197 research outputs found

    The European way out of recession

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    This paper proposes a two-regime Bounce-Back Function augmented Self-Exciting Threshold AutoRegression (SETAR) which allows for various shapes of recoveries from the recession regime. It relies on the bounce-back effects first analyzed in a Markov-Switching setup by Kim, Morley and Piger [2005] and recently extended by Bec, Bouabdallah and Ferrara [2011a]. This approach is then applied to post-1973 quarterly growth rates of French, German, Italian, Spanish and Euro area real GDPs. Both the linear autoregression and the standard SETAR without bounce-back effect null hypotheses are strongly rejected against the Bounce-Back augmented SETAR alternative in all cases but Italy. The relevance of our proposed model is further assessed by the comparison of its short-term forecasting performances with the ones obtained from a linear autoregression and a standard SETAR. It turns out that the bounce-back models one-step ahead forecasts generally outperform the other ones, and particularly so during the last recovery period in 2009Q3-2010Q4.Threshold autoregression, bounce-back effects, asymmetric business cycles.

    Removal of Solophenyl Red 3BL Dye from Textile Effluents by Adsorption Using a Natural Adsorbent Oxalis pes-caprae L.

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    The aim of the present study was to assess the adsorption potential of a natural adsorbent Oxalis pes-caprae L. for the removal of azo-dye solophenyl red 3BL (SR 3BL) from textile effluents. The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The effect of various parameters on the efficiency of the adsorption was studied. The optimum was found with the contact time of 35 minutes, pH of 6, and temperature of 25 °C. The equilibrium experimental data were fitted with the Langmuir, Freundlich, and Temkin models. Experimental data were well described with the Langmuir isotherm indicating monolayer adsorption. Pseudo-first-order, pseudo-second-order, and Elovich kinetic models were used to evaluate the adsorption kinetics. The adsorption kinetics was found to follow closely the pseudo-first-order kinetic model. Thermodynamics studies revealed that the adsorption process was spontaneous and exothermic. This work is licensed under a Creative Commons Attribution 4.0 International License

    3D NUMERICAL STUDY OF MAGNETOHYDRODYNAMIC INSTABILITY IN LIQUID METAL TAYLOR-COUETTE FLOW

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    This purpose is about a 3D study of magnetohydrodynamic (MHD) instability in liquid matal Taylor-Couette flow, this problem is receiving more and more research interest due to its application in the engineering, oceanography and the astrophysical research The Taylor-Couette system consists of two coaxial cylinders in differential rotation, which is considered as a hydrodynamic model system, allowed researchers to progress in understanding the laminar-turbulent transition phenomena. A set of states found in narrow gap of Taylor-Couette systems where the outer cylinder is held fixed and the inner cylinder speed increased. The symmetry breaking parameter is the Taylor number Ta that gives a measure of the ratio of centrifugal forces to viscous forces. When the liquid is replaced by an electrically conducting fluid and an external magnetic field is applied, this leads to MHD Taylor-Couette flow. Additional body force, Lorentz force, acting on the fluid arises. Lorentz force is in the direction perpendicular to both magnetic and electric fields. The behaviour of flow depends on strength and geometry of applied field, magnetic and electric properties of the liquid, cylinders and endplates. In this work, the MHD instability Taylor-Couette flow is considered for liquid sodium with its magnetic Prandtl number Pm <1. The results of pressure and angular momentum in the Taylor-Couette flow under the effect of an external uniform axial magnetic field B=4 Tesla are investigated numerically for the different cases of electrically conducting or insulating walls at the Ekman cell, at the middle of the first Taylor-votex flow (TVF) and between two cells

    Chemical recycling of poly(ethylene terephthalate). Application to the synthesis of multiblock copolyesters

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    The chemical recycling of the poly(ethylene terephthalate), (PET), has been successfully carried out by glycolysis in the presence of bis (2-hydroxyethyl) terephthalate (BHET) resulting in the formation of hydroxytelechelic oligomers. These oligomers were then treated with carboxytelechelic poly(ε-caprolactone) oligomers of Mn = 2300 and Mn = 730 g•mol–1 molecular weight, in the absence or presence of the titanium tetrabutyloxide (Ti(OBu)4) as a catalyst to get multiblock copolyesters. The chemical structure of the synthesized copolyesters was investigated by size exclusion chromatography (SEC) and proton Nuclear Magnetic Resonance (1H NMR) spectroscopy. Moreover the differential scanning calorimetry (DSC) was used to explore their thermal properties. The ester-ester interchange reaction was observed between the two oligopolyesters, was studied and discussed in detail

    Experimental Investigation of the Free Surface Effect on the Conical Taylor-Couette Flow System

