Un Nuevo modelo de estilos de aprendizaje: el aprendizaje preferencial complementario

El aprendizaje preferencial complementario es un nuevo modelo de estilos necesario para conocer la forma de aprender del alumno, proporcionar una atención individualizada por perfil y, en general, mejorar el proceso de enseñanza-aprendizaje. Todos los estilos que lo componen están presentes en la naturaleza de cada individuo, pero sólo uno de ellos es preferencial y describe el rol desarrollado por éste cuando aprende. Cuando un grupo de personas, cada una experta en un rol, cooperan para lograr un conocimiento lo hacen de forma complementaria, cada una siguiendo un ciclo análogo al del grupo, aunque con un resultado parcial diferente. Se ha desarrollado un proyecto de Innovación Educativa para estudiantes de Informática aplicando el modelo propuesto a dos grupos reducidos con resultados altamente satisfactorios, no sólo académicos sino también colaborativos y de sinergia entre los miembros del equipo. Seguiremos investigando y profundizando en este modelo ya que día a día descubrimos algo nuevo de cada estilo.Peer Reviewe

Ozone as oxidation agent in cyclic activation of biochar

Granular activated carbons were produced from grape seed biochar by cyclic activation with ozone. In each cycle, char was first oxidized by exposure to ozone and then subjected to high temperature in inert atmosphere to desorb oxygen groups formed. The study assessed the influence of operating conditions in the development of porosity, from a starting biochar with narrow microporosity (SBET: 47 m2 g− 1, SDA: 505 m2g− 1) prepared by flash pyrolysis of grape seed at 800 °C. The variables studied were the number of cycles applied and the oxidation and desorption temperatures (250–275 and 850–950 °C, respectively). High oxidation temperatures led to higher burn-off, which was also found to increase with the number of activation cycles. The burn-off needed to achieve a high surface area was lower than in conventional physical activation. After 7–9 activation cycles, activated carbons with SBET higher than 1200 m2 g− 1 and SDA above 1500 m2 g− 1 were obtained. The use of ozone resulted in mainly microporous activated carbons (0.37–0.52 cm3 g− 1) with very low contribution of mesopores (< 0.04–0.07 cm3 g− 1). The mean micropore size increased with the number of activation cycles due to pore widening, while mesopore mean size decreased along the cycles. The activated carbons showed a unique granular morphology with a hollow core and a porous shell, which is maintained even after 10 activation cyclesThe authors greatly appreciatefinancial support from the Spanish Ministerio de Ciencia e Innovación (CTQ2012-32821

Preparation of granular activated carbons from grape seeds by cycles of liquid phase oxidation and thermal desorption

Activation of grape seed char upon successive cycles of liquid phase oxidation followed by high temperature desorption permits a tailored development of porosity. In this work three different oxidants (HNO3, H 2O2, and (NH4)2S2O 8), have been tested and the desorption temperature has been varied within 850-950 C upon 10 activation cycles. A high increase of BET surface area was observed in the first five cycles with HNO3 as oxidizing agent giving rise to values higher than 1200 m2 g- 1 at around 50% burn-off. Activation with H2O2 and (NH 4)2S2O8 led to a significantly lower development of surface area, with 600 and 800 m2 g- 1 respectively at that burn-off. The analysis of the pore size distribution showed that porosity was generated through the creation of new micropores and widening of existing ones upon activation with HNO3 and (NH4) 2S2O8, whereas H2O2 mostly led to the widening of the narrow micropores already existing in the starting char. The activated carbons obtained are essentially microporous, with some small contribution of mesoporosity in the HNO3 series (V micro = 0.69 cm3 g- 1; Vmeso = 0.07 cm3 g- 1). SEM images showed that the activated carbons maintained the granular morphology of the seeds after 10 cycles showing a hollow core structure with a wall thickness of about 200 μmThe authors greatly appreciate the financial support from the Spanish Ministerio de Ciencia e Innovación (CTQ2009-09983

Granular mesoporous activated carbons from waste tires by cyclic oxygen chemisorption-desorption

