http://hdl.handle.net/2099.1/14912 Fri, 24 May 2013 14:23:45 GMT 2013-05-24T14:23:45Z webmaster.bupc@upc.edu Universitat Politècnica de Catalunya. Servei de Biblioteques i Documentació no http://eprints.upc.es:80/pfc/retrieve/149915/moute.JPG http://hdl.handle.net/2099.1/14912 http://hdl.handle.net/2099.1/18110 Title: Analisys and energy saving measures of kastvallen ice hockey rink arena Authors: Igual Bueno, Mario; Bielsa Azcona, José Enrique Abstract: Nowadays efficiency measures are more and more important because the price of the energy is increasing every year. Moreover, saving energy it is also important for decrease the environmental impact. Kastvallen is a hockey arena built in 1997 that cools the hockey rink with electric compressors. The changing rooms are heating by using district heating. Actually the total invoice of electricity is above the 800000 SEK. Meanwhile the district heating invoice reaches the 60000SEK. The aim of this project is reducing the amount of the electricity and heat invoice promoting smart energy improvements. The improvements proposals can be divided in three sections; energy savings of the changing rooms, efficiency increase of the compressors and dehumidifier energy savings. For heat the tap water and the changing room’s ventilation it is suggested to take profit from the heat released at the condenser and so reduce its heat load requirements. For this proposal two different configurations are studied. In order to increase the efficiency of the compressors the possibility of reducing the condenser temperature will be studied. Three proposals will be studied to carry out this commitment; Installing a condensing temperature control, installing a evaporate cooler and having a snow storage. Finally, one of the largest consumers of electricity in Kastvallen ice hockey rink is the dehumidifier. The current dehumidifier works with a desiccant wheel. The desiccant material extract the moisture from the processed air flow, after that the desiccant has to be reactivated with ‘fresh air’. This reactivation air needs to be heated 95ºC, so the waste air released after the reactivation of the desiccant is air at high temperature. The first proposal is preheat the reactivation air with the hot waste air in order to reduce the heating requirements. The second step is studied the possibility of heating the air with district heating, taking into account that district heating is three times cheaper than electricity. The last proposal is to combine preheating and heating with district heating. All the previous energy improvements proposals are studied with empirical and analytical methods and using the knowledge gained during the previous years of studies. The study concludes that the best proposal for the dehumidifier is combine the preheating and heating with district heating. For the refrigeration cycle, the study concludes that installing a controlled temperature control is the best option if the price of that is lower than 334726 SEK. If not the best option is heating the rooms and the ventilation with the condenser of the refrigeration cycle. These measures could reduce between 8% and 20% of the total energy invoice. Evaporative cooling and snow storage would be studying after with the data of the first year of the condensing temperature control; if it is installed. Wed, 08 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18110 2013-05-08T00:00:00Z Igual Bueno, Mario; Bielsa Azcona, José Enrique no Nowadays efficiency measures are more and more important because the price of the energy is increasing every year. Moreover, saving energy it is also important for decrease the environmental impact. Kastvallen is a hockey arena built in 1997 that cools the hockey rink with electric compressors. The changing rooms are heating by using district heating. Actually the total invoice of electricity is above the 800000 SEK. Meanwhile the district heating invoice reaches the 60000SEK. The aim of this project is reducing the amount of the electricity and heat invoice promoting smart energy improvements. The improvements proposals can be divided in three sections; energy savings of the changing rooms, efficiency increase of the compressors and dehumidifier energy savings. For heat the tap water and the changing room’s ventilation it is suggested to take profit from the heat released at the condenser and so reduce its heat load requirements. For this proposal two different configurations are studied. In order to increase the efficiency of the compressors the possibility of reducing the condenser temperature will be studied. Three proposals will be studied to carry out this commitment; Installing a condensing temperature control, installing a evaporate cooler and having a snow storage. Finally, one of the largest consumers of electricity in Kastvallen ice hockey rink is the dehumidifier. The current dehumidifier works with a desiccant wheel. The desiccant material extract the moisture from the processed air flow, after that the desiccant has to be reactivated with ‘fresh air’. This reactivation air needs to be heated 95ºC, so the waste air released after the reactivation of the desiccant is air at high temperature. The first proposal is preheat the reactivation air with the hot waste air in order to reduce the heating requirements. The second step is studied the possibility of heating the air with district heating, taking into account that district heating is three times cheaper than electricity. The last proposal is to combine preheating and heating with district heating. All the previous energy improvements proposals are studied with empirical and analytical methods and using the knowledge gained during the previous years of studies. The study concludes that the best proposal for the dehumidifier is combine the preheating and heating with district heating. For the refrigeration cycle, the study concludes that installing a controlled temperature control is the best option if the price of that is lower than 334726 SEK. If not the best option is heating the rooms and the ventilation with the condenser of the refrigeration cycle. These measures could reduce between 8% and 20% of the total energy invoice. Evaporative cooling and snow storage would be studying after with the data of the first year of the condensing temperature control; if it is installed. http://hdl.handle.net/2099.1/18109 Title: A suitable criterion for tube sizing in reverse cycle machines Authors: Rivero Vilà, Oriol del Abstract: To find the optimal diameters for the connecting tubes in reverse cycle machines we use in this paper a new criterion that we have recently developed, the Ecological Cost, “EC" (Kheiri et al. 2011) EC includes the environmental cost, in CO2 equivalent, of the exergy destroyed by head losses in the tubes and the refrigerant mass GWP (Global Warming Potential) in the same tubes, which is also provided by CO2 equivalent. Leakage effect can also be included in EC. We develop an expression for the optimal tube diameter on this basis. We consider simple cases with no heat exchange and single-phase fluid flows. Wed, 08 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18109 2013-05-08T00:00:00Z Rivero Vilà, Oriol del no To find the optimal diameters for the connecting tubes in reverse cycle machines we use in this paper a new criterion that we have recently developed, the Ecological Cost, “EC" (Kheiri et al. 2011) EC includes the environmental cost, in CO2 equivalent, of the exergy destroyed by head losses in the tubes and the refrigerant mass GWP (Global Warming Potential) in the same tubes, which is also provided by CO2 equivalent. Leakage effect can also be included in EC. We develop an expression for the optimal tube diameter on this basis. We consider simple cases