complex, which is located at Capivari de Baixo. The information utilized for the biomass path was obtained from the research performed in the thermoelectric power plant complex. The purpose of this task was to use the biomass from the rice farms as fuel. The analysis showed that the power plant is largely responsible for exergy destruction. Moreover it has the largest generated impact associated with the analyzed category. From these results, an exergoenvironmental analysis for the representative thermodynamic cycle was performed. The results showed that the boiler constitutes the equipment with the largest potential of improvement.  Finally, an exergoenvironmental global index was proposed to compare the exergoenvironmental impact of the thermoelectric generation process for both scenarios, which were compared with Carnot cycle scenario. The exergoenvironmental global index showed that 11% improvement is possible for the scenario B when compared with scenario A without taking in account the biomass microbial decomposition and up to the 35% when the decomposition was considered.

The Interaction of electromagnetic waves with dielectric bodies and metals has been extensively studied because of its importance to problems including propagation through rain or snow, scattering by and detection of air borne particles, coupling to missiles with plasma plumes or dielectric-filled apertures, performance of communication antennas in the presence of dielectric and magnetic inhomogeneities, and medical diagnostics and power absorption in biological bodies. Computational electromagnetics methods (CEM) offer and indispensable tool for calculating the electromagnetic scattering from an internal field distribution of arbitrarily shaped, inhomogeneous, dielectric bodies. The aim of this thesis is the study and simulation of a RF coils system design by developing a novel parallel fast Method of Moments (MoM) modeling approach suitable for the simulation of dielectric bodies and metals. The parallel fast MoM implementation uses volume and surface basis functions with special properties appropriate for the representation of flux current densities for perfect electric conductors (PEC) and dielectrics. The results obtained with our modeling method were confirmed by comparisons with analytical solutions and other commercial software results, yielding very good agreement. The RF coil is employed in high field Magnetic Resonance Imaging (MRI) to obtain high quality brain images. Among all the clinical imaging techniques, MRI stands as a noninvasive technique that provides accurate, detailed anatomic images, which has had a major impact in the diagnosis of human diseases. MRI is a widely use soft-tissue imaging modality that has involved over the past several years into a powerful and versatile medical diagnostic tool capable of providing in-vivo diagnostic images of human anatomy. Current research areas in MRI system design are driven by the need to obtain detailed high resolution images with improved image signal-to-noise ratio (SNR) at a given magnetic field strength. One of the most critical factor that influences the quality and resolution of the MRI is the homogeneity of the RF field. To this end, this requirement demands the development of high performance MRI radio frequency (RF) coils and a standard procedure for enhancing the uniformity of the field directly at the modeling stage of the RF Coil.

Nordic countries experience post-glacial rebound, a movement where geographical contours slowly change elevation with respect to the mean sea level. The glacial isostatic adjustment (GIA) model aims to explain the phenomena, which combined with seismic data allows geoscientists to reconstruct elastic coefficients and viscosities of the Earth's lithosphere and upper mantle. The use of standard commercial codes are not adequate for GIA simulations and result in significant errors in the displacement field. This negative outcome suggests the development of GIA codes that include advection of pre-stress in the model. The problem set up consists on a solid 2D elastic layer under a flat Earth approximation, described by three different models suggested by current studies in geophysics.For space discretization the mixed finite element method (mFEM) is used and efficient preconditioners are built for the resulting algebraic system in saddle point form. A three level GMRES iterative solution strategy is proposed, based on Schur Complement preconditioners coupled with Multigrid techniques. The implementation is presented as a ready-to-use toolbox that easily deals with problem parameters, geometries, compressible and fully incompressible materials and provides higher accuracy for the displacement field compared with the previously existent codes. It also can be easily extended to 3D geometries and allows the implementation of a viscoelastic mantle. The code is written in C++ using the deal.II library designed for FEM, permitting the use of readily-made software packages, such as Trilinos that are straightforwardly parallelizable.

