167 research outputs found

    ЭЛЕКТРОННЫЕ СИСТЕМЫ ПЛАТЕЖЕЙ

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    В работе представлена информация об электронных системах платежей. Рассмотрены достоинства системы и требования к ней, а так же варианты решения данных требований

    Inertia compensation while scanning screw threads on coordinate-measuring machines

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    Usage of scanning coordinate-measuring machines for inspection of screw threads has become a common practice nowadays. Compared to touch trigger probing, scanning capabilities allow to speed up measuring process while still maintaining high accuracy. However, in some cases accuracy drasticaly depends on the scanning speed. In this paper a compensation method is proposed allowing to reduce the influence of some dynamic effects while scanning screw threads on coordinate-measuring machines

    Identification d'un modèle d'efforts de coupe mécanistique et application dans le cas d'un contournage de cuivre pur

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    L'obtention des caractéristiques des pièces usinées ainsi que la bonne maîtrise du procédé d'usinage sont liées aux efforts de coupe. De nombreux modèles d'efforts de coupe ont déjà été développés, mais ils sont souvent appliqués dans le cas d'opérations d'usinage élémentaires (coupe orthogonale ou oblique), ce qui limite leur utilisation à la communauté scientifique. La méthode de discrétisation d'arête permet de généraliser les applications de ces modèles à des géométries d'outils plus complexes. Néanmoins, les applications restent généralement limitées à des opérations d'usinage simples (chariotage, dressage, fraisage flanc...) plutôt éloignées des besoins industriels. D'autre part, les modèles mécanistiques sont généralement critiqués car nécessitant d'être calibrés à partir d'un trop grand nombre d'essais. La présente étude propose de minimiser le nombre d'essais nécessaires à l'identification. Pour cela, les coefficients d'un modèle mécanistique ont été estimés par identification inverse, à partir de différents nombres d'essais de chariotage. Le modèle ainsi identifié est comparé, pour chaque couple de coefficients, à des essais couvrant une large plage de conditions de coupe. Ce modèle est ensuite appliqué dans le cas d'une opération de contournage. Les résultats obtenus par modélisation à partir de la trajectoire théorique, mais aussi de la trajectoire mesurée à vide sur la machine, sont comparés avec les efforts mesurés lors de l'opération de contournage

    A High Resolution and Full-Spherical Head-Related Transfer Function Database for Different Head-Above-Torso Orientations

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    Head-related transfer functions (HRTFs) capture the free-field sound transmission from a sound source to the listeners ears, incorporating all the cues for sound localization, such as interaural time and level differences as well as the spectral cues that originate from scattering, diffraction, and reflection on the human pinnae, head, and body. In this study, HRTFs were acoustically measured and numerically simulated for the FABIAN head-and-torso simulator on a full-spherical and high-resolution sampling grid. HRTFs were acquired for 11 horizontal head-above-torso orientations, covering the typical range of motion of +/-50°. This made it possible to account for head movements in dynamic binaural auralizations. Because of a lack of an external reference for the HRTFs, measured and simulated data sets were cross-validated by applying auditory models for localization performance and spectral coloration. The results indicate a high degree of similarity between the two data sets regarding all tested aspects, thus suggesting that they are free of systematic errors

    The FABIAN head-related transfer function data base

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    This data base includes head-related transfer functions (HRTFs), headphone transfer functions (HpTFs), and 3D-meshes of the FABIAN head and torso simulator. More detailed information is provided in the documentation within the data base.DFG, WE 4057/3-1, Simulation and Evaluation of Acoustical Environments (SEACEN

    The Pseudomonas fluorescens siderophore pyoverdine weakens arabidopsis thaliana defense in favor of growth in iron-deficient conditions

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    Pyoverdines are siderophores synthesized by fluorescent Pseudomonas spp. Under iron-limiting conditions, these high-affinity ferric iron chelators are excreted by bacteria in the soil to acquire iron. Pyoverdines produced by beneficial Pseudomonas spp. ameliorate plant growth. Here, we investigate the physiological incidence and mode of action of pyoverdine from Pseudomonas fluorescens C7R12 on Arabidopsis (Arabidopsis thaliana) plants grown under iron-sufficient or iron-deficient conditions. Pyoverdine was provided to the medium in its iron-free structure (apo-pyoverdine), thus mimicking a situation in which it is produced by bacteria. Remarkably, apo-pyoverdine abolished the iron-deficiency phenotype and restored the growth of plants maintained in the iron-deprived medium. In contrast to a P. fluorescens C7R12 strain impaired in apo-pyoverdine production, the wild-type C7R12 reduced the accumulation of anthocyanins in plants grown in iron-deficient conditions. Under this condition, apo-pyoverdine modulated the expression of around 2,000 genes. Notably, apo-pyoverdine positively regulated the expression of genes related to development and iron acquisition/redistribution while it repressed the expression of defense-related genes. Accordingly, the growth-promoting effect of apo-pyoverdine in plants grown under iron-deficient conditions was impaired in iron-regulated transporter1 and ferric chelate reductase2 knockout mutants and was prioritized over immunity, as highlighted by an increased susceptibility to Botrytis cinerea This process was accompanied by an overexpression of the transcription factor HBI1, a key node for the cross talk between growth and immunity. This study reveals an unprecedented mode of action of pyoverdine in Arabidopsis and demonstrates that its incidence on physiological traits depends on the plant iron status

    Involvement of <em>Pseudomonas fluorescens</em> pyoverdine in growth, defence responses and iron homeostasis in <em>Arabidopsis thaliana</em>

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    National audienceIron, the fourth major element in the Earth crust, is essential for growth and development of living organisms. However, due to its low solubility in the soil, it is weakly available for plants and micro-organisms. To efficiently assimilate iron, living organisms have evolved specific strategies. In plants such as Arabidopsis thaliana three trans-membrane proteins are involved in iron assimilation while in bacteria such as Pseudomonas fluorescens iron is taken up from the soil thanks to molecules displaying high affinity for iron called siderophores. It has been recently shown that pyoverdine, the major siderophore of the beneficial bacterium Pseudomonas fluorescens, is assimilated by A. thaliana through an unknown mechanism. Interestingly, pyoverdine improves plant growth and iron nutrition. It is currently accepted that iron competition is a key event during plant infection by pathogenic micro-organisms. Furthermore, a protective role conferred to plants by several beneficial bacteriosiderophores against pathogens has been proposed. To investigate the global incidence of pyoverdine on plants, we decided to perform a microarray analysis. We identified plant genes whose expression is highly modulated by pyoverdine. These genes mainly encode proteins involved in iron homeostasis and in defense reactions. Further work will include pathogenicity tests using mutants affected in the expression of the genes of interest to understand their role in pyoverdine effects. These set of data will give us a first view of the incidence of pyoverdine in the plant physiology and its capacity to face pathogen attack
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