Convertisseur de fréquence indirect à rapport de tension fixe:interface entre turbo-alternateurs à haute vitesse et réseau électrique

Many electric power generators use gas turbines as power sources. Typically they are connected to the turbines through a mechanical gearbox in order to adapt their synchronous speed to the optimal rotation speed of the turbine, which is very often much higher than the synchronous speed. However, due to direct network connection, the generator speed cannot be variable : it is imposed by the network and constant. To overcome this problem, we propose to replace the mechanical gearbox by a flexible electronic solution which offers a high efficiency. Using this approach, the turbine is directly connected to the synchronous generator, which is connected to the grid through an indirect static frequency converter with an intermediary DC circuit. However, this type of converter is not common in this application because of very high switching losses due to the high frequency of the PWM technique normally used for its control. In this dissertation, a new control strategy is proposed for the three level Neutral Point Clamped converter, characterized by its high efficiency due to the use of square-wave operation mode. The main advantage of this mode is the quasi absence of switching losses. In this mode, only the frequency can be varied between the input and the output voltage, but their magnitudes are not freely controllable. A voltage magnitude adaptation can be done by the generator's excitation. The produced active and reactive power can be controlled by the generator excitation as well as both the angle shift between the generator and rectifier voltages and between the inverter and network voltages. The capacitive intermediary circuit brings the advantage of decoupling of harmonics between the generator and the network currents. A control method is also proposed to resolve some problems incurred by using square wave operation mode, in particular to reduce the harmonics distortion of the output inverter voltage and current. As second important contribution, this thesis proposes a new fast-ramping DC-component elimination strategy for AC currents. In comparison to the usually slow transient that characterizes a DC component free current transient, we achieve that much faster transients also without DC-component, simply by choosing a well defined transition period. Simulation and experimental results for different operating points and transitions between them highlight the capabilities of the proposed control strategy. These include the ability to operate with unity power factor and better current quality without continuous component and less harmonics

L’efficacité de la redevabilité managériale en protection sociale via Cloud Computing : Quelle intelligence économique possible pour le cas du Maroc ?

En effet, les objectifs du management public interpellent d’assurer tous les principes de la bonne gouvernance principalement l’obligation de rendre compte. Dans ce sens, la redevabilité managériale joue un rôle très important, elle concerne l’obligation de rendre des comptes sur la qualité de la gestion publique. Cette recherche intitulée « l’efficacité de la redevabilité managériale en protection sociale via Cloud Computing : Quelle intelligence économique possible pour le cas du Maroc ? » traite cette question de la redevabilité managériale en matière de la protection sociale comme un domaine de cas d’étude de la gestion publique tout en se basant sur les outils des nouvelles technologies des Big Data. En effet, deux cas d’études complémentaires sont examinés dans cette recherche, le programme de la protection sociale au Maroc et l’expérience du Foursquare. L’idée principale de cet article est de tester la possibilité de s’appuyer sur le citoyen lui même pour avoir une performance de la gestion de l’action publique et assurer un contrôle et suivi performant des acteurs publics responsables. Ainsi, il parait fort possible de réaliser une efficacité de la redevabilité managériale via le système de l’intelligence économique et l’outil du Cloud Computing en matière d’analyse des Big Data relevant des réseaux sociaux

Hepatitis B infection in HIV-1-infected patients receiving highly active antiretroviral therapy in Lomé, Togo: Prevalence and molecular consequences

