Textura y Composición Mineral de Pizarras de Techar: Estudio con Microscopía Óptica, SEM, EMPA y TEM

[ES] Las pizarras comerciales son rocas de grano muy fino, con una esquistosidad del tipo slaty cleavage y una alta fisibilidad, condicionada por la microtextura de la roca (Barros et al., 1985). España es primer productor mundial de pizarras para cubiertas, con 114 plantas y más de 6.100 empleados. La producción anual de pizarra se ha venido incrementando hasta alcanzar en 2007 las 943 Kt (Federación Española de la Piedra Natural, 2008), con una facturación en torno a 400 M€/año. Gran parte de los yacimientos españoles de pizarra se concentran en la Zona Centroibérica (ZCI) del Macizo Ibérico, especialmente en el Dominio del Sinclinal de Truchas. Numerosas canteras se ubican también en la Zona Asturoccidental-leonesa (ZAOL). La mayor parte de las pizarras explotadas en el NO de España y todas las muestreadas en este trabajo son de edad ordovícica (Tabla 1), procediendo estas de las Formaciones Luarca, Casaio, Rozadais y Losadilla (Marcos, 1973; Barros, 1989).SIEl presente trabajo se ha financiado mediante el proyecto CGL2007- 60035/BTE del Ministerio de Ciencia e Innovación

Sulfur-substituted perylenediimides: Easy tunability of the electronic character

Perylenediimides (PDIs) are the focus of a huge number of research lines for their awesome properties which can be modulated over a wide range by chemical modification of their structure. However, industrial applications require reduced costs in materials preparation and transformation. In this contribution we explore the ability of sulfur-substituted PDIs to vary their electronic character from strong electron-donating to strong electron-accepting in just one reaction.This research is part of the I+D+i project PID2022‐140315NB-I00, funded by MICIU/AEI/10.13039/501100011033 and by ERDF/EU

XRD, electron microscopy (EMPA, SEM, TEM) and XRF characterization of roofing slates from NW Spain

[EN] The aim of this paper is to characterize thoroughly the mineralogy and petrography of a set of ten different types of commercial roofing slates from the NW of Spain. Representative samples of each type have been studied by transmitted and reflected-light optical microscopy, scanning and transmission electron microscopy, electron microprobe, X-ray fluorescence and X-ray diffraction techniques. Quantitative analyses of the main mineral percentages in each slate sample were made from XRD data using the Siroquant™ interpretation software system, based on Rietveld principles. The microscopic textures of the slates vary depending on the samples, and lepidoblastic to porphyroblastic textures have been described. Some slates with bands of sand layers display grano-lepidoblastic textures. White mica, quartz, chlorite and feldspar (albite) are the main minerals. The white micas and the chlorites have similar compositions in all the analyzed samples. Electron microprobe analyses indicate that the micas are K-rich dioctahedral varieties, having a composition close to muscovite with a phengitic component. They show the following average formula: (Na0.16 K1.39 Ca0.01) (Al3.83 Ti0.03 Fe0.15 Mg0.14) (Si6.22 Al1.78) O20 (OH)4. The chlorites are magnesian chamosites with an average formula of (Na0.02 K0.04 Ca0.01Al3.24 Ti0.01 Fe5.13 Mn0.03 Mg3.28) (Si5.23 Al2.77) O20 (OH)16. Accessory minerals are ilmenite, rutile, sulphides, carbonates, graphite, monazite, apatite, zircon and tourmaline. Two different associations of sulphide minerals are distinguished: 1) Type I with pyrite, pyrrhotite, pentlandite, cobaltite, chalcopyrite, sphalerite, galena, ullmannite and gersdorffite occurring as pre-kinematic porphydic aggregates; b) Type II mainly with post-kinematic pyrite and sporadic chalcopyrite and galena. The main carbonate mineral is ankerite ((Mg0.26, Ca0.49, Mn0.05, Fe0.19) CO3) with minor calcite and siderite also present.S

Synthesis of Dipyridylaminoperylenediimide–Metal Complexes and Their Cytotoxicity Studies

A new family of perylenediimide (PDI) silver and copper complexes has been successfully synthesized by reacting ortho- and bay-substituted (dipyrid-2′,2″-ylamino)perylenediimide ligands with metal phosphine fragments. The coordination of the metal center did not reveal a significant effect on the photophysical properties, which are mainly due to the PDI ligands, and in some cases quenching of the luminescence was observed. The antiproliferative effect of the free perylenediimide ligands and the metalloPDI complexes against the cervix cancer cell line HeLa was determined by MTT assay. The free perylenediimide ligands exhibited a moderate cytotoxic activity, but the coordination of silver or copper to the dypyridylamino fragment greatly enhanced the activity, suggesting a synergistic effect between the two fragments. In attempts to elucidate the cellular biodistribution of the PDIs and the complexes, a colocalization experiment using specific dyes for the lysosomes or mitochondria as internal standards revealed a major internalization inside the cell for the metal complexes, as well as a partial mitochondrial localization

Influence of substituents of Perylenebisimides on the surface energy and wettability: A systematic structure–property relationship analysis

