34 research outputs found

    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

    Acoustic characterization of the compressor stage of an automotive turbocharger

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    Turbochargers are a key component of internal combustion engines in the automotive industry. They contribute to the downsizing trend and allow constructors to respect more and more severe emissions norms. However, the turbocharger behaves as an acoustic source in the air intake system, and has an influence in the acoustic waves travelling in it. The passive and active acoustic characteristics of the turbocharger can be used as a starting point for the design and development of acoustic devices in the air intake system, or as an input of acoustic 1D simulations of engine intake lines. In this paper both the active and passive acoustic behaviours of a compressor stage of two different automotive turbochargers were studied. The active acoustic effect of the compressor was studied by its characterization as an acoustic source. This is performed experimentally by the computation of the acoustic power at the inlet and outlet of the compressor. This power was obtained by performing plane wave decomposition with the beamforming method over all the working points of the compressor map. Using the pressure decomposition, the acoustic intensity is calculated and then the acoustic power. In this way the acoustic power delivered by the compressor on the air intake system is measured. The passive acoustic effect is studied by the measurement of the acoustic Transmission Loss (TL) of the compressor through the calculation of its scattering matrix under two port considerations. Using also the beamforming method to decompose the incident and reflected waves at the inlet and outlet of the compressor, the transmission coefficients in both upwards and downwards directions are computed. Experimentally the TL of a static turbocharger was measured and results were extrapolated by a model to obtain the TL of the compressor over different working points of the compressor map. Numerically, 3D acoustic simulations were performed in order to compare to the model results. Numerical and experimental results were compared, and a predictive model for TL is proposed. This model will be compared in the future to real TL measurements on a working turbocharger

    Genome-wide association study of REM sleep behavior disorder identifies polygenic risk and brain expression effects

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    Rapid-eye movement (REM) sleep behavior disorder (RBD), enactment of dreams during REM sleep, is an early clinical symptom of alpha-synucleinopathies and defines a more severe subtype. The genetic background of RBD and its underlying mechanisms are not well understood. Here, we perform a genome-wide association study of RBD, identifying five RBD risk loci near SNCA, GBA, TMEM175, INPP5F, and SCARB2. Expression analyses highlight SNCA-AS1 and potentially SCARB2 differential expression in different brain regions in RBD, with SNCA-AS1 further supported by colocalization analyses. Polygenic risk score, pathway analysis, and genetic correlations provide further insights into RBD genetics, highlighting RBD as a unique alpha-synucleinopathy subpopulation that will allow future early intervention

    Immunity Traits in Pigs: Substantial Genetic Variation and Limited Covariation

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    BACKGROUND: Increasing robustness via improvement of resistance to pathogens is a major selection objective in livestock breeding. As resistance traits are difficult or impossible to measure directly, potential indirect criteria are measures of immune traits (ITs). Our underlying hypothesis is that levels of ITs with no focus on specific pathogens define an individual's immunocompetence and thus predict response to pathogens in general. Since variation in ITs depends on genetic, environmental and probably epigenetic factors, our aim was to estimate the relative importance of genetics. In this report, we present a large genetic survey of innate and adaptive ITs in pig families bred in the same environment. METHODOLOGY/PRINCIPAL FINDINGS: Fifty four ITs were studied on 443 Large White pigs vaccinated against Mycoplasma hyopneumoniae and analyzed by combining a principal component analysis (PCA) and genetic parameter estimation. ITs include specific and non specific antibodies, seric inflammatory proteins, cell subsets by hemogram and flow cytometry, ex vivo production of cytokines (IFNα, TNFα, IL6, IL8, IL12, IFNγ, IL2, IL4, IL10), phagocytosis and lymphocyte proliferation. While six ITs had heritabilities that were weak or not significantly different from zero, 18 and 30 ITs had moderate (0.1<h2≤0.4) or high (h2>0.4) heritability values, respectively. Phenotypic and genetic correlations between ITs were weak except for a few traits that mostly include cell subsets. PCA revealed no cluster of innate or adaptive ITs. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that variation in many innate and adaptive ITs is genetically controlled in swine, as already reported for a smaller number of traits by other laboratories. A limited redundancy of the traits was also observed confirming the high degree of complementarity between innate and adaptive ITs. Our data provide a genetic framework for choosing ITs to be included as selection criteria in multitrait selection programmes that aim to improve both production and health traits

    Tremor in multiple sclerosis

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    Tremor is estimated to occur in about 25 to 60 percent of patients with multiple sclerosis (MS). This symptom, which can be severely disabling and embarrassing for patients, is difficult to manage. Isoniazid in high doses, carbamazepine, propranolol and gluthetimide have been reported to provide some relief, but published evidence of effectiveness is very limited. Most trials were of small size and of short duration. Cannabinoids appear ineffective. Tremor reduction can be obtained with stereotactic thalamotomy or thalamic stimulation. However, the studies were small and information on long-term functional outcome is scarce. Physiotherapy, tremor reducing orthoses, and limb cooling can achieve some functional improvement. Tremor in MS remains a significant challenge and unmet need, requiring further basic and clinical research
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