Hydrogenation of furfural over supported Pd catalysts

Lignocellulosic biomass is the most abundant and economical non-fossil carbon source. Furthermore, it is not competitive with the food chain, coming from lignocellulosic wastes including agricultural and food processing, local urban solid and forestry wastes. However, these are made up of complex carbohydrates (mainly, cellulose and hemicellulose), which require to be broken down in their respective monomers. The hemicellulose is mainly composed of pentosans, which, after an initial hydrolysis step, are dehydrated to furfural. Furfural is an important platform molecule, since it has a wide range of applications, being considered the main chemical, aside from bioethanol, obtained from the sugar platform for the synthesis of chemicals, for plastics, agrochemical and pharmaceutical industries. In the present work, the hydrogenation of furfural in gas phase has been studied by using Pd as active phase, and different metal oxides as support, in order to elucidate the influence of the support on the catalytic performance. Furfural can be converted into chemicals with important applications in many different industrial fields. Thus, reduction of furfural can proceed through different pathways depending on the experimental conditions, where the nature of the catalysts plays a key role. In the case of Pd-based catalysts, the main products come from the decarbonylation of furfural.The catalytic results reveals that the nature of the support exerts an important influence on furfural conversion and yield. The highest conversion (92% after 5 h of TOS at 463 K) was attained with a Pd-SiO2 catalyst, with a furan yield of 70 mol%. This catalyst is the most selective to furan and a moderate deactivation is only observed after 5 h reaction. The catalytic performance demonstrates that decarbonylation reaction was the main pathway, although the formation of furfuryl alcohol and 2-methylfuran also suggests that the hydrogenation of the carbonyl group of furfural takes place.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Supported nickel nitride catalysts for the gas-phase hydrogenation of furfural

A series of catalysts with different nickel loading (2.5-30 wt%) has been prepared by UGR. The preparation of Ni3N phase was ascertained via Powder X-rays diffraction together with cubic nickel . The elemental chemical analysis and XPS data confirm the presence of the nitride phase. Their catalytic performance points out that catalysts with loading of 5-10 wt% Ni exhibit a higher stability, maintaining furfural conversion values higher than 75% after 5 h of time-on-stream at 170ºC, and the main products detected were furfuryl alcohol (hydrogenation) and furan (decarbonylation). This would indicate that two types of active sites are present on the catalyst surface. It is noteworthy the high catalytic activity of this family of catalyst, since they exhibit a better performance than Cu-ZnO catalysts, but using a lower reaction temperature and H2/furfural molar ratio, as well as a higher furfural concentration and WHSV values. The experimental conditions have been optimized in order to achieve the maximum yield in the target product, but preserving a high activity and stability. The fresh and spent catalysts have been characterized in order to elucidate structure-activity-stability relationships.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Experimental study on the bond behaviour between cfrp nsm strengthening system and concrete under fatigue loading

Strengthening techniques based on the use of Carbon Fibre Reinforced Polymer (CFRP) materials have been used in bridges to extend their service life, since it has been proved their excellent performance under fatigue loading. Despite that, only few studies regarding the CFRP-concrete bond behaviour under fatigue loading can be found in the literature. Therefore, there is a further need of investigating how fatigue conditions can affect the behaviour of the bonded joints, since this affects not only serviceability aspects, such as crack width and spacing, but also the ultimate capacity of the strengthened elements. This paper aims to contribute to the understanding of the bond behaviour of Near-Surface Mounted (NSM) CFRP-concrete specimens under fatigue loading. NSM CFRP-concrete specimens have been tested through direct pull-out tests under different fatigue loading conditions (20%-40%, 30%-50% and 40%-60% of the ultimate instantaneous load) at 5 Hz until 2.000.000 cycles. After the fatigue tests, specimens that did not fail under fatigue loading were tested monotonically until failure to study the residual bond response. A significant increase of slip between the CFRP and the concrete at the loaded end was observed with the increasing number of cycles, being higher with the average load increase. Furthermore, a decrease on the stiffness of the cycle’s loop and an increase of the residual slip were observed as the number of fatigue cycles increased. Finally, from the monotonic post-fatigue tests, a decrease on the load-slip stiffness was observed.- (undefined

Satisfacción con un destino turístico: Una investigación en Villavicencio (Colombia)

Este artículo presenta una visión de los niveles de satisfacción derivados de la experiencia del turista y de la vivencia de los habitantes de Villavicencio, en torno al desempeño de la ciudad como un destino turístico. Es un trabajo cuantitativo de análisis correlacional entre variables ordinales, para el cual se tomó como tamaño de muestra a 871 personas entre turistas y anfitriones. El objetivo permitió analizar los niveles de satisfacción de Villavicencio como destino turístico, a partir de las valoraciones realizadas por los turistas y por los residentes. Se destaca que para los turistas internacionales la mayor satisfacción se manifiesta por la amabilidad de los habitantes. En relación con los turistas nacionales, la satisfacción se manifiesta por el uso de espacios naturales. Finalmente, para el caso de los residentes, estos consideran que el desarrollo turístico de la ciudad les genera bajos niveles de satisfacción

Oxidative Condensation of Furfural with Ethanol Using Pd-Based Catalysts: Influence of the Support

