Application of photoluminescence and electroluminescence techniques to the characterization of intermediate band solar cells

The intermediatebandsolarcell (IBSC) is a photovoltaic device with a theoretical conversion efficiency limit of 63.2%. In recent years many attempts have been made to fabricate an intermediateband material which behaves as the theory states. One characteristic feature of an IBSC is its luminescence spectrum. In this work the temperature dependence of the photoluminescence (PL) and electroluminescence (EL) spectra of InAs/GaAs QD-IBSCs together with their reference cell have been studied. It is shown that EL measurements provide more reliable information about the behaviour of the IB material inside the IBSC structure than PL measurements. At low temperatures, the EL spectra are consistent with the quasi-Fermi level splits described by the IBSC model, whereas at room temperature they are not. This result is in agreement with previously reported analysis of the quantum efficiency of the solarcells

Study of the evolution of the seismic cycle of stress and strain associated to the El Salvador Fault Zone

• Central America: – Regional studies in Central America (Seismic Hazard). – El Salvador Fault Zone (ESFZ). – Aguacaliente‐Navarro Fault Zone (ANFZ), Central Valley of Costa Rica. – Haiti (seismic hazard) • Spain: – Regional‐Nacional studies of seismic hazards (applications to building codes, eurocode, emergency plans, etc.) – Betic range zone, south of Spain. – Ibero‐Maghrebi region (collision zone)

Experimental comparison of FBARs and SMRs responsitivities to mass loadings

The utilisation of thin film technology to develop film bulk acoustic resonators (FBARs) and solidly mounted resonators (SMRs), offers great potential to outperform the sensitivity and minimum detection limit of gravimetric sensors. Up to now, the choice between FBARs and SMRs depends primarily on the users' ability to design and fabricate Bragg reflectors and/or membranes, because neither of these two types of resonators has been demonstrated to be superior to the other. In the work reported here, it is shown that identically designed FBARs and SMRs resonating at the same frequency exhibit different responsitivities, Rm, to mass loadings, being the FBARs more responsive than the SMRs. For the specific device design and resonant frequency (~2 GHz) of the resonators presented, FBARs' mass responsitivity is ~20% greater than that of SMRs, and although this value should not be taken as universal for all possible device designs, it clearly indicates that FBAR devices should be favoured over SMRs in gravimetric sensing applications.

El fitness como factor determinante en el riesgo de discapacidad, su relación con la composición corporal y el estado cognitivo en población mayor institucionalizada y de vida independiente = Fitness as a determinant factor in the risk of disability, and its relationship to body composition and cognitive status in institutionalized elderly population and independent living

