Methanol dehydration over ZrO2 supported-activated carbons

Resumen comunicación congreso internacionalDME is playing an important role due to its potential use as an alternative fuel in diesel engines. The use of this fuel produces lower NOx emissions, and less engine noise compared to traditional diesel fuels. Moreover, this compound is used as building block for many value-added chemicals such as lower olefins. DME is usually produced via catalytic dehydration of methanol over a solid acid. The use of activated carbons in catalytic processes, acting directly as catalyst and as catalyst support, is focussing much attention. They can be obtained from different types of lignocellulosic waste, producing not only an environmental but an economical profit. In this sense, the preparation of activated carbons with phosphoric acid produces catalytic supports with certain surface acidity, which have shown high activity for alcohol dehydration. In this study, ZrO2 supported activated carbons were prepared from an industrial byproduct as lignin for the methanol dehydration to DME. The activated carbon was prepared by chemical activation with H3PO4, using Alcell® lignin as precursor. The impregnation ratio value (H3PO4/lignin) used was 3. The impregnated sample was activated under N2 flow at 500 ºC for 2h, washed and dried. The activated carbon was loaded with different amounts of ZrO(NO3)2, dried at 120ºC for 24h, and calcined in air at 250ºC for 2h, obtaining ZrO2 loadings of 5 and 10%, respectively. For the sake of comparison, pure ZrO2 was also used. Catalytic tests were performed at atmospheric pressure in a fixed bed reactor, at different space times and partial pressures. The activated carbon (ACP) prepared shows a well-developed porous structure, with an apparent surface area higher than 2000 m2/g, and a high contribution of mesoporosity. After metal loading, a maximum decrease of 20% in all structural parameters of the ACP was observed.The results show that ZrO2 loading produces an enhancing in the catalytic activity of the carbon materials compared to the parent activated carbon (0.1 g·s/μmol, PCH3OH= 0.02 atm in helium and 350 ºC). In this sense, a methanol conversion of 25% was observed with the addition of 10% w/w ZrO2 (ACP-10Zr), at steady state conditions (Figure 1). ACP shows negligible conversion, at the same conditions and for pure ZrO2 the methanol conversion was of 10%. Very high selectivity to DME (~100%) was found at temperatures lower than 350 ºC. The methanol conversion increases with temperature, reaching a value of 67% at 475ºC, but a slight decrease in DME selectivity is observed, resulting in a higher production of light hydrocarbons, mainly CH4. The results suggest that the addition of only a 10% of ZrO2 over an activated carbon prepared by chemical activation with H3PO4 enhances significantly the performance of the catalyst, compared to pure ZrO2.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Atomic-level characterization and cilostazol affinity of poly(lactic acid) nanoparticles conjugated with differentially charged hydrophilic molecules

Indexación: Scopus.M.F.M. acknowledges support from CONICYT-PFCHA/Doctorado Nacional/2014-21140225. M.M.M. thanks the FONCyT PICT-2015-2191, CONICET PIP 11220110100992, Secyt, Universidad Nacional de Cordoba. C.V. acknowledges support from CONICYT under FONDECYT #1161438 and BASAL Grant FB0807, MECESUP PMI-UAB1301, and H2020-MSCA-RISE-2016 #734801 MAGNAMED. The authors thank the High-Performance Computational Center (CCAD UNC) and Escuela de Ingeniería Civil en Bioinformática (Universidad de Talca) for access to supercomputers.Nanotherapeutics is a promising field for numerous diseases and represents the forefront of modern medicine. In the present work, full atomistic computer simulations were applied to study poly(lactic acid) (PLA) nanoparticles conjugated with polyethylene glycol (PEG). The formation of this complex system was simulated using the reactive polarizable force field (ReaxFF). A full picture of the morphology, charge and functional group distribution is given. We found that all terminal groups (carboxylic acid, methoxy and amino) are randomly distributed at the surface of the nanoparticles. The surface design of NPs requires that the charged groups must surround the surface region for an optimal functionalization/charge distribution, which is a key factor in determining physicochemical interactions with different biological molecules inside the organism. Another important point that was investigated was the encapsulation of drugs in these nanocarriers and the prediction of the polymer-drug interactions, which provided a better insight into structural features that could affect the effectiveness of drug loading. We employed blind docking to predict NP-drug affinity testing on an antiaggregant compound, cilostazol. The results suggest that the combination of molecular dynam ics ReaxFF simulations and blind docking techniques can be used as an explorative tool prior to experiments, which is useful for rational design of new drug delivery systems. © 2018 Matus et al.https://www.beilstein-journals.org/bjnano/articles/9/12

Loss of diversity in the community of small mammals of Doñana National Park (SW Spain): another effect of the local climate change ?

