Coal-Tar Pitch Utilization

Coal tar pitch has been traditionally used in the aluminium and graphite industry as a binder for anode and electrode manufacture. Further, coal-tar pitches have been studied as matrix precursors in carbon-carbon composites for carbon foam preparation and for energy storage carbons among others. The possibility of obtaining a wide range of carbon materials of different structure and properties,depending on the characteristics of the parent pitch, or even from the same pitch by simply changing the experimental conditions, makes pitch a very suitable product for the tailoring of carbon materials. Currently, improved coal-based pitches are in the process of being developed from tar fractions, such as anthracene-oil with no QI, with the aim of obtaining graphitic materials. This paper offers an overview of traditional uses of coal tar pitches, their main markets and their potential as carbon material precursors.Peer reviewe

Uncertainty of biomass stocks in Spanish forests: a comprehensive comparison of allometric equations

Biomass and carbon content are essential indicators for monitoring forest ecosystems and their role in climate action, but their estimation is not straightforward. A typical approach to solve these limitations has been the estimation of tree or stand biomass based on forest inventory data, using either allometric equations or biomass expansion factors. Many allometric equations exist, but very few studies have assessed how the calculation methods used may impact outcomes and how this impact depends on genera, functional group, climate or forest structural attributes. In this study we evaluate the differences in biomass estimates yielded by the most widely used biomass equations in Spain. We first quantify the discrepancies at tree level and among the main forest tree species. We observed that the divergences in carbon estimations between different equations increased with tree size, especially in the case of hardwoods and for diameters beyond the range used to calibrate the equations. At the plot level, we found considerable differences between the biomass values predicted using different methods (above 25% in one out of three plots), which constitutes a warning against the uncritical choice of equations to determine biomass or carbon values. The spatial representation of the differences revealed geographical patterns related to the dominance of fast-growing species such as Eucalyptus or Pinus pinaster, with a minor effect of forest structure, and almost no effect of climate. Finally, we observed that differences were mostly due to the data source rather than the modelling approach or equation used. Based on our results, BEF equations seem a valid and unbiased option to provide nation-level estimations of carbon balance, although local equations should preferably be used if they are available for the target area.This work was funded by the LIFE CLIMARK project (LIFE16 CCM/ES/000065) and by the Spanish State Research Agency through the UMBRACLIM project (PID2019-111781RB-I00). The authors would like to thank Lluis Coll for helpful discussions during the conceptualization of the study and Pere Gelabert for his help in map design and creation. Special thanks to Miquel de Caceres, Jordi Vayreda and Jordi Martinez-Vilalta for the creation of the Catalan Forestry Lab and the gathering and release of the IEFC data

5-Hy­droxy-7-phenyl-5-(prop-2-yn-1-yl)-5,6-dihydro-1-benzofuran-2(4H)-one monohydrate

In the title compound, C17H14O3·H2O, the six-membered ring, which adopts a half-chair conformation, makes a dihedral angle of 24.3 (2)° with the phenyl ring. In the crystal, the components are linked by O—H⋯O hydrogen bonds involving the water mol­ecule, and the hy­droxy and carbonyl groups of the organic compound. These inter­actions form a square-like supra­molecular synthon unit which propagates as chains parallel to the crystallographic b axis. A C—H⋯O interaction also occurs

Supercapacitor modified with methylene blue as redox active electrolyte

MWCNT-based supercapacitors (SC) containing methylene blue (MB) as redox active electrolyte were studied. MWCNTs were employed as model of electrode active material due to their ideal double-layer behavior facilitates the investigation of the energy storage mechanisms involved. MB led to a cell capacitance enhancement equal to 4.5 times the original cell capacitance of MWCNTs in sulphuric acid with a capacitance reduction of only 12% after 6000 charge–discharge cycles. The potential evolution of each electrode during galvanostatic cycling revealed that MB redox reaction develops in both electrodes simultaneously in the voltage range of 0–0.104 V and that this is the main cause of cell capacitance enhancement. Beyond this voltage range, the Faradaic contribution from the MB redox reaction decreases because the anode behaves as a capacitative electrode with a rather reduced charge-capacity due to the small surface area of MWCNTs. By means of a modified assembly composed of a Nafion membrane and MB and sulfuric acid solutions located in the cathode and anode compartments, respectively, it was demonstrated the limiting role of the capacitative electrode in the cell charge-capacity in this type of hybrid devices.The authors acknowledge the financial support of the MICINN (Project MAT2010-20601-C02-01). Silvia Roldán thanks MICINN for a FPI predoctoral research grant.Peer reviewe

