171 research outputs found

    Identification of sensitive R-L parameters of a Multi-phase drive by a vector control

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    This paper focuses on an experimental method to determine the electric parameters of a seven-phase low-voltage multiphase drive. The drive is a belt driven starter-alternator for powerful cars with Hybrid Electrical Vehicles (HEV) functions. The resistive and inductive parameters are necessary to obtain the six characteristic time constants of the control modeling. Classical direct measurements lead to imprecise results because of very low values for the windings electric resistance (a few mΩ) and inductance (a few ΌH). Effects of the imprecision on the measurements are all the more important that time constants are obtained by a ratio of cyclic inductances by resistance, with cyclic inductances being a linear combination of seven measured inductances. The methodology for identification detailed in this paper is based on a stator current vector control, in a multi-reference frame. This methodology allows us to get directly these time constants. Numerous measurements allow the robustness of the method to be evaluatedThis work was supported by the French car supplier Valeoand the regional council of France Region-Nord-Pas-De-Calais

    Gimonnet Bertrand. Les notes Ă  l’école ou le rapport Ă  la notation des enseignants de l’école Ă©lĂ©mentaire

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    Bertrand Gimonnet vient de publier, dans la collection Savoir et Formation,un ouvrage issu de sa thĂšse soutenue en 2005. L’ouvrage est composĂ© de neuf chapitres, dont un d’introduction et un de conclusion, les sept autres Ă©tant organisĂ©s en deux grandes parties : Pratique et condition de la pratique de la notation scolaire et Le rapport Ă  la notation des enseignants de l’école Ă©lĂ©mentaire. Le chapitre introductif parcourt les travaux contemporains sur l’évaluation et sa dimension notĂ©e depuis..

    Identification of a 7-phase claw-pole starter-alternator for a micro-hybrid automotive application

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    This paper deals with the identification of a new high power starter-alternator system, using both: a Finite Element Method (FEM) modeling and an experimental vector control. The drive is composed of a synchronous 7-phase claw-pole machine supplied with a low voltage / high current Voltage Source Inverter (VSI). This structure needs specific approaches to plan its electrical and mechanical behaviors and to identify the parameters needed for control purpose. At first, a Finite Element Method (FEM) modeling of the machine is presented. It is used for the predetermination of the electromotive forces and of the torque. Experimental results are in good accordance with numerical results. In a second part, resistive and inductive parameters of the drive are determined by an original experimental approach that takes into account each component of the drive: the battery, the VSI and the machine.Futurelec IV (Region Nord Pas de Calais

    Modeling and Control of a 7-phase Claw-pole Starter-alternator for a Micro-hybrid Automotive Application

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    This paper deals with the modeling and the control of a new high power 12V Integrated Starter Alternator (ISA). This system is used to bring micro-hybrid functions to standard Internal Combustion Engine (ICE) vehicles. The drive is composed of a seven-phase synchronous claw-pole machine with separate excitation, supplied with a seven-leg Voltage Source Inverter (VSI) designed for low voltage and high current. The system is modeled in a generalized Concordia frame and a graphical description is used to highlight energetic properties of such a complex system. A control scheme is then deduced from this graphical description. Two controls are achieved in generator mode and compared: one is using the VSI in a square-wave mode, the other in a Pulse Width Modulation (PWM) mode. Experimental results are provided.This work was supported by the French car supplier Valeoand the regional council of France Region-Nord-Pas-De-Calais

    Numerical Simulations to Evaluate and Compare the Performances of Existing and Novel Degrader Materials for Proton Therapy

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    The performance of the energy degrader in terms of beam properties directly impacts the design and cost of cyclotron-based proton therapy centers. The aim of this study is to evaluate the performances of different existing and novel degrader materials. The quantitative estimate is based on detailed GEANT4 simulations that analyze the beam-matter interaction and provide a determination of the beam emittance increase and transmission. Comparisons between existing (aluminum, graphite, beryllium) and novel (boron carbide and diamond) degrader materials are provided and evaluated against semi-analytical models of multiple Coulomb scattering. The results showing a potential in emittance reduction for novel materials are presented and discussed in detail.Comment: Submitted for IPAC 2018 "light peer review

    In vitro performance of fluticasone/salmeterol pressurized metered dose inhaler in combination with three different valved holding chambers

