The social educator in secondary education

La recent legislació educativa ha permés la incorporació professional de l'educador social als centres d'educació secundària. Aquesta incorporació porta associada l'oportunitat de generar nous marcs, espais i temps de treball educatiu. Aquest article presenta els fonaments teòrics, de l'organització i la posada en pràctica d'una experiència de treball educatiu en xarxa implementada en un lES de la província de Toledo. Pretén servir de far pel que fa a noves formes de treball educatiu que donin respostes a les demandes i necessitats de les comunitats educatives.La reciente legislación educativa ha permitido la incorporación profesional del educador social en los centros de educación secundaria. Dicha incorporación trae asociada la oportunidad de generar nuevos marcos, espacios y tiempos de trabajo educativo. El presente artículo da cuenta de los fundamentos teóricos, de la organización y la puesta en práctica de una experiencia de trabajo educativo en red implementada en un IES de la provincia de Toledo. Pretende servir de faro respecto a nuevas formas de trabajo educativo que den respuestas a las demandas y necesidades de las comunidades educativas.Recent educational legislation has permited the introduction of the profession of social educator in centres of secondary education, bringing with it the opportunity to create new frameworks, spaces and times for educational work. This article presents the theoretical and organisational bases and practical application of an experience in educational work in network, in a secondary school in the Province of Toledo. The aim of these incorporations is to act as a lighthouse' for new forms of educational work that respond to the demands and needs of educational communities

The role of stellar radial motions in shaping galaxy surface brightness profiles

Aims. The physics driving features such as breaks observed in galaxy surface brightness (SB) profiles remains contentious. Here, we assess the importance of stellar radial motions in shaping their characteristics. Methods. We use the simulated Milky Way-mass cosmological discs from the Ramses Disc Environment Study (RaDES) to characterise the radial redistribution of stars in galaxies displaying type-I (pure exponentials), II (downbending), and III (upbending) SB profiles. We compare radial profiles of the mass fractions and the velocity dispersions of different sub-populations of stars according to their birth and current location. Results. Radial redistribution of stars is important in all galaxies regardless of their light profiles. Type-II breaks seem to be a consequence of the combined effects of outward-moving and accreted stars. The former produce shallower inner profiles (lack of stars in the inner disc) and accumulate material around the break radius and beyond, strengthening the break; the latter can weaken or even convert the break into a pure exponential. Further accretion from satellites can concentrate material in the outermost parts, leading to type-III breaks that can coexist with type-II breaks, but situated further out. Type-III galaxies would be the result of an important radial redistribution of material throughout the entire disc, as well as a concentration of accreted material in the outskirts. In addition, type-III galaxies display the most efficient radial redistribution and the largest number of accreted stars, followed by type-I and II systems, suggesting that type-I galaxies may be an intermediate case between types-II and III. In general, the velocity dispersion profiles of all galaxies tend to flatten or even increase around the locations where the breaks are found. The age and metallicity profiles are also affected, exhibiting different inner gradients depending on their SB profile, being steeper in the case of type-II systems (as found observationally). The steep type-II profiles might be inherent to their formation rather than acquired via radial redistribution

Efecto de diferentes tratamientos químicos en las características sorbentes de residuos derivados de la industria olivarera

En este trabajo se han caracterizado, mediante técnicas potenciométricas y análisis de IR, tres residuos de la industria olivarera (hueso de aceituna, alpeorujo y ramón del olivo) para su aplicación como biosorbentes de metales pesados antes y después de ser sometidos a diversos tratamientos químicos. Las titulaciones potenciométricas y los espectros de IR han mostrado que, tanto para el hueso de aceituna como para el ramón, el tratamiento con NaOH aumenta considerablemente la concentración de grupos activos y esto se ha manifestado en un aumento de la capacidad de bioadsorción de plomo. Así, en el caso del hueso y para una concentración inicial de Pb(II) de 80 mg/L, la capacidad de bioadsorción ha pasado de 3,54 mg/g para el hueso sin tratar a 7,32 mg/g para el hueso tratado. Para el alpeorujo, aunque la concentración de grupos activos es mayor en el sólido sin tratar o tratado con hexano, la capacidad de bioadsorciones mayor para el alpeorujo tratado con NaOH.En general, el tratamiento con HCl y con agua destilada ha eliminado los componentes solubles de los residuos, por lo que la concentración total de grupos activos es menor, siendo esta disminución muy notable en el alpeorujo y el ramón

