Simulación del proceso de gasificación de biomasa

La tendencia actual en el mundo de los energéticos es intentar disminuir el uso de combustibles fósiles y disminuir la dependencia que la humanidad tiene de ellos -- Se ha buscado reemplazar a los combustibles fósiles con otras fuentes de energía que tengan un menor impacto sobre el medio ambiente, como es la biomasa -- Existen diferentes opciones para aprovechar el recurso biomásico, siendo la más popular la combustión directa -- También es posible obtener de la biomasa diversos productos combustibles a través de distintos procesos, como la carbonización (pirólisis) para obtener carbón vegetal, fermentación alcohólica para obtener bioetanol, esterificación para obtener biodiesel, y gasificación para obtener biogás -- Esta última opción, se puede realizar a través de bacterias en lo que se conoce como gasificación anaeróbica, o por medio de procesos termoquímicos, que se conoce como gasificación pirolítica -- Es la gasificación pirolítica el objeto de estudio de este trabajo, por lo tanto, a partir de ahora será referida simplemente como gasificación -- El objetivo de este trabajo es el desarrollo de un programa de simulación numérica que permita conocer el comportamiento de la biomasa en un proceso de gasificación y las características del gas que dicha biomasa produciría, como su composición y contenido energético. Se eligió el programa MATLAB1 para el desarrollo del simulador -- El simulador puede ser utilizado con cualquier biomasa de la que se conozca su composición (C, H, O, N, S) -- Se expone la técnica que se siguió para plantear y resolver el problema de la simulación numérica del proceso de gasificación y se describe la lógica detrás del programa que se escribió en MATLAB para tal propósit

A multistage graph-based procedure for solving a just-in-time flexible job-shop scheduling problem with machine and time-dependent processing costs

This paper deals with a new flexible job-shop scheduling problem in which the objective function to be minimised is the sum of the earliness and tardiness costs of the jobs and the costs of the operations required to perform the jobs, the latter depending on the machine and the time interval in which they are performed (as happens in many countries with the costs of electric power or those of manpower). We formalise the problem with a mathematical model and we propose a heuristic procedure that is based primarily on constructing a multistage graph and finding in it the shortest path from the source to the sink. We also describe the generation of the data-set used in an extensive computational experiment and expose and analyse the obtained results.Peer ReviewedPostprint (author's final draft

Current status of the torus palatinus and torus mandibularis

While there is a hereditary component to tori, this does not explain all cases. Tori tend to appear more frequently during middle age of life; the torus palatinus is more commonly observed in females, but this is not the case with the torus mandibularis. Certain ethnic groups are more prone to one torus or the other. The torus is mainly removed due to prostodontic reasons, as it may also be used as biomaterial, not only in periodontology, but also in implantology. The aim of this study was a review of the literature from the past twenty years

Proposal of a "Checklist" for endodontic treatment

Objectives: On the basis of the 'Surgical Checklist' proposed by the WHO, we propose a new Checklist model adapted to the procedures of endodontic treatment. Study Design: The proposed document contains 21 items which are broken down into two groups: those which must be verified before beginning the treatment, and those which must be verified after completing it, but before the patient leaves the dentist's office. Results: The Checklist is an easy-to-use tool that requires little time but provides, order, logic and systematization by taking into account certain basic concepts to increase patient safety. Discussion: We believe that the result is a Checklist that is easy to complete and which ensure the fulfillment of the key points on patient safety in the field of endodontics

Biodegradable Chitosan-Derived Thioureas as Recoverable Supported Organocatalysts – Application to the Stereoselective Aza-Henry Reaction

Producción CientíficaEight different biodegradable chitosan-supported bifunctional chiral thioureas have been prepared as a greener and more sustainable alternative to those supported on petrochemical-derived polymers. These organocatalysts promoted an enantioselective aza-Henry reaction, which afforded good product yields with moderate to high enantioselectivity. The activity and stereodirecting ability of these materials were dependent on the accessibility of the reactants to the active site and increased with the length of the tether that connected the thiourea to the biopolymer. The best performing catalyst was able to be recovered and recycled five times without a loss of activity.2018-10-10Ministerio de Economía, Industria y Competitividad (Project CTQ 2014-59870-P