La condición física, o como mejor se la conoce hoy en día el “fitness”, es una variable que está cobrando gran protagonismo, especialmente desde la perspectiva de la salud. La mejora de la calidad de vida que se ha experimentado en los últimos años en las sociedades desarrolladas, conlleva un aumento de la esperanza de vida, lo que hace que cada vez más personas vivan más años. Este rápido crecimiento de la población mayor de 60 años hace que, un grupo poblacional prácticamente olvidado desde el punto de vista de la investigación científica en el campo de la actividad física y del deporte, cobre gran relevancia, con el fin de poder ayudar a alcanzar el dicho “no se trata de aportar años a la vida sino vida a lo años”. La presente memoria de Tesis Doctoral tiene como principal objetivo valorar los niveles de fitness en población mayor española, además de analizar la relación existente entre el fitness, sus condicionantes y otros aspectos de la salud, tales como la composición corporal y el estado cognitivo. Entendemos que para poder establecer futuras políticas de salud pública en relación a la actividad física y el envejecimiento activo es necesario conocer cuáles son los niveles de partida de la población mayor en España y sus condicionantes. El trabajo está basado en los datos del estudio multicéntrico EXERNET (Estudio Multi-céntrico para la Evaluación de los Niveles de Condición Física y su relación con Estilos de Vida Saludables en población mayor española no institucionalizada), así como en los datos de dos estudios, llevados a cabo en población mayor institucionalizada. Se han analizado un total de 3136 mayores de vida independiente, procedentes de 6 comunidades autónomas, y 153 mayores institucionalizados en residencias de la Comunidad de Madrid. Los principales resultados de esta tesis son los siguientes: a) Fueron establecidos los valores de referencia, así como las curvas de percentiles, para cada uno de los test de fitness, de acuerdo a la edad y al sexo, en población mayor española de vida independiente y no institucionalizada. b) Los varones obtuvieron mejores niveles de fitness que las mujeres, excepto en los test de flexibilidad; existe una tendencia a disminuir la condición física en ambos sexos a medida que la edad aumenta. c) Niveles bajos de fitness funcional fueron asociados con un aumento en la percepción de problemas. d) El nivel mínimo de fitness funcional a partir del cual los mayores perciben problemas en sus actividades de la vida diaria (AVD) es similar en ambos sexos. e) Niveles elevados de fitness fueron asociados con un menor riesgo de sufrir obesidad sarcopénica y con una mejor salud percibida en los mayores. f) Las personas mayores con obesidad sarcopénica tienen menor capacidad funcional que las personas mayores sanas. g) Niveles elevados de fuerza fueron asociados con un mejor estado cognitivo siendo el estado cognitivo la variable que más influye en el deterioro de la fuerza, incluso más que el sexo y la edad. ABSTRACT Fitness is a variable that is gaining in prominence, especially from the health perspective. Improvement of life quality that has been experienced in the last few years in developed countries, leads to an expanded life expectancy, increasing the numbers of people living longer. This population consisting of people of over 60 years, an almost forgotten population group from the point of view of scientific research in the field of physical activity and sport, is becoming increasingly important, with the main aim of helping to achieve the saying “do not only add years to life, but also add life to years”. The principal aim of the current thesis was to assess physical fitness levels in Spanish elderly people, of over 65 years, analyzing relationship between physical fitness, its determinants, and other aspects of health such as body composition and cognitive status. In order to establish further public health policies in relation to physical activity and active ageing it is necessary to identify the starting physical fitness levels of the Spanish population and their determinants. The work is based on data from the EXERNET multi-center study ("Multi-center Study for the Evaluation of Fitness levels and their relationship to Healthy Lifestyles in noninstitutionalized Spanish elderly"), and on data from two studies conducted in institutionalized elderly people: a total of 3136 non-institutionalized elderly, from 6 Regions of Spain, and 153 institutionalized elderly in nursing homes of Madrid. The main outcomes of this thesis are: a) sex- and age-specific physical fitness normative values and percentile curves for independent and non-institutionalized Spanish elderly were established. b) Greater physical fitness was present in the elderly men than in women, except for the flexibility test, and a trend toward decreased physical fitness in both sexes as their age increased. c) Lower levels of functional fitness were associated with increased perceived problems. d) The minimum functional fitness level at which older adults perceive problems in their ADLs, is similar for both sexes e) Higher levels of physical fitness were associated with a reduced risk of suffering sarcopenic obesity and better perceived health among the elderly. f) The elderly with sarcopenic obesity have lower physical functioning than healthy counterparts. g) Higher strength values were associated with better cognitive status with cognitive status being the most influencing variable in strength deterioration even more than sex and age.

Emission inventories and modeling requirements for the development of air quality plans. Application to Madrid (Spain)

Modeling is an essential tool for the development of atmospheric emission abatement measures and air quality plans. Most often these plans are related to urban environments with high emission density and population exposure. However, air quality modeling in urban areas is a rather challenging task. As environmental standards become more stringent (e.g. European Directive 2008/50/EC), more reliable and sophisticated modeling tools are needed to simulate measures and plans that may effectively tackle air quality exceedances, common in large urban areas across Europe, particularly for NO2. This also implies that emission inventories must satisfy a number of conditions such as consistency across the spatial scales involved in the analysis, consistency with the emission inventories used for regulatory purposes and versatility to match the requirements of different air quality and emission projection models. This study reports the modeling activities carried out in Madrid (Spain) highlighting the atmospheric emission inventory development and preparation as an illustrative example of the combination of models and data needed to develop a consistent air quality plan at urban level. These included a series of source apportionment studies to define contributions from the international, national, regional and local sources in order to understand to what extent local authorities can enforce meaningful abatement measures. Moreover, source apportionment studies were conducted in order to define contributions from different sectors and to understand the maximum feasible air quality improvement that can be achieved by reducing emissions from those sectors, thus targeting emission reduction policies to the most relevant activities. Finally, an emission scenario reflecting the effect of such policies was developed and the associated air quality was modeled.

