The Langmuir's isotherm in the statistical mechanics of non-localized adsorption layer

info:eu-repo/semantics/publishe

Commande prédictive directe d'un convertisseur multicellulaire triphasé pour une application de filtrage actif

Les enjeux énergétiques liés à la qualité de la distribution de l énergie électrique nécessitent le développement des dispositifs de filtrage actif des réseaux électriques. L'objectif de la thèse est d'utiliser un convertisseur multicellulaire afin d'obtenir une source de courant avec une très bonne bande passante (pour compenser les courants perturbateurs). Une commande directe et prédictive est appliquée à un onduleur multicellulaire à 4 niveaux. Ce type de commande permet d'utiliser au mieux les avantages fréquentiels de cette structure de conversion d'énergie. L'utilisation de cet onduleur pour une application de filtrage actif se révèle très efficace au niveau de la compensation des harmoniques de courant. La loi de commande est implémentée dans le repère des tensions composées qui permet de prendre facilement en compte les déséquilibres. Un prototype expérimental, développé dans le cadre de la thèse nous permet de valider nos résultats obtenus tout d'abord en simulation.Energy issues related to the quality of the electrical distribution require the development of active power filtering devices. The aim of the thesis is to use a multicell inverter to obtain a current source with an excellent bandwidth. A direct and predictive control is applied to a 4 levels multicell inverter. This kind of command allows achieving the frequency benefits of this structure. The use of this inverter for an application of active filtering is very effective for the compensation of harmonic current. The frame control is based on the composed voltages and currents. Due to this frame, the currents can be balanced easily for unbalanced systems. An experimental prototype, developed during the thesis allows us to validate our results obtained first in simulation.TOULOUSE-ENSEEIHT (315552331) / SudocSudocFranceF

SURROGATE MODELS OF PM BRUSHLESS MOTOR FOR THE PRELIMINARY DESIGN OF A MULTI-ROTOR DRONE

International audienceMulti-rotor drones see their ranges of applications and dimensions expand rapidly. Their design often involves empirical knowledge based on previous products or prototypes. For new concepts, especially with heavy loads, design models are however interesting to avoid costly iterations. This article focuses on the definition and optimization of the electric propulsion system of multi-rotor UAVs. In particular, a focus will be made on the brushless motor / gearbox / propeller assembly in order to make a comparison between devices with or without gearbox for different ranges of drone dimensions. The design constraints can be of static (hover flight) or transient (take off) type, the models can be local (distributed parameters) or global (lumped parameters). In order to support the designer, a Model-Based Design methodology is proposed in order to represent distributed parameters models (3D FEM) by low cost surrogate models dedicated for sizing. The optimization loops at both local and global levels are implemented in an open source environment

SURROGATE MODELS OF PM BRUSHLESS MOTOR FOR THE PRELIMINARY DESIGN OF A MULTI-ROTOR DRONE

International audienceMulti-rotor drones see their ranges of applications and dimensions expand rapidly. Their design often involves empirical knowledge based on previous products or prototypes. For new concepts, especially with heavy loads, design models are however interesting to avoid costly iterations. This article focuses on the definition and optimization of the electric propulsion system of multi-rotor UAVs. In particular, a focus will be made on the brushless motor / gearbox / propeller assembly in order to make a comparison between devices with or without gearbox for different ranges of drone dimensions. The design constraints can be of static (hover flight) or transient (take off) type, the models can be local (distributed parameters) or global (lumped parameters). In order to support the designer, a Model-Based Design methodology is proposed in order to represent distributed parameters models (3D FEM) by low cost surrogate models dedicated for sizing. The optimization loops at both local and global levels are implemented in an open source environment

Model of an Ironless Axial Flux Permanent Magnet Motor Based on the Field Produced by a Single Magnet

International audienceThe Lorentz force law is proposed as an alternative to the Maxwell stress tensor to calculate the torque of an ironless Axial Flux Permanent Magnet motor. This alternative allows calculating only the magnetic field produced by the magnets. A model of this magnetic field based on the field produced by one magnet, the superposition principle and geometric transformations is proposed. A method for calculating the magnetic field of this single magnet, inspired by finite elements, is proposed to reduce the calculation time. The method is validated by 3D Finite Element Analysis simulations and experimental measurements performed on a test bench

