Transmission à variation continue pour articulation robotique

Ce mémoire présente le développement d'une transmission à variation continue pour les articulations robotiques. Le domaine de la robotique pourrait considérablement augmenter l'efficacité et la performance de ces systèmes en intégrant de nouveaux types de transmission au niveau de ses actionneius. En effet, les transmissions à ratio variables sont utilisées dans une multitude de domaines (transport, production d'énergie etc.) et permettent d'obtenir une plus grande polyvalence en gérant adéquatement la source de puissance disponible. Dans le cadre de ce projet, la transmission développée est principalement basée sur un mécanisme à cinq barres. Dans un premier temps, l'analyse cinématique et l'optimisation des dimensions du mécanisme sont exposées. Grâce à cette optimisation, un comportement performant et uniforme est atteint. En second lieu, une étude comparative avec un autre concept potentiel de transmission est présenté. Cette étude permet de démystifier le potentiel des train épicycloïdaux à double actionnement. Finalement, un prototype du mécanisme a été conçu et fabriqué. Ainsi, un chapitre est consacré aux composantes et aux méthodes de commande nécessaires au bon fonctionnement du prototype. Cette section inclut aussi une validation expérimentale du comportement espéré de la transmission et des essais expérimentaux qui permettent d'estimer l'efficacité effective du prototype fabriqué

Développement d'un outil d'évaluation de l'équilibre assis chez les individus ayant une lésion à la moelle épinière: Une étude exploratoire

Travail d'intégration réalisé dans le cadre du cours PHT-6113.Contexte : Les individus ayant une lésion de la moelle épinière (LMÉ) exécutent la majorité de leurs activités de la vie quotidienne en position assise. La stabilité posturale du tronc est donc une composante importante. Conséquemment, le manque de méthode d’évaluation de l’équilibre assis limite les résultats au niveau de la recherche d’interventions efficaces. Objectifs : Obtenir un portrait actuel de l’état des connaissances sur les outils d’évaluation et les traitements disponibles et suggérer des items clés pouvant être intégrés dans une première phase du développement d’un test standardisé de l’équilibre assis chez les individus ayant une LMÉ. Méthode : Une recension des tests d’équilibre assis existants pour d'autres populations a permis la création d’une banque d’items. Des items de cette banque ont été sélectionnés et d’autres ont été créés en fonction des composantes de l’équilibre assis et de la population ciblée. Les items ont ensuite été échelonnés par ordre de difficulté et les cotations ont été déterminées pour chaque item. Résultats : Un test standardisé de l’équilibre assis pour les individus ayant une LMÉ de 12 items a été proposé. Chaque item a une cote de 0 à 4 pour un score total de 56. Conclusion : Les retombés anticipées du test sont d’objectiver l’évaluation de l’équilibre assis, de connaître le risque de chute, de déterminer le niveau de supervision requis, d’évaluer l’efficacité des traitements et d’être sensible à la variabilité de la population des individus ayant une LMÉ

fMRI visualization of transient activations in the rat olfactory bulb using short odor stimulations

International audienceOdor-evoked activity in the olfactory bulb displays both spatial and temporal organization. The difficulty when assessing spatio-temporal dynamics of olfactory representation is to find a method that reconciles the appropriate resolution for both dimensions. Imaging methods based on optical recordings can reach high temporal and spatial resolution but are limited to the observation of the accessible dorsal surface. Functional magnetic resonance imaging (fMRI) may be useful to overcome this limitation as it allows recording from the whole brain. In this study, we combined ultra fast imaging sequence and short stimulus duration to improve temporal resolution of odor-evoked BOLD responses. Short odor stimulations evoked high amplitude BOLD responses and patterns of activation were similar to those obtained in previous studies using longer stimulations. Moreover, short odor exposures prevented habituation processes. Analysis of the BOLD signal time course in the different areas of activation revealed that odorant response maps are not static entities but rather are temporally dynamic as reported by recent studies using optical imaging. These data demonstrated that fMRI is a non-invasive method which could represent a powerful tool to study not only the spatial dimension of odor representation but also the temporal dimension of information processing

Talking about frailty: Health professional perspectives and an ideological dilemma

