Thermography and Sonic Anemometry to Analyze Air Heaters in Mediterranean Greenhouses

The present work has developed a methodology based on thermography and sonic anemometry for studying the microclimate in Mediterranean greenhouses equipped with air heaters and polyethylene distribution ducts to distribute the warm air. Sonic anemometry allows us to identify the airflow pattern generated by the heaters and to analyze the temperature distribution inside the greenhouse, while thermography provides accurate crop temperature data. Air distribution by means of perforated polyethylene ducts at ground level, widely used in Mediterranean-type greenhouses, can generate heterogeneous temperature distributions inside the greenhouse when the system is not correctly designed. The system analyzed in this work used a polyethylene duct with a row of hot air outlet holes (all of equal diameter) that expel warm air toward the ground to avoid plant damage. We have observed that this design (the most widely used in Almería’s greenhouses) produces stagnation of hot air in the highest part of the structure, reducing the heating of the crop zone. Using 88 kW heating power (146.7 W∙m−2) the temperature inside the greenhouse is maintained 7.2 to 11.2 °C above the outside temperature. The crop temperature (17.6 to 19.9 °C) was maintained above the minimum recommended value of 10 °C

Application of Semi-Empirical Ventilation Models in A Mediterranean Greenhouse with Opposing Thermal and Wind Effects. Use of Non-Constant Cd (Pressure Drop Coefficient Through the Vents) and Cw (Wind Effect Coefficient)

The present work analyses the natural ventilation of a multi-span greenhouse with one roof vent and two side vents by means of sonic anemometry. Opening the roof vent to windward, one side vent to leeward, and the other side vents to windward (this last vent obstructed by another greenhouse), causes opposing thermal GT (m3 s−1) and wind effects Gw (m3 s−1), as outside air entering the greenhouse through the roof vent circulates downward, contrary to natural convection due to the thermal effect. In our case, the ventilation rate RM (h−1) in a naturally ventilated greenhouse fits a second order polynomial with wind velocity uo (RM = 0.37 uo2 + 0.03 uo + 0.75; R2 = 0.99). The opposing wind and thermal effects mean that ventilation models based on Bernoulli’s equation must be modified in order to add or subtract their effects accordingly—Model 1, in which the flow is driven by the sum of two independent pressure fields GM1=√(∣∣G2T±G2w∣∣) , or Model 2, in which the flow is driven by the sum of two independent fluxes GM2=|GT±Gw| . A linear relationship has been obtained, which allows us to estimate the discharge coefficient of the side vents (CdVS) and roof vent (CdWR) as a function of uo [CdVS = 0.028 uo + 0.028 (R2 = 0.92); CdWR = 0.036 uo + 0.040 (R2 = 0.96)]. The wind effect coefficient Cw was determined by applying models M1 and M2 proved not to remain constant for the different experiments, but varied according to the ratio uo/∆Tio0.5 or δ [CwM1 = exp(−2.693 + 1.160/δ) (R2 = 0.94); CwM2 = exp(−2.128 + 1.264/δ) (R2 = 0.98)]

Simulation of gelled propellant doughs isothermal flow through extrusion dies using finite difference method

During the ram extrusion of gelled propellants, the possible flow instabilities can affect the extruded propellant quality. The numerical modelling helps to enhance the geometry of extrusion die, by minimizing the product distortion caused by material flow during this forming process. In the present work, a numerical model based on the finite difference method is proposed to analyze the flow simulation of double-base gelled propellant doughs through annular channels of extrusion dies. The proposed model implements the pseudo-plastic behavior described by these energetic materials. This model will be used to deduce the configuration of spider legs and annular channels that allow optimize the quality of extruded gelled propellant.The researchers acknowledge to the Spanish Ministry of Economy and Competitiveness and the European Commission their support throughout the ERDF (European Regional Development Fund) by the INNPACTO research project “Smart Propellants” (IPT-2011-0712-020000), involving EXPAL Systems S.A. and Universidad Politecnica de Cartagena (UPCT)

Un esquema centrado de cuarto orden no oscilatorio con compresión artificial para leyes de conservación hiperbólicas

En este trabajo se presenta un m´etodo numérico de cuarto orden, no oscilatorio, que utiliza un esquema centrado de volúmenes finitos para resolver leyes de conservación hiperbólicas. Para la discretización espacial se utiliza un algoritmo de reconstrucción de valores puntuales en función de valores promedio, el cual conserva la monotonía de los promedios en cada celda y garantiza que el número de puntos extremos en la solución no exceda del número de máximos y mínimos que posee la condición inicial. Las integrales temporales se evalúan mediante fórmulas de cuadratura gaussiana aproximando el flujo temporal mediante un esquema Runge-Kutta de orden 4 con la ayuda de una extensión natural continua y una interpolación de cuarto orden no oscilatoria. Para reducir la difusión numérica en las discontinuidades de contacto se aplica un procedimiento de compresión artificial basado en una corrección del flujo en las celdas afectadas por el salto. El esquema descrito se ha aplicado con éxito en la resolución de varios problemas tipo test, mostrando su carácter no oscilatorio, que los errores de precisión son de orden 4 y el buen grado de resolución en discontinuidades

El diálogo entre ciencia y sociedad en España. Experiencias y propuestas par avanzar hacia la Investigación y la Innovación Responsables desde la comunicación

Esta publicación es el resultado de la investigación "Estudio sobre el diálogo entre ciencia y sociedad en España: Propuestas para avanzar hacia la RRI desde la comunicación" financiada por la FECYT con referencia FCT-16-11124 y elaborada por un equipo de trabajo dirigido por el catedrático Domingo García Marzá y formado por los investigadores Francisco Fernández Beltrán, Rosana Sanahuja y Alicia Andrés.FECYT. FCT-16-1112