Computational Study of the Fe(CN)(2)CO Cofactor and Its Binding to HypC Protein.

In the intricate maturation process of [NiFe]-hydrogenases, the Fe(CN)2CO cofactor is first assembled in a HypCD complex with iron coordinated by cysteines from both proteins and CO is added after ligation of cyanides. The small accessory protein HypC is known to play a role in delivering the cofactor needed for assembling the hydrogenase active site. However, the chemical nature of the Fe(CN)2CO moiety and the stability of the cofactor–HypC complex are open questions. In this work, we address geometries, properties, and the nature of bonding of all chemical species involved in formation and binding of the cofactor by means of quantum calculations. We also study the influence of environmental effects and binding to cysteines on vibrational frequencies of stretching modes of CO and CN used to detect the presence of Fe(CN)2CO. Carbon monoxide is found to be much more sensitive to sulfur binding and the polarity of the medium than cyanides. The stability of the HypC–cofactor complex is analyzed by means of molecular dynamics simulation of cofactor-free and cofactor-bound forms of HypC. The results show that HypC is stable enough to carry the cofactor, but since its binding cysteine is located at the N-terminal unstructured tail, it presents large motions in solution, which suggests the need for a guiding interaction to achieve delivery of the cofactor.

Effects of diet and exercise on metabolic syndrome and the underlying factors = Efectos de la dieta y el ejercicio sobre el síndrome metabólico y sus factores

Introducción. El número de personas que padecen síndrome metabólico ha incrementado a nivel mundial durante las últimas dos décadas. Existen numerosos estudios que tratan de comparar prevalencias según los diferentes criterios y estimaciones del riesgo metabólico. De ellos se puede concluir que el principal hallazgo ha sido recalcar la necesidad de una definición estándar universal. A pesar de estas discrepancias no hay lugar a duda sobre el problema de salud pública que esto conlleva. Se necesitan medidas y estrategias urgentes para prevenir y controlar esta emergente epidemia global y para ello se debe prestar especial atención a los cambios en el estilo de vida, fundamentalmente dieta y ejercicio. A pesar de todo, existe a día de hoy una importante controversia sobre el tipo de ejercicio más efectivo y su combinación con la dieta para conseguir mejoras en la salud. Objetivos. Estudiar los índices de riesgo metabólico empleados en la literatura científica y las terapias basadas en dieta y ejercicio para el tratamiento de los factores del síndrome metabólico en adultos con sobrepeso. Diseño de investigación. Los datos empleados en el análisis de esta tesis son, primeramente un estudio piloto, y posteriormente parte del estudio “Programas de Nutrición y Actividad Física para el tratamiento de la obesidad” (PRONAF). El estudio PRONAF es un proyecto consistente en un estudio clínico sobre programas de nutrición y actividad física para el sobrepeso y la obesidad, desarrollado en España durante varios años de intervenciones. Fue diseñado, en parte, para tratar de comparar protocolos de entrenamiento de resistencia, cargas y combinado en igualdad de volumen e intensidad, con el objetivo de evaluar su impacto en los factores de riesgo y la prevalencia del síndrome metabólico en personas con sobrepeso y obesidad. El diseño experimental es un control aleatorio y el protocolo incluye 3 modos de ejercicio (entrenamiento de resistencia, con cargas y combinado) y restricción dietética sobre diversas variables determinantes del estado de salud. Las principales variables para la investigación que comprende esta tesis fueron: actividad física habitual, marcadores de grasa corporal, niveles de insulina, glucosa, triglicéridos, colesterol total, colesterol HDL, colesterol LDL, presión arterial y parámetros relacionados con el ejercicio. Conclusiones. A) Los índices de riesgo metabólico estudiados presentan resultados contradictorios en relación al riesgo metabólico en un individuo, dependiendo de los métodos matemáticos empleados para el cálculo y de las variables introducidas, tanto en mujeres sanas como en adultos en sobrepeso. B) El protocolo de entrenamiento combinado (de cargas y de resistencia) junto con la dieta equilibrada propuesto en este estudio fue la mejor estrategia para la mejora del riesgo de síndrome metabólico en adultos con sobrepeso. C) Los protocolos de entrenamiento supervisado de resistencia, con cargas y combinado junto con la restricción nutricional, no obtuvieron mejoras sobre el perfil lipídico, más allá de los cambios conseguidos con el protocolo de dieta y recomendaciones generales de actividad física habitual en clínica, en adultos con sobrepeso. Background. Over the past two decades, a striking increase in the number of people with the MetS worldwide has taken place. Many studies compare prevalences using different criteria and metabolic risk estimation formulas, and perhaps their main achievement is to reinforce the need for a standardized international definition. Although these discrepancies, there is no doubt it is a public health problem. There is urgent need for strategies to prevent and manage the emerging global epidemic, special consideration should be given to behavioral and lifestyle, mainly diet and exercise. However, there is still controversy about the most effective type of exercise and diet combination to achieve improvements. Objectives. To study the metabolic risk scores used in the literature and the diet and exercise therapies for the treatment of the MetS factors in overweight adults. Research design. The data used in the analysis was collected firstly in a pilot study and lately, as a part of the “Programas de Nutrición y Actividad física para el tratamiento de la obesidad” study (PRONAF). The PRONAF Study is a clinical research project in nutrition and physical activity programs for overweight and obesity, carried out in Spain (2008-2011). Was designed, in part, to attempt to match the volume and intensity of endurance, strength and combined training protocols in order to evaluate their impact on risk factors and MetS prevalence in overweight and obese people. The design and protocol included three exercise modes (endurance, strength and combined training) and diet restriction, in a randomized controlled trial concerning diverse health status variables. The main variables under investigation were habitual physical activity, markers of body fat, fasting serum levels of insulin, glucose, triglycerides, total, LDL and HDL cholesterol, blood pressure and diet and exercise parameters. Main outcomes. A) The metabolic risk scores studied presented contradictory results in relation to the metabolic risk of an individual, depending on the mathematical method used and the variables included, both in healthy women and overweight adults. B) The protocol proposed for combination of strength and endurance training combined with a balance diet was the optimal strategy for the improvement of MetS risk in overweight adults. C) The intervention program of endurance, strength or combined supervised training protocol with diet restriction did not achieved further improvements in lipid profile than a habitual clinical practice protocol including dietary advice and standard physical activity recommendations, in overweight adults.

