Methodology for assessing system performance loss within a proactive maintenance framework

Maintenance plays now a critical role in manufacturing for achieving important cost savings and competitive advantage while preserving product conditions. It suggests moving from conventional maintenance practices to predictive strategy. Indeed the maintenance action has to be done at the right time based on the system performance and component Remaining Useful Life (RUL) assessed by a prognostic process. In that way, this paper proposes a methodology in order to evaluate the performance loss of the system according to the degradation of component and the deviations of system input flows. This methodology is supported by the neuro-fuzzy tool ANFIS (Adaptive Neuro-Fuzzy Inference Systems) that allows to integrate knowledge from two different sources: expertise and real data. The feasibility and added value of such methodology is then highlighted through an application case extracted from the TELMA platform used for education and research

Dynamic nuclear polarization of a single charge-tunable InAs/GaAs quantum dot

We report on the dynamic nuclear polarization of a single charge-tunable self-assembled InAs/GaAs quantum dot in a longitudinal magnetic field of $\sim$0.2T. The hyperfine interaction between the optically oriented electron and nuclei spins leads to the polarization of the quantum dot nuclei measured by the Overhauser-shift of the singly-charged excitons ($X^{+}$ and $X^{-}$). When going from $X^{+}$ to $X^{-}$, we observe a reversal of this shift which reflects the average electron spin optically written down in the quantum dot either in the $X^{+}$ state or in the final state of $X^{-}$ recombination. We discuss a theoretical model which indicates an efficient depolarization mechanism for the nuclei limiting their polarization to ~10%.Comment: 4+ pages, 3 figure

Tight-binding calculations of image charge effects in colloidal nanoscale platelets of CdSe

International audienceCdSe nanoplatelets show perfectly quantized thicknesses of few monolayers. They present a situation of extreme, yet well de ned quantum con nement. Due to large dielectric contrast between the semiconductor and its ligand environment, interaction between carriers and their dielectric images strongly renormalize bare single particle states. We discuss the electronic properties of this original system in an advanced tight-binding model, and show that Coulomb interactions, including self-energy corrections and enhanced electron-hole interaction, lead to exciton binding energies up to several hundred meVs

Hyperfine interaction in InAs/GaAs self-assembled quantum dots : dynamical nuclear polarization versus spin relaxation

We report on the influence of hyperfine interaction on the optical orientation of singly charged excitons X+ and X- in self-assembled InAs/GaAs quantum dots. All measurements were carried out on individual quantum dots studied by micro-photoluminescence at low temperature. We show that the hyperfine interaction leads to an effective partial spin relaxation, under 50kHz modulated excitation polarization, which becomes however strongly inhibited under steady optical pumping conditions because of dynamical nuclear polarization. This optically created magnetic-like nuclear field can become very strong (up to ~4 T) when it is generated in the direction opposite to a longitudinally applied field, and exhibits then a bistability regime. This effect is very well described by a theoretical model derived in a perturbative approach, which reveals the key role played by the energy cost of an electron spin flip in the total magnetic field. Eventually, we emphasize the similarities and differences between X+ and X- trions with respect to the hyperfine interaction, which turn out to be in perfect agreement with the theoretical description.Comment: 10 pages, 5 figure

Pericytes support neutrophil subendothelial cell crawling and breaching of venular walls in vivo

Wellcome Trust (081172/Z/06/Z) to S. Nourshargh. D. Proebstl was supported by a Medical Research Council PhD studentship awarded to Barts and The London Medical School, and J. Whiteford is an Arthritis Research UK Fellow

D10.1. Laboratory tests of key advanced functionality of new ICT components to support e-maintenance architecture

It is the D10.1. of the European DYNAMITE projec

D10.2. Specification of the industrial test case and demonstration scenario,

It is the deliverable D10.2. of the European DYNAMITE projec

D2.1. Training sessions in advanced software tools

It is the deliverable D2.1. of the European Imapla projec

NTIC et Nouvelles Avancées en Maintenance... Vers une E-maintenance

L'e-maintenance est un concept innovant de maintenance généralement défini comme étant un mode de gestion de la maintenance selon lequel les biens sont surveillés et gérés via Internet. Cependant, de nombreuses autres définitions existent dans lesquelles sont introduits des principes complémentaires de collaboration, de connaissance, de pro-activité, de technologies ... Une première analyse de l'ensemble de ces définitions met en évidence de façon simplifiée que la e-maintenance émerge de deux facteurs principaux étroitement liés : d'une part, l'utilisation, au service de la maintenance, des NTIC, et, d'autre part, une nouvelle façon de penser la maintenance. L'objectif de cet article est de se focaliser plus spécifiquement sur le premier facteur en évaluant son impact vis-à-vis du nouveau besoin en maintenance et en l'illustrant à travers la notion d'infrastructure ou plate-forme de e-maintenance. En effet, existent déjà à ce jour de nombreuses plates-formes constituées d'un assemblage de progiciels, de e-technologies... plus à même d'offrir de nouveaux services en maintenance. Cependant, ces plates-formes matérialisent principalement une évolution de la maintenance conditionnelle (CBM) à laquelle sont ajoutés, pour de la prise de décision, des accès distants à des experts à travers des interfaces Web. Très peu de plates-formes récentes sont capables de fournir la quasi-totalité des services attendus en cohérence avec une vision stratégique de l'e-maintenance. La plate-forme TELMA du CRAN, utilisée dans le cadre du projet européen DYNAMITE, tend à être une de ces plates-formes et fait l'objet de la fin de l'article pour mettre en évidence certaines avancées caractéristiques des NTIC opérationnelles en e-maintenanc

E-maintenance : Nouvelle vision stratégique ou technologique de la maintenance?

L'E-maintenance est un concept émergent globalement défini par “a maintenance management concept whereby assets are monitored and managed over the Internet”. Cependant de nombreuses autres définitions existent dans lesquelles sont introduits des principes complémentaires de collaboration, de connaissance, d'intelligence ... Un consensus contextuel de la e-maintenance n'est donc pas encore approuvé avec de plus un nombre de travaux conséquent ne se référant, de façon unique, à aucun cadre réellement ratifié scientifiquement. Par conséquent, l'objectif de ce papier est de définir plus précisément le concept d'e-maintenance puis de proposer et de discuter un cadre de modélisation pour son déploiement. Ce cadre est basé sur le cadre de modélisation Zachman et structuré sur les niveaux stratégie, processus, organisation et infrastructur