Cinética de la biosorción de Cr(VI) con hueso de aceituna

En este trabajo se ha estudiado la cinética de biosorción de cromo(VI) usando hueso de aceituna como sólido sorbente.Los resultados muestran que el Cr(VI) es en parte retirado por el hueso y en parte reducido a Cr(III) y que, a partir de un tiempo de contacto próximo a 300 minutos, el porcentaje retirado de Cr(VI) y Cr total se mantiene constante, lo que indica que no se produce ninguno de los dos procesos. Así mismo, la capacidad de eliminación de Cr (VI) que tiene el hueso de aceituna disminuye con el aumento del pH, siendo este descenso mucho más acusado a pH>2. Para el Cr total los valores de la capacidad de eliminación resultan inferiores a los obtenidos para Cr(VI), lo que pone de manifiesto el efecto dela reducción de Cr(VI) a Cr(III). Los resultados experimentalesse han ajustado a los modelos de pseudo-primer orden, pseudo-segundo orden, Elovich y difusión intraparticular, siendo el modelo de pseudo-segundo orden el que mejor reproduce la cinética del proceso en todas las condiciones experimentales utilizadas. Finalmente, el efecto de la temperatura en la cinética del proceso muestra que, para Cr(VI), la capacidad de biosorción y la constante cinética aumentan cuando la  temperatura se eleva de 25 a 60 ºC, permaneciendo ambos parámetros prácticamente constantes cuando la temperaturaaumenta hasta 80 ºC

Performance of a LiBr water absorption chiller operating with plate heat exchangers

This paper studies the performance of a lithium bromide water absorption chiller operating with plate heat exchangers (PHE). The overall heat transfer coefficients in the desorber, the condenser and the solution heat recoverer are calculated using the correlations provided in the literature for evaporation, condensation and liquid to liquid heat transfer in PHEs. The variable parameters are the external driving temperatures. In the desorber, the inlet temperature of the hot fluid ranges from 75°C to 105°C. In the condenser and the absorber, the inlet temperature of the cooling water goes from 20°C to 40°C. The coefficient of performance (COP) obtained ranges from 0.5 to 0.8 for cooling duties ranging from 2 kW to 12 kW. The chiller response to different hot fluid temperatures and circulated mass flow rates is also presented. The performance and the internal parameters of the chiller at part load are, therefore, calculated. A higher efficiency results when the solution pumped from the absorber to the desorber decreases. The heat transfer analysis of the PHEs is also presented. The overall heat transfer coefficient in the desorber, equal to 790 W/m²K at the design conditions, is also analysed at part load. The condenser performance can be represented by a similar relationship found in conventional air cooled condensersThis work was partially funded by CICYT Ministerio de Ciencia y Tecnología (CLIMABCAR project no. DPI 2003-01567)Publicad

Life-cycle assessment of the thermal and catalytic pyrolysis over sepiolite of face masks

Since the start of the global COVID-19 pandemic, extensive quantities of face masks have been used and discarded. Most of these masks end up in landfills, causing a high environmental impact and no benefits. However, there are alternative ways to deal with this waste in a more sustainable way. For example, valorisation of face masks through pyrolysis has received special attention because it offers efficient application to produce a liquid oil that can be used as a diesel substitute and a solid char that can be used as an activated carbon substitute after activation. In this context, this study applies the Life-Cycle Assessment methodology to quantify and analyse the environmental impacts of different treatment scenarios based on the pyrolysis of surgical masks and FFP2 masks. It also compares their environmental performance with the conventional practice of landfilling. The scenarios studied include both thermal and catalytic pyrolysis by using sepiolite, a low-cost material abundant in Spain. Data on the pyrolysis process were obtained from laboratory experiments. It was found that the use of the produced oil as a diesel substitute very significantly reduces the environmental impact in all pyrolysis scenarios. Consequently, the pyrolysis of face masks can reduce the environmental impact caused by the treatment of this waste material. Furthermore, the thermal pyrolysis performs environmentally better than the catalytic pyrolysis. In all scenarios, freshwater ecotoxicity and marine ecotoxicity are the environmental impact categories that cause the highest environmental impact overall