Hair cortisol concentrations in a Spanish sample of healthy adults

Hair cortisol concentration (HCC), as a novel promising method to retrospectively measure hypothalamic-pituitary-adrenal (HPA) axis activation, is being increasingly studied. We tested the relationships between HCC and a range of possible confounding variables in a Spanish sample of healthy adults and pregnant women. In this sample of healthy Spaniards, results suggested an association between HCC and physical exercise and educational level. In pregnant women, the prevalence of HCC was higher than in non-pregnant woman, and was related to educational level. This study emphasises the need to determine the relationship between HCC and confounders such as sociodemographic and lifestyle variables in the general population and specific groups formed by individuals such as pregnant women.This research is part of a doctoral thesis. It has been economically supported by the "PSI2015-63494-P" I+D Project of the Spanish Ministry of Economy and Competitiveness (MINECO) and FEDE

Structural and mechanistic insights into the cleavage of clustered O-glycan patches-containing glycoproteins by mucinases of the human gut

Mucinases of human gut bacteria cleave peptide bonds in mucins strictly depending on the presence of neighboring O-glycans. The Akkermansia muciniphila AM0627 mucinase cleaves specifically in between contiguous (bis) O-glycans of defined truncated structures, suggesting that this enzyme may recognize clustered O-glycan patches. Here, we report the structure and molecular mechanism of AM0627 in complex with a glycopeptide containing a bis-T (Galβ1-3GalNAcα1-O-Ser/Thr) O-glycan, revealing that AM0627 recognizes both the sugar moieties and the peptide sequence. AM0627 exhibits preference for bis-T over bis-Tn (GalNAcα1-O-Ser/Thr) O-glycopeptide substrates, with the first GalNAc residue being essential for cleavage. AM0627 follows a mechanism relying on a nucleophilic water molecule and a catalytic base Glu residue. Structural comparison among mucinases identifies a conserved Tyr engaged in sugar-π interactions in both AM0627 and the Bacteroides thetaiotaomicron BT4244 mucinase as responsible for the common activity of these two mucinases with bis-T/Tn substrates. Our work illustrates how mucinases through tremendous flexibility adapt to the diversity in distribution and patterns of O-glycans on mucins

CONMEBOL Libertadores Cup: Altitude impact on goals and results in 16 years of soccer matches

Background: The CONMEBOL Libertadores Cup, is the continent’s most important international club tournament. Teams are exposed to different altitudes with short acclimatization periods. The present study describe the effect of altitude on the results and goals of soccer club teams matches between 2000 and 2015 in the CONMEBOL Libertadores Cup. Materials & Methods: All home and visiting matches from the group phase onwards and which have been played at the traditional team venue were taken into account, thus, 2039 games were analysed. The teams were classified into altitude categories according to the physiological impact and registered hometown altitude. Poisson´s generalized linear model was used to study the relationship between the altitude of both home and visiting teams and the number of goals scored for each team according to the altitude category. The probabilities that the home team winning, drawing, or losing the match were estimated using a regression model for ordinal variables and assuming a multinomial probability distribution with the logistic linkage. Factors as heat, temperature and general performance of the teams were not considered. Results: Local team scores more (2.62 goals) when the visiting team descends three altitude categories, followed by a descent of two altitude categories (2.01 goals) and an ascent of three altitude categories (1.89 goals). This is associated with an increase probability of winning for the local team, being 5.5 times more likely when the visiting team descends three altitude categories, 2.3 times more when it descends two categories, and 2.5 times more when it ascends three altitude categories. Conclusions: These findings suggest that the visiting team is more likely to lose a match when it has to descend two or three altitude categories and when it ascends three altitude categories