Frailty is increasingly used in clinical settings to describe a physiological state resulting from a combination of age-related co-morbidities. Frailty also has a strong 'lay' meaning that conjures a particular way of being. Recent studies have reported how frail older people perceive the term frailty, showing that frailty is often an unwanted and resisted label. While there are many scores and measures that clinicians can use to determine frailty, little has been published regarding how health-care professionals use and make sense of the term. This paper reports the findings of a qualitative study that explored how health professionals perceive frailty. Forty situated interviews were conducted with health-care professionals working in an emergency department in the English Midlands. The interview talk was analysed using discourse analysis. The findings show that the health professionals negotiate an 'ideological dilemma'-a tension between contradictory sets of meanings and consequences for action-based on their 'lay' and clinical experience of the term frailty. It is concluded that this dilemma could have a negative impact on the assessment of frailty depending on the system of assessment used

Development of 55 novel polymorphic microsatellite loci for the critically endangered L. (Actinopterygii: Perciformes: Percidae) and cross-species amplification in five other percids

International audienceBy combining biotin-enrichment protocol and next generation pyrosequencing, through 454 GS-FLX Titanium technology, 55 polymorphic microsatellites loci with perfect motif were isolated from the Rhone streber (), a critically endangered European fish species. Eight multiplex PCR kits were optimised in order to genotype a total of 58 polymorphic loci, including three previously published loci. The level of genetic diversity was assessed for 68 , 30 , 33 and four individuals. Amplification success was also assessed on and using single individuals. These markers will be useful to investigate the population structure of the highly fragmented Rhone streber. They represent a powerful tool for conservation issues and evolutionary approaches of this endemic species. Moreover, part of our markers demonstrated applicability to other percid species, allowing for potential applications to fisheries and aquaculture management

Optomechanical design of TMT NFIRAOS Subsystems at INO

The adaptive optics system for the Thirty Meter Telescope (TMT) is the Narrow-Field InfraRed Adaptive Optics System (NFIRAOS). Recently, INO has been involved in the optomechanical design of several subsystems of NFIRAOS, including the Instrument Selection Mirror (ISM), the NFIRAOS Beamsplitters (NBS), and the NFIRAOS Source Simulator system (NSS) comprising the Focal Plane Mask (FPM), the Laser Guide Star (LGS) sources, and the Natural Guide Star (NGS) sources. This paper presents an overview of these subsystems and the optomechanical design approaches used to meet the optical performance requirements under environmental constraints

Morphological assessment of non-human primate models of osteoarthritis: Comparisons of HR-MRI with CT arthrography (CTA)

International audienc

Electron quantum optics in ballistic chiral conductors

The edge channels of the quantum Hall effect provide one dimensional chiral and ballistic wires along which electrons can be guided in optics like setup. Electronic propagation can then be analyzed using concepts and tools derived from optics. After a brief review of electron optics experiments performed using stationary current sources which continuously emit electrons in the conductor, this paper focuses on triggered sources, which can generate on-demand a single particle state. It first outlines the electron optics formalism and its analogies and differences with photon optics and then turns to the presentation of single electron emitters and their characterization through the measurements of the average electrical current and its correlations. This is followed by a discussion of electron quantum optics experiments in the Hanbury-Brown and Twiss geometry where two-particle interferences occur. Finally, Coulomb interactions effects and their influence on single electron states are considered

Separation of the magnetic phases at the N\'{e}el point in the diluted spin-Peierls magnet CuGeO3

The impurity induced antiferromagnetic ordering of the doped spin-Peierls magnet Cu(1-x)Mg(x)GeO(3) was studied by ESR technique. Crystals with the Mg concentration x<4% demonstrate a coexistence of paramagnetic and antiferromagnetic ESR modes. This coexistence indicates the separation of a macroscopically uniform sample in the paramagnetic and antiferromagnetic phases. In the presence of the long-range spin-Peierls order (in a sample with x=1.71%) the volume of the antiferromagnetic phase immediately below the N\'{e}el point T_N is much smaller than the volume of the paramagnetic phase. In the presence of the short-range spin-Peierls order (in samples with x=2.88%, x= 3.2%) there are comparable volumes of paramagnetic and antiferromagnetic phases at T=T_N. The fraction of the antiferromagnetic phase increases with lowering temperature. In the absence of the spin-Peierls dimerization (at x=4.57%)the whole sample exhibits the transition into the antiferromagnetic state and there is no phase separation. The phase separation is explained by the consideration of clusters of staggered magnetization located near impurity atoms. In this model the areas occupied by coherently correlated spins expand with decreasing temperature and the percolation of the ordered area through a macroscopic distance occurs.Comment: 7pages, 10 figure