Parabolic trough collectors. Fundamentals of heat transfer applied to solar thermal energy.

Solar thermal energy has undergone major development in recent years. The most widely used technologies are central receiver solar towers and parabolic trough collectors (PTC)[1]. The latter technology has great advantages due to its higher optical and thermal efficiency, but, despite being a well-proven technique, it presents certain problems inherent to the manufacturing and durability of some critical elements in the system. They are generally composed of an absorber tube surrounded by a glass cover and in the intermediate space, a vacuum is created to minimize thermal losses by convection[2]. The absorber tube is located at the focal line of a parabolic mirror that concentrates sun’s rays. To predict the thermal behavior of this type of system, ray-tracing techniques are used to determine the thermal load and accurate correlations are also needed to calculate the convective heat transfer. Also, the original design shows some problems such as the selective coating applied on the absorber surface, whose thermal performance decays with time. Besides, the metal-glass welding are also a significant weak spot, which due to the thermal expansion can cause the partial or total loss of the vacuum in the aforementioned annulus. In this work we present the results of the modeling of this type of systems in different working configurations, as well as a new design proposal to improve the thermal transfer in this type of systems.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Seasonal variability of intermediate water masses in the Gulf of Cádiz: implications of the Antarctic and subarctic seesaw

Global circulation of intermediate water masses has been extensively studied; however, its regional and local circulation along continental margins and variability and implications on sea floor morphologies are still not well known. In this study the intermediate water mass variability in the Gulf of Cádiz (GoC) and adjacent areas has been analysed and its implications discussed. Remarkable seasonal variations of the Antarctic Intermediate Water (AAIW) and the Subarctic Intermediate Water (SAIW) are determined. During autumn a greater presence of the AAIW seems to be related to a reduction in the presence of SAIW and Eastern North Atlantic Central Water (ENACW). This interaction also affects the Mediterranean Water (MW), which is pushed by the AAIW toward the upper continental slope. In the rest of the seasons, the SAIW is the predominant water mass reducing the presence of the AAIW. This seasonal variability for the predominance of these intermediate water masses is explained in terms of the concatenation of several wind-driven processes acting during the different seasons. Our finding is important for a better understanding of regional intermediate water mass variability with implications in the Atlantic Meridional Overturning Circulation (AMOC), but further research is needed in order to decode their changes during the geological past and their role, especially related to the AAIW, in controlling both the morphology and the sedimentation along the continental slopes

Techno-economic analysis of forward osmosis pre-concentration before an anaerobic membrane bioreactor: Impact of draw solute and membrane material

This research investigated the impact of draw solute and membrane material on the economic balance of a forward osmosis (FO) system pre-concentrating municipal sewage prior to an anaerobic membrane bioreactor (AnMBR). Eight and three different draw solutes were evaluated for cellulose triacetate (CTA) and polyamide thin film composite (TFC) membranes, respectively. The material of the FO membrane was a key economic driver since the net cost of TFC membrane was substantially lower than the CTA membrane. The draw solute had a moderate impact on the economic balance. The most economically favourable draw solutes were sodium acetate and calcium chloride for the CTA membrane and magnesium chloride for the TFC membrane. The FO + AnMBR performance was modelled for both FO membrane materials and each draw solute considering three FO recoveries (50, 80 and 90%). The estimated COD removal efficiency of the AnMBR was similar regardless of the draw solute and FO membrane material. However, the COD and draw solute concentrations in the permeate and digestate increased as the FO recovery increased. These results highlight that FO membranes with high permselectivity are needed to improve the economic balance of mainstream AnMBR and to ensure the quality of the permeate and digestate

Programa Dáder de Seguimiento del Tratamiento Farmacológico. Resultados de la fase piloto

La Atención Farmacéutica (Pharmaceutical Care) o el Seguimiento del Tratamiento Farmacológico requiere de unaformación de pregrado, pero también de postgrado, continuada y reglada. En ese intento de proporcionar formacióncontinuada, se creó el Programa Dáder de Seguimiento del Tratamiento Farmacológico.Objetivo. El presente trabajo analiza los resultados de la fase piloto de la metodología Dáder para el SeguimientoFarmacoterapéutico, durante los meses de enero a marzo del 2000.Resultados. En 24 farmacias con 48 farmacéuticos comunitarios se realizó Seguimiento Farmacoterapéutico a 174pacientes. Se intervino en 194 PRM, de los que se resolvieron 167. La distribución de tipos de PRM fue de 31% denecesidad, 32,9% de efectividad y 36,1% de seguridad. Hubo de comunicarse con el médico en el 68% de lasocasiones, resolviéndose el 81% de estos, y el 92% de los que se comunicó sólo con el paciente.Conclusiones: La metodología Dáder para el Seguimiento Farmacoterapéutico es útil para identificar y resolverproblemas relacionados con medicamentos

Effect of the outer layer of Al coatings deposited by cold gas spray on the microstructure, mechanical properties and corrosion resistance of the AA 7075-T6 aluminum alloy

