Smart-antenna techniques for energy-efficient wireless sensor networks used in bridge structural health monitoring

Abstract: It is well known that wireless sensor networks differ from other computing platforms in that 1- they typically require a minimal amount of computing power at the nodes; 2- it is often desirable for sensor nodes to have drastically low power consumption. The main benefit of the this work is a substantial network life before batteries need to be replaced or, alternatively, the capacity to function off of modest environmental energy sources (energy harvesting). In the context of Structural Health Monitoring (SHM), battery replacement is particularly problematic since nodes can be in difficult to access locations. Furthermore, any intervention on a bridge may disrupt normal bridge operation, e.g. traffic may need to be halted. In this regard, switchbeam smart antennas in combination with wireless sensor networks (WSNs) have shown great potential in reducing implementation and maintenance costs of SHM systems. The main goal of implementing switch-beam smart antennas in our application is to reduce power consumption, by focusing the radiated energy only where it is needed. SHM systems capture the dynamic vibration information of a bridge structure in real-time in order to assess the health of the structure and to predict failures. Current SHM systems are based on piezoelectric patch sensors. In addition, the collection of data from the plurality of sensors distributed over the span of the bridge is typically performed through an expensive and bulky set of shielded wires which routes the information to a data sink at one end of the structure. The installation, maintenance and operational costs of such systems are extremely high due to high power consumption and the need for periodic maintenance. Wireless sensor networks represent an attractive alternative, in terms of cost, ease of maintenance, and power consumption. However, network lifetime in terms of node battery life must be very long (ideally 5–10 years) given the cost and hassle of manual intervention. In this context, the focus of this project is to reduce the global power consumption of the SHM system by implementing switched-beam smart antennas jointly with an optimized MAC layer. In the first part of the thesis, a sensor network platform for bridge SHM incorporating switched-beam antennas is modelled and simulated. where the main consideration is the joint optimization of beamforming parameters, MAC layer, and energy consumption. The simulation model, built within the Omnet++ network simulation framework, incorporates the energy consumption profiles of actual selected components (microcontroller, radio interface chip). The energy consumption and packet delivery ratio (PDR) of the network with switched-beam antennas is compared with an equivalent network based on omnidirectional antennas. In the second part of the thesis, this system model is leveraged to examine two distinct but interrelated aspects: Gallium Arsenide (GaAs) based solar energy harvesting and switched-beam antenna strategies. The main consideration here is the joint optimization of solar energy harvesting and switchedbeam directional antennas, where an equivalent network based on omnidirectional antennas acts as a baseline reference for comparison purposes.Il est bien connu que les réseaux de capteurs sans fils diffèrent des autres plateformes informatiques étant donné 1- qu’ils requièrent typiquement une puissance de calcul minimale aux noeuds du réseau ; 2- qu’il est souvent désirable que les noeuds capteurs aient une consommation d’énergie dramatiquement faible. La principale retombée de ce travail réside en la durée de vie allongée du réseau avant que les piles ne doivent être remplacées ou, alternativement, la capacité de fonctionner indéfiniment à partir de modestes sources d’énergie ambiente (glânage d’énergie). Dans le contexte du contrôle de la santé structurale (CSS), le remplacement de piles est particulièrement problématique puisque les noeuds peuvent se trouver en des endroits difficiles d’accès. De plus, toute intervention sur un pont implique une perturbation de l’opération normale de la structure, par exemple un arrêt du traffic. Dans ce contexte, les antennes intelligentes à commutation de faisceau en combinaison avec les réseaux de capteurs sans fils ont démontré un grand potentiel pour réduire les coûts de réalisation et d’entretien de systèmes de CSS. L’objectif principal de l’intégration d’antennes à commutation de faisceau dans notre application réside dans la réduction de la consommation énergétique, réalisée en concentrant l’énergie radiée uniquement là où elle est nécessaire. Les systèmes de CSS capturent l’information dynamique de vibration d’une structure de pont en temps réel de manière à évaluer la santé de la structure et prédire les failles. Les systèmes courants de CSS sont basés sur des senseurs piézoélectriques planaires. De plus, la collecte de données à partir de la pluralité de senseurs distribués sur l’étendue du pont est typiquement effectuée par le biais d’un ensemble coûteux et encombrant de câbles blindés qui véhiculent l’information jusqu’à un point de collecte à une extremité de la structure. L’installation, l’entretien, et les coûts opérationnels de tels systèmes sont extrêmement élevés étant donné la consommation de puissance élevée et le besoin d’entretien régulier. Les réseaux de capteurs sans fils représentent une alternative attrayante, en termes de coût, facilité d’entretien et consommation énergétique. Toutefois, la vie de réseau en termes de la durée de vie des piles doit être très longue (idéalement de 5 à 10 ans) étant donné le coût et les problèmes liés à l’intervention manuelle. Dans ce contexte, ce projet se concentre sur la réduction de la consommation de puissance globale d’un système de CSS en y intégrant des antennes intelligentes à commutation de faisceau conjointement avec une couche d’accès au médium (couche MAC) optimisée. Dans la première partie de la thèse, une plateforme de réseau de capteurs sans fils pour le CSS d’un pont incorporant des antennes à commutation de faisceaux est modélisé et simulé, avec pour considération principale l’optimisation des paramètres de sélection de faisceau, de la couche MAC et de la consommation d’énergie. Le modèle de simulation, construit dans le logiciel de simulation de réseaux Omnet++, incorpore les profils de consommation d’énergie de composants réels sélectionnés (microcontrôleur, puce d’interface radio). La consommation d’énergie et le taux de livraison de paquets du réseau avec antennes à commutation de faisceau est comparé avec un réseau équivalent basé sur des antennes omnidirectionnelles. Dans la deuxième partie de la thèse, le modèle système proposé est mis à contribution pour examiner deux aspects distrincts mais interreliés : le glânage d’énergie à partir de cellules solaire à base d’arséniure de Gallium (GaAs) et les stratégies liées aux antennes à commutation de faisceau. La considération principale ici est l’optimisation conjointe du glânage d’énergie et des antennes à commutation de faisceau, en ayant pour base de comparaison un réseau équivalent à base d’antennes omnidirectionnelles

