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Obtaining cell concentration measurements from a culture assay by using bioimpedance is a very useful method that can be used to translate impedances to cell concentration values. The purpose of this study was to find a method to obtain the cell concentration values of a given cell culture assay in real time by using an oscillator as the measurement circuit. From a basic cell–electrode model, enhanced models of a cell culture immersed in a saline solution (culture medium) were derived. These models were used as part of a fitting routine to estimate the cell concentration in a cell culture in real time by using the oscillation frequency and amplitude delivered by the measurement circuits proposed by previous authors. Using real experimental data (the frequency and amplitude of oscillations) that were obtained by connecting the cell culture to an oscillator as the load, the fitting routine was simulated, and real-time data of the cell concentration were obtained. These results were compared to concentration data that were obtained by using traditional optical methods for counting. In addition, the error that we obtained was divided and analyzed in two parts: the first part of the experiment (when the few cells were adapting to the culture medium) and the second part of the experiment (when the cells exponentially grew until they completely covered the well). Low error values were obtained during the growth phase of the cell culture (the relevant phase); therefore, the results obtained were considered promising and show that the fitting routine is valid and that the cell concentration can be measured in real time by using an oscillator.

Heart failure (HF) is a severe disease and one of the most important causes of death in our society nowadays. A significant percentage of patients hospitalized for decompensation of heart failure are readmitted after some weeks or months due to an expected bad and uncontrolled HF evolution due to the lack of the patient supervision in real time. Herein is presented a straightforward electric model useful for volume leg section calculus based on the bioimpedance test as a way to assist with the acute HF patient’s supervision. The method has been developed for time-evolution edema evaluation in patients’ corresponding legs. The data are picked up with a wearable device specifically developed for acute heart failure patients. As an initial step, a calibration method is proposed to extract the extracellular volume component from bioimpedance measurements done in healthy subjects, and then applied to unhealthy ones. The intra- and extracellular resistance components are calculated from fitted Cole–Cole model parameters derived from BI spectroscopy measurements. Results obtained in a pilot assay, with healthy subjects and heart failure subjects, show sensitivities in leg volume [mL/Ω], with much lower values for healthy than in unhealthy people, being an excellent biomarker to discriminate between both. Finally, circadian cycle evolution for leg volume has been measured from the bioimpedance test as an extension of the work, enabling an alternative parameter for the characterization of one day of human activity for any person. Ministerio de Ciencia, Innovación y Universidades DTS19/00134, DTS19/00137 Plan Andaluz de Investigación, Desarrollo e Innovación AT21-00010-USE

This article determines the internal parameters of a battery analyzed from its circuit equivalent, reviewing important information that can help to identify the battery’s state of charge (SOC) and its state of health (SOH). Although models that allow the dynamics of different types of batteries to be identified have been developed, few have defined the lead-acid battery model from the analysis of a filtered signal by applying a Kalman filter, particularly taking into account the measurement of noise not just at signal output but also at its input (this is a novelty raised from the experimental). This study proposes a model for lead-acid batteries using tools such as MATLAB® and Simulink®. First, a method of filtering the input and output signal is presented, and then a method for identifying parameters from 29 charge states is used for a leadacid battery. Different SOCs are related to different values of open circuit voltage (OCV). Ultimately, improvements in model estimation are shown using a filter that considers system and sensor noise since the modeled and filtered signal is closer to the original signal than the unfiltered modeled signal.

