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Numéro 02

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New Approach to Modeling a planar flexible continuum robot simulating elephant trunkt

Research on the modeling of continuum robots is focused on ways to construct the geometric models, while maintaining maximum specificities and mechanical properties of the robot. This paper presents a new approach of geometric modeling of continuum planar multi- sections robots, assuming that each section is curved in a circular arc, while having inextensible central axis of the structure. The direct geometric model is calculated analytically, whereas the extreme points (used in calculating the inverse geometric model) of each section are calculated numerically using a particle swarm optimization (PSO) method. One advantage of this method is to simplify the mathematical calculations and transform the complex problem into a simple numerical function ; which allows the knowledge of the form of the central axis of the robot. Simulation examples using this method are carried to validate the proposed approach.

Effect of surfactants in the synthesis of NiO nanoparticles bycolloidal thermal assisted reflux condensation method

Nickel oxide (NiO) nanoparticles were prepared by colloidal thermal assisted reflux condensation method using nickel acetate (precursor salt) and N, N - Dimethylformamide - DMF (solvent) with or without the addition of surfactants such as cetyl trimethyl ammonium bromide (CTAB), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) and sodium monododecyl sulphate (SDS) respectively. Finally, the prepared samples products were calcined at different temperatures systematically such as at 200oC, 400oC, 600oC, 800oC for 2 hrs each to get the phase pure product. The calcined nanoparticles were characterized by X-Ray Diffraction (XRD), Energy Dispersive X-ray Analysis (EDAX), Fourier Transform Infrared (FTIR) Spectroscopy, Particle Size Analysis, Scanning Electron Microscopy (SEM), Diffuse Reflectance Spectroscopy (DRS) and Photo Luminescence (PL) Spectroscopy techniques. All the samples were crystallized in cubic structure. Effect of surfactants in the synthesis of nickel oxide (NiO) particles is discussed and reported.

Nd:Yag Laser Ablation of Recuperated and Industrial Aluminum Alloys. Study of Threshold Ablation

In this work, we used a nanosecond Nd : Yag laser (=532 nm) with a pulse duration of 15 ns, and an energy of 50 mJ and, therefore, we studied the threshold ablation of industrial aluminum alloy. The composition of the recuperated aluminum (% mass) is (72.02 Al, Si 13.05, 6.34 Zn, 4.28 O, 2.08 Mg, 1.75 Cu, 0.48 Ni) and the industrial aluminum is (83.10 Al, 1.66 Si, 4.12 Fe 2.17 O, 1.20 Mg, 5.47 Cu, 1.74 Mn, 1.79 Pb). For nanosecond lasers, the primary energy is lost by thermal diffusion in the irradiated target, because there is enough time to convert optical energy into thermal energy and heat spread. Fusion and / or evaporation may take place if the surface temperature exceeds the critical point when the energy of radiation is above the ablation threshold. The results shows that the threshold ablation of the recuperated aluminum is lower than that of the aluminum industry, it is about 5 J.cm-2 for the recovered aluminum and 10 J.cm-2 for the industrial aluminum. The threshold ablation is shifted towards the low values when the number of pulses increases.

Irradiance and temperature impact on thin film materials I-V curves

The thin-film solar cells are becoming increasingly used in various applications ; this is mainly due to the continued high cost of mono or polycrystalline silicon. In addition, the thin film technology offers the most diverse applications including uses low solar irradiance. The main fields of thin film solar cells are : the chain of amorphous silicon (a-Si), the chain of cadmium telluride (CdTe) and chalcopyrite sector (CIS and CIGS material). In this paper, a study on the influence of light and temperature on the characteristics I (V) of different thin film photovoltaic cells (a-Si:H single, a-Si:H tandem a-Si:H tripple, CdTe and CIS) is detailed. Under standard conditions (illumination of 1000W/m2 and cell temperature 25° C), we see that the CdTe is the closest that the monocrystalline silicon which has a maximum value of short circuit current material (3,26A).

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