DATA ENVELOPMENT ANALYSIS OF BANKING SECTOR IN BANGLADESH

Banking sector of Bangladesh is flourishing and contributing to its economy. In this aspect measuring efficiency is important. Data Envelopment Analysis technique is used for this purpose. The data are collected from the annual reports of twenty four different banks in Bangladesh. Data Envelopment Analysis is mainly of two types - constant returns to scale and variable returns to scale. Since this study attempts to maximize output, so the output oriented Data Envelopment Analysis is used. The most efficient bank is one that obtains the highest efficiency score

Requirements for large-scale adoption of rapid manufacturing technologies

Despite the use of Additive Manufacturing (AM) technologies in a lot of applications including the production of some high-value products for end use, it is still very much an untapped potential. There is an increase in usage of AM technology for the manufacture of end-use products (Rapid Manufacturing (RM)) in recent years, but mass use of the technology in terms of speed, cost and quality, which is acceptable by the general consumer, is still not widely in existence today. The concept of RM as a viable production process is still not understood by many businesses/consumers, with thinking still dominated by the AM technologies for Rapid Prototyping (RP) applications. A key difference between RM and RP is in the supply chain. The RM supply chain is much more complicated than the RP supply chain. This research conducted a Delphi Study to identify the requirements or prerequisites necessary for the use of RM technologies as a viable means to manufacture end used products (RM application of AM) in mass scale. The paper identifies 36 requirements or pre-requisites and classified them into various classes of importance in order to highlight their significance. In addition to supply chain issues, the requirements unearthed are factors or features about RM technology (equipment), materials and processes that need modification, upgrading or creation

Resource metabolism of the construction sector : an application of material and exergy flow analysis

