Increasing the Discovery Space in Astrophysics - A Collation of Six Submitted White Papers

We write in response to the call from the 2020 Decadal Survey to submit white papers illustrating the most pressing scientific questions in astrophysics for the coming decade. We propose exploration as the central question for the Decadal Committee's discussions.The history of astronomy shows that paradigm changing discoveries are not driven by well formulated scientific questions, based on the knowledge of the time. They were instead the result of the increase in discovery space fostered by new telescopes and instruments. An additional tool for increasing the discovery space is provided by the analysis and mining of the increasingly larger amount of archival data available to astronomers. Revolutionary observing facilities, and the state of the art astronomy archives needed to support these facilities, will open up the universe to new discovery. Here we focus on exploration for compact objects and multi messenger science. This white paper includes science examples of the power of the discovery approach, encompassing all the areas of astrophysics covered by the 2020 Decadal Survey

Increasing the Discovery Space in Astrophysics - A Collation of Six Submitted White Papers

We write in response to the call from the 2020 Decadal Survey to submit white papers illustrating the most pressing scientific questions in astrophysics for the coming decade. We propose exploration as the central question for the Decadal Committee's discussions. The history of astronomy shows that paradigm changing discoveries are not driven by well formulated scientific questions, based on the knowledge of the time. They were instead the result of the increase in discovery space fostered by new telescopes and instruments. An additional tool for increasing the discovery space is provided by the analysis and mining of the increasingly larger amount of archival data available to astronomers. Revolutionary observing facilities, and the state of the art astronomy archives needed to support these facilities, will open up the universe to new discovery. Here we focus on exploration for compact objects and multi messenger science. This white paper includes science examples of the power of the discovery approach, encompassing all the areas of astrophysics covered by the 2020 Decadal Survey

Commande vectorielle de la machine a reluctance variable à stator lisse. Prise en compte de la saturation et de l'amortissement

This paper deals with the field-oriented control of a smooth stator, non excited salient rotor synchronous machine. First, a nonlinear modelling of the machine, taking into account both damping and saturation effects, is developed in PARK's rotor-bound frame. Then, a vector control strategy, which maintains a constant saturation level in the machine, is set-up. This strategy, wich consists in keeping the stator direct current at a high constant value, allows to linearize the model of the machine and to control it in the same way as a DC machine. A numerical simulation of a VRM, fed by a PWM-VSI and controlled thanks to this control strategy, is built up and the computed results are given and commented.
Cet article est consacré à la commande vectorielle d'une machine à réluctance variable à stator lisse et rotor massif. D'abord, une modélisation non linéaire de la machine a été effectuée dans le repère de Park. Cette dernière permet de prendre en compte l'effet d'amortissement dû au rotor massif, ainsi que celui de la saturation inhérent à ce genre de machine. Ensuite, une stratégie de contrôle vectoriel, qui maintient un niveau de saturation constant dans la machine, a été élaborée. Cette stratégie, qui consiste à maintenir le courant direct statorique à une valeur élevée, permet de linéariser le modèle de la machine et ainsi de pouvoir la contrôler comme une machine à courant continu. Une simulation numérique de la machine à réluctance variable, alimentée par un onduleur de tension à MLI et commandée par la stratégie mise au point, a été effectuée. Les résultats de cette simulation sont donnés et commentés à la fin de l'article

Selective harmonic elimination PWM applied to H-bridge topology in high speed applications

International audienc

Multi-converter multi-machine systems: application for electromechanical drives

A formalism is defined to describe systems composed of several electrical machines with several electrical and/or mechanical converters. So, a first classification of multi-converter multi-machine systems is proposed in order to point out their influences on the global power conversion: cost reduction, conversion quality... Three examples are presented with this specific formalism

Diagnosis of endometrial nerve fibers in women with endometriosis.

Recent studies indicated that there is a high density of small nerve fibers in the functional layer of the endometrium in women with endometriosis and that it can be used as a marker to detect endometriosis. In this study, the efficacy assessment of small nerve fibers' density as a diagnostic marker was compared in patients with and without endometriosis. In this study, women with history of pelvic pain and/or infertility who were candidates for laparoscopy or laparotomy in Rassoul hospital (2007-2009) were enrolled. Histological sections of endometrial tissue were prepared from endometrial biopsy from women with endometriosis (n = 12) (1) and without endometriosis (n = 15) (2). Protein gene product 9.5 and neurofilament were evaluated as marker from endometrial biopsies by immunohistochemical methods. There was no statistically significant difference between two groups according to age, body mass index. Nerve fibers were detected in all endometrial biopsies from all women with endometriosis but detected only in three women without endometriosis. The mean density of nerve fibers was 2.2 ± 4.7 mm(-2) in group without endometriosis and) 13.1 ± 3.3 (in group with endometriosis (p < 0.001). Women with endometriosis had significantly higher nerve fiber density in comparison with women without endometriosis. Our findings indicated that endometrial biopsy for detecting density of nerve fibers by usage of protein gene product 9.5, provided a reliable marker for diagnosis of endometriosis