PdO nanoparticles were deposited on several supports (β-zeolite, Al2O3, Fe2O3, MgO, and SiO2), which displayed different crystallinity, textural properties, and amount of acid and basic sites. These catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption–desorption isotherms at −196 °C, NH3 and CO2 thermoprogrammed desorption analyses (NH3- and CO2-TPD, and X-ray photoelectron spectroscopy (XPS). Pd-based catalysts were tested in the oxidative condensation of furfural with ethanol to obtain value-added chemicals. The catalytic results revealed high conversion values, although the presence of a high proportion of carbonaceous deposits, mainly in the case of the PdO supported on β-zeolite and Al2O3, is also noteworthy. The presence of basic sites led to a beneficial effect on the catalytic behavior, since the formation of carbonaceous deposits was minimized. Thus, the 2Pd-MgO (2 wt.% Pd) catalyst reached the highest yield of furan-2-acrolein (70%) after 3 h of reaction at 170 °C. This better catalytic performance can be explained by the high basicity of MgO, used as support, together with the large amount of available PdO, as inferred from XPS.The authors are grateful to financial support from the Spanish Ministry of Innovation, Science and Universities (Project RTI2018-094918-B-C44) and FEDER (European Union) funds, and University of Málaga (UMA18-FEDERJA-171)

Estudio de valoración del dolor en pacientes con fractura-luxación de Lisfranc

Objetivo: Cuantificar la presencia de dolor y pérdida de calidad de vida secundaria a la fractura-luxación de Lisfranc. Material y Métodos: Realizamos un estudio de cohortes transversal de 83 pacientes con diagnostico de fractura-luxación de Lisfranc. La presencia de dolor en reposo y en actividad se valoró mediante la aplicación de la Escala Visual Analógica (EVA) y el cuestionario de calidad de vida Espiditest. Resultados: La edad media de los pacientes estudiados fue de 38,36 años. No se detectaron diferencias en las puntuaciones por sexo y edad. No se encontró asociación entre calidad de vida en Espiditest y el tipo de tratamiento empleado, la cirugía precoz y su duración. Existía mayor consumo de analgésicos para control del dolor y más dificultad para regresar a su empleo o actividad laboral previa a la lesión en pacientes que presentaban peor calidad de vida en Espiditest. El grado de satisfacción por parte de los pacientes fue concordante con la calidad de vida. Conclusiones: La fractura-luxación de Lisfranc a pesar de ser una lesión incapacitante, no es tan limitante para la calidad de vida por causa del dolor.Objetives: To quantify the presence of pain and to determine loss of quality of life after a Lisfranc fracture-dislocation. Material and methods: We conducted a cross-sectional cohort study in 83 patients diagnosed with Lisfranc fracture-dislocation. The presence of pain at rest and during activity was assessed by means of a visual analogy scale (VAS) and the quality of life questionnaire Espiditest. Results: Patients in the study have a mean age of 38,36 years. The study results are not skewed by sex or gender of participants. No association whatsoever was found between the quality of life - according to the Espiditest - and the type of treatment being used, neither the early surgery nor the length of it. Patients with poorer quality of life - as shown in Espiditest - have a higher consumption of analgesics used for pain relief and more difficulty returning to their job or work activity prior to the injury. The degree of satisfaction by patients was consistent with the quality of their life. Conclusions: The Lisfranc fracture-dislocation, despite being a disabling injury, does not limit the quality of life because of pain

Estudio del yeísmo en el español de Barcelona a partir de materiales de PRESEEA

En enero de 2006, el equipo de investigación sociolingüística de la Universidad de Barcelona, integrado por profesores y doctorandos del Departamento de Filología Hispánica, se incorporó al Proyecto para el Estudio Sociolingüístico del Español de España y de América (PRESEEA), vinculado a la Asociación de Lingüística y Filología de América Latina (ALFAL), y que tiene como coordinador general a Francisco Moreno Fernández, Catedrático de Lengua Española de la Universidad de Alcalá. Dicho proyecto se organiza en una red internacional de equipos de investigación cuyo objetivo central es el de reunir un ingente corpus oral, sociolingüísticamente representativo, de un gran número de ciudades pertenecientes al mundo hispánico. La primera fase del proyecto, que se presentó en 1996, abarca hasta el año 2010 (Moreno Fernández 2006).1 Para el estudio de Barcelona, en el seno del grupo PRESEEA – BARCELONA – ES diseñamos una plantilla que contempla una representación de 108 informantes (los cuales deben haber nacido en la ciudad, haber llegado a ella antes de cumplir los diez años o llevar viviendo en el lugar más de veinte), distribuidos en tres variables de preestratificación: sexo, edad y nivel de instrucción. A este perfil general añadimos la variable ‘lengua primera’ (catalán / español), vista la repercusión que alcanza la convivencia de las dos lenguas en la ciudad (Torres 2007). En las páginas que siguen, nos proponemos abordar el avance real del yeísmo en la Ciudad Condal a partir de unas muestras seleccionadas de los datos de PRESEEABARCELONA- ES. El trabajo, que básicamente es de carácter fonético y presenta un análisis acústico centrado en aspectos frecuenciales, de duración y de intensidad de las muestras mencionadas, pretende ser un primer acercamiento al estadio en el que se encuentra el fenómeno en esta área específica

Nursing students bringing first aid to the community

AimThis study aimed to evaluate the theoretical and practical skills acquired by nursing students and school students after the service-learning project.MethodsThis study promotes nursing students and school students working together to gain awareness and basic theoretical knowledge of first aid. The learning project was conducted with nursing students (n = 67) and school students (n = 131) from April to June 2022. The nursing students gave scores higher than 8 on the aspects linked to expectations, self-perception, overall assessment, and attainment of the goals, and these results are in line with the qualitative analysis.ResultsMoreover, 100% of the school students reported a satisfactory outcome about the service.ConclusionService-learning is a challenging and motivating methodology for nursing students, which results in greater engagement with theory and practice and the development of essential skills for future professionals