Ésta tesis tiene como objetivo evaluar el consumo de recursos del sector de la construcción, los residuos y las emisiones generadas por el sector. Ésto está motivado por el hecho de que el sector de la construcción es responsable de una gran cantidad de consumo de recursos y representa casi el 9% el valor bruto añadido al producto interno bruto del mundo. La evaluación considera la perspectiva del ciclo de vida, desde la extracción de materias primas, a través de la construcción y fabricación de productos, materiales de transporte, la construcción, la generación de residuos de demolición, el transporte de residuos, el tratamiento y disposición final. El objetivo es identificar las oportunidades y mejorar los criterios de selección de materiales, el procesado, la reutilización y el reciclado para el uso sostenible de los recursos. Debido a la complejidad de los sistemas de edificios e infraestructuras, compuestas de muchos componentes que interactúan, siempre es difícil llevar a cabo una contabilidad de los recursos precisos dentro de éste sector. En esta perspectiva, el concepto de análisis de flujo de materiales y la evaluación del ciclo de vida (ACV), y el análisis de exergía se tratan como herramientas de contabilidad de recursos y se centra en sus aplicaciones en el sector de la construcción. Además del análisis sectorial, ésta tesis, también analiza la eficiencia de los procesos de fabricación y el ciclo de vida completo de los productos con base a exergía. Todos los procesos y los productos seleccionados son relevantes para el sector de la construcción, y éste análisis tiene como objetivo proporcionar conocimientos de despersonalización en el uso de materiales del sector. En el capítulo 1, se expone el marco teórico en que los análisis de flujo de exergía y los materiales se utilizan en la evaluación del metabolismo de los recursos del sector de la construcción, que destacan la importancia de éste sector en términos de flujos de recursos y la generación de residuos y emisiones. Éste capítulo, también introduce la eficiencia exérgica y herramientas de evaluación del ciclo de vida exergéticos, que explica las limitaciones del análisis de la energía y el ACV, y cómo la aplicación de éstos métodos a base de exergía puede ofrecer mejores perspectivas sobre la eficiencia del uso de los recursos en los procesos de fabricación en toda la vida de los productos, respectivamente. La Ecología Industrial, se presenta al introducir el enfoque basado en los sistemas y el marco termodinámico en el que el sector de la construcción se analiza en este estudio. El capítulo 2, presenta los resultados de los análisis de flujo de materiales y exergía del sector de la construcción catalana en el año 2001. En ese momento, Cataluña tenía un adicional de 52 millones de toneladas de existencias de materiales para el sector y generaba 7 millones de toneladas de residuos de construcción y demolición, de los cuales sólo el 6,5% son recicladas o regeneradas. El estudio muestra que la fase de fabricación consume la mayor parte de los recursos de energía durante el ciclo de vida del conjunto de los productos, seguidos de transporte de materiales, que representa el 57% y el 4% del consumo de exergía, respectivamente. Se señala que la mejora en la selección de materiales, tecnologías de fabricación y diseño para el desmontaje, conduce a la sostenibilidad del sector, para conseguir una mejora de la eficiencia del uso de recursos. En el capítulo 3, se menciona el rendimiento exergético de los procesos de producción, tanto en el proceso de producción primaria como secundaria (reciclaje), de los materiales de construcción que se calcula, con el fin de evaluar la calidad de los materiales, las pérdidas de exergía, y el potencial de mejora de procesos. Ésto sirve para cuantificar el potencial de mejora de los procesos de fabricación actuales que abordan las deficiencias de fabricación de los nueve principales materiales de construcción no renovables: aluminio, acero, cobre, cemento, hormigón, cerámica, vidrio, polipropileno y cloruro de polivinilo. La Eficiencia Exergía basada en la segunda ley de la termodinámica es determinada con el fin de comparar la eficiencia exergía teórica y la eficiencia exergía del proceso real. La gran diferencia entre los requisitos teóricos y empíricos de exergía en los procesos de fabricación sugiere que las oportunidades para una mejor utilización de exergía industrial todavía existen, pero requieren un diseño y mejoras en la tecnología. Los resultados demuestran que los recursos se utilizan de manera más eficiente en los procesos de reciclaje, en comparación con los procesos de fabricación primaria. En esta tesis se presenta una teoría (capítulo 4) para determinar como de eficientemente se utilizan los recursos en las aplicaciones de la construcción, utilizando la metodología de análisis del ciclo de vida exergético desde un enfoque universal. Esto incluye la extracción de materias primas, la fabricación de resina y de gestión de las etapas del ciclo de vida de los residuos al final de su vida. La irreversibilidad durante el ciclo de vida completo permite evaluar el grado de perfección termodinámica de los procesos de producción y llevar a cabo la evaluación de la cadena de producción entera. Ciclo de vida global de la eficiencia exérgica de polipropileno y cloruro de polivinilo se cuantifica en 27,1% y 9,3%, respectivamente, que se caracteriza