Doñana National Park is an important wetland located in the southwest Spain forming part of the Mediterranean Basin, a "biodiversity hotspot" especially vulnerable to climate change. In this study, we investigate changes in diversity and abundance occurred between 1978 and 2016 in the community of small mammals of Doñana and their relationship with local climate changes. Capture-mark-recapture methods were carried out for a total of 16 years, unevenly distributed over four decades. Our findings show a consistent loss of diversity and abundance decline in the community of small mammals. Eliomys quercinus and Rattus rattus have almost disappeared from the area and Apodemus sylvaticus has sharply reduced its abundance parallel to the progressive increase of Mus spretus. Such a process is worrying for conservation as small mammals represent, after rabbits, the most important prey for carnivores and raptors in Doñana. The detected changes could be at least partially explained by the progressive increase in local temperature observed during the study period. In line with this, the species that have suffered a greater decline are those of Eurasian origin and northern distribution as is the case for E. quercinus and R. rattus while the current dominant species, M. spretus, proceeds from Africa and has a Mediterranean distribution. A non-exclusive alternative is that the extreme rarefaction of rabbits may have caused a trophic cascade effect enhancing predation by carnivores and raptors towards gradually smaller species.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

High-accuracy determination of the neutron flux in the new experimental area n_TOF-EAR2 at CERN

A new high flux experimental area has recently become operational at the n_TOF facility at CERN. This new measuring station, n_TOF-EAR2, is placed at the end of a vertical beam line at a distance of approximately 20m from the spallation target. The characterization of the neutron beam, in terms of flux, spatial profile and resolution function, is of crucial importance for the feasibility study and data analysis of all measurements to be performed in the new area. In this paper, the measurement of the neutron flux, performed with different solid-state and gaseous detection systems, and using three neutron-converting reactions considered standard in different energy regions is reported. The results of the various measurements have been combined, yielding an evaluated neutron energy distribution in a wide energy range, from 2meV to 100MeV, with an accuracy ranging from 2%, at low energy, to 6% in the high-energy region. In addition, an absolute normalization of the n_TOF-EAR2 neutron flux has been obtained by means of an activation measurement performed with 197Au foils in the beam.Comisión Europea FP7/2007-2011 No.605203Centro Nacional de Ciencias de Polonia UMO- 2012/04/M/ST2/00700Centro Nacional de Ciencias de Polonia UMO-2016/22/M/ST2/00183Fundación de Ciencia Croata No. 168

El valor de la cartera de clientes de empresas de telecomunicaciones en México (The value of customer portfolio for telecommunication companies in Mexico)

Abstract. The purpose of this study is to determine which customers are more profitable. Companies must consider the income their customers generate, as well as the costs of acquiring and keeping them. However the analysis can’t end there, companies are well aware that, although customers´ past performance could be helpful to asses their future performance, it could also be tricky. Companies have started to pay attention to the unpredictable customers´ behavior, therefore, analyzing customers´ long term value, or even customers´ life time value (LTV). Nevertheless, only few companies have bothered to evaluate if their desirable individual customers are, from the risk stand point, are desirable collective customers based on the customers´ value change. The value of each customer changes to reflect the identity of the group it belongs to, as well as to reflect in advance, the effect it will have on it´s group. This analysis has been designed to obtain the correlation between the risk-return rate of a customer and a general portfolio as the result of customer´s contribution to the LTV of such portfolio in telecommunication companies. Resumen. Con el fin de determinar qué clientes serán más rentables, un negocio debe considerar en primer lugar los ingresos que éstos han estado generando y cuánto costará adquirirlos y mantenerlos. Pero el análisis no se puede detener ahí, las empresas son conscientes de que el desempeño pasado, si bien resulta útil para hacer predicciones, puede ser muy engañoso. Las empresas han comenzado a tratar el problema del comportamiento impredecible de los clientes. Los negocios se han dedicado al análisis del valor a largo plazo, o incluso el valor vitalicio del cliente individual, pero muy pocas se han molestado en evaluar si todos sus clientes individuales deseables son, desde el punto de vista del riesgo, deseables colectivamente. Puesto que el valor de un cliente cambia para reflejar tanto la identidad del grupo al que se suma como el efecto anticipado en la predictibilidad del mismo. Este análisis esta diseñado para captar la correlación entre la tasa riesgo-retorno del cliente y la de la cartera general teniendo como resultado la contribución al valor vitalicio al riesgo de una cartera de clientes de empresas de telecomunicaciones