Team MAVion entry in the IMAV'17 outdoor challenge – A tail-sitting trajectory-tracking µUAV

International audienceThis paper outlines current research conducted on tilt-body micro air vehicles at ISAE, and how we exploit recent advances to provide a tail-sitting flying-wing entry for the IMAV'17 outdoor challenge capable of performing automatic vertical takeoff , landing, and trajectory-tracking

Microswitch with mixed piezoelectric and electrostatic actuation

International audienceIn this article, a new concept of microswitch is investigated with the objective to decrease the actuation voltage. It consists in a component with two kinds of actuation mechanisms: piezoelectric actuation and electrostatic actuation. The structures were realized with a technology compatible with CMOs technology. Aluminium nitride (AIN) was selected as piezoelectric material for its maturity and integration capabilities

Sexual behavior, clinical outcomes and attendance of cervical cancer screening by HPV vaccinated and unvaccinated sexually active women

Concerns were raised about HPV vaccination possibly leading to riskier sexual behavior. We assessed sexual behaviors, risk of sexually transmitted infection, and attendance to cervical cancer screening by HPV vaccinated and unvaccinated young women. In this analysis, 1475 questionnaires completed by women aged 17–29 years were included. The majority of respondents (67.9%) were vaccinated against HPV. The proportion of those vaccinated decreased with age: from 93.2% in those aged 17–19 to 72.9% in those aged 20–22, and 21.8% in 23–29-year olds. A higher proportion of unvaccinated respondents had at least one sexual intercourse under the age of 15 when compared to those vaccinated (30% vs. 23%, p < .0001). The number of sexual partners during the last 12 months was similar between vaccinated and unvaccinated participants. Vaccinated participants reported more condom use (45% versus 38%; p = .0002), and less sexually transmitted infections (10% versus 28%; p < .0001), and less anogenital condylomas (2.2% vs. 11.6%; p < .0001). A screening test has been reported by 51% and 77% of vaccinated and unvaccinated participants, respectively (p < .0001). The association between vaccination status and cervical cancer screening disappeared when adjusting for participants’ age. The study results consolidate the existing body of data regarding the absence of an impact of HPV vaccination on sexual behavior or use of contraceptives

A(H1N1) pandemic influenza and its prevention by vaccination : Paediatricians’ opinions before and after the beginning of the vaccination campaign

Background: In June 2009, the World Health Organization declared an A(H1N1) influenza pandemic. In October 2009, the largest vaccination campaign in Canadian history began. The aim of this study was to document paediatricians’ knowledge, attitudes and practices (KAP) regarding A(H1N1) pandemic influenza and its prevention by vaccination just after the beginning of the A(H1N1) vaccination campaign and to compare the results with those obtained before campaign initiation. Methods: A self-administered mail-based questionnaire was sent to all Canadian paediatricians. Questionnaires were analyzed in two subsets: those received before and after the beginning of the vaccination campaign. Results: Overall the response rate was 50%. Respondents’ characteristics were comparable between the two subsets. Before the beginning of the campaign, 63% of paediatricians perceived A(H1N1) pandemic infection as a serious disease, that would occur frequently without vaccination compared to more than 75% after. Before the vaccination campaign, half of respondents or less thought that the A(H1N1) vaccine was safe (50%) and effective (35%) compared to 77% and 72% after. The proportion of paediatricians who reported they had received sufficient information on A (H1N1) vaccine increased from 31% before to 73% after the beginning of the vaccination campaign. The majority of respondents intended to get vaccinated against A(H1N1) influenza themselves (84% before and 92% after). Respondents’ intention to recommend the A(H1N1) vaccine to their patients increased from 80% before the beginning of the campaign to 92% after. In multivariate analysis, the main determinants of paediatricians’ intention to recommend the A(H1N1) vaccine were their intention to get vaccinated against A(H1N1) influenza themselves and a belief that A (H1N1) vaccine would be well accepted by health professionals who administer vaccines to the public. Conclusion: Results of this study show important increases in physicians’ level of confidence about A(H1N1) vaccine’s safety and immunogenicity and their willingness to recommend this vaccine to their patients. These changes could be explained, at least partially, by the important effort done by public health authorities to disseminate information regarding A(H1N1) vaccination.Medicine, Faculty ofPediatrics, Department ofNon UBCReviewedFacult