Els currículums de Ciències assenyalen la rellevància de comprendre els fenòmens elèctrics, a causa de les múltiples aplicacions tecnològiques actuals basades en l'electricitat. No obstant això, els estudiants tenen dificultats per comprendre la naturalesa electromagnètica de la matèria, i es requereixen evidències empíriques de les formes en què les idees dels estudiants es van transformant a mesura que adquireixen experiència i coneixement conceptual sobre electricitat. Aquest estudi es focalitza en l'anàlisi de les explicacions d'estudiants de secundària sobre fenòmens elèctrics, amb el propòsit de caracteritzar l'evolució dels seus models expressats durant una seqüència didàctica basada en fenòmens d'electrització. La proposta d'anàlisi qualitativa, des d'una perspectiva sistèmica, identifica els components d'estructura, procés i control referits pels 30 estudiants de la mostra, en les explicacions de cinc fenòmens observats, caracteritzant l'evolució del model elèctric dels estudiants. Els nostres resultats mostren que les trajectòries d'aprenentatge dels estudiants són poc convergents i presenten discontinuïtats. La descomposició del model elèctric ens ha permès evidenciar que els estudiants construeixen models limitats pels processos observats, i tenen dificultats per transitar al nivell microscòpic, el que pot contribuir a orientar la selecció de fenòmens per part dels professors per aconseguir processos de modelització més efectius. Science curricula indicate the relevance of understanding electrical phenomena, due to the multiple current technological applications based on electricity. However, students have difficulty understanding the electromagnetic nature of matter, and empirical evidence is required of the ways in which students' ideas are transformed as they gain experience and conceptual knowledge about electricity. This study focuses on the analysis of secondary school students' explanations of electrical phenomena, with the purpose of characterizing the evolution of their models expressed during a didactic sequence based on electrification phenomena. The proposal of qualitative analysis, from a systemic perspective, identifies the structure, process and control components referred by the 30 students of the sample, in the explanations of five observed phenomena, characterizing the evolution of students' electrical model. Our results show that the learning trajectories of students are not convergent and present discontinuities. The decomposition of the electrical model has allowed us to show that students build models limited by the observed processes, and have difficulties to move to the microscopic level, which can help to guide the selection of phenomena by teachers to achieve more effective modeling processes. Los currículos de Ciencias señalan la relevancia de comprender los fenómenos eléctricos, debido a las múltiples aplicaciones tecnológicas actuales basadas en la electricidad. Sin embargo, los estudiantes tienen dificultades para comprender la naturaleza electromagnética de la materia, y se requieren evidencias empíricas de las formas en que sus ideas se van transformando a medida que adquieren experiencia y conocimiento conceptual sobre electricidad. Este estudio se focaliza en el análisis de las explicaciones de estudiantes de secundaria sobre fenómenos eléctricos, con el propósito de caracterizar la evolución de sus modelos expresados durante una secuencia didáctica basada en fenómenos de electrización. La propuesta de análisis cualitativo, desde una perspectiva sistémica, identifica los componentes de estructura, proceso y control referidos por 30 estudiantes, en las explicaciones de cinco fenómenos observados, caracterizando la evolución del modelo eléctrico de los estudiantes. Nuestros resultados muestran que las trayectorias de aprendizaje son poco convergentes y presentan discontinuidades. La descomposición del modelo eléctrico nos ha permitido evidenciar que los estudiantes construyen modelos limitados por los procesos observados, y tienen dificultades para transitar al nivel microscópico, lo que puede contribuir a orientar la selección de fenómenos por parte de los profesores para lograr procesos de modelización más efectivos.

