Extra-Heavy Crude Oil Viscosity Reduction Using and Reusing Magnetic Copper Ferrite Nanospheres

The main objective of this study is the synthesis, use, and reuse of magnetic copper ferrite nanospheres (CFNS) for extra-heavy oil viscosity reduction. The CFNS were synthesized using a solvothermal method resulting in mean particle size of 150 nm. Interactions of CFNS with the crude oil were evaluated through asphaltene adsorption isotherms, as well as static and dynamic rheology measurements for two cycles at 25 ◦C. Adsorption and desorption experiments corroborated that most of the asphaltenes adsorbed can be removed for nanoparticle reuse. During the rheology tests, nanoparticles were evaluated in the first cycle at different concentrations from 300 to 1500 mg/L, leading to the highest degree of viscosity reduction of 18% at 500 mg/L. SiO2 nanoparticles were evaluated for comparison issues, obtaining similar results regarding the viscosity reduction. After measurements, the CFNS were removed with a magnet, washed with toluene, and further dried for the second cycle of viscosity reduction. Rheology tests were performed for a second time at a fixed concentration of 500 mg/L, and slight differences were observed regarding the first cycle. Finally, changes in the extra-heavy oil microstructure upon CFNS addition were observed according to the significant decrease in elastic and viscous moduli.Spanish Project ref. RTI2018-099,224-B-I00 from ERDF/Ministry of Science, Innovation and UniversitiesState Research Agency. M.V.L.-RJunta de Andalucía, Spain, RNM-366 research grou

Carbon-based honeycomb monoliths for environmental gas-phase applications

Honeycomb monoliths consist of a large number of parallel channels that provide high contact efficiencies between the monolith and gas flow streams. These structures are used as adsorbents or supports for catalysts when large gas volumes are treated, because they offer very low pressure drop, short diffusion lengths and no obstruction by particulate matter. Carbon-based honeycomb monoliths can be integral or carbon-coated ceramic monoliths, and they take advantage of the versatility of the surface area, pore texture and surface chemistry of carbon materials. Here, we review the preparation methods of these monoliths, their characteristics and environmental applications

Identificar cobertura vegetal de suelo clasificando pixeles en imágenes hiperepectrales con SVM (maquinas de soporte vectorial)

Se realizó un experimento para clasificar 4 clases de cobertura vegetal de suelo usando imágenes hiperespectrales, con 63 bandas. Se trabajó con un pixel representado por vector de 63 características (uno por banda). Se probaron nueve filtros y el análisis sin filtro. Para la clasificación se usó una máquina de soporte vectorial (SVM), con un kernel perceptor multicapa (MLP). Se obtienen precisiones aceptables, mejorando muchas encontradas en la literatura [1] [2]. Con este trabajo se demuestra que es mejor usar imágenes hiperespectrales que las comúnmente usadas. Los resultados sugieren que es necesario emplear otras técnicas o pre-proceso para mejorar las clasificaciones en este tipo de imágenes

Symmetric Supercapacitor Electrodes from KOH Activation of Pristine, Carbonized, and Hydrothermally Treated Melia azedarach Stones

Waste biomass-derived activated carbons (ACs) are promising materials for supercapacitor electrodes due to their abundance and low cost. In this study, we investigated the potential use of Melia azedarach (MA) stones to prepare ACs for supercapacitors. The ash content was considerably lower in MA stones (0.7% ash) than that found in other lignocellulosic wastes. ACs were prepared by KOH activation of pristine, carbonized, and hydrothermally-treated MA stones. The morphology, composition, surface area, porosity, and surface chemistry of the ACs were determined. Electrochemical measurements were carried out in three- and two-electrode cells, 3EC and 2EC, respectively, using 1 M H2SO4 as the electrolyte. The highest capacitance from galvanostatic charge-discharge (GCD) in 2EC ranged between 232 and 240 F·g−1 at 1 A·g−1. The maximum energy density reached was 27.4 Wh·kg−1 at a power density of 110 W·kg−1. Electrochemical impedance spectroscopy (EIS) revealed an increase in equivalent series resistance (ESR) and charge transfer resistance (RCT) with greater ash content. Electrochemical performance of MA stone-derived ACs was compared with that of other ACs described in the recent literature that were prepared from different biomass wastes and results showed that they are among the best ACs for supercapacitor applications.This work was supported by FEDER and Spanish MINECO (grant number CTQ-2013-44789-R); and Junta de Andalucía (grant numbers P12-RNM-2892, RNM172). HGR gratefully acknowledges COLCIENCIAS (Colombia) for supporting her PhD studies

