High speed operation design considerations for fractional slot axial flux PMSM

This paper discusses intensively the design considerations for the fractional slot axial flux permanent magnet synchronous (AFPMSMs) in order to work efficiently in the constant power speed range, also known as the field weakening (FW) region. The dominant parameter in the constant power speed region is called the characteristic current which equals the ratio of the magnet flux linkage over the synchronous inductance (− ψm/Ls). Several machine parameters is affecting the characteristic current including the machine geometry and the winding configurations. In this paper, the effect of many of these parameters on the FW has been discussed; including the outer diameter, inner to outer diameter ratio, magnet size, slot opening width, slots per poles combinations,and the multi phase configurations for the Axial flux permanent magnet synchronous machine (PMSM). Two main governors are considered to evaluate the parameters’ impact on the machine overall performance; the rated machine efficiency and the torque to weight ratio at the highest values. Selection of these governors is application driven where these governors are the most influencing factors on the axial flux PMSM design. The results of the present analysis show that the fine tuning of the discussed machine parameters would derive the motor to work in the required Constant Power Speed Region (CPSR) keeping the required high efficiency and torque to weight ratio. A previously proved analytical model has been used in this study to overcome the highly time consumption in the finite element model (FEM)

La crise des économies maghrébines : les politiques redistributives en question

Sid Ahmed Abdelkader. La crise des économies maghrébines : les politiques redistributives en question. In: Tiers-Monde, tome 34, n°135, 1993. La réhabilitation de la demande (sous la direction de Jean-Marc Fontaine) sous la direction de Jean-Marc Fontaine. pp. 565-583

Monnaie, prix, change et développement : le cas des économies exportatrices de pétrole du Tiers-Monde

Cet article a pour objectif l'étude de la monnaie, des prix et du taux de change dans une économie exportatrice d'hydrocarbures. Le rôle déterminant de la rente pétrolière dans ce type d'économie lui confère des caractéristiques macroéconomiques spécifiques très différentes de celles qui caractérisent une économie de production. L'analyse comparée des économies pétrolières du tiers-monde et de la Grande-Bretagne met en évidence l'impact discriminatoire exercé par la rente sur le prix des biens commerciaux et non commerciaux via la réappréciation "naturelle" du taux de change. Le secteur productif est découragé au profit du secteur des biens non commerciaux (bien souvent spéculatifs). Cet effet - observable partout - ajourne et peut-être compromet pour longtemps l'avènement de "l'après pétrole". Les pays pétroliers ne peuvent donc éluder le rôle joué par les variables financières et monétaires - notamment la politique du taux de change - dans la mise en place du processus de développement (Résumé d'auteur

Du "Dutch disease" à "l'OPEP disease" : quelques considérations théoriques autour de l'industrialisation des pays exportateurs de pétrole

La mise en valeur des gisements de gaz naturel aux Pays Bas et de façon plus générale du pétrole de la Mer du Nord ainsi que le boom minier en Australie ont permis la genèse d'un nouveau courant théorique majeur dont l'originalité est de s'interroger sur l'impact de la rente des hydrocarbures ou minière sur une économie déjà développée et industrialisée. L'objet de cet article est de préciser comment ce courant, en provenance des pays industrialisés pétroliers apporte une meilleure connaissance du fonctionnement et du développement des économies pétrolières du Su

Using Microsoft Multipoint Technology to Enhance Collaborative Learning in Primary Schools

Researches in psychology, education and pedagogical practices show the stunning impact of collaboration in learning, particularly for young children. However, current design of Personal Computer Applications for collaborative learning is limited and poor. The objective of this research is to use Microsoft Multipoint technology in order to create collaborative quiz game for leveraging collaboration among primary school students. Merging prototyping with Interaction Design is very suitable for the purpose of gaining experience and it identifies new opportunities to customize the interface for collaborative software and make full use of Microsoft Multipoint technology. Measuring usability attributes; Usefulness, Ease of Use, Ease of Learning and Satisfaction is a core step to test the prototype system and approve the successfulness of research objectives. One limitation of this paper is that there is no text-based activity in the prototype. All data was collected via using USE Questionnaire in order to test usability attributes from perspective of users. The results of this research revealed that students found the prototype useful, easy to use, easy to learn and they attained high satisfaction. Most importantly, observations revealed that students were extremely excited and they could collaborate effectively. The value of this project is to leverage collaborative learning in primary schools and clarify the importance of merging Interaction Design and Microsoft Multipoint technology; which in return could encourage collaboration. Placing this project in the public domain will, hopefully enable other researchers and practitioners in similar situations to relate to my experience and gain insights