The dicode workbench: A flexible framework for the integration of information and web services

Aiming to address requirements concerning integration of services in the context of ?big data?, this paper presents an innovative approach that (i) ensures a flexible, adaptable and scalable information and computation infrastructure, and (ii) exploits the competences of stakeholders and information workers to meaningfully confront information management issues such as information characterization, classification and interpretation, thus incorporating the underlying collective intelligence. Our approach pays much attention to the issues of usability and ease-of-use, not requiring any particular programming expertise from the end users. We report on a series of technical issues concerning the desired flexibility of the proposed integration framework and we provide related recommendations to developers of such solutions. Evaluation results are also discussed.

Health monitoring of web plastifying dampers subjected to cyclic loading through vibration tests

This article investigates experimentally the application of health monitoring techniques to assess the damage on a particular kind of hysteretic (metallic) damper called web plastifying dampers, which are subjected to cyclic loading. In general terms, hysteretic dampers are increasingly used as passive control systems in advanced earthquake-resistant structures. Nonparametric statistical processing of the signals obtained from simple vibration tests of the web plastifying damper is used here to propose an area index damage. This area index damage is compared with an alternative energy-based index of damage proposed in past research that is based on the decomposition of the load?displacement curve experienced by the damper. Index of damage has been proven to accurately predict the level of damage and the proximity to failure of web plastifying damper, but obtaining the load?displacement curve for its direct calculation requires the use of costly instrumentation. For this reason, the aim of this study is to estimate index of damage indirectly from simple vibration tests, calling for much simpler and cheaper instrumentation, through an auxiliary index called area index damage. Web plastifying damper is a particular type of hysteretic damper that uses the out-of-plane plastic deformation of the web of I-section steel segments as a source of energy dissipation. Four I-section steel segments with similar geometry were subjected to the same pattern of cyclic loading, and the damage was evaluated with the index of damage and area index damage indexes at several stages of the loading process. A good correlation was found between area index damage and index of damage. Based on this correlation, simple formulae are proposed to estimate index of damage from the area index damage.

