Design of a high-torque machine with two integrated motors axes reducing the electric vehicle consumption

The motorization of electric vehicle needs to work at a constant power on a wide range of speed. In order to be able to satisfy these requirements, we describe in this paper a solution, which consists in modifying of a simple structure of a permanent magnet motor by a double rotor structure integrating two motor axes into the same machine. This article describes, then, a design methodology of a permanent magnet motor with double rotor, radial flux, and strong starting torque for electric vehicles. This work consists on the analytical dimensioning of the motor by taking into account several operation constraints followed by a modelling by the finite elements method. This study is followed by the comparison between this motor and a motor with one rotor. A global model of the motor- converter is developed for the purpose to answer several optimisation problem

CuO Elaboration and Studies of the Influence of Heat Treatment on the Structural Properties

In the present work we synthesize nano powders of CuO by precipitation method, using CuCl2 as precursor. The obtained powder has undergone a heat treatment annealing 100°C, and 450°C. Structural analysis by X-Ray diffraction, Fourier transform infrared (FTIR) microscopy and scanning electron microscopy (SEM) reveal that CuO nano particles are in nano graphs forms and with improved crystallization at 450°C, annealing temperature as monoclinic crystal lattice structure. The radius of NCs calculated by the Scherrer formula is 12.31 nm

CuO Elaboration and Studies of the Influence of Heat Treatment on the Structural Properties

In the present work we synthesize nano powders of CuO by precipitation method, using CuCl2 as precursor. The obtained powder has undergone a heat treatment annealing 100°C, and 450°C. Structural analysis by X-Ray diffraction, Fourier transform infrared (FTIR) microscopy and scanning electron microscopy (SEM) reveal that CuO nano particles are in nano graphs forms and with improved crystallization at 450°C, annealing temperature as monoclinic crystal lattice structure. The radius of NCs calculated by the Scherrer formula is 12.31 nm

Phase transition of triangulated spherical surfaces with elastic skeletons

A first-order transition is numerically found in a spherical surface model with skeletons, which are linked to each other at junctions. The shape of the triangulated surfaces is maintained by skeletons, which have a one-dimensional bending elasticity characterized by the bending rigidity $b$, and the surfaces have no two-dimensional bending elasticity except at the junctions. The surfaces swell and become spherical at large $b$ and collapse and crumple at small $b$. These two phases are separated from each other by the first-order transition. Although both of the surfaces and the skeleton are allowed to self-intersect and, hence, phantom, our results indicate a possible phase transition in biological or artificial membranes whose shape is maintained by cytoskeletons.Comment: 15 pages with 10 figure

Coiling Instabilities in Multilamellar Tubes

Myelin figures are densely packed stacks of coaxial cylindrical bilayers that are unstable to the formation of coils or double helices. These myelin figures appear to have no intrinsic chirality. We show that such cylindrical membrane stacks can develop an instability when they acquire a spontaneous curvature or when the equilibrium distance between membranes is decreased. This instability breaks the chiral symmetry of the stack and may result in coiling. A unilamellar cylindrical vesicle, on the other hand, will develop an axisymmetric instability, possibly related to the pearling instability.Comment: 6 pages, 2 figure

Plantes vasculaires nouvelles ou rares pour la Tunisie presentes sur les iles (Galite, Zembra, Kuriat, Monastir, Kerkennah, Kneiss, Djerba)

Vascular plants new or rare for Tunisia occurring on the islands (Galite, Zembra, Kuriat, Monastir, Kerkennah, Kneiss, Djerba). - This study concerns the indigenous vascular plants newly reported for Tunisia and discovered on the islands during some field trips performed since 2014. Five native taxa are new to Tunisia: Bellis perennis, Carthamus creticus, Moraea mediterranea, Asplenium balearicum and Galium minutulum, the latter two also being new to North Africa. Information on 24 rare or poorly known taxa, most often of great biogeographical interest, is given, too. Most of these were discovered on the islands of the eastern coast (Kuriat, Monastir, Kerkennah, Kneiss, Djerba), but also on the northern islands of Zembra and La Galite. The new chorological data underline the first-rate conservation importance of these islands and islets for the preservation of the overall coastal biodiversity of Tunisia

Insights into the influence of the Ag loading on Al2O3 in the H2-assisted C3H6-SCR of NOx

International audienceThe addition of H2 has been reported to promote drastically the selective catalytic reduction of NOx by hydrocarbons (HC-SCR). Yet, the influence of the Ag loading on the H2-promoted HC-SCR has been the subject of a very limited number of investigations. The H2-HC-SCR earlier studies reported mostly on Ag/Al2O3 samples containing about 2 wt% Ag, since this particular loading has been shown to provide optimum catalytic performances in the HC-SCR reaction in the absence of H2. The present study highlights for the first time that the H2-C3H6-SCR catalytic performances of Ag/Al2O3 samples improved in the 150–550 °C temperature domain as the Ag loading (Ag surface density: x (View the MathML sourceAg/nmAl2O32)) decreased well below 2 wt%. A detailed kinetic study of H2-C3H6-SCR was performed in which the reaction orders in NO, C3H6 and H2, and the apparent activation energies were determined for the reduction of NOx to N2 on a Ag(x)/Al2O3 catalysts series, for which Ag was found to be in a highly dispersed state by TEM and HAADF-STEM. Remarkably, changes in these kinetic parameters were found to occur at an Ag surface density close to View the MathML source0.7 Ag/nmAl2O32 (Ag loading of 2.2 wt%) coinciding with the changes observed earlier in the NOx uptakes of the Al2O3 supporting oxide [18]. Interpretation of the activity and kinetic data led us to conclude that the H2-C3H6-SCR reaction proceeds via the activation of H2 and C3H6 on Ag species and their further reaction with NOx adspecies activated on the Al2O3 support. The unexpected higher catalytic performances of the Ag samples with the lower Ag surface densities was attributed to the higher concentration of active sites on the Al2O3 supporting oxide able to chemisorb NOx species, in agreement with the NOx uptake data. The kinetic data obtained for Ag surface densities lower than View the MathML source0.7 Ag/nmAl2O32 also suggest that the interaction between NOx and C3H6 adspecies would be rate determining in the C3H6-SCR process

Phase transition of meshwork models for spherical membranes

We have studied two types of meshwork models by using the canonical Monte Carlo simulation technique. The first meshwork model has elastic junctions, which are composed of vertices, bonds, and triangles, while the second model has rigid junctions, which are hexagonal (or pentagonal) rigid plates. Two-dimensional elasticity is assumed only at the elastic junctions in the first model, and no two-dimensional bending elasticity is assumed in the second model. Both of the meshworks are of spherical topology. We find that both models undergo a first-order collapsing transition between the smooth spherical phase and the collapsed phase. The Hausdorff dimension of the smooth phase is H\simeq 2 in both models as expected. It is also found that H\simeq 2 in the collapsed phase of the second model, and that H is relatively larger than 2 in the collapsed phase of the first model, but it remains in the physical bound, i.e., H<3. Moreover, the first model undergoes a discontinuous surface fluctuation transition at the same transition point as that of the collapsing transition, while the second model undergoes a continuous transition of surface fluctuation. This indicates that the phase structure of the meshwork model is weakly dependent on the elasticity at the junctions.Comment: 21 pages, 12 figure

On a class of stationary loops on SO(n) and the existence of multiple twisting solutions to a nonlinear elliptic system subject to a hard incompressibility constraint

For full abstract please refer to http://dx.doi.org/10.1186/s13661-018-1047-