This document is the accepted manuscript version of a published work that appeared in final form in Industrial and Engineering Chemistry Research, © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/ie201499hActivation upon cyclic oxygen chemisorption-desorption has proved to be an efficient way to develop porosity at low burn off from waste tires char. In this work the influence of particle size, desorption temperature, and the number of cycles is studied. Highest values of burnoff and specific surface area (S BET) are obtained for the largest particle diameter (3 mm average) and at intermediate desorption temperature (650 °C). In these conditions S BET values around 500 m 2/g can be achieved at burn-offs of about 30%, and close to 600 m 2/g at around 45% burnoff, with a mean pore size of 10 nm and a micropore volume close to 0.08 cm 3/g. Although the surface area is moderate, the low burnoff and high S BET/burnoff ratio achieved make it possible to maintain initial granular morphology of the particles even after 20 cycles of activationWe greatly appreciate finantial support from the Spanish Ministerio de Educacion y Ciencia through the project CTQ2009-0998

Modeling the variability of Au/ Ti/h BN/Au memris t ive devices

The variability of memristive devices using multilayer hexagonal boron nitride (h-BN) coupled with Ti and Au electrodes (i.e., Au/Ti/h-BN/Au) is analyzed in depth using different numerical techniques. We extract the reset voltage using three different methods, quantified its cycle-to-cycle variability, calculated the charge and flux that allows to minimize the effects of electric noise and the inherent stochasticity of resistive switching, described the device variability using time series analyses to assess the “memory” effect, and employed a circuit breaker simulator to understand the formation and rupture of the percolation paths that produce the switching. We conclude that the cycle-to-cycle variability of the Au/Ti/h-BN/Au devices presented here is higher than that previously observed in Au/h-BN/Au devices, and hence they may be useful for data encryption.Ministry of Science and Technology of China (2019YFE0124200, 2018YFE0100800)National Natural Science Foundation of China (61874075)Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía (Spain) and European Regional Development Fund (ERDF) under projects A-TIC-117-UGR18, A-FQM-66-UGR20, A-FQM-345- UGR18, B-TIC-624-UGR20 and IE2017-5414Grant PGC2018-098860-B-I00 supported by MCIU/AEI/FEDERMaria de Maeztu” Excellence Unit IMAG, reference CEX2020-001105-M, funded by MCIN/AEI/10.13039/501100011033King Abdullah University of Science and Technolog

Porous structure and morphology of granular chars from flash and conventional pyrolysis of grape seeds

This work studies the influence of the operating conditions used in the pyrolysis of grape seeds on the morphology and textural properties of the chars resulting. Flash and conventional (283Kmin-1 heating rate) pyrolysis have been used within a wide range of temperature (300-1000°C). The effect of a pretreatment for oil extraction has also been studied. The porous structure of the chars was characterized by adsorption of N2 at 77K, Ar at 77K and 87K, and CO2 at 273K and mercury intrusion porosimetry. The morphology was analyzed by scanning electron microscopy. All the materials prepared revealed an essentially microporous structure, with a poor or even negligible contribution of mesopores. Increasing pyrolysis temperature led to higher specific surface areas and lower pore size. The highest specific surface area values occurred within 700-800°C, reaching up to 500m2g-1 with pore sizes in the 0.4-1.1nm range. No significant morphological changes were observed upon carbonization so that the resulting chars were granular materials of similar size than the starting grape seeds. The hollow core structure of the chars, with most of the material allocated at the periphery of the granules can help to overcome the mass transfer limitations of most common (solid or massive) granular activated carbons. The chars showed a good mechanical strength during attrition tests. These chars can be potential candidates for the preparation of granular carbons molecular sieve or activated carbons raw materialsThe authors greatly appreciate financial support from the Spanish Ministerio de Ciencia e Innovación (CTQ2009-09983