por una baja eficiencia en la fabricación y los procesos de reciclaje para ambos materiales. Desde el punto de vista de la conservación de recursos, el reciclado mecánico se ha sugerido como la opción viable para la gestión de residuos de plástico al final de su vida, ya que los materiales de bucles vuelven a su ciclo de vida original y reduce las aportaciones de recursos primarios en la producción.This thesis aims to assess the resource consumption of the construction sector, and the wastes and emissions generated by the sector. This is motivated by the fact that the construction sector is responsible for large amounts of resource consumption and represents nearly 9% gross value added to the world's gross domestic product. The assessment considers the life cycle perspective from raw material extraction, through construction product manufacturing, material transport, construction and demolition waste generation, to waste transport, treatment, and final disposal. The aim is to pinpoint the opportunities for improved material selection criteria, processing, reuse, and recycling for sustainable resource use. Due to the system complexity of buildings and infrastructure, composed of many interacting components, it is always challenging to undertake an accurate resource accounting within this sector. In this perspective, the concepts of material flow analysis (MFA), life cycle assessment (LCA), and exergy analysis (ExA) are discussed as resource accounting tools focusing on their applications in the construction sector. Apart from sectoral analysis, this thesis also analyzes the efficiency of manufacturing processes and products' complete life cycle based on exergy. All the processes and products selected are relevant for the construction sector, and this analysis aims to provide deper insights into sectoral material use. Chapter 1 details the theoretical framework under which exergy and material flow analyses are used in assessing the resource metabolism of the construction sector highlighting the importance of this sector in terms of resource flows, and generation of waste and emissions. This chapter also introduces the exergy efficiency and exergetic life cycle assessment (ELCA) tools, explaining the limitations of energy analysis and LCA, and how the application of these exergy-based methods can provide better insights into resource use efficiency in manufacturing processes and throughout the products' life, respectively. Industrial ecology (IE) is presented to introduce the systems-based approach and thermodynamic framework on which of the construction sector is analyzed in this study. Chapter 2 presents the results of material and exergy flow analyses of the Catalan construction sector for the year 2001. In 2001, Catalonia had an additional 52 million tonnes of material stock to the sector and generated 7 million tonnes of construction and demolition waste (CDW) of which only 6.5% were recycled or reclaimed. The study shows that manufacturing stage consumes the largest fraction of energy resources during the products' whole lifecycle followed by material transport, accounting for 57% and 4% of exergy use, respectively. It is pointed out that improvement in material selection, manufacturing technologies, and design for disassembly lead to sustainability of the sector delivering improved resource use efficiency. In chapter 3, the exergetic efficiency of the production processes, both primary and secondary (recycling) production process, of construction materials is calculated in order to assess material quality, exergy losses, and process improvement potentials. This serves to quantify the improvement potentials for present manufacturing processes addressing the manufacturing inefficiencies of nine major non-renewable construction materials: aluminum, steel, copper, cement, concrete, ceramic, glass, polypropylene (PP), and polyvinyl chloride (PVC). Exergy efficiency based on the second law of thermodynamics is determined in order to compare the theoretical exergy efficiency and the real-process exergy efficiency. The large difference between theoretical and empirical exergy requirements in manufacturing processes suggests that opportunities for better industrial exergy utilization still exist but require design and/or technology improvements. The results demonstrate that resources are utilized more efficiently in recycling processes compared to primary manufacturing processes. This thesis has presented an effort (chapter 4) to pinpoint how efficiently resources are used in the construction applications, using exergetic life cycle assessment methodology in a cradle-to-grave life cycle approach. This included raw material extraction, resin manufacturing, and end-of-life waste management life-cycle stages. The irreversibility during the complete life cycle allows to evaluate the degree of thermodynamic perfection of the production processes and to conduct the assessment of the whole process chain. Overall life cycle exergy efficiency of PP and PVC is quantified 27.1% and 9.3%, respectively, characterized by a low efficiency of manufacturing and recycling processes for both materials. From resource conservation point of view, mechanical recycling has been suggested as the viable option for end-of-life plastic waste management, since it loops materials back directly into new life cycle and reduces primary resource inputs in the production