with no heat exchange and single-phase fluid flows. http://hdl.handle.net/2099.1/18108 Title: IIT MMAE Dept. Research project the homogeneous charge thermal ignition (HCTI) engine Authors: Domenech Menal, Joan Ignasi Abstract: Nowadays the main kinds of engines that are used in ground transportation are, gasoline Spark Ignition engines and diesel Compression Ignition engines. As every day more fuel is being used by a growing number of vehicles, fuel dependency growth and a growing concern for our environment health, it is a crucial point to gain in fuel efficiency for ground transportation engines. Many approaches are being investigated, but we will focus in one kind that we call the HCTI, homogeneous charge thermal ignition engine. The goal with this new kind of ignition is to increase engine efficiency both by igniting the mixture using a much bigger surface that a spark plug kernel would be, thus lowering pumping losses, and also by burning leaner mixtures that are thermodynamically more efficient with a reticulated ceramic matrix, something that couldn't be possible with SI because such lean mixtures wouldn't burn with a spark plug. In this paper an SI engine will be monitored and also the same version of the HCTI to try to determine if there are gains in efficiency according to the theory. Wed, 08 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18108 2013-05-08T00:00:00Z Domenech Menal, Joan Ignasi no Nowadays the main kinds of engines that are used in ground transportation are, gasoline Spark Ignition engines and diesel Compression Ignition engines. As every day more fuel is being used by a growing number of vehicles, fuel dependency growth and a growing concern for our environment health, it is a crucial point to gain in fuel efficiency for ground transportation engines. Many approaches are being investigated, but we will focus in one kind that we call the HCTI, homogeneous charge thermal ignition engine. The goal with this new kind of ignition is to increase engine efficiency both by igniting the mixture using a much bigger surface that a spark plug kernel would be, thus lowering pumping losses, and also by burning leaner mixtures that are thermodynamically more efficient with a reticulated ceramic matrix, something that couldn't be possible with SI because such lean mixtures wouldn't burn with a spark plug. In this paper an SI engine will be monitored and also the same version of the HCTI to try to determine if there are gains in efficiency according to the theory. http://hdl.handle.net/2099.1/18107 Title: Design and implementation of an interpolation filter for hearing-aid application Authors: Llimós Muntal, Pere Abstract: Abstract – In this master thesis the design and implementation of an interpolation filter for hearing-aid applications will be discussed. The aim of the design will be to minimize the current consumption, hardware demand and area needed for the implementation of the design. Keywords – Hearing aids, interpolation filter, sigma-delta modulator, D/A converter Hearing aids are devices with very strict specifications. They are attached in its owner’s ear, therefore to make them comfortable they must be small and light. The biggest and heaviest part of a hearing aid is the battery. This means that if a significant reduction of the size and weight of the device wants to be achieved, the battery’s dimensions and in consequence, its capacity, must be reduced. This solution conflicts with the fact that since the user will probably be wearing it all day, the working time per charge should be maximized. The design of the hearing aid will aim at the reduction of hardware demands that will lead to a reduction of current consumption that will allow the battery to be smaller. The D/A converter, which is the back-end stage of the audio processing chain of a hearing aid can be seen in Figure 1. It consists of an interpolation filter, a sigma-delta modulator, a digital pulse width modulation, a class-D output stage, a feedback chain and an output filter. The sigma-delta modulator is an oversampled data converter, so a previous oversampling is needed for its correct operation. This oversampling will be performed by the interpolation filter. This oversampling process will increase the sampling frequency by the oversampling ratio needed for the sigma delta modulator, which will lead to an increase of the band of interest. Since the input of the interpolation filter is discrete, its frequency spectrum will be repeated at every multiple of fs. Those frequency spectrum repetitions or images, will appear in the output band of interest of the filter, therefore they will need to be suppressed by the interpolation filter. The interpolation filter of this design will be separated into four stages as it can be seen in Figure 2. The first stages of the filter will be the sharpest ones, and in consequence the most hardware demanding ones since the will have to attenuate the closest images. The last stages of the filter will attenuate the furthest images, so filters with less hardware requirements will be suitable. This multistage approach will also allows the first stages of the filter to work at lower frequency, since the sampling frequency will be increased step by step. This paper will deal with the design of the first stage of the interpolation filter since it is the most hardware demanding one. An optimized design will be critical regarding the overall hardware savings of the interpolation filter. Wed, 08 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18107 2013-05-08T00:00:00Z Llimós Muntal, Pere no Abstract – In this master thesis the design and implementation of an interpolation filter for hearing-aid applications will be discussed. The aim of the design will be to minimize the current consumption, hardware demand and area needed for the implementation of the design. Keywords – Hearing aids, interpolation filter, sigma-delta modulator, D/A converter Hearing aids are devices with very strict specifications. They are attached in its owner’s ear, therefore to make them comfortable they must be small and light. The biggest and heaviest part of a hearing aid is the battery. This means that if a significant reduction of the size and weight of the device wants to be achieved, the battery’s dimensions and in consequence, its capacity, must be reduced. This solution conflicts with the fact that since the user will probably be wearing it all day, the working time per charge should be maximized. The design of the hearing aid will aim at the reduction of hardware demands that will lead to a reduction of current consumption that will allow the battery to be smaller. The D/A converter, which is the back-end stage of the audio processing chain of a hearing aid can be seen in Figure 1. It consists of an interpolation filter, a sigma-delta modulator, a digital pulse width modulation, a class-D output stage, a feedback chain and an output filter. The sigma-delta modulator is an oversampled data converter, so a previous oversampling is needed for its correct operation. This oversampling will be performed by the interpolation filter. This oversampling process will increase the sampling frequency by the oversampling ratio needed for the sigma delta modulator, which will lead to an increase of the band of interest. Since the input of the interpolation filter is discrete, its frequency spectrum will be repeated at every multiple of fs. Those frequency spectrum repetitions or images, will appear in the output band of interest of the filter, therefore they will need to be suppressed by the interpolation filter. The interpolation filter of this design will be separated into four stages as it can be seen in Figure 2. The first stages of the filter will be the sharpest ones, and in