The electrification of the transportation is one of the relevant solutions to reduce greenhouse gas emissions. Indeed, new European standards impose increasingly restrictive limits on CO2 emissions per km. This is an important industrial issue for automobile manufacturers. Therefore, the industries are moving towards hybrid and electric vehicles in which an electric traction chain is present. This consists of an electrical machine, powered by a static power electronic converter connected to an electrical energy source and storage elements. For more than two decades, different topologies have been studied for electric traction and several solutions have been marketed. These products are increasingly light, reliable and efficient while respecting the constraints of the automobile manufacturers on the costs. This thesis focuses on improving the reliability of electromechanical energy conversion chains. The objective of the thesis is to continue the development of new actuator control laws ensuring better reliability of the traction chain. With this in mind, reducing the number of sensors in control of the conversion chain will be considered. In fact, there are already current sensors in traction chains. However, these generate significant additional costs because of their frequent failures and the need for replacement. Thus, current sensorless control of the AC drive systems allows the elimination of the sensors of the stator of the machine and therefore to avoid their cost. In this thesis, the model-free adaptive controller (MFAC) is presented to be used in the control of the conversion chain to reduce the number of sensors. In this regard, MFAC is used in two different approaches. First, it is used for controlling a WRSM system, with and without additional current sensors. Then, it is used for the control of the power converters used in the conversion chain. The experimental results, obtained on a test bench built in the laboratory, are conclusive in transient and steady-state: the unmeasured currents are converged with a satisfying precision for an automotive application and allow performing a current sensorless control of the machine. In addition, a satisfactory performance of MFAC is also obtained for controlling the power converters with only using one voltage sensor.; L’électrification des moyens de transport est considérée comme l’une des solutions pertinentes pour réduire les émissions des gaz à effet de serre. En effet, les nouvelles normes européennes imposent des limites de plus en plus restrictives sur les émissions de CO2 par km. Ceci est un enjeu industriel important pour les constructeurs d’automobiles. Par conséquent, ces derniers s’orientent vers les véhicules hybrides et électriques dans lesquels une chaine de traction électrique est présente. Celle-ci est constituée d’une machine électrique, alimentée par un convertisseur statique d’électronique de puissance connecté à une source d’énergie électrique et des éléments de stockage. Depuis plus de deux décennies, différentes topologies ont été étudiées pour la traction électrique et plusieurs solutions ont été commercialisées. Ces produits sont de plus en plus légers, fiables et efficaces tout en respectant les contraintes des constructeurs d’automobile sur les coûts. Cette thèse s’inscrit sur l’amélioration de la fiabilité des chaînes de conversion d’énergie électromécanique. Le travail de thèse a pour objectif de poursuivre le développement de nouvelles lois de commande d’actionneur assurant une meilleure fiabilité de la chaîne de traction. Dans cette optique, réduire le nombre de capteurs de la chaîne de conversion dans la commande sera envisagée. En effet, il existe déjà des capteurs de courant dans les chaînes de traction. Cependant, ceux-ci engendrent des surcoûts importants à cause de leurs défaillances fréquentes et la nécessité de remplacement très couteuse. Ainsi l’étude réalisée de commande de machine synchrone à griffes sans capteur de courant permet la suppression des capteurs du stator de la machine et donc de s’affranchir de leur coût. Dans cette thèse, le model-free adaptive Controller (MFAC) est présenté pour être utilisé dans le contrôle de la chaîne de conversion pour réduire le nombre de capteurs. À cet égard, MFAC est utilisé dans deux approches différentes. Premièrement, il a été utilisé pour le contrôle d'un système WRSM, avec et sans capteurs de courant supplémentaires. Puis, il a été utilisé pour le contrôle des convertisseurs de puissance utilisés dans la chaîne de conversion. Les résultats expérimentaux, obtenus sur un banc de test réalisé en laboratoire, sont concluants en régime établi : les courants non mesurés sont contrôlés avec une précision satisfaisante pour une application automobile et permettent le contrôle sans capteur de courant de la machine. En plus, une performance satisfaisante du MFAC est également obtenue pour commander les convertisseurs de puissance avec un seul capteur de tension.

