ID-HALL, a new double stage Hall thruster design. I. Principle and hybrid model of ID-HALL

International audienceIn Hall thrusters, ions are extracted from a quasineutral plasma by the electric field induced by the local drop of electron conductivity associated with the presence of a magnetic barrier. Since the electric field is used both to extract and accelerate ions and to generate the plasma, thrust and specific impulse are not independent in a Hall thruster. There is a need for versatile thrusters that can be used for a variety of maneuvers, i.e., that can operate either at high thrust or at high specific impulse for a given power. The double stage Hall thruster (DSHT) design could allow a separate control of ionization and acceleration, and hence separate control of thrust and specific impulse. In the DSHT configuration, a supplementary plasma source (ionization stage), independent of the applied voltage, is added and placed upstream of the magnetic barrier (acceleration stage). The DSHT concept is also well adapted to the use of alternative propellants, lighter and with a less efficient ionization than xenon. Several designs of double stage Hall thrusters have been proposed in the past, but these attempts were not really successful. In this paper, we present a brief review of the main DSHT designs described in the literature, we discuss the relevance of the DSHT concept, and, on the basis of simple physics arguments and simulation results, we propose a new design, called ID-HALL (Inductive Double stage HALL thruster). In this design, the ionization stage is a magnetized inductively coupled RF plasma. The inductive coil is inside the central cylinder of the thruster and located nearby the acceleration stage. Preliminary modeling results of this DSHT are described. Published by AIP Publishing. https://doi

Politicising government engagement with corporate social responsibility: “CSR” as an empty signifier

Governments are widely viewed by academics and practitioners (and society more generally) as the key societal actors who are capable of compelling businesses to practice corporate social responsibility (CSR). Arguably, such government involvement could be seen as a technocratic device for encouraging ethical business behaviour. In this paper, we offer a more politicised interpretation of government engagement with CSR where “CSR” is not a desired form of business conduct but an element of discourse that governments can deploy in structuring their relationships with other social actors. We build our argument through a historical analysis of government CSR discourse in the Russian Federation. Laclau and Mouffe's (Hegemony and socialist strategy: Towards a radical democratic politics,Verso Books, London, 1985) social theory of hegemony underpins our research. We find that “CSR” in the Russian government’s discourse served to legitimise its power over large businesses. Using this case, we contribute to wider academic debates by providing fresh empirical evidence that allows the development of critical evaluation tools in relation to governments’ engagement with “CSR”. We find that governments are capable of hijacking CSR for their own self-interested gain. We close the paper by reflecting on the merit of exploring the case of the Russian Federation. As a “non-core”, non-western exemplar, it provides a useful “mirror” with which to reflect on the more widely used test-bed of Western industrial democracies when scrutinising CSR. Based on our findings, we invite other scholars to adopt a more critical, politicised stance when researching the role of governments in relation to CSR in other parts of the world

Maquette de T.P.

Les travaux pratiques réalisés à l'ENSEEIHT à l'aide de la maquette OPTIMAG mettent en évidence d'une part, la création du couple électromagnétique dans une machine à aimants permanents à induit sans encoche et, d'autre part, l'optimisation de la forme d'onde du couple créé

Platine d'expérimentation MicroMAG : à la découverte de la machine synchrone autopilotée

L'objectif de cet article est de présenter la platine d'expérimentation MicroMAG utilisée en 1ère année d'école d'Ingénieurs ENSEEIHT (niveau L2). Cette maquette permet d'appréhender les principes de fonctionnement d'une machine synchrone autopilotée, à partir d'une approche pratique des phénomènes physiques mis en jeu. Cet article détaille tout d'abord la maquette de travail puis décrit les différentes étapes de l'étude en s'appuyant sur les bases théoriques de l'électrodynamique

Ironless Axial Flux Wind Turbine Motor with Two Cylindrical Magnet Rings

International audienceAn ironless axial flux wind turbine motor is presented in this paper. The aim of this paper is to propose a motor that can be manufactured from simple components: magnets, copper and plastic. The motor must be feasible even in remote areas where machining facilities are limited. The winding and mechanical supports are sized from the magnets. The motor is therefore designed to be simple to reproduce and affordable in terms of manufacturing costs. Two rows of magnets are used to improve the performance of the motor. During design, choices on dimensions were made with fast calculations of output performance using models developed specifically for ironless motors. The performance measured on the prototype is in perfect agreement with the finite element simulations and the proposed models

Hybrid piezoelectric motor based on electroactive lubrication principle

A novel conception of hybrid piezoelectric motor is presented in this paper. Proposed conception required synchronized work of quasi-static and resonant piezoelectric actuators that results in a rotary movement. The motor's working principle is explained and the main characteristics are described. Studied topology is compared to the existing piezoelectric motors with regards to its field of applications. The assembling process of the motor is briefly explained with emphasis put on the frequency and impedance tuning of the piezoelectric actuators. Next, the power supply system is described. Finally, conclusions are presented concerning the features of the hybrid piezoelectric motor and possible solutions of the faced problems

Assembling and testing of quasi-static hybrid piezoelectric motor based on electroactive lubrication principle

The presented paper concerns a novel concept of hybrid piezoelectric motor based on electroactive lubrication principle. Its structure is combined of quasi-static and resonance piezoelectric actuators, synchronizing their work to generate the rotary movement. The hybrid motor topology is compared to the existing piezoelectric motors, regarding its field of applications in embedded systems with very high security requirements. The electroactive lubrication principle is briefly presented with regards to optimization of the hybrid motor. The performance principle of the hybrid motor is described in terms of its working cycle. The assembling process of the prototype hybrid motor is briefly explained with emphasis put on the frequency and impedance tuning of the applied quasi-static and resonance piezoelectric actuators. Next, the hybrid motor power supply system is described and chosen measured performance characteristics are presented. Finally, conclusions concerning the features of the tested prototype hybrid motor and possible solutions of the faced issues, during assembling and testing, are presented

Assembling and testing of quasi-static hybrid piezoelectric motor based on electroactive lubrication principle

The presented paper concerns a novel concept of hybrid piezoelectric motor based on electroactive lubrication principle. Its structure is combined of quasi-static and resonance piezoelectric actuators, synchronizing their work to generate the rotary movement. The hybrid motor topology is compared to the existing piezoelectric motors, regarding its field of applications in embedded systems with very high security requirements. The electroactive lubrication principle is briefly presented with regards to optimization of the hybrid motor. The performance principle of the hybrid motor is described in terms of its working cycle. The assembling process of the prototype hybrid motor is briefly explained with emphasis put on the frequency and impedance tuning of the applied quasi-static and resonance piezoelectric actuators. Next, the hybrid motor power supply system is described and chosen measured performance characteristics are presented. Finally, conclusions concerning the features of the tested prototype hybrid motor and possible solutions of the faced issues, during assembling and testing, are presented

A Rupture Between Human Beings and Earth: A Philosophical Critical Approach to Coviability

International audienc