consequence the most hardware demanding ones since the will have to attenuate the closest images. The last stages of the filter will attenuate the furthest images, so filters with less hardware requirements will be suitable. This multistage approach will also allows the first stages of the filter to work at lower frequency, since the sampling frequency will be increased step by step. This paper will deal with the design of the first stage of the interpolation filter since it is the most hardware demanding one. An optimized design will be critical regarding the overall hardware savings of the interpolation filter. http://hdl.handle.net/2099.1/18085 Title: VHDL-AMS modeling and simulation of a PMSM control system for automotive applicartions Authors: López Sanz, Jorge Abstract: The goal of the present thesis is to present a novel alternative for modeling and simulating the controls of the PMSM of a battery electric car using VHDL AMS. With this aim a valid model integrating the mechanics and electronic concepts behind the PMSM and the method to control it were implemented using the mentioned hardware description language. The motor model with its equations related to the d-q reference was choosed in order to apply the effective motor control strategy called Field Oriented Control. Finally the validation with the simulator of the model and its controls was successfully carried out obtaining the desired response and concluding with useful observations not only about the system itself like the importance of the inverter switching frequency for a smooth response but also about the best method to apply for solving the problem optimizing time. Tue, 07 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18085 2013-05-07T00:00:00Z López Sanz, Jorge no The goal of the present thesis is to present a novel alternative for modeling and simulating the controls of the PMSM of a battery electric car using VHDL AMS. With this aim a valid model integrating the mechanics and electronic concepts behind the PMSM and the method to control it were implemented using the mentioned hardware description language. The motor model with its equations related to the d-q reference was choosed in order to apply the effective motor control strategy called Field Oriented Control. Finally the validation with the simulator of the model and its controls was successfully carried out obtaining the desired response and concluding with useful observations not only about the system itself like the importance of the inverter switching frequency for a smooth response but also about the best method to apply for solving the problem optimizing time. http://hdl.handle.net/2099.1/18083 Title: A prefeasibility study of integrating WoodRoll gasification technology into Ovako Steel and HEAB replacing fosssil fuels in Hofors Authors: Moner Lasheras, Alodia Baldesca Abstract: Biomass gasification is considered a key technology in reaching targets for renewable energy and CO2 emissions reduction. This thesis studies the feasibility of a new technology of biomass gasification called WoodRoll for the production of Syngas with the aim to replace fossil fuels in the furnaces of the steel company OVAKO in Hofors. This research attempts to study the techno-economic viability of WoodRoll technology integration with the district heating company HEAB, creating a synergy between the companies and WoodRoll technology. Moreover, a theoretically study of the environmental impact, concerning greenhouse effect and pollutants it is also carried out. In the future scenario HEAB, as an energy supplier will be the gasification plant owner supplying with Syngas 5% cheaper than the fuels that they use today to Ovako. Three different scenarios have been studied varying the capacity of the gasification plant. The scenarios are 5MW, 10MW and 15MW capacity. The study show that the system is technically viable being possible to create a synergy between the three process improving efficiency and decreasing cost and CO2 emissions. The results from the economic study show that biomass gasification using WoodRoll technology is a highly interesting investment option for HEAB. From Ovako side, the project is very interesting too since the company can have a combustible 5% cheaper than the fuels used today without doing any investment. In 5MW scenario, 40GWh per year are converted in Ovako from oil to Syngas. With an investment for HEAB of 9.8 mSEK, profits were a Net Present Value of 6.3mSEK with 7.8 years of payback period. In 10MW scenario 80GWh were replaced. In this scenario, required investment was 146 mSEK with a NPV of 32.5 mSEK . Payback in this case was 6.3 years. The most profitable scenario was the case of 15M. With an investment of 188 mSEK the profits of the project were 60mSEK with a payback period of 5.8 years. In the three cases, especially in 15MW case, sensitivity study of the system show that it is very robust to changes in biomass cost and Syngas price. This parameters have a big impact on the profits but a big margin until becomes unfeasible. From Ovako side, savings for the fuel conversion were 1.2; 2.4 and 3.6mSEK for the 5, 10 and 15MW respectively. Reduction of CO2 emissions was 11, 20 and 30 thousands of CO2 tons for the three scenarios allowing the company to sell CO2 allowances and having an extra profit of 3, 6 and 8mSEK per year in the 5, 10 and 15MW scenario respectively. Tue, 07 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18083 2013-05-07T00:00:00Z Moner Lasheras, Alodia Baldesca no Biomass gasification is considered a key technology in reaching targets for renewable energy and CO2 emissions reduction. This thesis studies the feasibility of a new technology of biomass gasification called WoodRoll for the production of Syngas with the aim to replace fossil fuels in the furnaces of the steel company OVAKO in Hofors. This research attempts to study the techno-economic viability of WoodRoll technology integration with the district heating company HEAB, creating a synergy between the companies and WoodRoll technology. Moreover, a theoretically study of the environmental impact, concerning greenhouse effect and pollutants it is also carried out. In the future scenario HEAB, as an energy supplier will be the gasification plant owner supplying with Syngas 5% cheaper than the fuels that they use today to Ovako. Three different scenarios have been studied varying the capacity of the gasification plant. The scenarios are 5MW, 10MW and 15MW capacity. The study show that the system is technically viable being possible to create a synergy between the three process improving efficiency and decreasing cost and CO2 emissions. The results from the economic study show that biomass gasification using WoodRoll technology is a highly interesting investment option for HEAB. From Ovako side, the project is very interesting too since the company can have a combustible 5% cheaper than the fuels used today without doing any investment. In 5MW scenario, 40GWh per year are converted in Ovako from oil to Syngas. With an investment for HEAB of 9.8 mSEK, profits were a Net Present Value of 6.3mSEK with 7.8 years of payback period. In 10MW scenario 80GWh were replaced. In this scenario, required investment was 146 mSEK with a NPV of 32.5 mSEK . Payback in this case was 6.3 years. The most profitable scenario was the case of 15M. With an investment of 188 mSEK the profits of the project were 60mSEK with a payback period of 5.8 years. In the three cases, especially in 15MW case, sensitivity study of the system show that it is very robust to changes in biomass cost and Syngas price. This parameters have a big impact on the profits but a big margin until becomes unfeasible. From Ovako side, savings for the fuel conversion were 1.2; 2.4 and 3.6mSEK for