Influence of the hydrodynamic size and ζ potential of manganese ferrite nanozymes as peroxidase‒mimicking catalysts at ph 4 in different buffers

Peroxidase-mimicking activity of manganese ferrite nanoparticles was studied, based on the oxidation of TMB (3,3’,5,5’-tetramethylbenzidine) by H2O2 at pH 4 using acetate and citrate buffers. The aim of this study was to examine this reaction not only by enzymology (Michaelis-Menten kinetics model) but also by surface science methods of heterogeneous catalysis. Nanoparticles were characterized by different techniques to determine their phase composition, surface area, surface composition, surface charge, pH at the point of zero charge, magnetization, mean size, and morphology. Results show that the nanozymes are coated with buffer anions that form a shell around them. In addition, the hydrodynamic size and ζ potential of the nanoparticles under reaction conditions play an important role in the proposed Fenton-type oxidation mechanism. A greater amount of Mn ions than Fe ions leaches from the nanozymes during TMB oxidation, likely because Fe is better protected than Mn by the buffer coating the outer surface of the nanoparticles. This shortcoming must be addressed when applying these nanomaterials.Operative Program, and Junta de Andalucía FEDER 2014-2020 (Projects FEDER-UJA-138062

Surface Characteristics and Electrochemical Performance of Activated Carbons from Schinus molle Stones Prepared by Hydrothermal Carbonization and KOH Activation

Schinus molle (SM) stones contain ca. 47 % C and 1 % N and are therefore a potential raw material for the preparation of activated carbons (ACs) with N functionalities. In this study, we investigated the usefulness of SM stones to prepare ACs by hydrothermal carbonization (HTC) followed by KOH activation. For comparison purposes, ACs were also prepared by direct KOH activation of pristine SM stones. The objective was to study the effects of each preparation method on the physico-chemical surface and electrochemical performance of the ACs obtained. Ash content was lower and N content higher in ACs produced by HTC-KOH activation (HSM series) versus direct KOH activation (SM series). All ACs, except the most highly activated sample from the HSM series, had narrow micropores or constricted micropore entrances. The highest surface area and mesopore volume obtained were 1464 m2 g-1 and 0.29 cm3 g-1, respectively. Examination of AC porosity and surface area indicated that SM stones were more reactive to KOH activation after HTC. AC HSM200-2 had the largest capacitance, 235 F g-1 at 0.5 A g-1, and the highest energy density, 7.83 Wh kg-1, at a power density of 400 W kg-1. The electrochemical performance of this sample was comparable to that recently reported for a wide variety of biomass-based ACs

Modeling Urban Digital Twins over the Cloud-to-Thing Continuum

The interest in the development of smart cities and the proliferation of digital twins as a powerful information processing technology have lead to the definition of Urban Digital Twins (UDTs). UDTs model city aspects such as transportation, water supply or air pollution, together with their inherent complexity. For addressing this complexity, in this paper we propose the use of models distributed over the Cloud-to-Thing Continuum, in order to take advantage of the flexibility, scalability and computational capacity of digital services through the multiple physical infrastructures offered by this environment. Following this philosophy, we have modelled a distributed digital twin of the public bus service of the city of Malaga and the users who travel on it. We have validated the model against the real system using the USE tool, and used it to perform simulations and inferences.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Wavelet and Neural Structure: A New Tool for Diagnostic of Power System Disturbances

The Fourier transform can be used for analysis of nonstationary signals, but the Fourier spectrum does not provide any time-domain information about the signal. When the time localization of the spectral components is needed, a wavelet transform giving the time-frequency representation of the signal must be used. In this paper, using wavelet analysis and neural systems as a new tool for the analysis of power system disturbances, disturbances are automatically detected, compacted, and classified. An example showing the potential of these techniques for diagnosis of actual power system disturbances is presented