A New Methodology for Building-Up a Robust Model for Heliostat Field Flux Characterization

The heliostat field of solar central receiver systems (SCRS) is formed by hundreds, even thousands, of working heliostats. Their adequate configuration and control define a currently active research line. For instance, automatic aiming methodologies of existing heliostat fields are being widely studied. In general, control techniques require a model of the system to be controlled in order to obtain an estimation of its states. However, this kind of information may not be available or may be hard to obtain for every plant to be studied. In this work, an innovative methodology for data-based analytical heliostat field characterization is proposed and described. It formalizes the way in which the behavior of a whole field can be derived from the study of its more descriptive parts. By successfully applying this procedure, the instantaneous behavior of a field could be expressed by a reduced set of expressions that can be seen as a field descriptor. It is not intended to replace real experimentation but to enhance researchers’ autonomy to build their own reliable and portable synthetic datasets at preliminary stages of their work. The methodology proposed in this paper is successfully applied to a virtual field. Only 30 heliostats out of 541 were studied to characterize the whole field. For the validation set, the average difference in power between the flux maps directly fitted from the measured information and the estimated ones is only of 0.67% (just 0.10946 kW/m2 of root-mean-square error, on average, between them). According to these results, a consistent field descriptor can be built by applying the proposed methodology, which is hence ready for use

Written Composition, Media influence, and Spelling. Research in Primary Education Classrooms

El avance tecnológico está cambiando la sociedad, la escuela no puede permitirse alejarse de esta realidad. Por ello, el presente estudio analizó la influencia mediática en la composición escrita de los estudiantes de segundo tramo de Educación Primaria, estableciendo relaciones con respecto a la ortografía. Se llevó a cabo una intervención en dos colegios de la Región de Murcia, con un total de 180 participantes. En dichos centros el alumnado realizó una narración a partir de una imagen vinculada con la Literatura Infantil que actuaba como pretexto, posteriormente, se analizaron de manera cualitativa todas las composiciones con el programa informático Atlas. Ti y se contabilizaron las faltas de ortografía en cada una de ellas. Los principales resultados indicaron gran influencia mediática en la escritura de los estudiantes, mediante la extracción de elementos mediáticos no vinculados con el pretexto dado, en su relación ortográfica, destacó la videoconsola como el elemento mediático que más faltas contenía en las producciones que había sido citado

Experimental and numerical analysis of the flanging process by SPIF

This paper analyses the flangeability of AA2024-T3 sheets using single point incremental forming (SPIF). With this purpose, a series of process parameters is considered including flange length and width, tool radius and spindle speed. An initial experimental campaign is carried out for the evaluation of the limiting strain states of the flanges within the material forming limit diagram (FLD). Numerical modelling through finite element analysis (FEA) is used in order to provide a better understanding of the sheets flangeability and forming conditions that either allow manufacturing or lead to failure in this process using concave dies. The capability of the SPIF process to improve formability is discussed.Altair Engineering, Inc.,Amada Foundation,AutoForm Engineering GmbH as Platinum and Dinner,et al.,ITOCHU Techno-Solutions Corporation,JSOL Corporatio

Consumption of watermelon juice enriched in L-citrulline and pomegranate ellagitannins enhanced metabolism during physical exercise

L-Citrulline is a nonessential amino acid precursor of arginine and indirectly a precursor of nitric oxide (NO), which is a vasodilator and increases mitochondrial respiration. On the other hand, the antioxidant pomegranate ellagitannins are precursors of urolithin A, which has been associated with mitophagy and increased muscle function. To elucidate if a single dose of watermelon enrichment with these compounds could have a positive effect after high-intensity exercise (eight sets of eight repetitions of half-squat exercise), a double-blind randomized crossover in vivo study was performed in healthy male subjects (n = 19). Enrichment juices maintained basal levels of blood markers of muscle damage, such as lactate dehydrogenase and myoglobin, and showed a significant maintenance of force during the exercise and a significant decrease in the rating of perceived exertion and muscle soreness after exercise. A positive effect was observed between l-citrulline and ellagitannins, improving the ergogenic effect of watermelon juice.Actividad Física y Deport

Declarativas e interrogativas en Tortosa y Lleida. Comparación de su entonación

Las entonaciones de Tortosa y de Lleida poseen diferencias entre sí a pesar de ser dos subdialectos del catalán occidental. En las frases sin expansión en el sujeto u objeto, con sólo dos acentos tonales prenucleares, se encontraron diferencias, sobre todo, en las interrogativas absolutas encabezadas por la conjunción "que", pues el "tortosi" carecía de un segundo pico que sí presentaba el "lleidatà" (Martínez Celdrán et alii, 2005). Con este estudio se pretende comprobar si en frases más largas, con expansión en el sujeto o en el objeto, que poseen, por tanto, más acentos tonales, sigue sucediendo lo mismo o, por el contrario, las diferencias aumentan o disminuyen. Los resultados indican que para las enunciativas y para las interrogativas sin "que" los hablantes de Lleida muestran una tendencia clara a marcar todos los acentos tonales de la frase mientras que los de Tortosa se inclinan por desacentuar uno de ellos, normalmente el del núcleo del constituyente que posee expansión. En las interrogativas con "que" Lleida muestra más claramente que Tortosa dos niveles de tesitura bien diferenciados. El trabajo se inserta en el marco del proyecto europeo AMPER (Atlas Multimedia de Prosodia del Espacio Románico)