the 5, 10 and 15MW respectively. Reduction of CO2 emissions was 11, 20 and 30 thousands of CO2 tons for the three scenarios allowing the company to sell CO2 allowances and having an extra profit of 3, 6 and 8mSEK per year in the 5, 10 and 15MW scenario respectively. http://hdl.handle.net/2099.1/18082 Title: Reduced model and inverse methods: Thermal performance of elementary components/ optimal composition materials Authors: Masbernat Megias, Laia Abstract: One of the main goals of the research centre of Lafarge is to establish their innovating materials in the building market of emerging countries. For this purpose, is necessary to study the advantages and added values that these materials can provide to constructions. The objective of this thesis is to create a parametric model which serves to evaluate the contribution of these materials to the dwellings energy performance, specially their impact on building’s thermal inertia. The project has been structured in 4 parts: bibliography, TRNSYS simulation model and study 1 and study 2. The purpose of the bibliography is to understand thermal inertia concept, its contribution to construction materials and its effect on buildings energy performance. The objective of the second part is to describe the process followed to design and validate the parametric model, including the hypotheses done. In Study 1the impact that non load baring walls have on building’s thermal inertia, will be evaluated with the TRNSYS model .The study will be focused in wet hot climates, specifically in Mumbai (India) and Rio de Janeiro (Brazil). Study 2 is a world analysis done with the TRNSYS model to determine in which climates a better energy performance is achieved by using Lafarge’s materials. Tue, 07 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18082 2013-05-07T00:00:00Z Masbernat Megias, Laia no One of the main goals of the research centre of Lafarge is to establish their innovating materials in the building market of emerging countries. For this purpose, is necessary to study the advantages and added values that these materials can provide to constructions. The objective of this thesis is to create a parametric model which serves to evaluate the contribution of these materials to the dwellings energy performance, specially their impact on building’s thermal inertia. The project has been structured in 4 parts: bibliography, TRNSYS simulation model and study 1 and study 2. The purpose of the bibliography is to understand thermal inertia concept, its contribution to construction materials and its effect on buildings energy performance. The objective of the second part is to describe the process followed to design and validate the parametric model, including the hypotheses done. In Study 1the impact that non load baring walls have on building’s thermal inertia, will be evaluated with the TRNSYS model .The study will be focused in wet hot climates, specifically in Mumbai (India) and Rio de Janeiro (Brazil). Study 2 is a world analysis done with the TRNSYS model to determine in which climates a better energy performance is achieved by using Lafarge’s materials. http://hdl.handle.net/2099.1/18075 Title: Détection de synergies industrielles Mise en oeuvre d’une démarche d’écologie industrielle au sein d’une zone d’activité économique Authors: Moreno Mestre, Sindara Abstract: Le but de ce rapport est de montrer le travail effectué pendant les six mois de stage au sein du bureau d’étude Ecores spécialisé dans le conseil en développement durable. La mission s’intègre dans le projet d’écozoning qui consiste à la mise en oeuvre d’une démarche d’écologie industrielle au sein de la zone d’activité économique de Tertre-Hautrage-Villerot située en Région wallonne en Belgique. Le travail se focalise sur la détection de synergies industrielles en termes d’échanges de matières entre les sept entreprises participant au projet : Advachem, Erachem, Euloco, Polyol, Shanks-Hainaut (division Villerot) Belgium, WOS Hautrage et Yara Tertre. La méthodologie utilisée dans la mission est basée sur une approche à la fois scientifique, pragmatique et participative. C’est l’analyse des flux de matières entrants et sortants des entreprises avec l’aide d'outils issus de l’écologie industrielle qui nous a permis de mettre en évidence les synergies potentielles. Le résultat principal de cette étude est l'obtention de plus de quinze synergies potentielles dont certaines seront sélectionnées pour la réalisation d’une étude de faisabilité ultérieure. Enfin, ce stage m'a permis d’approfondir sur le sujet de l'écologie industrielle qui est définitivement une démarche innovante et collaborative d'avenir. Ce travail a été l’occasion d’acquérir non seulement des connaissances théoriques, mais aussi de les mettre en pratique dans des cas réels. Mon, 06 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18075 2013-05-06T00:00:00Z Moreno Mestre, Sindara no Le but de ce rapport est de montrer le travail effectué pendant les six mois de stage au sein du bureau d’étude Ecores spécialisé dans le conseil en développement durable. La mission s’intègre dans le projet d’écozoning qui consiste à la mise en oeuvre d’une démarche d’écologie industrielle au sein de la zone d’activité économique de Tertre-Hautrage-Villerot située en Région wallonne en Belgique. Le travail se focalise sur la détection de synergies industrielles en termes d’échanges de matières entre les sept entreprises participant au projet : Advachem, Erachem, Euloco, Polyol, Shanks-Hainaut (division Villerot) Belgium, WOS Hautrage et Yara Tertre. La méthodologie utilisée dans la mission est basée sur une approche à la fois scientifique, pragmatique et participative. C’est l’analyse des flux de matières entrants et sortants des entreprises avec l’aide d'outils issus de l’écologie industrielle qui nous a permis de mettre en évidence les synergies potentielles. Le résultat principal de cette étude est l'obtention de plus de quinze synergies potentielles dont certaines seront sélectionnées pour la réalisation d’une étude de faisabilité ultérieure. Enfin, ce stage m'a permis d’approfondir sur le sujet de l'écologie industrielle qui est définitivement une démarche innovante et collaborative d'avenir. Ce travail a été l’occasion d’acquérir non seulement des connaissances théoriques, mais aussi de les mettre en pratique dans des cas réels. http://hdl.handle.net/2099.1/18074 Title: Design and implemantation of a resonant gate-drive circuit with capability of high frequency and high efficiency operation Authors: Rius Rueda, Armand Abstract: This document deals with the design and implementation of a resonant gate-drive circuit capable of high frequency and high efficiency operation. This gate-drive circuit is characterized by a resonant inductor connected in series with the gate terminal of a driven MOSFET, forming a series resonant circuit, which enables to charge or discharge the gate to source input capacitance of the transistor with low power consumption. This circuit aims to be applied in high frequency inverters used in power systems for wireless power transmission. More specifically, the first goal is to make a particular transistor switch at 1MHz. The used transistor must be able to conduct a current on the order of 15.5A, and to be biased with 387V. Experimentation is carried out without any power circuit connected to the grate-drive circuit, and shorting the drain and source terminals of the driven MOSFET, obtaining satisfactory results of the switching operation at frequencies above 1MHz. Due to its adequacy with regard to electric vehicle chargers, mentioned wireless power transmission systems consist in magnetic resonance coupling. In this type of circuits, achieving size and weight reductions require high frequency