Fishery-Based Ecotourism in Developing Countries Can Enhance the Social-Ecological Resilience of Coastal Fishers—A Case Study of Bangladesh

The importance of recreational fishing, in many coastal areas and less developed nations, is increasing rapidly. Connecting fisheries to tourism can create innovative tourism products and provide new income sources. The present study is the first to explore the concept of coastal fishery-based ecotourism (FbE) to enhance the social–ecological resilience of coastal fishing communities in a specific tourist spot in Bangladesh. A combination of primary (quantitative and qualitative) and secondary (literature databases) data sources were used in this study. It applied a social–ecological system (SES) and social–ecological resilience (SER) concept to collect quantitative and qualitative data (120 in-depth individual interviews, four focus group discussions, and strengths, weakness, opportunities, and threats-SWOT analyses) and frame their interpretation. The study found that Bangladesh needs to adopt a firm policy to utilize tourism’s potential in national economic development and societal progress. The findings show the considerable potential of the concept that integrates business, education, and an environmental conservation perspective in Bangladesh, specifically for Saint Martin’s Island: 32% of interviewees expressed that increasing employment opportunities and the Gross Domestic Products (GDP) is the primary potential, whereas 31% said it would attract fishing tourists and 23% believed it would develop the local infrastructure and facilities for fishing and tourism. Similarly, most of the respondents (31%) thought that the lack of awareness and promotional activities is the main limitation preventing this initiative from being well accepted. Moreover, based on the findings, specific measures for strengthening the social–ecological resilience of the coastal fishers via FbE at the local level were suggested, including building communal links, developing community infrastructures, revising prevailing rules and regulations, offering alternative means of generating income for fishers during disaster periods, and more active sharing of responsibility between stakeholders and government for the management of FbE. Finally, with its focus on the prospects and challenges of coastal FbE development on Saint Martin’s Island, this article provides a useful reference point for future discourse on similar social and economic strategies. While this study focuses on Bangladesh’s coastal fishing villages, the results are possibly applicable more broadly in similar contexts and developing countries worldwide

Fishery-Based Ecotourism in Developing Countries Can Enhance the Social-Ecological Resilience of Coastal Fishers—A Case Study of Bangladesh

The importance of recreational fishing, in many coastal areas and less developed nations, is increasing rapidly. Connecting fisheries to tourism can create innovative tourism products and provide new income sources. The present study is the first to explore the concept of coastal fishery-based ecotourism (FbE) to enhance the social–ecological resilience of coastal fishing communities in a specific tourist spot in Bangladesh. A combination of primary (quantitative and qualitative) and secondary (literature databases) data sources were used in this study. It applied a social–ecological system (SES) and social–ecological resilience (SER) concept to collect quantitative and qualitative data (120 in-depth individual interviews, four focus group discussions, and strengths, weakness, opportunities, and threats-SWOT analyses) and frame their interpretation. The study found that Bangladesh needs to adopt a firm policy to utilize tourism’s potential in national economic development and societal progress. The findings show the considerable potential of the concept that integrates business, education, and an environmental conservation perspective in Bangladesh, specifically for Saint Martin’s Island: 32% of interviewees expressed that increasing employment opportunities and the Gross Domestic Products (GDP) is the primary potential, whereas 31% said it would attract fishing tourists and 23% believed it would develop the local infrastructure and facilities for fishing and tourism. Similarly, most of the respondents (31%) thought that the lack of awareness and promotional activities is the main limitation preventing this initiative from being well accepted. Moreover, based on the findings, specific measures for strengthening the social–ecological resilience of the coastal fishers via FbE at the local level were suggested, including building communal links, developing community infrastructures, revising prevailing rules and regulations, offering alternative means of generating income for fishers during disaster periods, and more active sharing of responsibility between stakeholders and government for the management of FbE. Finally, with its focus on the prospects and challenges of coastal FbE development on Saint Martin’s Island, this article provides a useful reference point for future discourse on similar social and economic strategies. While this study focuses on Bangladesh’s coastal fishing villages, the results are possibly applicable more broadly in similar contexts and developing countries worldwide