The electrification of the transportation is one of the relevant solutions to reduce greenhouse gas emissions. Indeed, new European standards impose increasingly restrictive limits on CO2 emissions per km. This is an important industrial issue for automobile manufacturers. Therefore, the industries are moving towards hybrid and electric vehicles in which an electric traction chain is present. This consists of an electrical machine, powered by a static power electronic converter connected to an electrical energy source and storage elements. For more than two decades, different topologies have been studied for electric traction and several solutions have been marketed. These products are increasingly light, reliable and efficient while respecting the constraints of the automobile manufacturers on the costs. This thesis focuses on improving the reliability of electromechanical energy conversion chains. The objective of the thesis is to continue the development of new actuator control laws ensuring better reliability of the traction chain. With this in mind, reducing the number of sensors in control of the conversion chain will be considered. In fact, there are already current sensors in traction chains. However, these generate significant additional costs because of their frequent failures and the need for replacement. Thus, current sensorless control of the AC drive systems allows the elimination of the sensors of the stator of the machine and therefore to avoid their cost. In this thesis, the model-free adaptive controller (MFAC) is presented to be used in the control of the conversion chain to reduce the number of sensors. In this regard, MFAC is used in two different approaches. First, it is used for controlling a WRSM system, with and without additional current sensors. Then, it is used for the control of the power converters used in the conversion chain. The experimental results, obtained on a test bench built in the laboratory, are conclusive in transient and steady-state: the unmeasured currents are converged with a satisfying precision for an automotive application and allow performing a current sensorless control of the machine. In addition, a satisfactory performance of MFAC is also obtained for controlling the power converters with only using one voltage sensor., L’électrification des moyens de transport est considérée comme l’une des solutions pertinentes pour réduire les émissions des gaz à effet de serre. En effet, les nouvelles normes européennes imposent des limites de plus en plus restrictives sur les émissions de CO2 par km. Ceci est un enjeu industriel important pour les constructeurs d’automobiles. Par conséquent, ces derniers s’orientent vers les véhicules hybrides et électriques dans lesquels une chaine de traction électrique est présente. Celle-ci est constituée d’une machine électrique, alimentée par un convertisseur statique d’électronique de puissance connecté à une source d’énergie électrique et des éléments de stockage. Depuis plus de deux décennies, différentes topologies ont été étudiées pour la traction électrique et plusieurs solutions ont été commercialisées. Ces produits sont de plus en plus légers, fiables et efficaces tout en respectant les contraintes des constructeurs d’automobile sur les coûts. Cette thèse s’inscrit sur l’amélioration de la fiabilité des chaînes de conversion d’énergie électromécanique. Le travail de thèse a pour objectif de poursuivre le développement de nouvelles lois de commande d’actionneur assurant une meilleure fiabilité de la chaîne de traction. Dans cette optique, réduire le nombre de capteurs de la chaîne de conversion dans la commande sera envisagée. En effet, il existe déjà des capteurs de courant dans les chaînes de traction. Cependant, ceux-ci engendrent des surcoûts importants à cause de leurs défaillances fréquentes et la nécessité de remplacement très couteuse. Ainsi l’étude réalisée de commande de machine synchrone à griffes sans capteur de courant permet la suppression des capteurs du stator de la machine et donc de s’affranchir de leur coût. Dans cette thèse, le model-free adaptive Controller (MFAC) est présenté pour être utilisé dans le contrôle de la chaîne de conversion pour réduire le nombre de capteurs. À cet égard, MFAC est utilisé dans deux approches différentes. Premièrement, il a été utilisé pour le contrôle d'un système WRSM, avec et sans capteurs de courant supplémentaires. Puis, il a été utilisé pour le contrôle des convertisseurs de puissance utilisés dans la chaîne de conversion. Les résultats expérimentaux, obtenus sur un banc de test réalisé en laboratoire, sont concluants en régime établi : les courants non mesurés sont contrôlés avec une précision satisfaisante pour une application automobile et permettent le contrôle sans capteur de courant de la machine. En plus, une performance satisfaisante du MFAC est également obtenue pour commander les convertisseurs de puissance avec un seul capteur de tension.