operation, and that is the reason why the Industry-Science-Medical (ISM) frequency band is one of the candidates for this application, in terms of respecting the Standard and improving the size and weight of the circuits. Hence, the final goal of these wireless EV chargers is to operate at a frequency of 13.56MHz. Using conventional silicon power transistors with a large input capacitance makes difficult achieving that frequency operation, especially when dealing with several kilowatts of power. However, certain frequency multiplying circuits have the capability of achieve high frequencies at the output thanks to an operation combining a multi-phase inverter and a multi-core transformer. The number of phases is equal to the factor of multiplication, so that a frequency of 13.56MHz could be achieved, for example, using five phases and an input frequency of 2.712MHz. Accordingly, this document also includes considerations about how to reduce the power consumption and how to reach a correct switching operation at a frequency of 2.712MHz Mon, 06 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18074 2013-05-06T00:00:00Z Rius Rueda, Armand no This document deals with the design and implementation of a resonant gate-drive circuit capable of high frequency and high efficiency operation. This gate-drive circuit is characterized by a resonant inductor connected in series with the gate terminal of a driven MOSFET, forming a series resonant circuit, which enables to charge or discharge the gate to source input capacitance of the transistor with low power consumption. This circuit aims to be applied in high frequency inverters used in power systems for wireless power transmission. More specifically, the first goal is to make a particular transistor switch at 1MHz. The used transistor must be able to conduct a current on the order of 15.5A, and to be biased with 387V. Experimentation is carried out without any power circuit connected to the grate-drive circuit, and shorting the drain and source terminals of the driven MOSFET, obtaining satisfactory results of the switching operation at frequencies above 1MHz. Due to its adequacy with regard to electric vehicle chargers, mentioned wireless power transmission systems consist in magnetic resonance coupling. In this type of circuits, achieving size and weight reductions require high frequency operation, and that is the reason why the Industry-Science-Medical (ISM) frequency band is one of the candidates for this application, in terms of respecting the Standard and improving the size and weight of the circuits. Hence, the final goal of these wireless EV chargers is to operate at a frequency of 13.56MHz. Using conventional silicon power transistors with a large input capacitance makes difficult achieving that frequency operation, especially when dealing with several kilowatts of power. However, certain frequency multiplying circuits have the capability of achieve high frequencies at the output thanks to an operation combining a multi-phase inverter and a multi-core transformer. The number of phases is equal to the factor of multiplication, so that a frequency of 13.56MHz could be achieved, for example, using five phases and an input frequency of 2.712MHz. Accordingly, this document also includes considerations about how to reduce the power consumption and how to reach a correct switching operation at a frequency of 2.712MHz http://hdl.handle.net/2099.1/18068 Title: The impact of Cloud Computing adoption on IT Service Accounting approaches – A Customer Perspective on IaaS Pricing Models Authors: Cots Salleras, Gerard Abstract: Cloud computing has been recently a trending topic beyond the technological field, due to its implementation and expansion thanks to the internet revolution. Although it has reached end-users’ hands during the past two years, the technology has been used for a longer period in the business world. In a scenario where cost-cutting strategies and start-up companies seem to have an increasing importance in global economy, cloud computing has been one of the pillars of many business’ success in recent times. Companies like Netflix, Instagram or Spotify are recent examples of how an enterprise can grow spectacularly quick and become a market-leader basing its business activity on the cloud technology. This master thesis tries to explain how companies should behave when acquiring a cloud service. Due to the wideness of the cloud market, the specific focus of the work is infrastructure as a service, and pay-as-you-go model was chosen for the study due to the novelty it introduces in the information technology market. Apart from technical details, the economic point of view of cloud computing has also been researched, as not only providers care about how their service have to be priced, but also companies want to predict the expenditure to make in their brand new information service. Through the pages of the work, the predecessors of cloud computing are presented as well as the theories appeared to explain its costs and accounting aspects, to finally explain how cloud computing changed the role. After a brief introduction to cloud computing and its different service models, a market analysis of different providers is performed, to extract the patterns and peculiarities of the actual situation of cloudmarket. Transferring the knowledge obtained in the market analysis, an accounting model is developed, based on costs categories and factors and a metering framework. Finally, a case study is performed applying the model to the market situation extracted from the market analysis. Fri, 03 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18068 2013-05-03T00:00:00Z Cots Salleras, Gerard no Cloud computing has been recently a trending topic beyond the technological field, due to its implementation and expansion thanks to the internet revolution. Although it has reached end-users’ hands during the past two years, the technology has been used for a longer period in the business world. In a scenario where cost-cutting strategies and start-up companies seem to have an increasing importance in global economy, cloud computing has been one of the pillars of many business’ success in recent times. Companies like Netflix, Instagram or Spotify are recent examples of how an enterprise can grow spectacularly quick and become a market-leader basing its business activity on the cloud technology. This master thesis tries to explain how companies should behave when acquiring a cloud service. Due to the wideness of the cloud market, the specific focus of the work is infrastructure as a service, and pay-as-you-go model was chosen for the study due to the novelty it introduces in the information technology market. Apart from technical details, the economic point of view of cloud computing has also been researched, as not only providers care about how their service have to be priced, but also companies want to predict the expenditure to make in their brand new information service. Through the pages of the work, the predecessors of cloud computing are presented as well as the theories appeared to explain its costs and accounting aspects, to finally explain how cloud computing changed the role. After a brief introduction to cloud computing and its different service models, a market analysis of different providers is performed, to extract the patterns and peculiarities of the actual situation of cloudmarket. Transferring the knowledge obtained in the market analysis, an accounting model is developed, based on costs categories and factors and a metering framework. Finally, a case study is performed applying the model to the market situation extracted from the market analysis. http://hdl.handle.net/2099.1/18067 Title: Analysis of the treatment of pain