Low-Carbon Energy Technologies: Potentials of Solar and Nuclear Energy Sources for Sustainable Economic Development in Bangladesh

Electricity shortage has become a major challenge to continued economic growth in Bangladesh. The country is growing in terms of GDP growth at a rate of 7% a year. Bangladesh is expected to move towards 23rd position globally by 2050 from its position 31 in 2014, in terms of GDP at purchasing power parity (PPP). The demand for electricity is forecasted to be 61,164 MW within the same period. Currently, electricity generation in Bangladesh is highly dependent on fossil fuels, nearly 59% is produced from natural gas followed by furnace oil, diesel and coal, while only 3% from renewables. Electricity generation is the largest single source of GHG (greenhouse gas) emissions in Bangladesh, and thus finding alternative energy source has become imperative for the country. Solar and nuclear energy sources have the potentials to be utilized for low-carbon energy sector and thus for a sustainable economic development in Bangladesh. Barriers to solar and nuclear energy will be reduced significantly in coming years with technological advancement. However, energy policies need to be revised to facilitate low-carbon energy technologies. Besides, more international collaboration is highly required not only to import new technologies but also to enhance the capacity of research and development (R&D) as well as overall adoption of the technologies

Resource metabolism of the construction sector An application of material and exergy flow analysis

Ésta tesis tiene como objetivo evaluar el consumo de recursos del sector de la construcción, los residuos y las emisiones generadas por el sector. Ésto está motivado por el hecho de que el sector de la construcción es responsable de una gran cantidad de consumo de recursos y representa casi el 9% el valor bruto añadido al producto interno bruto del mundo. La evaluación considera la perspectiva del ciclo de vida, desde la extracción de materias primas, a través de la construcción y fabricación de productos, materiales de transporte, la construcción, la generación de residuos de demolición, el transporte de residuos, el tratamiento y disposición final. El objetivo es identificar las oportunidades y mejorar los criterios de selección de materiales, el procesado, la reutilización y el reciclado para el uso sostenible de los recursos. Debido a la complejidad de los sistemas de edificios e infraestructuras, compuestas de muchos componentes que interactúan, siempre es difícil llevar a cabo una contabilidad de los recursos precisos dentro de éste sector. En esta perspectiva, el concepto de análisis de flujo de materiales y la evaluación del ciclo de vida (ACV), y el análisis de exergía se tratan como herramientas de contabilidad de recursos y se centra en sus aplicaciones en el sector de la construcción. Además del análisis sectorial, ésta tesis, también analiza la eficiencia de los procesos de fabricación y el ciclo de vida completo de los productos con base a exergía. Todos los procesos y los productos seleccionados son relevantes para el sector de la construcción, y éste análisis tiene como objetivo proporcionar conocimientos de despersonalización en el uso de materiales del sector. En el capítulo 1, se expone el marco teórico en que los análisis de flujo de exergía y los materiales se utilizan en la evaluación del metabolismo de los recursos del sector de la construcción, que destacan la importancia de éste sector en términos de flujos de recursos y la generación de residuos y emisiones. Éste capítulo, también introduce la eficiencia exérgica y herramientas de evaluación del ciclo de vida exergéticos, que explica las limitaciones del análisis de la energía y el ACV, y cómo la aplicación de éstos métodos a base de exergía puede ofrecer mejores perspectivas sobre la eficiencia del uso de los recursos en los procesos de fabricación en toda la vida de los productos, respectivamente. La Ecología Industrial, se presenta al introducir el enfoque basado en los sistemas y el marco termodinámico en el que el sector de la construcción se analiza en este estudio. El capítulo 2, presenta los resultados de los análisis de flujo de materiales y exergía del sector de la construcción catalana en el año 2001. En ese momento, Cataluña tenía un adicional de 52 millones de toneladas de existencias de materiales para el sector y generaba 7 millones de toneladas de residuos de construcción y demolición, de los cuales sólo el 6,5% son recicladas o regeneradas. El estudio muestra que la fase de fabricación consume la mayor parte de los recursos de energía durante el ciclo de vida del conjunto de los productos, seguidos de transporte de materiales, que representa el 57% y el 4% del consumo de exergía, respectivamente. Se señala que la mejora en la selección de materiales, tecnologías de fabricación y diseño para el desmontaje, conduce a la sostenibilidad del sector, para conseguir una mejora de la eficiencia del uso de recursos. En el capítulo 3, se menciona el rendimiento exergético de los procesos de producción, tanto en el proceso de producción primaria como secundaria (reciclaje), de los materiales de construcción que se calcula, con el fin de evaluar la calidad de los materiales, las pérdidas de exergía, y el potencial de mejora de procesos. Ésto sirve para cuantificar el potencial de mejora de los procesos de fabricación actuales que abordan las deficiencias de fabricación de los nueve principales materiales de construcción no renovables: aluminio, acero, cobre, cemento, hormigón, cerámica, vidrio, polipropileno y cloruro de polivinilo. La Eficiencia Exergía basada en la segunda ley de la termodinámica es determinada con el fin de comparar la eficiencia exergía teórica y la eficiencia exergía del proceso real. La gran diferencia entre los requisitos teóricos y empíricos de exergía en los procesos de fabricación sugiere que las oportunidades para una mejor utilización de exergía industrial todavía existen, pero requieren un diseño y mejoras en la tecnología. Los resultados demuestran que los recursos se utilizan de manera más eficiente en los procesos de reciclaje, en comparación con