The corrosion of AA 7075-T6 aluminum alloy is a critical issue for many industries. In this study, aluminum coatings were deposited onto AA 7075-T6 by cold gas spray and the effect of the porous outer layer on different properties of the coating, including corrosion-resistance was investigated. As-prepared and polished samples were used to study the microstructure, morphology, mechanical properties and corrosion resistance of the coating in 3.5 wt.% NaCl solution. Cross-sectional analysis showed a dense structure, low porosity (0.8%) and thickness up to 300 lm (* 100 lm for the porous outer layer and * 200 lm for the compact inner layer). The sliding wear test resulted in a volume loss of 3.2 9 10-4 mm3/Nm with an adhesive wear mechanism. The abrasive wear test showed a wear rate of 1.1 9 10-4 mm3/Nm for the asprepared coating and 0.8 9 10-4 mm3/Nm for the polished coating. The as-prepared coating pores and interparticle spacing in the outer layer were mostly responsible for the increase in wear rate. For the polished coating immersed in 3.5 wt.% NaCl solution during 900 h, the electrolyte reached some specific points of the substrate as revealed by the cross-sectional analysis. Inspection of the as-prepared coating demonstrated that the coating/substrate interface

Influence of cold gas spray parameters on the corrosion resistance of Al-Al2O3 coatings sprayed on carbon steel

This work describes the influence of standoff distance (SoD), and gas temperature on the morphology and corrosion resistance of Al-10%Al2O3 coatings deposited by cold gas spray (CGS) on carbon steel. The results showed that the standoff distance had little effect on the thickness and microstructure of the coating. However, a 100 °C decrease of the spraying temperature reduced the coating thickness by 300 μm. The use of electrochemical analyses and SEM images showed that all the coatings studied were able to protect the substrate during at least 1300 h of immersion, due to the dense microstructure obtained by CGS

Cumplimiento, conocimiento y automedicación como factores asociados a los resultados clínicos negativos de la farmacoterapia

The patient plays a fundamental role in the attainment of good results in pharmacotherapy. Noncompliance,self-medication, or insufficient knowledge of the therapy being employed may provide asource for the causes of these negative clinical outcomes, otherwise known as medicine related problems(MRP). he Dader method was used in the evaluation, identification and classification of MRP. Theassociation of variables was established through the statistical Chi square test. Patient knowledge of themedicine, degree of compliance to therapy and self-medication were studied as causes of the negativeoutcomes encountered. 2556 patients were interviewed throughout the year that the study took place,giving a total of 2261 of valid cases. 33% presented an MRP as the cause of his/her visit to the hospitalemergency ward. Knowledge of the medicine, compliance and self-medication were only studied in thepopulation that presented an MRP and in this work it is demonstrated that these are aspects that areassociated with different dimensions of MRP. It is not possible to establish an association between theexistence or not of negative clinical outcomes in patients with the factors of knowledge of medication,compliance and self-medication. This is due to the fact that these variables are not attributable to thepatient himself, but rather are associated with the characteristics of each medicine.El paciente juega un papel primordial en la consecución de los resultados terapéuticos. El incumplimiento,la automedicación, o la falta de conocimiento del la farmacoterapia pueden ser causas de esosresultados clínicos negativos, denominados en ocasiones problemas relacionados con medicamentos(PRM). El método Dáder se utilizó para la evaluación, identificación y clasificación de PRM. Laasociación de variables se estableció mediante el estadístico chi cuadrado. El conocimiento de la medicación,el cumplimiento y la automedicación fueron estudiados como causa de estos resultados negativosde la medicación. Fueron entrevistados 2556 pacientes durante el año de estudio, resultando 2261 casosválidos. El 33 % presentaron un PRM como causa de visita a urgencias. El conocimiento de la medicación,el cumplimiento y la automedicación fueron estudiados solo en la población que presentó unPRM y se demuestra que son aspectos asociados a las distintas dimensiones de PRM. No es posibleestablecer asociación entre la existencia o no de resultados clínicos negativos en los pacientes con elconocimiento de la medicación, el cumplimiento y la automedicación, debido a que estas variables noson atributos del paciente sino que están asociadas a cada medicamento

Corrosion behavior of WC-Co coatings deposited by cold gas spray onto AA 7075-T6

This work reports a morphological, mechanical, and corrosion resistance characterization of WC-12Co and WC-25Co coatings deposited by cold gas spray (CGS) onto AA 7075-T6 alloy. Cross-sectional images of the coatings revealed dense structures with low porosities. The coating thicknesses were 65 mu m for WC-12Co and 118 pm for WC-25Co. XRD analysis showed that no fragile phases were formed in the coatings. SEM images and electro-chemical results obtained after 700 h exposure to NaCl solution showed that WC-25Co exhibited better corrosion resistance performance. The WC-12Co and WC-25Co coatings withstood 1000 and 3000 h of salt fog spray test, respectively

Intervenciones de restauración en inmuebles patrimoniales: técnicas de análisis para la diferenciación de materiales cerámicos esmaltados.

Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUECentro de Investigaciones Científicas (CSIC-UCM)Comunidad de MadridUNEDpu