Proceedings of the International Micro Air Vehicles Conference and Flight Competition 2017 (IMAV 2017)

The IMAV 2017 conference has been held at ISAE-SUPAERO, Toulouse, France from Sept. 18 to Sept. 21, 2017. More than 250 participants coming from 30 different countries worldwide have presented their latest research activities in the field of drones. 38 papers have been presented during the conference including various topics such as Aerodynamics, Aeroacoustics, Propulsion, Autopilots, Sensors, Communication systems, Mission planning techniques, Artificial Intelligence, Human-machine cooperation as applied to drones

Relevance of cycle threshold values in mass screening by reverse-transcription-PCR during COVID-19 pandemic in Belgium: a decision-making support?

peer reviewedAim: The Belgium’s strategy against COVID-19 was partly based on mass screening. Here, we reported the results observed in a Belgian mass screening center. Materials & methods: Between October 2020 and February 2021, 32,089 samples were collected analyzed with reverse-transcription PCR (Thermo Fisher Scientific kits and apparatus). Patients were categorized according to their contagiousness (extrapolated from the cycle threshold [Ct] values and the recommendation of Sciensano). Results: We observed association between Ct values and age, with higher Ct observed in extreme age groups (75 years). Conclusion: The analysis of the evolution of the contagiousness of these patients tested twice within a 7-day period showed the relevancy of the recommendation edited by Sciensano

A Short–Time Scale Colloidal System Reveals Early Bacterial Adhesion Dynamics

The development of bacteria on abiotic surfaces has important public health and sanitary consequences. However, despite several decades of study of bacterial adhesion to inert surfaces, the biophysical mechanisms governing this process remain poorly understood, due, in particular, to the lack of methodologies covering the appropriate time scale. Using micrometric colloidal surface particles and flow cytometry analysis, we developed a rapid multiparametric approach to studying early events in adhesion of the bacterium Escherichia coli. This approach simultaneously describes the kinetics and amplitude of early steps in adhesion, changes in physicochemical surface properties within the first few seconds of adhesion, and the self-association state of attached and free-floating cells. Examination of the role of three well-characterized E. coli surface adhesion factors upon attachment to colloidal surfaces—curli fimbriae, F-conjugative pilus, and Ag43 adhesin—showed clear-cut differences in the very initial phases of surface colonization for cell-bearing surface structures, all known to promote biofilm development. Our multiparametric analysis revealed a correlation in the adhesion phase with cell-to-cell aggregation properties and demonstrated that this phenomenon amplified surface colonization once initial cell-surface attachment was achieved. Monitoring of real-time physico-chemical particle surface properties showed that surface-active molecules of bacterial origin quickly modified surface properties, providing new insight into the intricate relations connecting abiotic surface physicochemical properties and bacterial adhesion. Hence, the biophysical analytical method described here provides a new and relevant approach to quantitatively and kinetically investigating bacterial adhesion and biofilm development

Scale effect concerning hydraulic quasi-stationary oscillations on a turbine model and test circuit

For the continuation of the study undertaken during the Amsterdam Symposium and within the framework of the "Work Group on the Behavior of Hydraulic Machinery under steady oscillatory conditions" the authors have the following objectives: - comparison between the experimental responses of the circuit to a piston machine excitation and the calculated responses by the impedance method; - comparison between the experimental responses of the circuit to a piston machine excitation and the responses to excitation produced by the flow at partial load; - conditions under which a pulsation phenomenon occurs at high loads. The first aim is achieved but yet under restrictive conditions. The second investigation shows that the scale effects of fluctuations versus/test head have the same tendencies as the frequency responses of the circuit but that the occurence of cavitation deeply changes such responses. Finally, the occurence of pulsations at high loads is closely related to the axisymmetric vapor amount in the draft tube and the pulsation frequency also varies with the characteristics of this vapor amount

Examen expérimental de la stabilité des turbines Francis sur modèle et sur prototype à charge partielle

Les définitions de la stabilité étant précisées, Ia première contribution porte sur l'influence du degré de cavitation sur les amplitudes des fréquences et Ies phases de plusieurs signaux de pression et celui du couple. Cinq chutes d'essais sont également expérimentées en vue d'éclairer la question de Ia similitude des effets dynamiques. Un aperçu est donné concernant les variations du bruit émis en fonction du régime. Trois exemples de problèmes de stabilité sur de grands prototypes sont décrits, l'un concernant des implosions dans l'aspirateur et les deux autres des résonances avec la conduite. Les conclusions portent sur l'interêt de réaliser des essais spécifiques permettant de préparer des modèles mathématiques qui amélioreront Ia prévision de la stabilité

Editorial IJMAV: Special issue IMAV 2017

IMAV 2017 has gathered more than 280 participants from 30 different countries including Asia, North, Central and South America, Europe, and Australia. The special issue IMAV 2017 includes a selection of the best papers nominated for the "Best Paper Award"