Shall y Will en el Corpus of History English Texts

Este artículo estudia los significados de las formas verbales shall y will en inglés moderno tardío, tal y como aparecen en el Corpus of History English Texts (1700-1900). Existen trabajos específicos sobre verbos modales en períodos históricos de la lengua inglesa, como Fachinetti (1997) y Gotti (2003). Para el estudio de estos modales, se emplean herramientas de corpus para identificar los sentidos de estos dos verbos en contexto. Los datos resultantes de este análisis se agrupan de acuerdo con estos significados. El concepto de modalidad que seguimos se basa principalmente en Palmer (1986; 2001), Hoye (2008) y van der Auwera y Plungian (1998). Las conclusiones muestran que estas formas verbales tenían, de hecho, significados modales, incluso si su uso perifrástico para indicar futuro era evidente.This paper deals with the meanings of the verbal forms shall and will in the late Modern English period, as evinced in the Corpus of History English Texts (1700-1900). Earlier literature on modal verbs in historical periods includes Fachinetti (1997) and Gotti (2003). We study these modals using corpus tools in order to identify the senses of these two verbs in context and to group findings according to meaning. Our notion of modality mainly follows from Palmer (1986; 2001), Hoye (2008) and van der Auwera and Plungian (1998). Conclusions show that these verbal forms had indeed modal meanings, even if their periphrastic use to indicate future was evident

Un nuevo modelo de estilos de aprendizaje: el aprendizaje preferencial complementario

El aprendizaje preferencial complementario es un nuevo modelo de estilos necesario para conocer la forma de aprender del alumno, proporcionar una atención individualizada por perfil y, en general, mejorar el proceso de enseñanza-aprendizaje. Todos los estilos que lo componen están presentes en la naturaleza de cada individuo, pero sólo uno de ellos es preferencial y describe el rol desarrollado por éste cuando aprende. Cuando un grupo de personas, cada una experta en un rol, cooperan para lograr un conocimiento lo hacen de forma complementaria, cada una siguiendo un ciclo análogo al del grupo, aunque con un resultado parcial diferente. Se ha desarrollado un proyecto de Innovación Educativa para estudiantes de Informática aplicando el modelo propuesto a dos grupos reducidos con resultados altamente satisfactorios, no sólo académicos sino también colaborativos y de sinergia entre los miembros del equipo. Seguiremos investigando y profundizando en este modelo ya que día a día descubrimos algo nuevo de cada estilo

Effect of structural ordering of the carbon support on the behavior of Pd catalysts in aqueous-phase hydrodechlorination

Catalysts consisting of Pd supported on virgin and heat-treated carbon blacks (homemade and commercial), graphites (natural and synthetic) and commercial carbon nanofibers were prepared and tested in the aqueous phase hydrodechlorinaton (HDC) of 4-chlorophenol (4-CP) under near ambient conditions (30 °C, 1 atm) in order to explore the effect of the support on the catalytic behavior. The homemade graphitized supports were prepared from commercial carbon black (CB) and from a carbon black-like material (CBPE) obtained from pyrolysis of low-density polyethylene. All the catalysts prepared yielded complete 4-CP conversion, although a wide range of activity was observed (10.7–173.5 mmol gPd−1 min−1). The graphitized carbon black provided the most active catalysts, showing Pd nanoparticles around 3 nm in size and a well-balanced contribution of Pd species (Pdn+/Pd0 = 0.9). Substantial differences of activity were found between the graphitized and not graphitized supports, even for catalysts with similar Pd nanoparticle size. The higher activity of the catalysts with graphitized supports can be partly associated to a more balanced initial Pdn+ to Pd0 ratio. Moreover, higher selectivity to hydrogenation products (cyclohexanone) was also achieved with those catalysts due to a higher contribution of the Pd0 speciesThe authors greatly appreciate financial support from the Spanish MINECO (CTQ2012-32821

HEODAR: Herramienta para la evaluación de objetos didácticos de aprendizaje reutilizables

[ES]Hasta el momento para evaluar Objetos de Aprendizaje (OAs) se consideran algunas herramientas con criterios específicos, sin embargo, no se ha promovido una metodología de valoración que considere tanto el valor asignado al OA en sí, como el porcentaje de la cantidad de evaluadores, que permita visualizar los resultados para comparar la calidad de recursos. Como ocurre en el caso de diversos productos que se ofrecen a través de la red respaldados por una valoración de usuarios unificada en un ranking, el propósito de este artículo es sugerir una propuesta para la valoración automatizada de los expertos quienes puedan observar visiblemente los aspectos mejor o peor valorados de los OAs