Comparison of aerodynamic models for Vertical Axis Wind Turbines

Multi-megawatt Vertical Axis Wind Turbines (VAWTs) are experiencing an increased interest for floating offshore applications. However, VAWT development is hindered by the lack of fast, accurate and validated simulation models. This work compares six different numerical models for VAWTS: a multiple streamtube model, a double-multiple streamtube model, the actuator cylinder model, a 2D potential flow panel model, a 3D unsteady lifting line model, and a 2D conformal mapping unsteady vortex model. The comparison covers rotor configurations with two NACA0015 blades, for several tip speed ratios, rotor solidity and fixed pitch angle, included heavily loaded rotors, in inviscid flow. The results show that the streamtube models are inaccurate, and that correct predictions of rotor power and rotor thrust are an effect of error cancellation which only occurs at specific configurations. The other four models, which explicitly model the wake as a system of vorticity, show mostly differences due to the instantaneous or time averaged formulation of the loading and flow, for which further research is needed.Aerodynamics, Wind Energy & PropulsionAerospace Engineerin

La détermination des causes de décès par autopsie verbale : étude de la mortalité palustre en zone rurale sénégalaise

Alors que le paludisme constitue actuellement un problème majeur de santé en Afrique au sud du Sahara, la mortalité qui lui est associée est difficile à estimer. Se basant sur la méthode d’autopsie verbale, nous présentons la mortalité palustre survenue avant l’âge de 5 ans à Bandafassi, Mlomp et Niakhar, trois populations rurales du Sénégal qui font simultanément l’objet d’un suivi démographique depuis 1985. Dans les trois sites, l’évolution de la mortalité palustre concorde avec le contexte épidémiologique et thérapeutique local mais des limites associées à la méthode utilisée sont possibles. Pour les étudier, nous analysons les diagnostics portés sur les décès d’enfants survenus depuis 2000. Ainsi, nous montrons qu’il existe une bonne concordance entre les médecins en charge du diagnostic, y compris s’agissant du paludisme - maladie pourtant reconnue comme étant peu spécifique. Par ailleurs, l’analyse des déterminants associés au diagnostic palustre nous assure d’une relative continuité des séries statistiques de la mortalité palustre depuis 2000 malgré d’importants changements dans le protocole d’enquête pour deux de ces trois sites. En l’absence de réelle statistique de causes de décès, les données fournies par le biais de la méthode d’autopsie verbale mise en place dans les sites de suivi démographique permettent donc de disposer d’informations précises dans le domaine épidémiologique, y compris concernant le paludisme

Application of agent-based modelling to simulate ribosome translation

Translation is a key process in the cell that encompasses the formation of proteins. However, how the translation mechanisms are affected by physiological changes is yet to be determined. Saccharomyces cerevisiae is one of the most used microorganisms to express recombinant proteins, showing great industrial/commercial value. Modelling the translation process in this yeast can thus bring forward novel insights into its mechanisms and how they are affected by changes in the environment. The present work introduces an agent-based model describing the elongation step of the translation process in the yeast. The simulated and theoretical elongation times were almost identical, with a standard deviation of 0.0018\\%, demonstrating the usefulness of the model to simulate this type of scenarios. Results also show a negative correlation between tRNA levels and estimated decoding times of codons, in accordance with biological knowledge. The model holds considerable potential to help unveil new ways of manipulation and thus increase the production of economically relevant yeast-derived products, namely biopharmaceuticals. Further development will address more complex scenarios, such as ribosome queuing or all the phases in the translation process.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit, BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte, and of the PhD Grant SFRH/BD/143491/2019. Additionally, it received funding through Base Funding - UIDB/00511/2020 of the Laboratory for Process Engineering, Environment, Biotechnology and Energy – LEPABE - funded by national funds through the FCT/MCTES (PIDDAC).info:eu-repo/semantics/publishedVersio