los procesos de fabricación primaria. En esta tesis se presenta una teoría (capítulo 4) para determinar como de eficientemente se utilizan los recursos en las aplicaciones de la construcción, utilizando la metodología de análisis del ciclo de vida exergético desde un enfoque universal. Esto incluye la extracción de materias primas, la fabricación de resina y de gestión de las etapas del ciclo de vida de los residuos al final de su vida. La irreversibilidad durante el ciclo de vida completo permite evaluar el grado de perfección termodinámica de los procesos de producción y llevar a cabo la evaluación de la cadena de producción entera. Ciclo de vida global de la eficiencia exérgica de polipropileno y cloruro de polivinilo se cuantifica en 27,1% y 9,3%, respectivamente, que se caracteriza por una baja eficiencia en la fabricación y los procesos de reciclaje para ambos materiales. Desde el punto de vista de la conservación de recursos, el reciclado mecánico se ha sugerido como la opción viable para la gestión de residuos de plástico al final de su vida, ya que los materiales de bucles vuelven a su ciclo de vida original y reduce las aportaciones de recursos primarios en la producción.This thesis aims to assess the resource consumption of the construction sector, and the wastes and emissions generated by the sector. This is motivated by the fact that the construction sector is responsible for large amounts of resource consumption and represents nearly 9% gross value added to the world’s gross domestic product. The assessment considers the life cycle perspective from raw material extraction, through construction product manufacturing, material transport, construction and demolition waste generation, to waste transport, treatment, and final disposal. The aim is to pinpoint the opportunities for improved material selection criteria, processing, reuse, and recycling for sustainable resource use. Due to the system complexity of buildings and infrastructure, composed of many interacting components, it is always challenging to undertake an accurate resource accounting within this sector. In this perspective, the concepts of material flow analysis (MFA), life cycle assessment (LCA), and exergy analysis (ExA) are discussed as resource accounting tools focusing on their applications in the construction sector. Apart from sectoral analysis, this thesis also analyzes the efficiency of manufacturing processes and products’ complete life cycle based on exergy. All the processes and products selected are relevant for the construction sector, and this analysis aims to provide deper insights into sectoral material use. Chapter 1 details the theoretical framework under which exergy and material flow analyses are used in assessing the resource metabolism of the construction sector highlighting the importance of this sector in terms of resource flows, and generation of waste and emissions. This chapter also introduces the exergy efficiency and exergetic life cycle assessment (ELCA) tools, explaining the limitations of energy analysis and LCA, and how the application of these exergy-based methods can provide better insights into resource use efficiency in manufacturing processes and throughout the products’ life, respectively. Industrial ecology (IE) is presented to introduce the systems-based approach and thermodynamic framework on which of the construction sector is analyzed in this study. Chapter 2 presents the results of material and exergy flow analyses of the Catalan construction sector for the year 2001. In 2001, Catalonia had an additional 52 million tonnes of material stock to the sector and generated 7 million tonnes of construction and demolition waste (CDW) of which only 6.5% were recycled or reclaimed. The study shows that manufacturing stage consumes the largest fraction of energy resources during the products’ whole lifecycle followed by material transport, accounting for 57% and 4% of exergy use, respectively. It is pointed out that improvement in material selection, manufacturing technologies, and design for disassembly lead to sustainability of the sector delivering improved resource use efficiency. In chapter 3, the exergetic efficiency of the production processes, both primary and secondary (recycling) production process, of construction materials is calculated in order to assess material quality, exergy losses, and process improvement potentials. This serves to quantify the improvement potentials for present manufacturing processes addressing the manufacturing inefficiencies of nine major non-renewable construction materials: aluminum, steel, copper, cement, concrete, ceramic, glass, polypropylene (PP), and polyvinyl chloride (PVC). Exergy efficiency based on the second law of thermodynamics is determined in order to compare the theoretical exergy efficiency and the real-process exergy efficiency. The large difference between theoretical and empirical exergy requirements in manufacturing processes suggests that opportunities for better industrial exergy utilization still exist but require design and/or technology improvements. The results demonstrate that resources are utilized more efficiently in recycling processes compared to primary manufacturing processes. This thesis has presented an effort (chapter 4) to pinpoint how efficiently resources are used in the construction applications, using exergetic life cycle assessment methodology in a cradle-to-grave life cycle approach. This included raw material extraction, resin manufacturing, and end-of-life waste management life-cycle stages. The irreversibility during the complete life cycle allows to evaluate the degree of thermodynamic perfection of the production processes and to conduct the assessment of the whole process chain. Overall life cycle exergy efficiency of PP and PVC is quantified 27.1% and 9.3%, respectively, characterized by a low efficiency of manufacturing and recycling processes for both materials. From resource conservation point of view, mechanical recycling has been suggested as the viable option for end-of-life plastic waste management, since it loops materials back directly into new life cycle and reduces primary resource inputs in the production

