Charcoal obtained from cherry stones in different carbonization atmospheres

The exploitation of using agro-industrial residues as the cherry stone to produce charcoal and activated carbon is very relevant nowadays due to the high demand of these materials and their environmental advantages. This work describes the methods to prepare charcoal from cherry stones (CS) using final heating temperature of 600 °C, with or without the application of an equal flow of nitrogen or air. The isothermal time has been of 2 hours, an adequate time to study carbonisation by varying the atmosphere. The charcoal obtained has the appropriate characteristics as precursors of activated carbon. Of the three samples prepared in different atmospheres, *N, N∼ and AN, the third is an activated carbon. It is evidenced that the yield in material carbonaceous is somewhat lower when applying the nitrogen current and approximately 5% less when applying the air current. For the different samples, in this work we have studied the effects of the atmosphere during the heat treatment of CS, the yield, the chemical composition and the structure, as well as the pore structure of the same

Comprehensive educational model based on Challenge-Based Learning for the improvement of competency performance

"Insanity is doing the same thing over and over again and expecting different results". This phrase, attributed to Albert Einstein, contains a message that sums up what is happening in education systems. Fortunately, an increasing number of "madmen" are choosing to do something different to "innovate" in the teaching-learning process. This paper shows the influence of innovating in four key aspects that influence learning: instruction, methodology, space and time, if we want to improve competence performance and start to make the objectives of the Bologna Declaration a reality, through experiences carried out in the School of Industrial Engineering (EII) of the University of Extremadura

Recubrimientos multicapa microestructurados de ZrO2-Y2O3-Al2O3 obtenidos por la vía sol-gel para aplicaciones tecnológicas

Estructuras y revestimientos de óxido de circonio (ZrO2) y alúmina (Al2O3) se utilizan con frecuencia en muchas aplicaciones tecnológicas. Los ejemplos más comunes son herramientas de corte, revestimientos de barrera térmica, cámaras de combustión, etc. En estas y otras aplicaciones, los materiales trabajan bajo condiciones extremas (altas tensiones de contacto, agentes químicos, etc.) que pueden inducir un fallo catastrófico del sistema. El objetivo general del proyecto es diseñar, fabricar y caracterizar revestimientos microestructuradas multicapa basados en sistemas ZrO2-Y2O3 and ZrO2-Y2O3-Al2O3 mediante la combinación adecuada del método sol-gel y la técnica de recubrimiento por inmersión. En particular, se estudió la influencia del % Al2O3, incorporado en las películas protectoras, investigando su influencia en las características y propiedades de los recubrimientos a fin de establecer las pautas a seguir en el diseño de estructuras multicapa más resistentes, tenaces y con mejores propiedades superficiales.Structures and coatings of zirconia (ZrO2) and alumina (Al2O3) are frequently used in many technological applications. Common examples are cutting tools, thermal barrier coatings, combustion chambers, etc. In these and other applications, the materials work under extreme conditions (high contact stresses, chemical agents, etc.) which can induce catastrophic failure of the system. The general objective of the project is to design, fabricate and characterize microstructured and multilayered coatings based on ZrO2-Y2O3 and ZrO2-Y2O3-Al2O3 systems, by the adequate combination of sol-gel method and dip-coating technique. In particular, we studied the influence of % Al2O3, built in the protective films, investigating their influence on the characteristics and properties of the coatings in order to establish the guidelines to follow in designing more resilient, tenacious multilayer structures microstructured and with improved surface properties

Recubrimientos multicapa microestructurados de ZrO2-Y2O3-Al2O3 obtenidos por la vía sol-gel para aplicaciones tecnológicas

