Search results for "Lector"
showing 10 items of 341 documents
Optimization of a thermoelectric system for power generation realized by ‘‘hidden’’ components
2014
Abstract Today the utilization of renewable energy sources is very important to support the traditional ones, and also in order to reach the objectives fixed by the Kyoto Protocol. In this context, also well-known technologies related to the electric energy production, formerly not suitable – due to the poor technological level of the components or due to the high costs linked to the system efficiency – may now find a suitable collocation. Among these technologies, the thermoelectric effect may be very advantageous in some particular applications of small power. A power generation system utilizing this technology has been studied by the authors. This system utilizes the thermal difference b…
Efficiency increase in thermal desalination plants by matching thermal and solar distillation: theoretical analysis
2005
Abstract The effluent streams from MSF and MED plants retain substantial thermal and mechanical energy which is usually wasted as the streams are rejected into the environment. Recent environmental studies pose the question of environmental sustainability of desalination due to the large amount of heat and brine dissipated into the sea. Moreover the use of renewable energy so far have been confined to experimental studies or to the use in remote areas and no studies have been carried out on the coupling of a solar still plant with an existing thermal desalination installation in order to take advantage of the heat streams generated by the thermal plants. The combination of a solar desalinat…
A novel solar trigeneration system integrating PVT (photovoltaic/thermal collectors) and SW (seawater) desalination: Dynamic simulation and economic …
2014
Abstract The paper investigates the integration of renewable energy sources and water systems, presenting a novel solar system producing simultaneously: electrical energy, thermal energy, cooling energy and domestic water. Such system is designed for small communities in European Mediterranean countries, rich in renewable sources and poor in fossil fuels and water resources. The polygeneration system under analysis includes PVT (photovoltaic/thermal solar collectors), a MED (multi-effect distillation) system for SW (seawater) desalination, a single-stage LiBr–H2O ACH (absorption chiller) and additional components, such as storage tanks, AHs (auxiliary heaters) and BOP (balance of plant) dev…
Electrical-optical characterization of multijunction solar cells under 2000X concentration
2014
In the framework of the FAE "Fotovoltaico ad Alta Efficienza" ("High Efficiency Photovoltaic") Research Project (PO FESR Sicilia 2007/2013 4.1.1.1), we have performed electrical and optical characterizations of commercial InGaP/InGaAs/Ge triple-junction solar cells (1 cm2) mounted on a prototype HCPV module, installed in Palermo (Italy). This system uses a reflective optics based on rectangular off-axis parabolic mirror with aperture 45×45 cm2 leading to a geometrical concentration ratio of 2025. In this study, we report the I-V curve measured under incident power of about 700 W/m2 resulting in an electrical power at maximum point (PMP) of 41.4 W. We also investigated the optical properties…
Sarraute's plays : poplyphony and enunciation
2014
The corpus is formed of six plays of Nathalie Sarraute; it hides a duplication of enunciation types in the characters’ dialogue. This duplication is latent due to personal pronouns and verb tenses’ neutralization. The transition from an enunciation layer to another is not marked at all or not traditionally marked. Therefore, deciphering will be more complicated to any reader, listener or spectator. These works of art are also highly polyphonic in terms of enunciation as in semantics, as several voices are intertwined and as the characters resort to authorities of point of view. Thus, readers, listeners and spectators should identify enunciation sources and “other” authorities of point of vi…
Los hábitos lectores en inglés de futuros maestros: Implicaciones didácticas
2014
Se presenta un estudio exploratorio y descriptivo sobre los hábitos lectores en inglés de estudiantes universitarios españoles para detectar cuáles son las áreas de atención prioritaria para poder seguir un Grado en inglés según el EEES. Se midió el nivel de inglés mediante el Oxford Online Placement Test. Se evaluaron los hábitos lectores y el tipo de materiales académicos que los estudiantes leen en inglés mediante un cuestionario. Gran parte de la muestra se encontraba en los niveles elementales e intermedios de dominio del inglés. Un porcentaje muy elevado de estudiantes declaró no tener el hábito de leer en inglés y leer solo materiales académicos obligatorios. Sin embargo, existe una …
The image of the candidates in the 2019 General Elections in Spain
2019
[Resumen] Las Elecciones Generales de 1977 en España obligaron a los partidos a explicar cuestiones elementales como “qué significaba votar”. En general, la imagen proyectada de los candidatos era una cuestión “menor”, dada la falta de cultura democrática del momento. Tras 42 años desde la transición, el contexto político y comunicativo ha dado un vuelco que exige de una aproximación más compleja. Los partidos políticos son conscientes de la importancia que tiene construir la imagen pública de sus candidatos. En este trabajo analizamos la imagen del principal cartel de campaña de los candidatos a presidente en las Elecciones Generales de abril de 2019 de Vox, PP, C’s, PSOE, UP y del candida…
Mejorando la efectividad instruccional del texto educativo en ciencias: primeros resultados
1993
Resumen basado en el de la publicación Resumen en inglés Se compilan y analizan las variables textuales que participan en los procesos de comprensión y aprendizaje en textos científicos. A continuación, se propone una nueva clasificación que puede aplicarse al texto instructivo. Esta propuesta es evaluada en un experimento con diferentes grupos de estudiantes y varias tareas de aprendizaje. Se discuten los primeros resultados. ESP
Thermoeconomic optimization of a renewable polygeneration system serving a small isolated community
2015
During the last years, special attention has been paid to renewable polygeneration technologies, able of simultaneously producing thermal, cooling, electrical energy and desalinated water from seawater. This paper focuses on an innovative polygeneration system driven by renewable energy sources, including the following technologies: hybrid photovoltaic/thermal collectors, concentrating parabolic trough (CPVT), a biomass heater, a single-stage absorption chiller and a multiple-effect distillation desalination system. The system is designed to cover the base load of an isolated small community. In previous papers, the dynamic simulation model about plant operation is discussed. In this paper,…
Exergetic and exergoeconomic analysis of a renewable polygeneration system and viability study for small isolated communities
2015
Abstract A great interest has recently arisen for the sustainable supply of energy and fresh water, due to the growing demand from developing countries. Facing this demand by traditional technologies implies evident risks related with the high cost of fossil fuels and their environmental impact. Then, alternative solutions based on the use of renewable sources and innovative technologies must be considered. In this paper a renewable polygeneration system is examined, which includes a solar field based on parabolic trough photovoltaic/thermal collectors, a biomass heater, an absorption chiller and a Multiple Effect Distillation desalination unit. Plant operation under dynamic conditions has …