Approximation of the formal Bayesian model comparison using the extended conditional predictive ordinate criterion

The optimal method for Bayesian model comparison is the formal Bayes factor (BF), according to decision theory. The formal BF is computationally troublesome for more complex models. If predictive distributions under the competing models do not have a closed form, a cross-validation idea, called the conditional predictive ordinate (CPO) criterion can be used. In the cross-validation sense, this is a ''leave-out one'' approach. CPO can be calculated directly from the Monte Carlo (MC) outputs, and the resulting Bayesian model comparison is called the pseudo Bayes factor (PBF). We can get closer to the formal Bayesian model comparison by increasing the ''leave-out size'', and at ''leave-out all'' we recover the formal BF. But, the MC error increases with increasing ''leave-out size''. In this study, we examine this for linear and logistic regression models. Our study reveals that the Bayesian model comparison can favour a different model for PBF compared to BF when comparing two close linear models. So, larger ''leave-out sizes'' are preferred which provide result close to the optimal BF. On the other hand, MC samples based formal Bayesian model comparisons are computed with more MC error for increasing ''leave-out sizes''; this is observed by comparing with the available closed form results. Still, considering a reasonable error, we can use ''leave-out size'' more than one instead of fixing it at one. These findings can be extended to logistic models where a closed form solution is unavailable.Science, Faculty ofStatistics, Department ofGraduat

Rapid, low-cost dielectrophoretic diagnosis of bladder cancer in a clinical setting

Bladder cancer is the 9th most common cancer worldwide. Diagnosing bladder cancer typically involves highly invasive cystoscopy, with followup monitored using uteroscopy. Molecular methods have been developed as an adjunct to this, but tend to be expensive or require expert operator input. Here we present a study of the use of dielectrophoresis (DEP) of voided cells from eight cancer-presenting patients and eight healthy controls as an alternative low-cost and operator-independent method of bladder cancer detection. This study suggests that there are statistically significant differences (p=0.034) between characteristics of the DEP spectrum of clinical samples, and that using this marker we were able to obtain sensitivity of 75% and specificity of 87.5%, in line with many molecular methods; exclusion of samples where a DEP spectrum is not present (due to low cell counts) shows this can be improved by increasing the cell collection rate. As samples were analyzed a day after collection, we suggest that the method may be amenable to a centralized mail-in analysis service