Estructuras y revestimientos de óxido de circonio (ZrO2) y alúmina (Al2O3) se utilizan con frecuencia en muchas aplicaciones tecnológicas. Los ejemplos más comunes son herramientas de corte, revestimientos de barrera térmica, cámaras de combustión, etc. En estas y otras aplicaciones, los materiales trabajan bajo condiciones extremas (altas tensiones de contacto, agentes químicos, etc.) que pueden inducir un fallo catastrófico del sistema. El objetivo general del proyecto es diseñar, fabricar y caracterizar revestimientos microestructuradas multicapa basados en sistemas ZrO2-Y2O3 and ZrO2-Y2O3-Al2O3 mediante la combinación adecuada del método sol-gel y la técnica de recubrimiento por inmersión. En particular, se estudió la influencia del % Al2O3, incorporado en las películas protectoras, investigando su influencia en las características y propiedades de los recubrimientos a fin de establecer las pautas a seguir en el diseño de estructuras multicapa más resistentes, tenaces y con mejores propiedades superficiales.Structures and coatings of zirconia (ZrO2) and alumina (Al2O3) are frequently used in many technological applications. Common examples are cutting tools, thermal barrier coatings, combustion chambers, etc. In these and other applications, the materials work under extreme conditions (high contact stresses, chemical agents, etc.) which can induce catastrophic failure of the system. The general objective of the project is to design, fabricate and characterize microstructured and multilayered coatings based on ZrO2-Y2O3 and ZrO2-Y2O3-Al2O3 systems, by the adequate combination of sol-gel method and dip-coating technique. In particular, we studied the influence of % Al2O3, built in the protective films, investigating their influence on the characteristics and properties of the coatings in order to establish the guidelines to follow in designing more resilient, tenacious multilayer structures microstructured and with improved surface properties

Adsorption of Paracetamol in Hospital Wastewater Through Activated Carbon Filters

In recent years, pharmaceutical products have been causing a serious environmental problem in hospital wastewater and water purification plants. The elimination of these pollutants is difficult due to their resistance to biological degradation. Paracetamol has been detected in higher concentrations in hospital wastewater than in other buildings. Activated carbons are a good material for removing paracetamol from hospital wastewater. One of the starting materials to obtain activated carbons is kenaf, which is an easy plant to cultivate. To study the elimination of paracetamol from hospital wastewater by activated carbon, the textural and chemical characterization of activated carbon, as well as the kinetic study and the analysis of the paracetamol adsorption mechanism by the adsorbent, have been carried out. The activated carbon samples studied are micro-mesoporous, with high specific surface values. The chemical composition with presence of oxygen groups favours the adsorption process. The adsorption kinetics were adjusted to a pseudo-second order model. The adsorption mechanism followed the intraparticular diffusion model, carried out in two stages: a fast first stage on the surface of the adsorbent and a slow one inside the pore. Based on the kinetic study, the use of this type of carbon is a good application for the removal of paracetamol from hospital wastewater

Numerical Simulation of the Cleaning Performance of a Venturi Scrubber

Industrial applications need to use different systems for the problem of gas cleaning. A lot of processes have been developed, such as the use of a venturi for gas cleaning and pollution reduction. Additionally, several studies have been developed especially in terms of pressure drop because it is one of the main parameters to determine its efficiency. While the phenomenon of mass transfer in a venturi scrubber has not found much attention, in the present study, a mass transfer two-dimensional simulation is developed for gasification gas cleaning through a venturi scrubber with boundary conditions represented in air inlet velocities of 10, 15, and 20 m/s and water inlet mass flow of 0.02, 0.04 and 0.06 kg/s. In this work, Navier–Stokes equations are solved numerically and the mass transfer technique is treated by the volume of fluid (VOF) model, using CFD software. The obtained results were analyzed by presenting the mass fraction, velocity and pressure contours, and profiles. The probability density function (PDF) of mass transfer is studied too, showing how the removal efficiency of the venturi scrubber increases with a decrease in the liquid flow rate and an increase in the gas velocity. Therefore, the results show that the proposed venturi has the best mass transfer performance with a PDF that reaches 97.6 for velocity liquid of 20 m/s and the removal efficiency showed higher values at low liquid flow rates