Resumen En Costa Rica, la mayor parte de la energía eléctrica generada proviene de plantas hidroeléctricas. No obstante, estas han traído consigo fuertes impactos socioambientales, provocando conflictos en decenas de comunidades del país. El artículo analiza la tensión entre la expansión de proyectos hidroeléctricos y las resistencias comunitarias en defensa de los ríos en Costa Rica, desde una perspectiva geográfica. Por tanto, se discuten e interpretan estos conflictos a través del mapeo de las plantas hidroeléctricas en operación, así como los núcleos de resistencia comunal frente a aquellas, a escala nacional. Para ello, se consultaron y combinaron diversos tipos de fuentes y se realizó una sistematización de dichos proyectos y resistencias. Entre los resultados se identificaron numerosos procesos de resistencia comunal en defensa de los ríos, ampliamente distribuidas por diferentes regiones del país. Muestra de ello es que muchos proyectos, que estaban planeados para ser construidos, fueron detenidos por estas resistencias, sobre todo en las últimas dos décadas. A raíz de estas luchas, se ha conformado un movimiento social en defensa de los ríos a escala nacional, posicionando a las comunidades y sus organizaciones como actores sociales y políticos en un campo que históricamente les había excluido de la toma de decisiones. Ideas destacadas: artículo de investigación que analiza la tensión existente entre la expansión hidroeléctrica y las resistencias comunitarias en defensa de los ríos en Costa Rica, desde una perspectiva geográfica. A raíz de estas resistencias, se ha conformado en las últimas dos décadas un movimiento social en defensa de los ríos a escala nacional. Abstract Most of the electric power in Costa Rica comes from hydroelectric power plants, which have caused strong socio-environmental impacts and provoked conflicts in many of the country's communities. The article analyzes the tension between the expansion of hydroelectric projects and community resistance in defense of the rivers of Costa Rica, from a geographic perspective. To that effect, it discusses and interprets those conflicts by mapping the operating hydroelectric plants and the focal points of community resistance to them, at the national level. Different types of sources were consulted and combined, and the projects and resistance movements were systematized. One of the results was the identification of numerous processes of community resistance in defense of the rivers, widely distributed throughout the country's different regions. Proof of that is the fact that many projects about to be built have been stopped due to those resistance movements, especially in the last two decades. Those struggles gave rise to a nationwide social movement in defense of the rivers, thus positioning the communities and their organizations as social actors in a field that had historically excluded them from decision making. Main Ideas: Research paper that analyzes, from a geographic perspective, the tension existing between hydroelectric expansion and community resistance movements in defense of the rivers of Costa Rica. Due to these resistance movements, a nationwide social movement in defense of the rivers has arisen in the last two decades. Resumo Na Costa Rica, a maior parte da energia elétrica gerada provém de usinas hidrelétricas. Contudo, estas têm trazido consigo fortes impactos socioambientais, o que provoca conflitos em dezenas de comunidades do país. Este artigo analisa a tensão entre a expansão de projetos hidrelétricos e as resistências comunitárias em defesa dos rios na Costa Rica, sob uma perspectiva geográfica. Portanto, são discutidos e interpretados esses conflitos por meio do mapeamento das usinas hidrelétricas em operação, bem como dos núcleos de resistência comunal ante aquelas, a escala nacional. Para isso foram consultadas e combinadas diferentes fontes de informação e realizada uma sistematização desses projetos e resistências. Entre os resultados, foram identificados numerosos processos de resistência comunal em defesa dos rios, amplamente distribuídas por diferentes regiões do país. Mostra disso é que muitos projetos de construção de usinas foram detidos por essas resistências, principalmente nas últimas duas décadas. Devido a essas lutas, conformou-se um movimento social em defesa dos rios no âmbito nacional, posicionando as comunidades e suas organizações como atores sociais e políticos em um campo que, historicamente, estavam excluídos da tomada de decisões. Ideias destacadas: artigo de pesquisa que analisa a tensão existente entre a expansão hidrelétrica e as resistências comunitárias em defesa dos rios na Costa Rica, sob uma perspectiva geográfica. Devido a essas resistências, conformou-se, nas últimas duas décadas, um movimento social em defesa dos rios em todo o país.

International audience; Power estimation of a DBD device supplied by a current source converter is studied in this article, pointing out the prominent contribution of the transformer parasitic elements. The impact of the stray capacitance and magnetizing inductance is stated and an iterative method that estimates the electrical power and DBD waveforms is presented. Results show that the magnetizing inductance can enhance the electrical power without changing the current ratings of the converter and that the stray capacitance must be minimized. Moreover, the experimental results reveal the need for a better DBD model to properly estimate the power. In consequence, an improved model is proposed and validated using a DBD excimer lamp in a wide range of electrical operating conditions.