This paper seeks to elucidate the influence on the surface wettability of a variety of substituents located in different positions of the perylene bisimide (PBI) core (ortho versus imide) with distinct electron-donor or -withdrawing character and diverse steric demand, using for this more than 20 planar PBIs. The correlation between the polarity of the individual functional group on the PBI and the surface wettability has been addressed by means of substituent descriptors in terms of Hansch-Fujita π parameter, Hammett σmeta and σpara constants, and steric parameters (Taft-Dubois Es’ and Charton υ). With these parameters, a quantitative structure–property relationship (QSPR) analysis has been performed using multivariable linear regression (MLR) fittings. The relationship of Surface Energy, determined by the static contact angle method with three different solvents, to structural properties of PBIs is described. As well, the polar and dispersive contributions have been determined. For planar PBIs, a predominant influence of the substituents in the imide position on the surface wettability has been found despite of the electronic nature and steric hindrance of the substituents simultaneously located in ortho positions. This effect is more pronounced with the longer alkyl substituents at the imide position. This study paves the way for a rational chromophore design considering the on surface behavior, which will ultimately condition the contact and thus their performance in optoelectronic devices

Optical microscope and SEM evaluation of roofing slate fissility and durability

Texto en español e inglés.[ES] Para evaluar la fisibilidad y la durabilidad de pizarras de techar comerciales, muestras representativas de diez yacimientos del NO de España han sido estudiadas mediante microscopía óptica de luz transmitida y reflejada, microscopía electrónica de barrido y ensayos tecnológicos. Los sulfuros dominantes en las diferentes pizarras estudiadas son pirita o pirrotina, por lo que la alterabilidad de estas es muy variable. La especie carbonatada dominante es ankerita, lo que explica la baja reactividad de estas pizarras en medios ácidos. El espesor comercial mínimo varía en función de la microtextura de la roca, oscilando entre 3,5 y 5 mm. Se propone el uso de la metodología desarrollada en este trabajo, con objeto de eliminar la subjetividad de los inputs de entrada utilizados en las metodologías actuales de evaluación y modelización de yacimientos, lo que incidiría en la mejora de los rendimientos de las explotaciones y en la minimización de la producción de estériles.[EN] The fissility and durability of representative samples of commercial roofing slates from ten deposits in the NW of Spain have been evaluated using transmitted and reflectedlight optical microscopy, scanning electron microscopy, chemical testing and geomechanical procedures. The dominant sulphides in the different slate samples are pyrite and pyrrhotite, the weathering potential of which can be highly variable. The dominant carbonate mineral is ankerite, which explains the low reactivity of these slates in acidic media. The minimum commercial plate thickness varies between 3.5 and 5 mm, depending on the microtexture of the rock. The methodology used in this paper is proposed in order to eliminate the subjectivity of input data that are used in current methods of evaluation and modelling of slate deposits, thus producing an improvement in the profitability of mining operations and a reduction in waste materials.S

Sensitivity analysis of a stress strain model for steel fiber reinforced concrete plates

p. 2941-2954This article deals with the sensitivity study of a given model for the behavior of thin laminar elements of SFRC (steel fiber reinforced concrete). In order to carry out this analysis, a brief description of the model used for the behavior of the SFRC in laminar elements is presented. The analysis was made by means of ABAQUS finite element software with a particular model for the behavior of SFRC. The limit of the fragile-plastic behavior of SFRC plates has been established as an outcome of the analysis. The results of test performed on plates were compared with the numerical simulation. Good correlation between experimental results and those obtained in the numerical simulation was observed as an adequate support for the model.Lopez-Gayarre, F.; Serrano, MA.; Lázaro Fernández, CM.; Domingo Cabo, A.; Pelufo Carbonell, MJ. (2009). Sensitivity analysis of a stress strain model for steel fiber reinforced concrete plates. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/668

Efficient passivated phthalocyanine-quantum dot solar cells

The power conversion efficiency of CdSe and CdS quantum dot sensitized solar cells is enhanced by passivation with asymmetrically substituted phthalocyanines. The introduction of the phthalocyanine dye increases the efficiency up to 45% for CdSe and 104% for CdS. The main mechanism causing this improvement is the quantum dot passivation. This study highlights the possibilities of a new generation of dyes designed to be directly linked to QDs instead of the TiO2 electrodes.This work has been supported by the Spanish Ministry of Science and Innovation, Generalitat Valenciana and the European FEDER funds (CTQ2011-26455, PROMETEO 2012/010, ACOMP/2013/024 and ISIC/2012/008)

Diels–Alder reaction on perylenediimides: synthesis and theoretical study of core-expanded diimides

A one-step reaction for the fusion of aromatic rings to one or both bay areas of perylenediimides using benzynes is presented. Yields as high as 70% for naphthoperylenendiimide 2 and 80% for dibenzocoronenediimide 3 are obtained. The reaction is also carried out using substituted benzynes, heteroaromatic benzynes and substituted perylenediimides. A combined experimental/theoretical approach, based on measuring redox and absorption/emission properties and performing density functional theory calculations, indicates that increasing the π-skeleton of PDIs transversally leads to significant and unexpected changes in the electronic, redox and optical properties. The observed trends are rationalized in terms of molecular orbital topology and overlap according to three different levels of core expansion, and can be used as design principles for obtaining PDIs with improved functionalities

Efficient deep-red light-emitting electrochemical cells based on a perylenediimide-iridium-complex dyad

A two-layer light-emitting electrochemical cell device based on a new perylenediimide-iridium-complex dyad is presented emitting in the deep-red region with high external quantum efficiencies (3.27%).Costa Riquelme, Ruben Dario, [email protected] ; Orti Guillen, Enrique, [email protected] ; Bolink, Henk, [email protected] ; Gierschner, Johannes, [email protected]