10 research outputs found

    Assessing the potential of hybrid fossil–solar thermal plants for energy policy making: Brayton cycles

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    This paper proposes a first study in-depth of solar-fossil hybridization from a general perspective. It develops a set of useful parameters for analyzing and comparing hybrid plants, it studies the case of hybridizing Brayton cycles with current solar technologies and shows a tentative extrapolation of the results to integrated combined cycle systems (ISCSS). In particular, three points have been analyzed: the technical requirements for solar technologies to be hybridized with Brayton cycles, the temperatures and pressures at which hybridization would produce maximum power per unit of fossil fuel, and their mapping to current solar technologies and Brayton cycles. Major conclusions are that a hybrid plant works in optimum conditions which are not equal to those of the solar or power blocks considered independently, and that hybridizing at the Brayton cycle of a combined cycle could be energetically advantageous

    Using contex-awarenes to foster active lifestyles

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    This paper describes a context-aware mobile application which aims at adaptively motivating its users to assume active lifestyles. The application is built on a model which combines ‘motion patterns’ with ‘activity profiles’, in order to evaluate the user’s real level of activity and decide which actions to take to give advice or provide feedback. In particular, a ‘move-to-uncover’ wallpaper puzzle interface is employed as motivating interface; at the same time, context-aware notifications are triggered when low activity levels are detected. In order to accelerate the application’s design and development cycle, a mobile service oriented framework – CASanDRA Mobile - has been used and improved. CASanDRA Mobile provides standard features to facilitate context acquisition, fusion and reasoning in mobile devices, making easier access to sensors and context-aware applications cohabitatio

    Application of the DRAG Methodology to the Analysis of Road Safety in Spain and Evaluation of the Main Factors of Influence.

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    Application of the DRAG methodology to the analysis of road safety in Spain and evaluation of the main factors of influence

    Análisis de la seguridad vial española: un modelo integrado para la evaluación de los principales factores de influencia.

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    Durante décadas, los investigadores han intentado identificar los factores más importantes que afectan a la seguridad vial, tratando además, de medir el grado de tal efecto. Este interés se ha acentuado de forma considerable en los últimos años, lo que se ha visto reflejando en el planteamiento de las nuevas políticas estratégicas, con la fijación de objetivos numéricos. Para poder analizar de forma rigurosa el efecto de los factores que influyen sobre la seguridad vial, y poder utilizar dichos resultados para establecer objetivos realistas en los planes estratégicos marcados en las políticas de seguridad vial, es imprescindible disponer de herramientas econométricas adecuadas. En este sentido, cabe destacar la metodología DRAG, la cual permite solucionar los problemas más importantes asociados al desarrollo de modelos en series temporales, tales como la heterocedasticidad, la autocorrelación o la forma funcional, a la vez que presentan una estructura multicapa que analiza las tres dimensiones principales de la seguridad vial (exposición, frecuencia de accidentes y severidad). Cada una de estas dimensiones es objeto de una ecuación propia que analiza los principales factores de influencia: variables económicas, infraestructura, climatología, conductores, características del parque, vigilancia, velocidad y medidas legislativas en seguridad, entre otros. Dado el gran éxito obtenido en la aplicación de esta metodología en diversos países y regiones, el INSIA ha adaptado la metodología DRAG a la situación de la seguridad vial española, realizando el modelo DRAG-España. Por su mayor interés, este trabajo presenta únicamente los resultados de los modelos desarrollados para accidentes, los cuales estudian los accidentes con heridos y los accidentes mortales de forma diferenciada, lo que ha permitido analizar la diferente influencia de una misma variable sobre estos distintos tipos de accidentes

    The interurban DRAG-Spain model: the main factors of influence on road accidents in Spain

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    This paper presents the results of applying DRAG methodology to the identification of the main factors of influence on the number of injury and fatal accidents occurring on Spain’s interurban network. Nineteen independent variables have been included in the model grouped together under ten categories: exposure, infrastructure, weather, drivers, economic variables, vehicle stock, surveillance, speed and legislative measures. Highly interesting conclusions can be reached from the results on the basis of the different effects of a single variable on each of the accident types according to severity. The greatest influence revealed by the results is exposure, which together with inexperienced drivers, speed and an ageing vehicle stock, have a negative effect, while the increased surveillance on roads, the improvement in the technological features of vehicles and the proportion of high capacity networks have a positive effect, since the results obtained show a significant drop in accidents

    Impact of hospitalization on nutritional status in persons aged 65 years and over (NUTRIFRAG Study): Protocol for a prospective observational study

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    [ES] Background Malnutrition is a recurring problem that has become more relevant in recent years. The aim of this study is to assess the risk of malnutrition and nutritional status on admission and its evolution until discharge in patients aged 65 and over admitted to medical and surgical hospitalization units in hospitals of the Spanish National Health System. Methods Prospective observational study to be carried out in the medical-surgical hospitalization units of 9 public hospitals between 01/09/2022 and 31/12/2024. Using consecutive sampling, a total of 4077 patients will be included (453 in each hospital). Variables included are related to the care process, functionality, cognition and comorbidity, risk profile, nutritional status and dysphagia; as well as frailty, dietary quality and contextual variables. The incidence of risk of malnutrition, undernutrition and dysphagia during the care process and at discharge will be calculated. The association with risk factors will be studied with logistic regression models and multivariate Cox regression models. In addition, an analysis of participants’ satisfaction with food services will be carried out. The study was approved by the Ethics and Research Committee on 30/09/2020, approved for funding on 02/12/2021 and with registration number RBR-5jnbyhk in the Brazilian clinical trials database (ReBEC) for observational studies. Discussion Some studies address nutritional status or dysphagia in older people in various care settings. However, there is a lack of large sample studies including both processes of the impact of hospitalization. The results of the project will provide information on the incidence and prevalence of both pathologies in the study subjects, their associated factors and their relationship with the average length of stay, mortality and early readmission. In addition, early detection of a problem such as malnutrition related to the disease and/or dysphagia during a hospital stay will favor the action of professionals to resolve both pathologies and improve the health status of patients.This study has been funded by Instituto de Salud Carlos III (ISCIII) through the Project "PI21/00738" and co-funded by the European Union. The funders did not and will not have a role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    Impact of hospitalization on nutritional status in persons aged 65 years and over (NUTRIFRAG Study): Protocol for a prospective observational study