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    Spacer devices are used to optimize airway aerosol deposition from pressurized metered-dose inhalers (pMDI). The in vitro performance of the combination fluticasone/salmeterol pMDI alone and connected to 3 different valved holding chambers (VHC) was compared by measuring impactor entry port (“throat”) deposition and fine particle dose (FPD) of each medication. Salmeterol (SX) and Fluticasone (FP) throat deposition was reduced over 90 % by all VHC compared to pMDI alone (p < 0,001). The FPD obtained from pMDI alone and connected to VHCs VortexÂź, AeroChamber PlusÂź and Able SpacerÂź for Salmeterol (25 ÎŒg nominal dose) were 12.2 ± 0.7, 12.5 ± 0.5, 11.6 ± 0.8, and 7.9 ± 0.9 ÎŒg, respectively. For Fluticasone (125 ÎŒg nominal dose) the FPD were 42.5 ± 2.6, 36.3 ± 3.1, 39.8 ± 2.4, and 22.8 ± 3.5 ÎŒg, respectively. There were no statistical differences in FPD between devices, except for AbleSpacerÂź that delivered a lower FPD for both drugs (p < 0.001).Colegio de FarmacĂ©uticos de la Provincia de Buenos Aire

    Kallikrein 5 induces atopic dermatitis–like lesions through PAR2-mediated thymic stromal lymphopoietin expression in Netherton syndrome

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    Netherton syndrome (NS) is a severe genetic skin disease with constant atopic manifestations that is caused by mutations in the serine protease inhibitor Kazal-type 5 (SPINK5) gene, which encodes the protease inhibitor lymphoepithelial Kazal-type–related inhibitor (LEKTI). Lack of LEKTI causes stratum corneum detachment secondary to epidermal proteases hyperactivity. This skin barrier defect favors allergen absorption and is generally regarded as the underlying cause for atopy in NS. We show for the first time that the pro-Th2 cytokine thymic stromal lymphopoietin (TSLP), the thymus and activation-regulated chemokine, and the macrophage-derived chemokine are overexpressed in LEKTI-deficient epidermis. This is part of an original biological cascade in which unregulated kallikrein (KLK) 5 directly activates proteinase-activated receptor 2 and induces nuclear factor ÎșB–mediated overexpression of TSLP, intercellular adhesion molecule 1, tumor necrosis factor α, and IL8. This proinflammatory and proallergic pathway is independent of the primary epithelial failure and is activated under basal conditions in NS keratinocytes. This cell-autonomous process is already established in the epidermis of Spink5−/− embryos, and the resulting proinflammatory microenvironment leads to eosinophilic and mast cell infiltration in a skin graft model in nude mice. Collectively, these data establish that uncontrolled KLK5 activity in NS epidermis can trigger atopic dermatitis (AD)–like lesions, independently of the environment and the adaptive immune system. They illustrate the crucial role of protease signaling in skin inflammation and point to new therapeutic targets for NS as well as candidate genes for AD and atopy

    Inactivation of TIF1Îł Cooperates with KrasG12D to Induce Cystic Tumors of the Pancreas

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    Inactivation of the Transforming Growth Factor Beta (TGFÎČ) tumor suppressor pathway contributes to the progression of Pancreatic Ductal AdenoCarcinoma (PDAC) since it is inactivated in virtually all cases of this malignancy. Genetic lesions inactivating this pathway contribute to pancreatic tumor progression in mouse models. Transcriptional Intermediary Factor 1 gamma (TIF1Îł) has recently been proposed to be involved in TGFÎČ signaling, functioning as either a positive or negative regulator of the pathway. Here, we addressed the role of TIF1Îł in pancreatic carcinogenesis. Using conditional Tif1Îł knockout mice (Tif1Îłlox/lox), we selectively abrogated Tif1Îł expression in the pancreas of Pdx1-Cre;Tif1Îłlox/lox mice. We also generated Pdx1-Cre;LSL-KrasG12D;Tif1Îłlox/lox mice to address the effect of Tif1Îł loss-of-function in precancerous lesions induced by oncogenic KrasG12D. Finally, we analyzed TIF1Îł expression in human pancreatic tumors. In our mouse model, we showed that Tif1Îł was dispensable for normal pancreatic development but cooperated with Kras activation to induce pancreatic tumors reminiscent of human Intraductal Papillary Mucinous Neoplasms (IPMNs). Interestingly, these cystic lesions resemble those observed in Pdx1-Cre;LSL-KrasG12D;Smad4lox/lox mice described by others. However, distinctive characteristics, such as the systematic presence of endocrine pseudo-islets within the papillary projections, suggest that SMAD4 and TIF1Îł don't have strictly redundant functions. Finally, we report that TIF1Îł expression is markedly down-regulated in human pancreatic tumors by quantitative RT–PCR and immunohistochemistry supporting the relevance of these findings to human malignancy. This study suggests that TIF1Îł is critical for tumor suppression in the pancreas, brings new insight into the genetics of pancreatic cancer, and constitutes a promising model to decipher the respective roles of SMAD4 and TIF1Îł in the multifaceted functions of TGFÎČ in carcinogenesis and development

    Application de méthodes de neutronique au transport d'électrons à basse énergie dans les solides et notamment à l'émission d'électrons secondaires

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    Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

    Transport models for elastic electron backscattering from solid surfaces

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    info:eu-repo/semantics/nonPublishe
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