Els currículums de Ciències assenyalen la rellevància de comprendre els fenòmens elèctrics, a causa de les múltiples aplicacions tecnològiques actuals basades en l'electricitat. No obstant això, els estudiants tenen dificultats per comprendre la naturalesa electromagnètica de la matèria, i es requereixen evidències empíriques de les formes en què les idees dels estudiants es van transformant a mesura que adquireixen experiència i coneixement conceptual sobre electricitat. Aquest estudi es focalitza en l'anàlisi de les explicacions d'estudiants de secundària sobre fenòmens elèctrics, amb el propòsit de caracteritzar l'evolució dels seus models expressats durant una seqüència didàctica basada en fenòmens d'electrització. La proposta d'anàlisi qualitativa, des d'una perspectiva sistèmica, identifica els components d'estructura, procés i control referits pels 30 estudiants de la mostra, en les explicacions de cinc fenòmens observats, caracteritzant l'evolució del model elèctric dels estudiants. Els nostres resultats mostren que les trajectòries d'aprenentatge dels estudiants són poc convergents i presenten discontinuïtats. La descomposició del model elèctric ens ha permès evidenciar que els estudiants construeixen models limitats pels processos observats, i tenen dificultats per transitar al nivell microscòpic, el que pot contribuir a orientar la selecció de fenòmens per part dels professors per aconseguir processos de modelització més efectius., Science curricula indicate the relevance of understanding electrical phenomena, due to the multiple current technological applications based on electricity. However, students have difficulty understanding the electromagnetic nature of matter, and empirical evidence is required of the ways in which students' ideas are transformed as they gain experience and conceptual knowledge about electricity. This study focuses on the analysis of secondary school students' explanations of electrical phenomena, with the purpose of characterizing the evolution of their models expressed during a didactic sequence based on electrification phenomena. The proposal of qualitative analysis, from a systemic perspective, identifies the structure, process and control components referred by the 30 students of the sample, in the explanations of five observed phenomena, characterizing the evolution of students' electrical model. Our results show that the learning trajectories of students are not convergent and present discontinuities. The decomposition of the electrical model has allowed us to show that students build models limited by the observed processes, and have difficulties to move to the microscopic level, which can help to guide the selection of phenomena by teachers to achieve more effective modeling processes., Los currículos de Ciencias señalan la relevancia de comprender los fenómenos eléctricos, debido a las múltiples aplicaciones tecnológicas actuales basadas en la electricidad. Sin embargo, los estudiantes tienen dificultades para comprender la naturaleza electromagnética de la materia, y se requieren evidencias empíricas de las formas en que las ideas de los estudiantes se van transformando a medida que adquieren experiencia y conocimiento conceptual sobre electricidad. Este estudio se focaliza en el análisis de las explicaciones de estudiantes de secundaria sobre fenómenos eléctricos, con el propósito de caracterizar la evolución de sus modelos expresados durante una secuencia didáctica basada en fenómenos de electrización. La propuesta de análisis cualitativo, desde una perspectiva sistémica, identifica los componentes de estructura, proceso y control referidos por los 30 estudiantes de la muestra, en las explicaciones de cinco fenómenos observados, caracterizando la evolución del modelo eléctrico de los estudiantes. Nuestros resultados muestran que las trayectorias de aprendizaje de los estudiantes son poco convergentes y presentan discontinuidades. La descomposición del modelo eléctrico nos ha permitido evidenciar que los estudiantes construyen modelos limitados por los procesos observados, y tienen dificultades para transitar al nivel microscópico, lo que puede contribuir a orientar la selección de fenómenos por parte de los profesores para lograr procesos de modelización más efectivos.