Evaluating capacitive deionization for water desalination by direct determination of chloride ions

Ionic conductivity and capacitance measurements are widely used methods for evaluating the desalination efficiency in capacity deionization processes. In this study, these methods are revised and several problems associated to them are identified and evaluated. Furthermore, a new method based on the determination of the chloride ion concentration by means of a chloride selective electrode is proposed as a more reliable alternative for evaluating the desalination performance in these systems. This method has been shown not only to be precise in a wide range of salt concentrations but also to be independent of pH, one of the main limitations of the determinations based on ionic conductivity measurements.The authors thank MICINN and the European Union (project MAT2010-20601-C02-01) for the financial support provided. Patricia Díaz thanks MICINN for a FPI predoctoral research grant (FPI: BES-2011-045394).Peer reviewe

Método de obtención de oxido de material pregrafítico, oxido de grafeno o grafeno a partir de materiales pregrafíticos y productos obtenidos por dicho método

Método de obtención de óxido de material pregrafítico, óxido de grafeno o grafeno a partir de materiales pregrafíticos y productos obtenidos por dicho método. Método de obtención de un producto seleccionado del grupo que consiste en óxido de material pregrafítico, óxido de grafeno y grafeno, caracterizado porque comprende transformar al menos un material pregrafítico en el producto sin tratamiento de grafitización. Preferiblemente, el material pregrafítico es coque (comercial o preparado a partir de breas, tanto de petróleo como de carbón o sintéticas)Peer reviewedConsejo Superior de Investigaciones CientíficasB1 Patente sin examen previ

Comparison between electrochemical capacitors based on NaOH and KOH activated carbons

This work describes the chemical activation of a coke using two different activating agents to investigate their behavior as electrodes in supercapacitors. A coke was chemically activated with two hydroxides (KOH and NaOH) under nitrogen flow, at a constant mass hydroxide/coke ratio of 2 and temperatures of 600, 650, and 700 °C. All of the samples were characterized in terms of porosity by N2 sorption at 77 K, surface chemistry by temperature-programmed desorption (TPD), and electrical conductivity. Their electrochemical behavior as electric double-layer capacitors was determined using galvanostatic, voltammetric, and impedance spectroscopy techniques in an aqueous medium with 1 M H2SO4 as the electrolyte. Large differences in capacitive behavior with the increase in the current density were found between the two series of activated samples. The different trends were correlated with the results obtained from the TPD analysis of the CO-type oxygen groups. It was found that these oxygen groups make a positive contribution to capacitance, finding a good correlation between the specific capacitance values, and the amount of these oxygen groups was found for both series.This work was supported by the MICIN (Project MAT2007-61467).Peer reviewe

La aplicación del cuadro de mando integral para la mejora de la calidad de atención al usuario en el Ministerio Público - distrito fiscal de Chincha - 2016

La investigación es de tipo Hipotético – Deductivo con un diseño correlacional no experimental que buscó determinar la relación que existe entre la aplicación del Cuadro de Mando Integral y la Mejora de la Calidad de Atención en el Ministerio Público de Chincha, 2016. La muestra es no probabilística. Se utilizó una encuesta de elaboración propia como instrumento de evaluación, el cual fue aplicado a 85 usuarios elegidos aleatoriamente. Para la variable la aplicación del Cuadro de Mando Integral, se tuvo en cuenta cuatro dimensiones: esfuerzo económico, atención al usuario, procesos operativos, crecimiento y aprendizaje Y para la variable mejora de la calidad de atención al usuario, se tuvo en cuenta las dimensiones de Confiabilidad, Eficiencia, Eficacia, Cumplimiento. Al correlacionar los datos, se encontró lo siguiente: existe una correlación estadísticamente significativa entre la aplicación del cuadro de mando integral y la mejora de la calidad de atención al usuario. (p < 0.05; r = 0.72). Asimismo, se encontraron correlaciones entre el cuadro de mando integral y cada una de las dimensiones teóricas: confiabilidad (p < 0.05; r = 0.46), eficiencia (p < 0.05; r = 0.64), eficacia (p < 0.05; r = 0.66), cumplimiento (p < 0.05; r = 0.46), Por lo tanto, se concluye que existe correlación entre la aplicación del Cuadro de Mando Integral y la Mejora de la Calidad de Atención en el Ministerio Público de Chincha

