Modification of polyetherimide membranes with ZIFs fillers for CO2 separation

[EN] Flat hybrid membranes composed of polyetherimide (PEI) as matrix and zeolitic imidazolate frameworks (ZIFs) as fillers at concentrations of 10 and 20 wt% were prepared. Apparent permeability coefficient and apparent diffusivity coefficient of gases (CO2 and N-2) for these hybrid membranes (PZIFs) were determined by the "timelag" method. The experimental conditions used were from 25 degrees C to 55 degrees C with pressures of 2, 3 and 5 bar. The PZIFs with fillers of ZIF-8 (PZ-Zn) and ZIF-67 (PZ-Co) showed apparent selectivities (alpha(pa(CO2)/pa(N2))) of 39.6 and 27.5, respectively, higher than the alpha(pa(CO2)/pa(N2)) of the reference membrane PEI, while the membrane with filler of ZIF-Mix (PZ-Zn/Co) showed the lowest alpha(pa(CO2)()/pa(N2)) selectivity of 10.3 in the membrane series (under conditions of 25 degrees C and 2 bar). It is proposed that the selectivity of the membrane series can be attributed to two critical factors: the particle size/distribution ratio in the polymer base and sorption of CO2 at local sites of the bimetallic mixture. On the other hand, gas permeation studies (O-2, CO2 and CH4, and CO2/CH(4 )and CO2/C2H4 mixtures), were carried out in the series of PZIFs membranes. Permeability data were obtained by an isostatic method based on a permeation cell connected in series to a gas chromatograph where the rate of permeated gases was analyzed until a stationary state was reached. The complementary characterization techniques were: scanning electron microscopy, thermogravimetric analysis, and powder X-ray diffraction, which support the existence of the amorphous/crystalline phases of the PZIFs.This research has been supported by the ENE/2015-69203-R project, granted by the Ministerio de Economia y Competitividad (MINECO), Spain; Also authors are grateful to UNAM-DGAPA-PAPIIT projects IG-100185, and IG-114818. This study was partially supported by the CONACyT (Mexico) projects 2013-05-231461 and CB -2014-01-235840.Vega, J.; Andrio, A.; Lemus, A.; Díaz, J.; Del Castillo, L.; Gavara, R.; Compañ Moreno, V. (2019). Modification of polyetherimide membranes with ZIFs fillers for CO2 separation. Separation and Purification Technology. 212:474-482. https://doi.org/10.1016/j.seppur.2018.11.033S47448221

Regionalización de la variación temporal del factor de turbidez linke TL en México a partir de algoritmos de machine learning

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: El agrupamiento de áreas geográficas, por medio de análisis de clusters, es una tarea que permite identificar regiones de acuerdo a los comportamientos de las variables geoclimáticas. En este trabajo de investigación se agrupó al TL Linke en regiones similares de la república mexicana de acuerdo con su varianza temporal anual del año 2015. Mediante algoritmos y técnicas de Machine Learning (aprendizaje automático), como son las mezclas de gaussianos mixtos y análisis de componentes principales, se han obtenido dos mapas, de 10 y 9 regiones que permiten identificar de una manera visual dichas regiones y analizar el comportamiento del TL Linke en la república mexicana.ABSTRACT: The clustering of geographic zones, by cluster analysis, is a task which enables to identify geographic’s regions according to the behavior of geoclimatic’s variables. In this work, the TL Linke was grouped in similar regions in the Mexico country according to the temporal annual variance of the year 2015. Using machine learning algorithms and techniques like Gaussian mixture models and principal components analysis, we obtained two maps of 10 and 9 regions which enables identify and analyze the TL Linkes behavior on Mexico country.info:eu-repo/semantics/publishedVersio