Evaluación de la biosorción de cobre con cáscara de almendra

En este trabajo se analiza el potencial de la cáscara de almendra para su utilización como biosorbente de cobre presente en disoluciones acuosas. En primer lugar, se realizó una caracterización físico-química del biosorbente. Así, se ha determinado que los poros que posee la cáscara de almendra son mesoporos, con un ancho deporo medio de 54,5 Å y que la cantidad total de grupos activos es de 0,592 mmol/g, siendo el grupo carboxílico el mayoritario. A continuación, se analizó la influencia de las principales variables que intervienen en el proceso de biosorción. Se ha encontrado que el pH es uno de los parámetros más importantes que controlan la eliminación de cobre con cáscara de almendra, obteniéndose la máxima eficiencia del proceso a pH=5. El estudio cinético reveló que, en general, el proceso es rápido, aunque puede dividirse en dos etapas, una primera más rápida (primeros 20 minutos) y otra segunda etapa donde el proceso transcurre de forma más lenta. Se ha encontrado que el modelo de pseudo-segundo orden reproduce de forma adecuada el proceso. Por otra parte, el estudio del equilibrio mostró que a medida que aumenta la concentración inicial de cobre, se eleva la capacidad de biosorción del sólido hasta alcanzar un valor prácticamente constante para concentraciones superiores a 100 mg/L. El modelo de Langmuires el que mejor reproduce los resultados experimentales, obteniéndose una capacidad máxima de biosorción decobre de 9,44 mg/g

Liquid hot water pretreatment and enzymatic hydrolysis as a valorization route of Italian green pepper waste to delivery free sugars

In this work, liquid hot water pretreatment (autohydrolysis) was used to improve enzymatic hydrolysis of a commonly consumed vegetable waste in Spain, Italian green pepper, to finally produce fermentable sugars. Firstly, the effect of temperature and contact time on sugar recovery during pretreatment (in insoluble solid and liquid fraction) was studied in detail. Then, enzymatic hydrolysis using commercial cellulase was performed with the insoluble solid resulting from pretreatment. The objective was to compare results with and without pretreatment. The results showed that the pretreatment step was effective to facilitate the sugars release in enzymatic hydrolysis, increasing the global sugar yield. This was especially notable when pretreatment was carried out at 180 °C for 40 min for glucose yields. In these conditions a global glucose yield of 61.02% was obtained. In addition, very low concentrations of phenolic compounds (ranging from 69.12 to 82.24 mg/L) were found in the liquid fraction from enzymatic hydrolysis, decreasing the possibility of fermentation inhibition produced by these components. Results showed that Italian green pepper is an interesting feedstock to obtain free sugars and prevent the enormous quantity of this food waste discarded annually

On the pressure drop in plate heat exchangers used as desorbers in absorption chillers

The influence of the pressure drop in Plate Heat Exchangers (PHE) in the boiling temperature of LiBr H₂O and NH₃ H₂O solutions is studied. For the NH₃H₂O solution, the pressure drop-temperature saturation relationship estates that high pressure drops can be allowed in the solution with negligible changes in the saturation temperature, and in the PHE performance. Besides, in the case of the LiBr H₂O solution, as the working pressure is usually very low, the analysis of the pressure drop must be taken as a main limiting parameter for the use of Plate Heat Exchangers as vapour generators. In this case, the pressure drop may considerably change the boiling temperature of the solution entering the heat exchanger and therefore a higher heating fluid temperature may be required. A guideline to design these systems is proposedThis work has been partly supported by the ‘‘Ayuda a grupos” of CAM under the project numbers CCG07 UC3M/AMB 3412 and CCG08 UC3M/AMB 4227Publicad