Effect of biofilm formation on the aggregation of microplastics in upper-ocean turbulence

The impact of biofilm formation on marine microplastics in the upper layers of the ocean has been investigated using direct numerical simulations with an Eulerian-Lagrangian point-particle approach. The influence of biofilm is modeled through the coalescence efficiency, also known as the stickiness parameter, which quantifies the probability of aggregation after a collision event. The results indicate that, owing to the small size of the particles, both microplastics and biogenic debris essentially behave as tracers, following the fluid flow. Differences in features such as aggregates formation and preferential concentration weakly depend on the tendency of aggregation. While this model simplifies the actual conditions of biofouled microplastics in the ocean, it provides a robust foundation for future numerical and experimental studies.Postprint (published version

Suitability of immersed-boundary methods for high-fidelity computational aeroacoustics

This work presents a preliminary assessment of the suitability of the immersed boundary method (IBM) for high-fidelity direct sound computations. A ghost-cell IBM is implemented in conjunction with a recently developed non-dissipative and robust numerical framework based on kinetic-energy and pressure-equilibrium preserving discretizations. The strategy is validated using the well-known canonical benchmark of acoustic scattering of a steady cylinder, providing accurate results and thus holding great promise for its application in complex scenarios.Postprint (published version

SAR Analysis of the ocean surface : aplication to the NW mediterranean marine pollution and dynamic features

The interaction between multiple scales in nature and mainly in turbulent flows produces fractals or multifractal structures. We use multi-fractal analysis to investigate the scales and influence of stratification in different types of surface eddies in the ocean, and specially, near the coastline. We will also show and discuss the structure and residence time in oil spills and slicks in the ocean surface. This method, of multifractal analysis on the intensity SAR signals, as an example will also be applied to experiments of unstable mixing fronts driven by Rayleigh-Taylor Instabilities. These hydrodynamic instabilities are a fundamental buoyancy or acceleration driven mixing process since they are the main causes of mixing and regulate for example the overturning process. A turbulent model is used in order to study the self-similar mixing process. The results are parameterized in terms of the Atwood number, which in terms of initial condition evaluation seems more convenient than using reduced gravity or buoyancy flux. The advance of the mixing front can be compared to several laboratory and field measurements, showing the effects of the initial perturbations and the two-dimensionality and boundary conditions of a model that combines 3 and 2 dimensional effects. The multi-fractal analysis reflects the flow conditions and allows us to understand further the mixing processes.Postprint (published version

Mathematical modeling, numerical simulation and experimental comparison of the desorption process in a metal hydride hydrogen storage system

Peer ReviewedPostprint (author's final draft

Effect of metal hydride properties in hydrogen absorption through 2D-axisymmetric modeling and experimental testing in storage canisters

A two-dimensional axisymmetric model is developed to study the hydrogen absorption reaction and resultant mass and heat transport phenomena inside a metal hydride canister. The model is compared against published literature and experimental data. Experimental tests are performed on an in-house fabricated setup using different cooling scenarios. An extensive study on the effects of the metal properties on charging performance is carried out through non-destructive testing (NDT). Results show that the properties that most influence the charging performance are: absorption rate constant (Ca), activation energy (Ea) and thermal conductivity (km). A Higher porosity (e) reduces charging time and amount of hydrogen stored while a higher cooling level produces a faster charging process. These results can be used to select metal hydride materials but also to estimate the metal hydride internal state and the process can be used for future evaluation of metal hydride degradation.Postprint (author's final draft

Artificial compressibility method for high-pressure transcritical fluids at low Mach numbers

Supercritical fluids possess unique properties that makes them relevant in various scientific and engineering applications. However, the experimental investigation of these fluids is challenging due to the high pressures involved and their complex thermophysical behavior. To overcome these limitations, computational researchers employ scale-resolving methods, such as direct numerical simulation and large-eddy simulation to study them. Nonetheless, these methods require substantial computational resources, especially in the case of low-Mach-number regimes due to the disparity between acoustic and hydrodynamic/thermal time scales. This work, therefore, addresses this problem by extending the artificial compressibility method to high-pressure transcritical fluids. This method is based on decoupling the thermodynamic and hydrodynamic parts of the pressure field, such that the acoustic time scales can be externally modified without severely impacting the flow physics of the problem. In addition, the method proposed has two key characteristics: (i) the splitting method presents low computational complexity, and (ii) an automatic strategy for selecting the speedup factor of the approach is introduced. The effectiveness of the resulting methodology is demonstrated through comprehensive numerical tests of increasing complexity, showcasing its ability to accurately simulate a wide range of high-pressure transcritical flows including turbulence. The results obtained indicate that the approach proposed can readily lead to computational speedups larger than without significantly compromising the accuracy of the numerical solutions.This work is funded by the European Union (ERC, SCRAMBLE, 101040379). Views and opinions expressed are however those of the authors only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them.Peer ReviewedPostprint (published version