En este documento se presenta los flujos de carga en el sistema eléctrico CHEC para los años 2017 y 2022, en demanda máxima y mínima con escenario de generación máxima y mínima, se tendrán en cuenta las exigencias tanto de la CREG como de las UPME. Se lleva a cabo simulaciones que involucra la generación aprobada por la UPME, la que se encuentra revisando el OR (estudios de conexión) y la futura a desarrollar (han manifestado conectarse al sistema), donde estas se involucran en un modelo eléctrico que represente la importancia de cada zona de Caldas y parte de Risaralda, de esta forma se realiza simulaciones por medio del software DigSilent, Power Factory, lo que permite definir las condiciones eléctricas del sistema en corto, mediano y largo plazo. Se aplican metodologías de planeación de la infraestructura y la valoración de sus activos basados en la resolución 015 de 2018 y de esta manera determinar que equipos se deben cambiar en el sistema eléctrico del OR CHEC. Adicionalmente las conexiones proyectadas cuentan con parámetros, capacidad de generación y años de entrada de puesta en operación, lo que permite llevar a un modelo datos reales, con el fin de obtener resultados muy aproximados en un horizonte de análisis. Aparte de los parámetros mencionados se cuenta con información de demanda de cada zona y del Sistema Interconectado Nacional, proyectos futuros de transmisión como de generación. Con el desarrollo de la tesis se obtienen resultados y conclusiones. El aporte principal es entregar un diagnóstico que dé una visión acerca de las necesidades y requerimientos del sistema eléctrico que lleve a tomar decisiones más acertadas y con menores márgenes de error en cuanto a la inversión Abstract: This document analyzes the load flows in the CHEC electric system for the years 2017 and 2022, in maximum and minimum demand with maximum and minimum generation scenario, as well as the requirement of the CREG and the UPME. Simulations are carried out involving the generation approved by the UPME, which is reviewing the OR (connection studies) and the future to develop (have manifested to connect to the system), when these are involved in an electric model that represents the importance of each area of Caldas and part of Risaralda, in this way simulations are carried out using software DigSilent Power Factory, which allows defining the electrical conditions of the system in the short, medium and long term. This analysis allows to apply the measures of infrastructure planning and the valuation of assets in resolution 015 of 2018 and in this way determine which equipment should be changed in the electric system of the CHEC OR. The projected connections have parameters, generation capacity and years of entry into operation, which makes it possible to carry out a real data model, in order to obtain very approximate results in an analysis horizon. Other parameters related to the information of each zone and the National Interconnected System, future transmission and generation projects. With the development of the thesis results and conclusions are obtained. The main contribution is to deliver a diagnosis of a vision about the needs and requirements of the electrical system that leads to more accurate decisions and with lower margins of error in terms of investment Maestría

We evaluated the effects of changes in blood flow due to abdominal aortic aneurysm (AAA) surgery by using a simple zero-dimension model and applied theoretical values to clinical data. The zero-dimension electronic circuit model and diagram of blood flow distribution were created by setting the resistance of the aorta, bilateral iliac arteries, renal arteries, and aneurysm. Resistance of the aneurysm and resistance of the aorta before surgery were compared with that of the aorta after surgery. We set the radius length of each anatomical parameter to calculate theoretical values. Renal flow increased 13.4% after surgery. Next, we analyzed contrast-enhanced computed tomography data of 59 patients who underwent AAA surgery. A total of 19 patients were treated with a Y graft and 7 patients were treated with a straight graft during open surgery. However, 33 patients were treated with a bifurcated stent graft. A significant linear relationship between the increased estimated glomerular filtration rate (eGFR) ratio and the decreased aneurysm ratio was found only for the straight graft group. Using a circuit model, renal blood flow theoretically increased after AAA surgery. Clinically, there was a correlation between volume regression and eGFR improvement only in the limited AAA group.