The impact of unconventional monetary policy tools on the independence of the central bank (case study of the FED)

تبرز أهمية الدراسة من خلال الدور الكبير والفعال الذي تلعبه استقلالية البنك المركزي في تحقيق فعالية السياسة النقدية، فعدم خضوع البنك المركزي لاعتبارات وتدخلات سياسية سيزيد من شفافية ومصداقية السياسات النقدية، فالأزمة المالية العالمية لسنة 2008 والتي عصفت بمعظم الاقتصاديات الكبرى، قد أثرت  في أداء البنوك المركزية لمختلف الدول وظهور اتجاهات حديثة في استقلاليتها، وكذا تبرز الأهمية من خلال عرض تجربة النظام الاحتياطي الفدرالي الأمريكي الذي يعتبر من بين أهم البنوك المركزية الذي استطاع الصمود في وجه الأزمة المالية أمام اتجاهات حديثة سواء في سياسته النقدية أو استقلاليته وخلصت دراستنا أن اتباع السياسات النقدية غير تقليدية تؤدي إلى تقييد استقلالية البنك المركزي وهذا ما تبين على النظام الفيديرالي الأمريكي.The importance of the study is highlighted by the significant and effective role played by the independence of the Central Bank in achieving the effectiveness of monetary policy. The failure of the Central Bank to be subject to political considerations and interventions will increase the transparency and credibility of monetary policies. For different countries and the emergence of modern trends in their independence, as well as the importance highlights by presenting the experience of the FED, which is considered among the most important central banks that was able to withstand the financial crisis in front of modern trends, whether in its monetary policy or its independence. Our study concluded that following monetary policies is not This traditionally leads to restricting the independence of the central bank, and this is what was shown in the FED

Probiotic potential of Enterococcus faecalis strains isolated from meconium

107 bacterial isolates with Gram positive staining and negative catalase activity, presumably assumed as LAB, were isolated from samples of meconium of six donors at Roubaix hospital, in the north of France. All these bacterial isolates were identified by MALDI-TOF mass spectrometry as Enterococcus faecalis. However, only six isolates among which E. faecalis 14, E. faecalis 28, E. faecalis 90, E. faecalis 97 and E. faecalis 101 (obtained from donor 3) and E. faecalis 93 (obtained from donor 5) were active against some Gram negative bacteria (GNB) and Gram positive bacteria (GPB), through production of lactic acid and bacteriocin like inhibitory substances (BLIS). The identification of these isolates was confirmed by 16rDNA sequencing and their genetic relatedness was established by REP-PCR and pulsed field gel electrophoresis (PFGE) methods. Importantly, the aforementioned antagonistic isolates were sensitive to various classes of antibiotics tested, exhibited high scores of coaggregation and hydrophobicity, and were not hemolytic. Taken together, these properties render these strains as potential candidates for probiotic applications

Multiphase induction motor drives - a technology status review

The area of multiphase variable-speed motor drives in general and multiphase induction motor drives in particular has experienced a substantial growth since the beginning of this century. Research has been conducted worldwide and numerous interesting developments have been reported in the literature. An attempt is made to provide a detailed overview of the current state-of-the-art in this area. The elaborated aspects include advantages of multiphase induction machines, modelling of multiphase induction machines, basic vector control and direct torque control schemes and PWM control of multiphase voltage source inverters. The authors also provide a detailed survey of the control strategies for five-phase and asymmetrical six-phase induction motor drives, as well as an overview of the approaches to the design of fault tolerant strategies for post-fault drive operation, and a discussion of multiphase multi-motor drives with single inverter supply. Experimental results, collected from various multiphase induction motor drive laboratory rigs, are also included to facilitate the understanding of the drive operatio

Interplane cross-saturation in multiphase machines

The use of electrical machines in electric vehicles and high-power drives frequently requires multiphase machines and multiphase inverters. While appropriate mathematical models under the linear magnetic conditions are readily available for multiphase machines, the same cannot be said for the models of the saturated multiphase machines. This paper examines the saturation in an asymmetrical six-phase induction machine under different supply conditions and addresses the applicability of the existing saturated three-phase machine models for representation of saturated multiphase machines. Specifically, the mutual coupling between different sequence planes in the vector space decomposed model under saturated conditions is analyzed. The paper relies on analytical considerations, finite element analysis and experimental results. It is shown that the saturation of the main flux path is influenced by the current components in the orthogonal (non-fundamental) sequence plane. This implies the need to develop new multiphase machine models which take this effect into account

Etude de la structure du manteau superieur sous le continent africain a partir d'enregistrements longue periode

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Étude théorique en régime périodique d'un écoulement forcé à plan directeur

117 p. : ill. ; 30 cmNous traitons à travers ce mémoire le problème de Graetz en régime périodique, dans le cas ou la conduction transversale dans la paroi solide est tenue en compte. L’étude comprend trois parties essentielles:Dans la première partie, une solution exacte utilisant la méthode de la transformation intégrale généralisée est développée pour un écoulement piston dans un conduit à deux plaques parallèles. L’analyse de la réponse thermique est établie, à travers cette solution, en fonction des paramètres thermo-physiques affectant le problème. Un nouveau modèle utilisant la méthode de Ritz est également développé dans cette partie, pour les deux formes géométriques du conduit (deux plaques parallèles et/ ou tube cylindrique) et un profil de vitesse parabolique. Les résultats issus de ce modèle (dit M.V.R) sont validés par rapport à la solution exacte précitée et confrontés avec les travaux utilisant l’hypothèse de l’isothermicité. La deuxième partie est consacrée à la simulation numérique par la méthode des volumes finis du même problème. Le modèle ici développé est validé par rapport à la solution exacte développée dans la première partie. Dans la troisième partie, une approche quasi-stationnaire (dite simplifiée) du problème est proposée. Une comparaison avec le modèle analytique (M.V.R) est établie en fonction de la fréquence thermique à l’entrée du conduit. En guise d’application, la fin de cette étude est consacrée à l’étude d’un régénérateur à plaques destiné pour le stockage d’énergi

Analysis of the effects of inlet temperature frequency in fully developed laminar duct flows

Unsteady heat transfer for a fully developed laminar flow inside a parallel-plate channel and circular duct that are subjected to a periodically varying inlet temperature is studied. The thermal capacitance of the duct wall and the boundary condition that accounts for external convection are considered. An exact solution is presented for this extended Graetz problem as the result of using a new methodology based on a variational method. The quasi-steady approach that employs a heat transfer coefficient at the liquid–solid interface is also investigated, and the results are compared with the variational solution. The damping and phase lag coefficients as functions of the inlet temperature frequency are presented in graphical for

Application of integral transform technique to the transient laminar flow heat transfer in the ducts

In this paper, a theoretical study of laminar forced convection inside ducts, subjected to periodically varying inlet temperature is presented. A thermal diffusion in the duct walls and a boundary condition which accounts for external convection are considered. In the first part, this problem is solved by applying a Generalized Integral Transform Technique (GITT). The complex eigenvalues and coefficients results are listed and compared with the literature. In the second part, the Quasi-steady Approach (QSA) which employs a constant heat transfer coefficient at liquid–solid interface is also investigated and compared with the GITT solution. The bulk temperature, Nusselt number, the damping and phase lag coefficients as function of the inlet temperature frequency are plotte