Methodology for Dynamic Stability and Robustness Analysis of Commercial-Power-Module-Based DC-Distributed Systems

El propósito de esta tesis es presentar una metodología para realizar análisis de la dinámica en pequeña señal y el comportamiento de sistemas de alimentación distribuidos de corriente continua (CC), formados por módulos comerciales. Para ello se hace uso de un método sencillo que indica los márgenes de estabilidad menos conservadores posibles mediante un solo número. Este índice es calculado en cada una de las interfaces que componen el sistema y puede usarse para obtener un índice global que indica la estabilidad del sistema global. De esta manera se posibilita la comparación de sistemas de alimentación distribuidos en términos de robustez. La interconexión de convertidores CC-CC entre ellos y con los filtros EMI necesarios puede originar interacciones no deseadas que dan lugar a la degradación del comportamiento de los convertidores, haciendo el sistema más propenso a inestabilidades. Esta diferencia en el comportamiento se debe a interacciones entre las impedancias de los diversos elementos del sistema. En la mayoría de los casos, los sistemas de alimentación distribuida están formados por módulos comerciales cuya estructura interna es desconocida. Por ello los análisis presentados en esta tesis se basan en medidas de la respuesta en frecuencia del convertidor que pueden realizarse desde los terminales de entrada y salida del mismo. Utilizando las medidas de las impedancias de entrada y salida de los elementos del sistema, se puede construir una función de sensibilidad que proporciona los márgenes de estabilidad de las diferentes interfaces. En esta tesis se utiliza el concepto del valor máximo de la función de sensibilidad (MPC por sus siglas en inglés) para indicar los márgenes de estabilidad como un único número. Una vez que la estabilidad de todas las interfaces del sistema se han evaluado individualmente, los índices obtenidos pueden combinarse para obtener un único número con el que comparar la estabilidad de diferentes sistemas. Igualmente se han analizado las posibles interacciones en la entrada y la salida de los convertidores CC-CC, obteniéndose expresiones analíticas con las que describir en detalle los acoplamientos generados en el sistema. Los estudios analíticos realizados se han validado experimentalmente a lo largo de la tesis. El análisis presentado en esta tesis se culmina con la obtención de un índice que condensa los márgenes de estabilidad menos conservativos. También se demuestra que la robustez del sistema está asegurada si las impedancias utilizadas en la función de sensibilidad se obtienen justamente en la entrada o la salida del subsistema que está siendo analizado. Por otra parte, la tesis presenta un conjunto de parámetros internos asimilados a impedancias, junto con sus expresiones analíticas, que permiten una explicación detallada de las interacciones en el sistema. Dichas expresiones analíticas pueden obtenerse bien mediante las funciones de transferencia analíticas si se conoce la estructura interna, o utilizando medidas en frecuencia o identificación de las mismas a través de la respuesta temporal del convertidor. De acuerdo a las metodologías presentadas en esta tesis se puede predecir la estabilidad y el comportamiento de sistemas compuestos básicamente por convertidores CC-CC y filtros, cuya estructura interna es desconocida. La predicción se basa en un índice que condensa la información de los márgenes de estabilidad y que permite la obtención de un indicador de la estabilidad global de todo el sistema, permitiendo la comparación de la estabilidad de diferentes arquitecturas de sistemas de alimentación distribuidos. ABSTRACT The purpose of this thesis is to present dynamic small-signal stability and performance analysis methodology for dc-distributed systems consisting of commercial power modules. Furthermore, the objective is to introduce simple method to state the least conservative margins for robust stability as a single number. In addition, an index characterizing the overall system stability is obtained, based on which different dc-distributed systems can be compared in terms of robustness. The interconnected systems are prone to impedance-based interactions which might lead to transient-performance degradation or even instability. These systems typically are constructed using commercial converters with unknown internal structure. Therefore, the analysis presented throughout this thesis is based on frequency responses measurable from the input and output terminals. The stability margins are stated utilizing a concept of maximum peak criteria, derived from the behavior of impedance-based sensitivity function that provides a single number to state robust stability. Using this concept, the stability information at every system interface is combined to a meaningful number to state the average robustness of the system. In addition, theoretical formulas are extracted to assess source and load side interactions in order to describe detailed couplings within the system. The presented theoretical analysis methodologies are experimentally validated throughout the thesis. In this thesis, according to the presented analysis, the least conservative stability margins are provided as a single number guaranteeing robustness. It is also shown that within the interconnected system the robust stability is ensured only if the impedance-based minor-loop gain is determined at the very input or output of each subsystem. Moreover, a complete set of impedance-type internal parameters as well as the formulas according to which the interaction sensitivity can be fully explained and analyzed, is provided. The given formulation can be utilized equally either based on measured frequency responses, time-domain identified internal parameters or extracted analytic transfer functions. Based on the analysis methodologies presented in this thesis, the stability and performance of interconnected systems consisting of converters with unknown internal structure, can be predicted. Moreover, the provided concept to assess the least conservative stability margins enables to obtain an index to state the overall robust stability of distributed power architecture and thus to compare different systems in terms of stability.

