Collective action of water molecules in zeolite dealumination

When exposed to steam, zeolite catalysts are irreversibly deactivated by loss of acidity and framework degradation caused by dealumination. Steaming typically occurs at elevated temperatures, making it challenging to investigate the mechanism with most approaches. Herein, we follow the dynamics of zeolite dealumination in situ, in the presence of a realistic loading of water molecules by means of enhanced sampling molecular dynamics simulations. H-SSZ-13 zeolite is chosen as a target system. Monte Carlo simulations predict a loading of more than 3 water molecules per unit cell at representative steaming conditions (450 °C, 1 bar steam). Our results show that a higher water loading lowers the free energy barrier of dealumination, as water molecules cooperate to facilitate hydrolysis of Al–O bonds. We find free energies of activation for dealumination that agree well with the available experimental measurements. Clearly, the use of enhanced sampling molecular dynamics yields a major step forward in the molecular level understanding of the dealumination; insight which is very hard to derive experimentally

Teaching inclusive values through the inclusive logical disjunction

Introducción .El operador lógico de la disyunción admite dos posibilidades, la incluyente y la excluyente, siendo esta última la más arraigada en el pensamiento. El presente estudio trata de analizar si la enseñanza en los dos tipos de disyunción lógica favorece actitudes más incluyentes o inclusivas ante situaciones sociales hipotéticas que se presentan como disyunciones. Método. El estudio se ha realizado con niños y niñas de entre 10 y 13 años y se compara una condición en la que se realiza una instrucción en la disyunción lógica incluyente y excluyente con otra condición de control en la que no hay instrucción alguna. Se aplica un cuestionario tipo test en el que aparecen situaciones sociales y académicas sobre cinco aspectos relaciona-dos con la diversidad: orientación sexual; educación en valores éticos/religiosos; apertura religiosa; identidad de género y migración. Resultados. Los resultados indican que, salvo en la orientación sexual, los participantes de la condición de instrucción en disyunción lógica eligen en mayor medida la respuesta incluyente que integra ambas alternativas de la disyunción en las respuestas al cuestionario. Discusión y conclusiones. Los resultados apuntan hacia la utilidad pedagógica de la enseñanza de la disyunción incluyente a la hora de favorecer en el alumnado actitudes más inclusivasIntroduction: The logical disjunction operator supports two possibilities, the inclusive dis-junction one and the exclusive one. The last one is the most deeply rooted in our thinking.The present study tries to analyze if disjunction teaching promotes more inclusive attitudes in hypothetical social situations presented as disjunctions. Method: In the study participated boys and girls between 10 and 13 years old and compares a condition in which an instruction is carried out in the inclusive and exclusive logical disjunc-tion with another control condition in which there is no instruction. We applied a question-naire with social and academic situations related to aspects of diversity: sexual orientation; education in ethical/religious values; religious flexibility; gender identity and migration. Results:The results indicate that, except in sexual orientation, participants of the logical dis-junction instructional condition choose, to a greater extent, the inclusive responses which in-tegrates both disjunction alternatives in the questionnaire. Discussion or Conclusion: The results show the pedagogical utility of the use of inclusive disjunction to promote more inclusive attitudes in student

Influence of post-synthetic modifications on the composition, acidity and textural properties of ZSM-22 zeolite

[EN] In this work, an extensive investigation of the preparation of a large body of desilicated ZSM-22 zeolites and their basic characterization is presented. We investigate the effects of the properties of the starting zeolite, and we employ mixtures of NaOH with CTAB or TBAOH as well as subsequent acid washings to create mesoporous zeolites. Scanning and transmission electron microscopy and nitrogen adsorption revealed that the cristal morphology of the starting zeolite appears to be the dominant parameter which influences the mesopore generation. Mesopores were effectively created within the rod-like commercial crystallites, whereas the thinner dimensions of the needle-shaped particles of the lab-made zeolite represent an obstacle for an intra-mesopore creation. The alkaline, surfactant-assisted or combined NaOH/TBAOH desilication methods resulted in mesopores with different shape and size from the commercial zeolite. The sequential acid washing generally resulted in increased micropore volume with respect to the desilicated samples. Elemental analysis showed that extra-framework Al species were generated upon the desilication treatments, which are eventually removed by the acid treatment. The acidity studied by FTIR demonstrated that this occurs without a marked modification of the Brønsted acidity, whereas the concentration of surface silanol hydroxyl groups is increased. The comparison between the total Al concentration and the amount of Al in acidic sites quantified by pyridine adsorption shows that the acidity was recovered after the acid washing and suggests that original non-acidic Al species in the starting materials may have a role in the formation of both Lewis and extra-framework species upon desilication.This publication is a part of the inGAP Centre of research-based Innovation, which receives financial support from the Norwegian Research Council under contract no. 174893. F.R and M.T.N thank to MINECO for financial support through projects MAT2015-71842-P and SEV-2012-0267. All the authors thank the Electron Microscopy Service of the Universitat Politecnica de Valencia.Del Campo Huertas, P.; Beato, P.; Rey Garcia, F.; Navarro, MT.; Olsbye, U.; Lillerud, K.; Svelle, S. (2018). Influence of post-synthetic modifications on the composition, acidity and textural properties of ZSM-22 zeolite. Catalysis Today. 299:120-134. https://doi.org/10.1016/j.cattod.2017.04.042S12013429

Tracking Structural Deactivation of H-Ferrierite Zeolite Catalyst During MTH with XRD

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Influence of Football Match-Play on Isometric Knee Flexion Strength and Passive Hip Flexion Range of Motion in Football Referees and Assistant Referees.

The aim of this study was to examine the acute effect of officiating a football (soccer) match on isometric knee flexion strength and passive hip flexion range-of-motion (ROM) in referees and assistant football referees. Twelve referees (25.3 ± 3.3 years) and twenty-three assistant referees (25.1 ± 4.8 years) underwent measurements on isometric knee flexion strength and passive hip flexion ROM before and after officiating an official football match. Referees’ and assistant referees’ running patterns were monitored during the match using GPS technology. In comparison to pre-match values, referees reduced their isometric knee flexion strength (−12.36%, p = 0.046, Effect size [ES] = −0.36) in the non-dominant limb, while no significant differences were reported in the dominant limb (−0.75%, p = 0.833, ES = −0.02). No effect of the match was found in hip flexion ROM values in dominant (−4.78%, p = 0.102, ES = −0.15) and non-dominant limb (5.54%, p = 0.544, ES = 0.19). In assistant referees, the pre-to-post-match changes in isometric knee flexion strength (dominant limb −3.10%, p = 0.323, ES = −0.13; non-dominant limb −2.18%, p = 0.980, ES= 0.00) and hip flexion ROM (dominant limb 1.90% p = −0.816, ES = 0.13; non-dominant limb 3.22% p = 0.051, ES = 0.23) did not reach statistical significance. Officiating a match provoked a reduction in isometric knee flexion strength in the non-dominant limb of football referees, while no differences were reported in assistant referees.post-print676 K