and anxiety in the anesthesia care in an ERCP: Process Mining application in Heath Care Authors: Carbonell Gutiérrez, Arnau Abstract: Healthcare is seen as an essential matter in developed societies, and providing patients with an outstanding quality service has been the main core objective of healthcare organizations for decades. However, the use of the very best and new techniques to provide this high quality service made the cost of the patient’s cares dramatically increase. Nonetheless, this tendency is starting to change due to, among other factors, the recent push for healthcare changes that governments and health insurance companies are introducing. This is the reason why medical institutions have lately been facing huge pressure in order to streamline their resources, so they can be able to care for more patients, attending the increasing demand for healthcare, and reduce costs while still delivering a high quality service [Anyanwu et al., 2003; Mans et al., 2009]. High amounts of data are stored in these organizations, normally for financial administration. However, until recently they were barely used to optimize the processes. This is why the medical environment is told to be “Information Rich and Knowledge Poor” [Kaur and Wasan, 2006]. A study from the Institute of Medicine (IOM) of the National Academies stated that there is a real lack of progress in the use of Information Technology (IT) to improve administrative and clinical processes. However, this scenario is starting to change with the extended use of Information Systems in modern organizations, as well as hospitals. One of the different ways hospitals can optimize their processes is by using this valuable data in order to create standardized procedures or paths via process modeling. Normally, care paths are based on the expertise of the doctors, but finding the correct model to predict the way a doctor will react to specific cases would be outstanding. We want to discover the best outcome; however, this does not mean that it has to be the most dominant. By having standardized processes, every patient will no longer be seen as a completely different and unique case. Patients with common characteristics can be cared for in a similar way. The procedures in an operation room, even though they may vary, can be seen as more uniform and process oriented than other healthcare techniques. Achieving these standardized paths is not a trivial issue. First, one will have to decide which specific techniques to apply. Healthcare processes have to deal with an extraordinary uncertainty and healthcare organizations, because of their processes, are seen as highly dynamic, complex, ad hoc, and multi-­‐disciplinary [Rebuge & Ferreira, 2012]. That is why mining techniques will be the best option. However, these techniques are usually not meant for the medical environment, they are more likely to be used in business processes, so searching for the most suitable procedure will be key. To carry out the study, two databases of the anesthesia care of ERCP (Endoscopic Retrograde Cholangio Pancreatography) will be used. The Beth Israel Deaconess Medical Centre in Boston will provide both datasets. First, we started the study with a small dataset of 33 patients, while we were waiting for the large dataset, which contained 848 patients.Many different paths can be found using process mining techniques. Usually, to make business decisions while mining, the decision is based in the cost influence, the revenue and the operational efficiency maintaining the level of care [Silver et al, 2001]. Nevertheless, in this study, the most prominent factor will be to find a standard path, so the variance should be reduced as much as possible. Searching for a standardized path does not mean that we are searching for the dominant one, but the goal will be to discover the best outcome for each situation. If a path has got a high variance, it will probably not be worth to implement it due to inefficiency and higher costs. Applying pre-­‐processing techniques such as clustering can reduce some of the variability. Other factors to take into account are the simplicity of the path, the medical correctness and the reduction of the risk for the patient. Nonetheless, the main problem we will face is to find models that are medically correct. Previous studies failed to achieve these good models while applying process mining techniques to describe process models related to healthcare. Hence, the challenge of this study is to demonstrate that these medical processes can be analyzed after process mining techniques are applied to a dataset. Fri, 03 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18067 2013-05-03T00:00:00Z Carbonell Gutiérrez, Arnau no Healthcare is seen as an essential matter in developed societies, and providing patients with an outstanding quality service has been the main core objective of healthcare organizations for decades. However, the use of the very best and new techniques to provide this high quality service made the cost of the patient’s cares dramatically increase. Nonetheless, this tendency is starting to change due to, among other factors, the recent push for healthcare changes that governments and health insurance companies are introducing. This is the reason why medical institutions have lately been facing huge pressure in order to streamline their resources, so they can be able to care for more patients, attending the increasing demand for healthcare, and reduce costs while still delivering a high quality service [Anyanwu et al., 2003; Mans et al., 2009]. High amounts of data are stored in these organizations, normally for financial administration. However, until recently they were barely used to optimize the processes. This is why the medical environment is told to be “Information Rich and Knowledge Poor” [Kaur and Wasan, 2006]. A study from the Institute of Medicine (IOM) of the National Academies stated that there is a real lack of progress in the use of Information Technology (IT) to improve administrative and clinical processes. However, this scenario is starting to change with the extended use of Information Systems in modern organizations, as well as hospitals. One of the different ways hospitals can optimize their processes is by using this valuable data in order to create standardized procedures or paths via process modeling. Normally, care paths are based on the expertise of the doctors, but finding the correct model to predict the way a doctor will react to specific cases would be outstanding. We want to discover the best outcome; however, this does not mean that it has to be the most dominant. By having standardized processes, every patient will no longer be seen as a completely different and unique case. Patients with common characteristics can be cared for in a similar way. The procedures in an operation room, even though they may vary, can be seen as more uniform and process oriented than other healthcare techniques. Achieving these standardized paths is not a trivial issue. First, one will have to decide which specific techniques to apply. Healthcare processes have to deal with an extraordinary uncertainty and healthcare organizations, because of their processes, are seen as highly dynamic, complex, ad hoc, and multi-­‐disciplinary [Rebuge & Ferreira, 2012]. That is why mining techniques will be the best option. However, these techniques are usually not meant for the medical environment, they are more likely to be used in business processes, so searching for the most suitable procedure will be key. To carry out the study, two databases of the anesthesia care of ERCP (Endoscopic Retrograde Cholangio Pancreatography) will be used. The Beth Israel Deaconess Medical Centre in Boston will provide both