Surface ablation of RbTiOPO4 by femtosecond laser

We report here the results obtained in surface ablation of RbTiOPO4 single crystals by femtosecond laser. We fabricated and characterized one-dimensional (1D) diffraction gratings with different lattice spacings of 15 and 20 μm, and with a sub-modulation of the period introduced in the later. The optical and electronic microscopy characterization and filling factor analysis of these diffraction gratings are reported. We also show that the roughness generated on the grooves by the ablation process can be improved by chemical etching.This work was partially funded by the European Commission under the Seventh Framework Program under Project Cleanspace FP7-SPACE-2010-1-GA-263044, supported by the Spanish Government under Projects PI09/90527, TEC2009-09551, AECID A/024560/09, FIS2009-09522, HOPE CSD2007-00007 and SAUUL CSD2007-00013 (Consolider-Ingenio 2010), by Catalan Government under Projects 2009SGR235 and 2009SGR549, by Junta de Castilla y León under Project GR27, and by the Research Center on Engineering of Materials and Systems (EMaS) of the URV. J.J.C. is supported by the Education and Science Ministry of Spain and European Social Fund under the Ramón y Cajal program, RYC2006-858. We also acknowledge support from the Centro de Laseres Pulsados, CLPU, Salamanca, Spain

A first-principles approach to electrical transport in atomic-scale nanostructures

We present a first-principles numerical implementation of Landauer formalism for electrical transport in nanostructures characterized down to the atomic level. The novelty and interest of our method lies essentially on two facts. First of all, it makes use of the versatile Gaussian98 code, which is widely used within the quantum chemistry community. Secondly, it incorporates the semi-infinite electrodes in a very generic and efficient way by means of Bethe lattices. We name this method the Gaussian Embedded Cluster Method (GECM). In order to make contact with other proposed implementations, we illustrate our technique by calculating the conductance in some well-studied systems such as metallic (Al and Au) nanocontacts and C-atom chains connected to metallic (Al and Au) electrodes. In the case of Al nanocontacts the conductance turns out to be quite dependent on the detailed atomic arrangement. On the contrary, the conductance in Au nanocontacts presents quite universal features. In the case of C chains, where the self-consistency guarantees the local charge transfer and the correct alignment of the molecular and electrode levels, we find that the conductance oscillates with the number of atoms in the chain regardless of the type of electrode. However, for short chains and Al electrodes the even-odd periodicity is reversed at equilibrium bond distances.Comment: 14 pages, two-column format, submitted to PR

Exploring the genomic diversity of black yeasts and relatives (Chaetothyriales, Ascomycota)

The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12,817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sex-related genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT 1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi

A MODEL SUGGESTION FOR THE DETERMINATION OF THE TRAFFIC ACCIDENT HOTSPOTS ON THE TURKISH HIGHWAY ROAD NETWORK: A PILOT STUDY

Sugestão de modelo para a determinação de pontos críticos de acidentes de tráfego na rede de estradas de rodagem da Turquia: um estudo pilot

Nutrient flux and budget in the Ebro estuary

The Ebro river flows to the Mediterranean coast of Spain. During its final stretch, the Ebro behaves in a similar way to a highly stratified estuary. This paper describes the transport of nutrients to the Ebro estuary, evaluates the general movement of nutrients in the estuarine region, using a mass balance approach, and estimates the amounts of nutrients discharged to the coastal environment. Given the strong saline stratification, this study only includes the surface layer that contains the continental freshwater. The annual nutrient budget for the Ebro estuary shows a net excess for nitrogen and phosphorus, while silicate almost attains equilibrium between addition and removal. There are several reasons for gains in nitrogen and phosphorous: a contribution of dissolved and particulate compounds in the freshwater (some of which are mineralized); a lower uptake of phytoplankton indicated by chlorophyll reduction in the estuary; an entrainment of the nutrient-rich upper part of the salt wedge; and, to a lesser extent, the impact of wastewater and agricultural water use. The biggest load discharged into the Mediterranean Sea by the Ebro is nitrogen, followed by silicate with over 10 000 tons of each deposited annually. Phosphorus is discharged at relatively low concentrations and with an annual load of about 200 t yr¿1.This project was funded by the European Union in the framework of the MAST-III research project: "Preparation and Integration of Analysis Tools towards Operational Forecast of Nutrients in Estuaries of European Rivers (PIONEER)", Reference No. MAS3-CT98-0170.Falco Giaccaglia, SL.; Niencheski, L.; Rodilla Alamá, M.; Romero Gil, I.; González Del Rio Rams, J.; Sierra, J.; Mösso, C. (2010). Nutrient flux and budget in the Ebro estuary. Estuarine, Coastal and Shelf Science. 87(1):92-102. doi:10.1016/j.ecss.2009.12.020S9210287