Covalent immobilization of Candida rugosa lipase at alkaline pH and their application in the regioselective deprotection of per-O-acetylated thymidine

Lipase from Candida rugosa (CRL) was stabilized at alkaline pH to overcome the inactivation problem and was immobilized for the first time by multipoint covalent attachment on different aldehyde-activated matrices. PEG was used as a stabilizing agent on the activity of CRL. At these conditions, CRL maintained 50% activity at pH 10 after 17 h incubation in the presence of 40% (w/v) of PEG, whereas the enzyme without additive was instantaneously inactive after incubation at pH 10. Thus, this enzyme was covalently immobilized at alkaline pH on three aldehyde-activated supports: aldehyde-activated Sepharose, aldehyde-activated Lewatit105 and heterofunctional aldehyde-activated EDA-Sepharose in high overall yields. Heterogeneous stable CRL catalysts at high temperature and solvent were obtained. The aldehyde-activated Sepharose-CRL preparation maintained 70% activity at 50 °C or 30% (v/v) acetonitrile after 22 h and exhibited high regioselectivity in the deprotection process of per-O-acetylated thymidine, producing the 3ʹ-OH-5ʹ-OAc-thymidine in 91% yield at pH 5.Fil: Rivero, Cintia Wanda. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Investigación en Biotecnología Sustentable; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Palomo, Jose M.. Consejo Superior de Investigaciones Científicas; Españ

Alkaline activation of metakaolin. Effect of the soluble silicate addition and curing temperature

[ES] El objetivo del presente trabajo es determinar el efecto que la cantidad de sílice soluble presente en la disolución activadora (relación molar SiO2/Na2O entre 0 y 0.69) y la temperatura de curado (85ºC, 150ºC y 200ºC) ejercen sobre las propiedades físico-mecánicas y las características mineralógicas y microestructurales de los productos formados por activación alcalina de metacaolín. Para ello se determinaron los valores de resistencia mecánica a compresión de los materiales objeto de estudio y se realizó un estudio mineralógico y microestructural de los mismos por DRX, SEM-EDX, 29Si RMN-MAS y porosimetría de mercurio. Los resultados obtenidos muestran que la resistencia mecánica del material guarda una estrecha relación con la naturaleza, microestructura y composición química de los productos de reacción así como con las condiciones de curado. En todos los casos se genera, como principal producto de reacción, un polímero inorgánico alcalino con propiedades cementantes (gel N-A-S-H) responsable, en mayor medida, de las propiedades mecánicas del material. Como productos secundarios se forman algunas zeolitas cuya proporción y tipo (sodalita, zeolita A, faujasita, …) dependen tanto de la naturaleza del activador como de las condiciones de curado. La presencia de sílice soluble en la disolución activadora conduce a la formación de geles con una mayor relación Si/Al y a la ralentización de la zeolitización, factores, ambos, con un efecto positivo sobre la resistencia mecánica. Con respecto a la temperatura de curado, existe un valor umbral, en función de la composición del material, a partir del cual un incremento en dicha temperatura deja de tener efectos positivos sobre la evolución de la resistencia mecánica.[EN] This study has been undertaken to determine the effect that the soluble silica content in the activating solution (molar ratio SiO2/Na2O between 0 and 0.69) and curing temperature (85ºC, 150ºC, and 200ºC) have on the physico-mechanical properties and mineralogical and microstructural characteristics of products formed by alkaline activation of metakaolin. The compression strength of the materials obtained was determined and a mineralogical and microstructural study of these materials was conducted by XRD, SEM-EDX, 29Si MAS-NMR, and mercury porosimetry. The results show that the mechanical strength of the material is closely related to the nature, microstructure, and chemical composition of the reaction products, as well as to the curing conditions. In all cases, the main reaction product that forms is an inorganic alkaline polymer with cementing properties (N-A-S-H gel), which is largely responsible for the mechanical properties of the material. Some zeolites form as by-products, whose quantity and type (sodalite, zeolite A, faujasite, etc.) depend on the nature of the activator and the curing conditions. The presence of soluble silica in the activating solution leads to the formation of gels with a larger Si/Al ratio and slower zeolitisation, these both being factors with a positive effect on mechanical strength. The curing temperature exhibits a threshold value that depends on the composition of the material, beyond which an increase in curing temperature ceases to positively affect the evolution of the material’s mechanical strength.Programa de Alta Especialización en Tecnologías Industriales “Nuevas técnicas y recubrimientos cerámicos de baja temperatura” (IMAETA/2004/15-IMAETB/2005/12-IMAETB/2006/18) financiado por el Instituto de la Pequeña y Mediana Industria de la Generalitat Valenciana (IMPIVA) y a la Uunión Europea (Fondo Social Europeo), a la Dirección General de Investigación Científica y Técnica por la financiación del proyecto BIA2004-04835 y al CSIC/Fondo Social Europeo por el contrato de investigador en prácticas REF I3P-PC2004L.Peer reviewe