Graphene materials with different structures prepared from the same graphite by the Hummers and Brodie methods

[EN] Graphene materials containing different functional groups were prepared from a natural graphite, by means of two different oxidation methods (Hummers and Brodie). It was observed that the differences in the structure of the resultant graphite oxides (GOs) greatly affect the structure of the graphenes resulting from their thermal exfoliation/reduction. Although the oxidation of the graphite was more effective with the modified Hummers method than with Brodie’s method (C/O of 1.8 vs 2.9, as determined by XPS), the former generated a lower residual oxygen content after thermal exfoliation/reduction and a better reconstruction of the 2D graphene structure (with fewer defects). This is explained by the presence of conjugated epoxy and hydroxyl groups in the GO obtained by Brodie’s method, which upon thermal treatment, lead to the incorporation of oxygen into the carbon lattice preventing its complete restoration. Additionally, graphene materials obtained with Brodie’s method exhibit, in general, smaller sheet size and larger surface area.The authors thank MICINN and European Union (CONSOLIDER INGENIO 2010, Ref. CSD2009-00050, MAT2010-16194) for their financial support. Dr. Patricia Alvarez thanks MICINN for her Ramon y Cajal contract.Peer reviewe

Global transpiration data from sap flow measurements: the SAPFLUXNET database

Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land–atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The “sapfluxnetr” R package – designed to access, visualize, and process SAPFLUXNET data – is available from CRAN.EEA Santa CruzFil: Poyatos, Rafael. Universitat Autònoma de Barcelona. Bellaterra (Cerdanyola del Vallès); EspañaFil: Poyatos, Rafael. CREAF. Bellaterra (Cerdanyola del Vallès); EspañaFil: Granda, Víctor. Universitat Autònoma de Barcelona. Bellaterra (Cerdanyola del Vallès); EspañaFil: Granda, Víctor. Joint Research Unit CREAF-CTFC. Bellaterra; EspañaFil: Flo, Víctor. Universitat Autònoma de Barcelona. Bellaterra (Cerdanyola del Vallès); EspañaFil: Adams, Mark A. Swinburne University of Technology. Faculty of Science Engineering and Technology; Australia.Fil: Adams, Mark A. University of Sydney. School of Life and Environmental Sciences; Australia.Fil: Adorján, Balázs. University of Debrecen. Faculty of Science and Technology. Department of Botany; HungríaFil: Aguadé, David. Universitat Autònoma de Barcelona. Bellaterra (Cerdanyola del Vallès); EspañaFil: Aidar, Marcos P. M. Institute of Botany. Plant Physiology and Biochemistry; BrasilFil: Allen, Scott. University of Nevada. Department of Natural Resources and Environmental Science; Estados UnidosFil: Alvarado-Barrientos, M. Susana. Instituto de Ecología A.C. Red Ecología Funcional; México.Fil: Anderson-Teixeira, Kristina J. Center for Tropical Forest Science-Forest Global Earth Observatory, Smithsonian Tropical Research Institute; PanamáFil: Anderson-Teixeira, Kristina J. Conservation Ecology Center. Smithsonian Conservation Biology Institute; Estados UnidosFil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Martínez-Vilalta, Jordi. CREAF. Bellaterra (Cerdanyola del Vallès); EspañaFil: Martínez-Vilalta, Jordi. Universitat Autònoma de Barcelona. Bellaterra (Cerdanyola del Vallès); Españ