Clean Coal Technologies Scenario and Evaluation of Present CO2 Dwindling Initiatives to Approach Zero Emission Power Stations By Coal Combustion. Deployment Situation and Evaluation Study

In the present uncertain global context of reaching an equal social stability and steady thriving economy, power demand expected to grow and global electricity generation could nearly double from 2005 to 2030. Fossil fuels will remain a significant contribution on this energy mix up to 2050, with an expected part of around 70% of global and ca. 60% of European electricity generation. Coal will remain a key player. Hence, a direct effect on the considered CO2 emissions business-as-usual scenario is expected, forecasting three times the present CO2 concentration values up to 1,200ppm by the end of this century. Kyoto protocol was the first approach to take global responsibility onto CO2 emissions monitoring and cap targets by 2012 with reference to 1990. Some of principal CO2emitters did not ratify the reduction targets. Although USA and China spur are taking its own actions and parallel reduction measures. More efficient combustion processes comprising less fuel consuming, a significant contribution from the electricity generation sector to a CO2 dwindling concentration levels, might not be sufficient. Carbon Capture and Storage (CCS) technologies have started to gain more importance from the beginning of the decade, with research and funds coming out to drive its come in useful. After first researching projects and initial scale testing, three principal capture processes came out available today with first figures showing up to 90% CO2 removal by its standard applications in coal fired power stations. Regarding last part of CO2 reduction chain, two options could be considered worthy, reusing (EOR & EGR) and storage. The study evaluates the state of the CO2 capture technology development, availability and investment cost of the different technologies, with few operation cost analysis possible at the time. Main findings and the abatement potential for coal applications are presented. DOE, NETL, MIT, European universities and research institutions, key technology enterprises and utilities, and key technology suppliers are the main sources of this study. A vision of the technology deployment is presented.

Use of calculus of variations to determine the shape of hovering rotors of minimum power and its application to micro air vehicles

In this paper, calculus of variations and combined blade element and momentum theory (BEMT) are used to demonstrate that, in hover, when neither root nor tip losses are considered; the rotor, which minimizes the total power (MPR), generates an induced velocity that varies linearly along the blade span. The angle of attack of every blade element is constant and equal to its optimum value. The traditional ideal twist (ITR) and optimum (OR) rotors are revisited in the context of this variational framework. Two more optimum rotors are obtained considering root and tip losses, the ORL, and the MPRL. A comparison between these five rotors is presented and discussed. The MPR and MPRL present a remarkable saving of power for low values of both thrust coefficient and maximum aerodynamic efficiency. The result obtained can be exploited to improve the aerodynamic behaviour of rotary wing micro air vehicles (MAV). A comparison with experimental results obtained from the literature is presented.

Instrumental Colour Evaluation and Visual Consumer Study of Commercial Beverages Made with Fruit Juice and Milk

Análisis del color de bebidas formuladas con leche y frutas mediante análisis de imagen y estudio de la aceptación del color por los consumidores