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-06T13:59:11Z No. of bitstreams: 1 VALDEMIR DA SILVA BRITO - TESE (PPGEE) 2016.pdf: 24283842 bytes, checksum: 359b3901fbb8d95187c4a580e505a74f (MD5) Made available in DSpace on 2018-06-06T13:59:11Z (GMT). No. of bitstreams: 1 VALDEMIR DA SILVA BRITO - TESE (PPGEE) 2016.pdf: 24283842 bytes, checksum: 359b3901fbb8d95187c4a580e505a74f (MD5) Previous issue date: 2016-10-07 Capes Este trabalho propõe um modelo elétrico de supressor de surto de ZnO que o representa com exatidão nas três regiões de operação, em uma ampla faixa de frequência e amplitude. O Modelo Elétrico Proposto (MEP) foi validado a partir de um banco de dados, contendo resultados de medições de tensão e corrente. Este banco de dados é constituído por medições em doze varistores de ZnO de cinco fabricantes diferentes, com diferentes dimensões físicas e características elétricas. Nos ensaios, os varistores foram submetidos a diversos níveis de tensão na região de baixas correntes. Também foram aplicados aos varistores vários níveis de amplitude de impulsos de corrente de manobra (30/60 µs), descarga atmosférica (8/20 µs), alta corrente (4/10 µs) e impulsos de corrente com frentes de onda mais rápidas (1,5/26 µs e 3/6 µs), abordando as regiões altamente não linear e altas correntes. Adicionalmente, outros ensaios foram realizados com objetivo de verificar a presença do acoplamento indutivo e a influência do invólucro do supressor de surto na medição da tensão residual. A partir do banco de dados, foram realizadas simulações com o MEP, e com os modelos Convencional e IEEE, já consolidados no meio científico. Os resultados dos modelos foram comparados entre si, e com os resultados de medição. O MEP apresentou melhores resultados em praticamente todos os casos, nas três regiões de operação. O MEP também foi avaliado em estudos reais de energização de linha de transmissão, rejeição de carga e coordenação de isolamento. Os resultados de simulação dos estudos apresentaram níveis de amplitude condizentes com o esperado, e não apresentaram oscilações numéricas ou instabilidade. Os parâmetros do MEP são de fácil determinação, e todas as informações necessárias estão contidas nos datasheets dos fabricantes. This work proposes an electric model of ZnO surge arresters that represents accurately the ZnO surge arresters in a wide range of frequencies and amplitudes. The Proposed Electric Model (PEM) was validated from a database, containing results of voltage and current measurements. This database are based in twelve ZnO varistors of five different manufacturers, with different physical dimensions and electrical characteristics. In the lab tests, the varistors were submitted to different voltage levels in the low current region. There were also applied to the varistors multilevel amplitude of switching current impulses (30/60 µs), lightning current impulses (8/20 µs), high current impulses (4/10 µs) and current impulses with very fast front time (1.5/26 µs and 3/6 µs), addressing the highly nonlinear and high current regions. In addition, other lab tests were conducted in order to verify the presence of inductive coupling and the infuence of the surge arrester housing in the residual voltage measuring. From the database, simulations were performed with the PEM, with the Conventional and IEEE models which are already consolidated in the scientific community. The results of the models were compared among themselves, and with the measurement results. The PEM presented best results in practically all cases, in all three operating regions. The PEM was also evaluated in real studies of transmission line energization, load shedding and insulation coordination. The simulation results of the studies presented amplitude levels as expected and did not presented numerical oscillations or instability. The PEM parameters are easily determined, besides that all necessary information is contained in the manufacturers datasheet.

Проанализированы различные подходы к математическому моделированию тепловых процессов отапливаемых зданий. Предложены упрощенные тепловая, электрическая и соответствующая математическая модели, позволяющие с достаточной для практики степенью точности моделировать тепловые процессы зданий. На основании предложенной математической модели обоснован закон управления тепловой мощностью, позволяющий поддерживать постоянную комфортную температуру внутреннего воздуха независимо от внешних погодных условий. Для реализации предложенного закона управления требуемая информация о средних температурах ограждения и внутреннего наполнения здания формируется динамическим наблюдателем состояния. Приведены результаты компьютерного моделирования, которые подтверждают эффективность предложенного алгоритма управления. Different approaches to mathematical modelling of the thermal processes of heated buildings were analysed. The simplified thermal, electric and corresponding mathematical models which allow modelling thermal processes of buildings with a sufficient degree of accuracy for practical use are offered. The offered mathematical model contains three criteria of similarity, which allows analysing and forecasting of the thermal processes of families of similar buildings in the relative dimensionless time. On the grounds of the offered mathematical model the control law of thermal capacityis substantiated, that allows maintaining a constant comfortable indoor air temperature regardless of external weather conditions. The initial information for the implementation of the offered control law is the temperatures of indoor and outdoor air. For implementation of the offered control law the required information about average temperatures of the enclosure and building internal filling is formed by dynamic observer of the state. The results of the computer modelling, which prove the efficiency of the offered control algorithm are given.