datasets. First, we started the study with a small dataset of 33 patients, while we were waiting for the large dataset, which contained 848 patients.Many different paths can be found using process mining techniques. Usually, to make business decisions while mining, the decision is based in the cost influence, the revenue and the operational efficiency maintaining the level of care [Silver et al, 2001]. Nevertheless, in this study, the most prominent factor will be to find a standard path, so the variance should be reduced as much as possible. Searching for a standardized path does not mean that we are searching for the dominant one, but the goal will be to discover the best outcome for each situation. If a path has got a high variance, it will probably not be worth to implement it due to inefficiency and higher costs. Applying pre-­‐processing techniques such as clustering can reduce some of the variability. Other factors to take into account are the simplicity of the path, the medical correctness and the reduction of the risk for the patient. Nonetheless, the main problem we will face is to find models that are medically correct. Previous studies failed to achieve these good models while applying process mining techniques to describe process models related to healthcare. Hence, the challenge of this study is to demonstrate that these medical processes can be analyzed after process mining techniques are applied to a dataset. http://hdl.handle.net/2099.1/18065 Title: Mechanical Response of the Endothelial Glycocalyx to Pulsatile Flow Authors: Perdigó Oliveras, Arnau Abstract: The endothelial glycocalyx is a thin layer lining the internal wall of all blood vessels. It is in the arteries wall where cholesterol and other fatty materials can accumulate eventually obstructing the blood flow and causing atherosclerosis and other vascular diseases to occur. Although the correlation between regions of this arterial disease and areas with low and disturbed wall shear stress has been established, its patterns still do not match. The glycocalyx is considered to be responsible for the transduction of the fluid-induced shear stress to biomechanical forces in the endothelium. A mechanical model of the glycocalyx as a dense matt of regularly distributed stiff rods attached to the endothelial cell membrane and subject to the wall shear stress and drag forces has been developed to study how blood flow forces are actually ‘felt’ by the arterial wall. It is found that for oscillating forces with high amplitude, compared to its average value, the frequency of the applied force is a key factor to determine the actual pulling force transferred through the fibres of the glycocalyx to the endothelium. However, the post-processing of simulated wall shear stress in a rabbit’s descending thoracic aorta with the developed mechanical model has not revealed major changes in the transduced force pattern. Fri, 03 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18065 2013-05-03T00:00:00Z Perdigó Oliveras, Arnau no The endothelial glycocalyx is a thin layer lining the internal wall of all blood vessels. It is in the arteries wall where cholesterol and other fatty materials can accumulate eventually obstructing the blood flow and causing atherosclerosis and other vascular diseases to occur. Although the correlation between regions of this arterial disease and areas with low and disturbed wall shear stress has been established, its patterns still do not match. The glycocalyx is considered to be responsible for the transduction of the fluid-induced shear stress to biomechanical forces in the endothelium. A mechanical model of the glycocalyx as a dense matt of regularly distributed stiff rods attached to the endothelial cell membrane and subject to the wall shear stress and drag forces has been developed to study how blood flow forces are actually ‘felt’ by the arterial wall. It is found that for oscillating forces with high amplitude, compared to its average value, the frequency of the applied force is a key factor to determine the actual pulling force transferred through the fibres of the glycocalyx to the endothelium. However, the post-processing of simulated wall shear stress in a rabbit’s descending thoracic aorta with the developed mechanical model has not revealed major changes in the transduced force pattern. http://hdl.handle.net/2099.1/18064 Title: Influence du soudage sur la fragilisation des aciers et leur tenue à la corrosion sous contrainte Authors: Martínez Pérez, Carlos Abstract: Ce projet est proposé par l’entreprise TOTAL qui veut étudier le comportement mécanique de l’acier pour pouvoir estimer la durée de vie des pipes et déterminer la fréquence de leur maintenance. L’objectif immédiat est la mise en place et la validation d’une procédure de caractérisation et d’essais. Le traitement du plan d’expérience établi permet d’évaluer l’influence de la méthode de polissage sur le niveau de contraintes d’une éprouvette. La manière dont évoluent les contraintes d’une éprouvette lorsqu’un chargement mécanique lui est appliqué a été analysée. MOTS CLES : Acier ferritique / Contraintes résiduelles / Corrosion sous contrainte / Essai de flexion / Diffraction des rayons X Fri, 03 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18064 2013-05-03T00:00:00Z Martínez Pérez, Carlos no Ce projet est proposé par l’entreprise TOTAL qui veut étudier le comportement mécanique de l’acier pour pouvoir estimer la durée de vie des pipes et déterminer la fréquence de leur maintenance. L’objectif immédiat est la mise en place et la validation d’une procédure de caractérisation et d’essais. Le traitement du plan d’expérience établi permet d’évaluer l’influence de la méthode de polissage sur le niveau de contraintes d’une éprouvette. La manière dont évoluent les contraintes d’une éprouvette lorsqu’un chargement mécanique lui est appliqué a été analysée. MOTS CLES : Acier ferritique / Contraintes résiduelles / Corrosion sous contrainte / Essai de flexion / Diffraction des rayons X http://hdl.handle.net/2099.1/18063 Title: Safety aspects of Ceramic Fully Encapsulated fuel for Light Water Reactors Authors: Díez Fernández, Guillermo Abstract: Japan’s nuclear disaster has highlighted important inherent weaknesses regarding to the nuclear fuel behavior after shutdown in Light Water Reactors. The low thermal conductivity and the low fission products retention capacity of oxide fuel, combined with important amounts of zirconium in the clad, lead to an uncontrollably soon fuel failure after losing the coolant inside the core. The purpose of this thesis is to study the feasibility of replacing current oxide fuel used in Light Water Reactor with an alternative fuel that performs a better behavior under these accident conditions. The alternative fuel studied is the Fully Ceramic Micro-encapsulated (FCM) fuel based on the TRISO particles technology, which enhances safety after a loss-of-coolant accident because of its better thermal conductivity and fission products retention capability. The aim of the project is to compare the neutronics behavior and safety parameters between the current 17x17 Westinghouse fuel assembly and a new fuel assembly model, designed to replace the original but using FCM fuel. The analyses have been done using the SERPENT code, based in the Monte Carlo probabilistic methodology. The thesis is mainly divided in three stages. The first part involves the design of the fuel assembly models desired to benchmark, with especial attention to the description of the FCM fuel configuration, result of a compatibility study with the original. The second part is addressed to obtain all the simulation parameters decided to use for the following calculations. The last part is focused on analyzing the results obtained