Social Education, Professional Ethics and University Education

El ejercicio profesional de la educación social se asocia a los valores cívicos, a los derechos de la ciudadanía y a la responsabilidad, la proximidad y la escucha al sujeto como protagonista de su propio proceso. El artículo plantea una reflexión sobre la dimensión ética de la profesión y de los estudios de educación social. La metodología ha consistido en la consulta a profesionales de los ámbitos laboral y académico. De acuerdo con ese componente ético de la profesión, las obligaciones éticas y sociales deben incluirse en el currículum de los estudios y en el espacio organizativo y relacional de la institución.L’exercici professional de l’educació social s’associa als valors cívics, als drets de la ciutadania i de la responsabilitat, la proximitat i l’escolta al subjecte com a protagonista del seu propi procés. L’article planteja una reflexió sobre la dimensió ètica de la professió i dels estudis d’educació social. La metodologia ha consistit en la consulta a professionals dels àmbits laboral i acadèmic. D’acord amb aquest component ètic de la professió, les obligacions ètiques i socials s’han d’incloure en el currículum dels estudis i en l’espai organitzatiu i relacional de la institució.The professional exercise of social education is associated with civic values, with the rights of citizenship and with responsibility, proximity and listening to the subject as the protagonist of their own process. The article, which proposes a reflection on the ethical dimension of the profession and of social education studies, adopted a methodology of consulting professionals working in the field and in higher education. It seems clear that the declared ethical component of the profession requires that ethical and social obligations be included in the training curriculum and in the organizational and relational space of the institution

Relación de la nota de selectividad y la nota media del primer y segundo curso de los Grados de Energía y Mecánica de la EUETIB

This work explains te relationships between the final mark of the first and second courses of the Mechanical Engineering degree and Energy Engineering degree with the acces note of the EUETIB. El presente trabajo presenta la relación entre la nota de acceso a la uni-versidad y las notas finales del primer y Segundo curso de los grados de Ingeniería Mecánica e Ingeniería de la Energía de la EUETIB.Postprint (published version

Monitorització, via Internet, d'una estació de fabricació flexible electropneumàtica

El objetivo persigue la implementación de una arquitectura de telemonitorización de una célula de fabricación electroneumática del laboratorio de Mecánica de Fluidos y Termotecnia de la EUETIB. Se presentan las diferentes soluciones adoptadas en función de las disponibilidades y funcionalidad deseada. Desde la propia programación del autómata que se ha utilizado hasta la configuración de una red privada virtual para conexiones con el equipo más allá del entorno propio de la Escuela

El programa intergeneracional Compartir la Infància / Sharing Childhood: l’avaluació com a element de promoció dels projectes intergeneracionals

Sharing Childhood (2013-2015) és un projecte intergeneracional que ha estat coordinat per GIFES (Grup d’Investigació i Formació Educativa i Social de la UIB, Espanya) i ha comptat amb dues entitats col·laboradores: Foundation for the development of the education system (Lodz, Polònia) i Bayat Halk Eğitim Merkezi Mudurlugu (Afyonkarahisar, Turquia). El projecte s’emmarca en la convocatòria Lifelong Learning Programme de la Comissió Europea, dins del subprograma Grundtvig. Es tracta d’un projecte educatiu intergeneracional que pretén fomentar la interrelació entre diferents generacions en espais educatius de vida quotidiana, concretament, el centre escolar. A l’inici de l’experiència ens plantejàrem dos reptes. El primer era el coneixement sobre la millora de les relacions intergeneracionals i els efectes de la intervenció sobre el context d’aplicació del programa: participants, família, professionals i comunitat. El segon repte era l’elaboració d’una guia de bones pràctiques. En aquest article presentam el resultat de l’experiència.Sharing Childhood (2013-2015) es un proyecto intergeneracional que ha sido coordinado por GIFES (Grupo de Investigación y Formación Educativa y Social de la UIB, España) y ha contado con dos entidades colaboradoras: Foundation for the development of the education system (Lodz, Polonia) y Bayat Halk Eğitim Merkezi Mudurlugu (Afyonkarahisar, Turquía). El proyecto se enmarca en la convocatoria Lifelong Learning Programme de la Comisión Europea, dentro del subprograma Grundtvig. Se trata de un proyecto educativo intergeneracional que pretende fomentar la interrelación entre diferentes generaciones en espacios educativos de vida cotidiana, concretamente, el centro escolar. Al inicio de la experiencia nos planteamos dos retos. El primero era el conocimiento sobre la mejora de las relaciones intergeneracionales y los efectos de la intervención en el contexto de aplicación del programa: participantes, familia, profesionales y comunidad. El segundo era la elaboración de una guía de buenas prácticas. En este artículo presentamos el resultado de la experienci