Background. No data are available on HIV/hepatitis B virus (HBV) or hepatitis C virus coinfection in Togo, and patients are not routinely tested for HBV infection.Objectives. To determine the prevalence of HBV and the risk of HBV drug resistance during antiretroviral treatment in HIV-coinfected patients in Togo.Method. This cross-sectional study was carried out in Lomé, Togo, from January 2010 to December 2011 among HIV-infected patients who had been on antiretroviral therapy (ART) for at least 6 months.Results. In total, 1 212 patients (74.9% female) living with HIV/AIDS and treated with ART were included in the study. The seroprevalence of hepatitis B surface antigen (HBsAg) was 9.7% (117/1 212; 95% confidence interval (CI) 8.04 - 11.45). Of these 117 HBsAg-positive patients, 16 (13.7%) were hepatitis B e antigen (HBeAg)-positive, and 115 (98.3%) were on lamivudine. The HBV DNA load was >10 IU/ mL in 33/117 patients overall (38%), and in 87.5% of 16 HBeAg positive patients (p<0.0001). In multivariate analysis, factors associated with HBV DNA load >10 IU/mL were HBeAg positivity (adjusted odds ratio (aOR) 6.4; p=0.001) and a higher level of education (aOR 6.5; p=0.026). The prevalence of HBV resistance to lamivudine was 13.0% (15/115; 95% CI 7.0 - 19.0). The detected resistance mutations were rtL180M (14/15 patients) and rtM204V/I (15/15).Conclusion. The seroprevalence of HBV among ART-treated HIV-infected patients in Togo was 9.7%. The prevalence of HBV lamivudine resistance mutations after 2 years of ART was 13.0%. These results suggest that HBV screening before ART initiation can be based on HBsAg testing

Towards Business-to-IT Alignment in the Cloud

Cloud computing offers a great opportunity for business process (BP) flexibility, adaptability and reduced costs. This leads to realising the notion of business process as a service (BPaaS), i.e., BPs offered on-demand in the cloud. This paper introduces a novel architecture focusing on BPaaS design that includes the integration of existing state-of-the-art components as well as new ones which take the form of a business and a syntactic matchmaker. The end result is an environment enabling to transform domain-specific BPs into executable workflows which can then be made deployable in the cloud so as to become real BPaaSes

Hepatitis B infection in HIV-1-infected patients receiving highly active antiretroviral therapy in Lomé, Togo: Prevalence and molecular consequences

Background. No data are available on HIV/hepatitis B virus (HBV) or hepatitis C virus coinfection in Togo, and patients are not routinely tested for HBV infection.Objective. To determine the prevalence of HBV and the risk of HBV drug resistance during antiretroviral treatment in HIV-coinfected patients in Togo.Method. This cross-sectional study was carried out in Lomé, Togo, from January 2010 to December 2011 among HIV-infected patients who had been on antiretroviral therapy (ART) for at least 6 months.Results. In total, 1 212 patients (74.9% female) living with HIV/AIDS and treated with ART were included in the study. The seroprevalence of hepatitis B surface antigen (HBsAg) was 9.7% (117/1 212; 95% confidence interval (CI) 8.04 - 11.45). Of these 117 HBsAg-positive patients, 16 (13.7%) were hepatitis B e-antigen (HBeAg)-positive, and 115 (98.3%) were on lamivudine. The HBV DNA load was >10 IU/mL in 33/117 patients overall (38%), and in 87.5% of 16 HBeAg-positive patients (p<0.0001). In multivariate analysis, factors associated with HBV DNA load >10 IU/mLwere HBeAg positivity (adjusted odds ratio (aOR) 6.4; p=0.001) and a higher level of education (aOR 6.5; p=0.026). The prevalence of HBV resistance to lamivudine was 13.0% (15/115; 95% CI 7.0 - 19.0). The detected resistance mutations were rtL180M (14/15 patients) and rtM204V/I (15/15).Conclusion. The seroprevalence of HBV among ART-treated HIV-infected patients in Togo was 9.7%. The prevalence of HBV lamivudine resistance mutations after 2 years of ART was 13.0%. These results suggest that HBV screening before ART initiation can be based on HBsAg testing

Pregnancy and Infant Outcomes among HIV-Infected Women Taking Long-Term ART with and without Tenofovir in the DART Trial

Diana Gibb and colleagues investigate the effect of in utero tenofovir exposure by analyzing the pregnancy and infant outcomes of HIV-infected women enrolled in the DART trial

Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142904/1/hep29800.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142904/2/hep29800_am.pd