from these simulations, especially comparing the safety parameters between both fuel configurations. The final results show a better behavior of FCM fuel regarding to the neutronics under accident conditions. However, temperature feedbacks tend to be more positive with the new fuel, especially at the end of the cycle and with a significant concentration of boron in the water. Fri, 03 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18063 2013-05-03T00:00:00Z Díez Fernández, Guillermo no Japan’s nuclear disaster has highlighted important inherent weaknesses regarding to the nuclear fuel behavior after shutdown in Light Water Reactors. The low thermal conductivity and the low fission products retention capacity of oxide fuel, combined with important amounts of zirconium in the clad, lead to an uncontrollably soon fuel failure after losing the coolant inside the core. The purpose of this thesis is to study the feasibility of replacing current oxide fuel used in Light Water Reactor with an alternative fuel that performs a better behavior under these accident conditions. The alternative fuel studied is the Fully Ceramic Micro-encapsulated (FCM) fuel based on the TRISO particles technology, which enhances safety after a loss-of-coolant accident because of its better thermal conductivity and fission products retention capability. The aim of the project is to compare the neutronics behavior and safety parameters between the current 17x17 Westinghouse fuel assembly and a new fuel assembly model, designed to replace the original but using FCM fuel. The analyses have been done using the SERPENT code, based in the Monte Carlo probabilistic methodology. The thesis is mainly divided in three stages. The first part involves the design of the fuel assembly models desired to benchmark, with especial attention to the description of the FCM fuel configuration, result of a compatibility study with the original. The second part is addressed to obtain all the simulation parameters decided to use for the following calculations. The last part is focused on analyzing the results obtained from these simulations, especially comparing the safety parameters between both fuel configurations. The final results show a better behavior of FCM fuel regarding to the neutronics under accident conditions. However, temperature feedbacks tend to be more positive with the new fuel, especially at the end of the cycle and with a significant concentration of boron in the water. http://hdl.handle.net/2099.1/18062 Title: Torque split between left and right drive shaft over a front wheel drive differential Authors: Ollé Bernades, Marc Abstract: Steering feel and vehicle steering motion is affected by wheel torques from propulsion, especially for front wheel drive cars. Often these problems are referred to as “torque steer”. Many systems interact to cause these problems: propulsion, steering and suspension. Torque steer contributors are not only the differential (friction, self locking effect, Torsen differential), but also the input from the ground and car geometry such as road conditions (friction and surface), the vehicle state (cornering, rolling, acceleration) and weight distribution (loading). In addition, the suspension design contributes as well, like the suspension geometry (kingpin offset, camber, caster, tolerances), the tire quality (conicity, wear, profile) and wheel geometry (size, uniformity, wheel offset). Finally, regarding the transmission contributors, the engine (torque, alignment) and drive shafts (alignment, length, symmetry) are contributors as well. Particularly, within the propulsion system, it is partly the asymmetry in differential and drive-shafts that could cause torque steer. In fact, the friction of the gear meshing and bearings, and mainly the contact with the housing (carrier) during slippery and static conditions or the housing stiffness itself might be causes of this torque steer problem. Hence, the losses over the differential can explain the torque steer effect due to the torque difference between left and right driveshaft. This fact affects the behaviour of the vehicle. This is the reason why Volvo Cars Corporation (VCC) is interested in studying the friction in a differential to use it in further simulations (vehicle dynamics purposes) or understand which parts of the design may be modified or changed in order to reduce or increase (depending on the goal, either getting as close as possible an open or a limited slip differential behaviour) the overall friction. The motivation of the thesis work comes from this problem. The thesis derives a model for an open differential in order to qualify and quantify the difference of torque between left and right side. In addition, to be able to test the differential, a rig is designed and machined outhouse. Moreover, during testing the model is updated and the parameters are changed according to the statistic experiment plan and the results from the FEM analysis carried out. Finally, not only all the conclusions and results are written down, but also some vehicle dynamics simulations to show the effect of the differential in the behaviour of the car. Fri, 03 May 2013 00:00:00 GMT http://hdl.handle.net/2099.1/18062 2013-05-03T00:00:00Z Ollé Bernades, Marc no Steering feel and vehicle steering motion is affected by wheel torques from propulsion, especially for front wheel drive cars. Often these problems are referred to as “torque steer”. Many systems interact to cause these problems: propulsion, steering and suspension. Torque steer contributors are not only the differential (friction, self locking effect, Torsen differential), but also the input from the ground and car geometry such as road conditions (friction and surface), the vehicle state (cornering, rolling, acceleration) and weight distribution (loading). In addition, the suspension design contributes as well, like the suspension geometry (kingpin offset, camber, caster, tolerances), the tire quality (conicity, wear, profile) and wheel geometry (size, uniformity, wheel offset). Finally, regarding the transmission contributors, the engine (torque, alignment) and drive shafts (alignment, length, symmetry) are contributors as well. Particularly, within the propulsion system, it is partly the asymmetry in differential and drive-shafts that could cause torque steer. In fact, the friction of the gear meshing and bearings, and mainly the contact with the housing (carrier) during slippery and static conditions or the housing stiffness itself might be causes of this torque steer problem. Hence, the losses over the differential can explain the torque steer effect due to the torque difference between left and right driveshaft. This fact affects the behaviour of the vehicle. This is the reason why Volvo Cars Corporation (VCC) is interested in studying the friction in a differential to use it in further simulations (vehicle dynamics purposes) or understand which parts of the design may be modified or changed in order to reduce or increase (depending on the goal, either getting as close as possible an open or a limited slip differential behaviour) the overall friction. The motivation of the thesis work comes from this problem. The thesis derives a model for an open differential in order to qualify and quantify the difference of torque between left and right side. In addition, to be able to test the differential, a rig is designed and machined outhouse. Moreover, during testing the model is updated and the parameters are changed according to the statistic experiment plan and the results from the FEM analysis carried out. Finally, not only all the conclusions and results are written down, but also some vehicle dynamics simulations to show the effect of the differential in the behaviour of the car.