Numerical Simulation of the Cleaning Performance of a Venturi Scrubber

Industrial applications need to use different systems for the problem of gas cleaning. A lot of processes have been developed, such as the use of a venturi for gas cleaning and pollution reduction. Additionally, several studies have been developed especially in terms of pressure drop because it is one of the main parameters to determine its efficiency. While the phenomenon of mass transfer in a venturi scrubber has not found much attention, in the present study, a mass transfer two-dimensional simulation is developed for gasification gas cleaning through a venturi scrubber with boundary conditions represented in air inlet velocities of 10, 15, and 20 m/s and water inlet mass flow of 0.02, 0.04 and 0.06 kg/s. In this work, Navier–Stokes equations are solved numerically and the mass transfer technique is treated by the volume of fluid (VOF) model, using CFD software. The obtained results were analyzed by presenting the mass fraction, velocity and pressure contours, and profiles. The probability density function (PDF) of mass transfer is studied too, showing how the removal efficiency of the venturi scrubber increases with a decrease in the liquid flow rate and an increase in the gas velocity. Therefore, the results show that the proposed venturi has the best mass transfer performance with a PDF that reaches 97.6 for velocity liquid of 20 m/s and the removal efficiency showed higher values at low liquid flow rates

Análisis de la presión de la boquilla de varios hidrogeles en la bioimpresión basada en extrusión utilizando dinámica de fluidos computacional

Comunicación presentada a las XXXIX Jornadas de Automática, celebradas en Badajoz del 5 al 7 de Septiembre de 2018 y organizada por la Universidad de Extremadura.Extrusion bioprinting is an additive manufacturing technology with huge possibilities in the creation of engineered tissues. There are many researches about materials, cells and their interrelation. Nevertheless, there are not many researches about how the mechanics affect to cellular viability. In this way, we have done CFD simulations to check how the viscosity of materials can affect the pressure distribution in the tip of a nozzle. These results will be updated, in future works, with simulations of several materials and geometries.La bioimpresión por extrusión es una tecnología de fabricación aditiva con grandes posibilidades en la creación de tejidos de ingeniería. Hay muchas investigaciones sobre los materiales, las células y su interrelación. Sin embargo, no hay muchas investigaciones sobre cómo la mecánica afecta a la viabilidad celular. De esta manera, hemos realizado simulaciones de CFD para verificar cómo la viscosidad de los materiales puede afectar la distribución de la presión en la punta de una boquilla. Estos resultados se actualizarán, en trabajos futuros, con simulaciones de varios materiales y geometrías.Consejería de Economía e Infraestructuras, Junta de Extremadura. Project IB16200 “Optimización y mejora de técnicas de bioimpresión para regeneración de cartílago y prótesis vasculares”peerReviewe

Nozzle pressure analysis of several hydrogel on extrusion-based bioprinting using computational fluid dynamics

[Abstract] Extrusion bioprinting is an additive manufacturing technology with huge possibilities in the creation of engineered tissues. There are many researches about materials, cells and their interrelation. Nevertheless, there are not many researches about how the mechanics affect to cellular viability. In this way, we have done CFD simulations to check how the viscosity of materials can affect the pressure distribution in the tip of a nozzle. These results will be updated, in future works, with simulations of several materials and geometries.[Resumen] La bioimpresión por extrusión es una tecnología de fabricación aditiva con grandes posibilidades en la creación de tejidos de ingeniería. Hay muchas investigaciones sobre los materiales, las células y su interrelación. Sin embargo, no hay muchas investigaciones sobre cómo la mecánica afecta a la viabilidad celular. De esta manera, hemos realizado simulaciones de CFD para verificar cómo la viscosidad de los materiales puede afectar la distribución de la presión en la punta de una boquilla. Estos resultados se actualizarán, en trabajos futuros, con simulaciones de varios materiales y geometrías.Junta de Extremadura; IB1620