Due to the continue trend of technology for circuit scaling; optimal sizes for transistors and cables are needed, this scaling comes along with power increase and undesired cross talk effects between the wires which might affect the signal itself. A trade-off curve between power, area and delay is required so that a tuned solution for a specific problem might be found.  Here, an approach based on the dominant time constant optimization technique for modelling of the delay is investigated for an initial square topology with uniform wire and repeater sizing based on convex optimization and Linear Matrix Inequalities. Results with optimal buffer insertion across the bus are also investigated. 

In a Fiber to the Home (FTTH) system, the fiber is connected until the household users. A passive optical network (PON) is a particular type of FTTH networks that uses P2MP (point-to-multipoint fiber premises) in which part of the infrastructure is shared, to allow sending information of multiple channels through one fiber. This study presents a summary of the main concepts about access networks and PON systems and some technologies used to its development, including Time Division Multiplexing (TDM) and Wavelength division multiplexing (WDM), independently or in hybrid configuration (TWDM). From here the key commercial devices for its implementation are identified and modelled, specifying its characteristic parameters to fulfill the minimum requirements of the new international standard ITU-T G.989 for FTTH networks. This project evaluates this standard, which proposes the implementation of NG-PON2 systems at 4x10Gbit/s, that will use the hybrid architecture TWDM and tunable transceivers and ensures coexistence with other legacy PON systems, allocating the downstream and upstream traffic in appropriate wavelength bands without overlapping. The work of analysis is focused in the identification of key devices, such as tunable transmitters and tunable receivers at ONU to achieve the minimum specified requirements. Besides, a first approximation to the coexistence element (CE) is made, for supporting the legacy PON systems. Once the minimum requirements are specified and the key devices identified, the network is designed and built in the commercial simulator VPIphotonicsTM, using CW lasers, external intensity modulators, wavelength multiplexers and the appropriate power splitters. In reception a direct detection scheme is implemented using PIN and APD photodiodes and tunable filters at ONU. Once the design is completed different test are run, the results are analyzed and the design is optimized, in order to dimension the network in terms of fiber reach, number of users, power budget, bandwidth capacity, etc. En un Sistema de Fibra hasta el hogar (FTTH, Fiber to the Home), la fibra es conectada hasta el hogar de los usuarios. Una red óptica pasiva (PON) es un tipo particular de red redes FTTH que utiliza instalaciones punto a multipunto (P2MP), en las cuales se comparte parte de la infraestructura permitiendo enviar información de múltiples canales a través de una sola fibra. Este trabajo presenta un compendio de los principales conceptos sobre redes de acceso y sistemas PON y algunas de las tecnologías usadas para el desarrollo de los mismos, incluyendo multiplexación por división en el tiempo (TDM, Time Division Multiplexing) y multiplexación por división de la longitud de onda (WDM, Wavelength Division Multiplexing), independientes o en configuración híbrida (TWDM). A partir de aquí se identifican y modelan los dispositivos comerciales clave para su implementación, especificando sus parámetros característicos para cumplir con los requerimientos del nuevo estándar internacional ITU-T G.989 para redes FFTH. Este proyecto evalúa dicho estándar, el cual plantea la implementación de sistemas NG-PON2 a 4x10GBit/s, los cuales usarán una arquitectura híbrida TWDM y transceptores sintonizables, además de garantizar la coexistencia con otros sistemas PON heredados, ubicando el tráfico en downstream y upstream en unas bandas de longitud de onda adecuadas sin solapamiento. El trabajo de análisis se enfoca en la identificación de los dispositivos clave, como transmisores y receptores ópticos sintonizables en la ONU para alcanzar los requerimientos mínimos especificados. Además se da una primera aproximación al diseño del elemento de coexistencia (CE, Coexistence element) para el soporte de los sistemas PON heredados. Una vez especificados los requerimientos mínimos e identificados los dispositivos clave, se diseña e implementa la red en el simulador VPIphotonicsTM usando láseres de onda continua, moduladores externos de intensidad, multiplexores de longitud de onda y divisores de potencia apropiados. En recepción se usa detección directa con fotodiodos PIN y APD y filtros ópticos sintonizables en la ONU. Una vez completado el diseño, se realizan diferentes test, se analizan los resultados y se optimiza el diseño para dimensionar la red en términos de número de usuarios, alcance, balance de potencias, capacidad de acho de banda, etc.