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    The aim of this work is to highlight the critical thresholds corresponding to the onset of different instabilities considered in the flow between two vertical coaxial cones with and without free surface. The inner cone is rotating and the outer one is maintained at rest. Both cones have the same apex angle Φ =12° giving a constant annular gap δ =d/R1max. The height of the fluid column is H=155mm and It can be progressively decreased for each studied case of the flow system. Two kinds of configurations are studied, small and large gap. The working fluid is assumed as Newtonian and having constant properties like density and viscosity within the range of the required experimental conditions. By means of visualization technique of the flow we have been able to show the different transition modes occurring in the conical flow system according to the aspect ratio and then the induced action of the free surface which introduces a delay in the onset of different instability modes. The obtained results in term of features and stability of the flow are compared to those of Wimmer and Noui-Mehidi

    myCopter: Enabling Technologies for Personal Air Transport Systems

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    This paper describes the European Commission Framework 7 funded project myCopter (2011-2014). The project is still at an early stage so the paper starts with the current transportation issues faced by developed countries and describes a means to solve them through the use of personal aerial transportation. The concept of personal air vehicles (PAV) is briefly reviewed and how this project intends to tackle the problem from a different perspective described. It is argued that the key reason that many PAV concepts have failed is because the operational infrastructure and socio-economic issues have not been properly addressed; rather, the start point has been the design of the vehicle itself. Some of the key aspects that would make a personal aerial transport system (PATS) viable include the required infrastructure and associated technologies, the skill levels and machine interfaces needed by the occupant or pilot and the views of society as a whole on the acceptability of such a proposition. The myCopter project will use these areas to explore the viability of PAVs within a PATS. The paper provides an overview of the project structure, the roles of the partners, and hence the available research resources, and some of the early thinking on each of the key project topic areas

    myCopter: Enabling Technologies for Personal Air Transport Systems - an Early Progress Report

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    This paper describes the European Commission (EC) Framework 7 funded project myCopter (2011-2014). The project is still at an early stage so the paper starts with the current transportation issues faced by developed countries and describes a means to solve them through the use of personal aerial transportation. The concept of personal air vehicles (PAV) is briefly reviewed and how this project intends to tackle the problem from a different perspective described. It is argued that the key reason that many PAV concepts have failed is because the operational infrastructure and socio-economic issues have not been properly addressed; rather, the start point has been the design of the vehicle itself. Some of the key aspects that would make a personal aerial transport system (PATS) viable include the required infrastructure and associated technologies, the skill levels and machine interfaces needed by the occupant or pilot and the views of society as a whole on the acceptability of such a proposition. The myCopter project will use these areas to explore the viability of PAVs within a PATS. The paper reports upon the early progress made within the project. An initial reference set of PAV requirements has been collated. A non-physical flight simulation model capable of providing a wide range of handling qualities characteristics has been developed and its function has undergone limited verification. Results from this exercise show that the model behaves as intended and that it can deliver a predictable range of vehicle dynamics. The future direction of the themes of work described within the paper are then described

    Targeting intratumoral B cells with rituximab in addition to CHOP in angioimmunoblastic T-cell lymphoma. A clinicobiological study of the GELA.

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    Background In angioimmunoblastic T-cell lymphoma, symptoms linked to B-lymphocyte activation are common, and variable numbers of CD20(+) large B-blasts, often infected by Epstein-Barr virus, are found in tumor tissues. We postulated that the disruption of putative B-T interactions and/or depletion of the Epstein-Barr virus reservoir by an anti-CD20 monoclonal antibody (rituximab) could improve the clinical outcome produced by conventional chemotherapy. DESIGN AND METHODS: Twenty-five newly diagnosed patients were treated, in a phase II study, with eight cycles of rituximab + chemotherapy (R-CHOP21). Tumor infiltration, B-blasts and Epstein-Barr virus status in tumor tissue and peripheral blood were fully characterized at diagnosis and were correlated with clinical outcome. RESULTS: A complete response rate of 44% (95% CI, 24% to 65%) was observed. With a median follow-up of 24 months, the 2-year progression-free survival rate was 42% (95% CI, 22% to 61%) and overall survival rate was 62% (95% CI, 40% to 78%). The presence of Epstein-Barr virus DNA in peripheral blood mononuclear cells (14/21 patients) correlated with Epstein-Barr virus score in lymph nodes (P&lt;0.004) and the detection of circulating tumor cells (P=0.0019). Despite peripheral Epstein-Barr virus clearance after treatment, the viral load at diagnosis (&gt;100 copy/μg DNA) was associated with shorter progression-free survival (P=0.06). Conclusions We report here the results of the first clinical trial targeting both the neoplastic T cells and the microenvironment-associated CD20(+) B lymphocytes in angioimmunoblastic T-cell lymphoma, showing no clear benefit of adding rituximab to conventional chemotherapy. A strong relationship, not previously described, between circulating Epstein-Barr virus and circulating tumor cells is highlighted
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