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    Background: Malnutrition is a recurring problem that has become more relevant in recent years. The aim of this study is to assess the risk of malnutrition and nutritional status on admission and its evolution until discharge in patients aged 65 and over admitted to medical and surgical hospitalization units in hospitals of the Spanish National Health System. Methods: Prospective observational study to be carried out in the medical-surgical hospitalization units of 9 public hospitals between 01/09/2022 and 31/12/2024. Using consecutive sampling, a total of 4077 patients will be included (453 in each hospital). Variables included are related to the care process, functionality, cognition and comorbidity, risk profile, nutritional status and dysphagia; as well as frailty, dietary quality and contextual variables. The incidence of risk of malnutrition, undernutrition and dysphagia during the care process and at discharge will be calculated. The association with risk factors will be studied with logistic regression models and multivariate Cox regression models. In addition, an analysis of participants' satisfaction with food services will be carried out. The study was approved by the Ethics and Research Committee on 30/09/2020, approved for funding on 02/12/2021 and with registration number RBR-5jnbyhk in the Brazilian clinical trials database (ReBEC) for observational studies. Discussion: Some studies address nutritional status or dysphagia in older people in various care settings. However, there is a lack of large sample studies including both processes of the impact of hospitalization. The results of the project will provide information on the incidence and prevalence of both pathologies in the study subjects, their associated factors and their relationship with the average length of stay, mortality and early readmission. In addition, early detection of a problem such as malnutrition related to the disease and/or dysphagia during a hospital stay will favor the action of professionals to resolve both pathologies and improve the health status of patients.This study has been funded by Instituto de Salud Carlos III (ISCIII) through the project "PI21/00738" and co-funded by the European Union. The funders did not and will not have a role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S

    Hibridación termosolar en centrales convencionales de generación de electricidad (HiTERCON)

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    El modelo energético actual está marcado por el predominio de los combustibles fósiles y el intento de introducir energías renovables para evolucionar hacia un modelo más sostenible. Entre las distintas alternativas, las plantas híbridas solar-fósil parecen una solución interesante ya que combinan las ventajas de las dos fuentes de energía. Hasta el momento, las líneas de investigación y análisis de plantas híbridas se ha centrado en el acoplamiento de tecnología solar a plantas o ciclos de potencia operativos. Este enfoque, tiene sentido en un marco como el actual, donde las plantas híbridas operativas no disponen de sistema de almacenamiento y donde se intenta reducir los costes, acoplando tecnología solar a ciclos de potencia existentes. Sin embargo, resta generalidad al análisis de la hibridación, imponiendo el diseño de la planta. Resulta interesante por tanto, realizar estudios que analicen la hibridación desde un punto de vista más general y que permitan a la propia planta, optimizar su diseño. Este estudio pretende aportar conocimiento en esta línea, analizando distintas posibilidades de diseño de futuras plantas híbridas operando en modo Fuel saving mode (FSM). Para ello, se ha realizado un estudio general y sistemático de distintas topologías de plantas híbridas, las cuales consideran como ciclo de potencia el ciclo Brayton y el ciclo Rankine. Para aportar la máxima generalidad posible, se han considerado un amplio abanico de condiciones operativas en ambos bloques. Como aporte al resto de estudios, éste estudio analiza la hibridación desde el punto de vista del bloque termosolar lo que indirectamente permite analizar el funcionamiento de la planta en modo híbrido. Para ello, se han identificado dos casos de diseño: 1. Caso A: Diseño de planta híbrida a partir de una planta o bloque convencional 2. Caso B: Diseño de planta híbrida a partir de una tecnología solar determinada La distinción entre casos de diseño, permite por un lado, establecer el potencial de la hibridación en las dos situaciones que se pueden plantear en la práctica estableciendo además, una base comparativa de resultados y por otro lado, identificar las condiciones de funcionamiento óptimas en las que diseñar la planta. Como conclusión principal, el estudio realizado demuestra que las condiciones de funcionamiento que optimizan la planta híbrida pueden diferir dependiendo del caso de diseño que se considere, lo que implica que el funcionamiento de la planta no tiene porqué estar optimizado simultáneamente para sus dos modos de funcionamiento (modo fósil y modo híbrido). Por tanto, se considera que el diseño final de la planta híbrida debería estar en función del tiempo en que la planta opera en cada uno de los modos, es decir, del Solar Capacity Factor (SCF). Además, el estudio realizado identifica dos situaciones concretas para las cuales la hibridación estaría desaconsejada desde un punto de vista energético. Aunque los resultados obtenidos son sólo una primera aproximación del diseño final de la planta híbrida, proporcionan unas directrices a partir de la cuales iniciar su desarrollo. Esto es especialmente interesante de cara a políticas estratégicas, donde en función de los objetivos vigentes o que se puedan plantear, se puede modificar el diseño de la planta en su estructura básica
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