The Biological Station Torretes (Ibi, Alicante): a space for the conservation of odonates

Los odonatos son indicadores biológicos de la calidad de los medios acuáticos, ya que requieren, en la mayoría de los casos, aguas limpias y bien oxigenadas para desarrollar sus etapas larvarias. Muchas especies han sido incluidas en la Lista Roja de especies amenazadas. Se ha llevado a cabo un estudio de la fauna de Odonatos en la Estación Biológica Torretes - Jardín Botánico de la Universidad de Alicante (Ibi, Alicante), un espacio de bosque mediterráneo de 53 hectáreas, que está gestionado por el Instituto de Investigación CIBIO de la Universidad de Alicante. Este centro está destinado a investigar y difundir el valor de la biodiversidad y la conservación. Se han estudiado diversos puntos de agua permanentes con el objetivo de determinar áreas de conservación de la biodiversidad. En la estación biológica se registraron 16 especies de odonatos de los 28 citadas en ambientes naturales para la provincia de Alicante, lo que resaltan la importancia de este espacio natural en la conservación de estos insectos.Odonates are biological indicators of the aquatic environments quality, because them require, in most cases, clean and well oxygenated waters to develop their larval stages. Many species have been included in the Red List of threatened species for their vulnerability to contaminated environments. A study of odonata fauna was carried out in several permanent water points in the Biological Station – Botanical Garden of Torretes (Ibi, Alicante), a Mediterranean forest space of 53 hectares, managed by the Research Institute CIBIO of the University of Alicante. This center aims to investigate and disseminate the value of biodiversity and conservation. In the biological station was collected 16 species Odonates of the 28 reported in natural environments for the Alicante province, which highlight the importance of this natural space in the conservation and biodiversity of these insects

Clumsiness and Motor Competence in Physical Education and Sport Pedagogy

One of the main objectives of physical education and sport (PES) pedagogy in schools is to develop motor competence in children. While many schoolchildren practice sports, there is a group of children that does not receive the educational opportunities to be competent. These children show low motor competence and poor motor coordination. International agencies have called this condition as developmental coordination disorders (DCD) and its definition in short is “poor motor performance in daily activities that is not consistent with the child’s age and intelligence, and is not due to medical condition.” Physical education and sport teachers are the first interventionist with these children. They have the first opportunity of providing primary care to these children. In this chapter, motor coordination problems in school, its prevalence, how these children learn, how physical education and sport teachers can detect them, and why physical education and sport pedagogy must be concerned with this problem, will be analyzed