In addition of binding the patch to the cracked material, adhesives play an important role in bonded composite repair because they make the bridge of transfer of loads between the patch and the cracked material. Indeed, any damage in adhesives will affect the efficiency and the performance of the repaired structure by composite patches.In this paper, two different adhesive shapes were numerically investigated, using finite element method in order to estimate the damage zone area on the adhesive bonded composite repair in 5083 marine grade aluminum alloy and its effect on the efficiency and performance of the repaired structure. The obtained results proved that the circular shape causes less damage than the rectangular one for the three crack lengths chosen. Moreover, both shapes of adhesive maintain their performance repair without disband risk and without reaching the critical value defined by Ban and co-authors (Dr=0.2474). Furthermore, it is concluded that the damage zone increases with the increase of the adhesive thickness and the decrease of the patch thickness and the use of circular shape is more effective than the rectangular one for the configurations and loading conditions studied.

In this paper an experimental investigation of mechanical behavior of a thermoplastic polymer (polyamide PA 66) processed by constrained groove pressing (CGP) using several passes is presented. To this end, corrugating and straightening tools are designed and manufactured. The effects of the number of passes and the hold time on the mechanical behavior of the polyamide have been highlighted. The obtained results show that the material properties and the microstructure are significantly altered under CGP process. It has been found that the microhardness and the tensile properties have been progressed accordingly to the number of cycles, especially when the samples are processed using a hold time of five minutes. Hence, it can be concluded that this latter plays a very important role on the reorientation and stabilization of the microstructure when the processed material is a polymer.

In this paper, the simultaneous effect of corrosion and cracking on the performance of the bonded composite patch repair in aluminum alloy A5083 marine structure was investigated using three-dimensional finite element methods. To this end, two patches made of carbon/epoxy and boron/epoxy, bonded on corroded plates with and without crack, were tested under different applied loads. The effect of both corroded and cracked materials on the damage of the adhesive FM73 was also highlighted. The obtained results show that the corrosion has a significant effect on the quality of the repair performance. Indeed, it is proved that, the rate of damage increases with the increase of the applied load and is more significant in the case of plates cracked and repaired by carbon/epoxy patch compared to that of boron/epoxy patches.

This paper proposes the impact of the Dynamic model in Input-Output State Feedback Linearization (IO-SFL) technique for trajectory tracking of differential drive mobile robots, which has been restricted to using just the kinematics in most of the previous approaches. To simplify the control problem, this paper develops a novel control approach based on the velocity and position control strategy. To improve the results, the dynamics are taken into account. The objective of this paper is to illustrate the flaws unseen when adopting the kinematics-only controllers because the nonlinear kinematic model will suffice for control design only when the inner velocity (dynamic) loop is faster than the slower outer control loop. This is a big concern when using kinematic controllers to robots that don’t have a low-level controller, Arduino robots for example. The control approach is verified using the Lyapunov stability analysis. MATLAB/SIMULINK is carried out to determine the impact of the proposed controller for the trajectory tracking problem, from the simulation, it was discovered that the proposed controller has an excellent dynamic characteristic, simple, rapid response, stable capability for trajectory-tracking, and ignorable tracking error. A comparison between the presence and absence of the dynamic model shows the error in tracking due to dynamic system that must be taken into account if our system doesn’t come with a built-in one, thus, confirming the superiority of the proposed approach in terms of precision, with a neglectable difference in computations.

Algerian flora is rich in medicinal plants used locally to care for many sicknesses and diseases. Ridolfia segetum is one of these plants that grows in the southwest of the country in the Saoura Bechar region. The essential oil of seeds of Ridolfia segetum was extracted by hydro distillation and analyzed by chromatography and mass spectrography (CG/MS). The obtained results show that the most important compounds are carvone (69.9%) and apiole (12.41%) as major products and dihydrocarvone (6.66%) and limonene (5.62%) and traces of perillaldehyde, dihydrocarveol, linalool, p-cymene, and β-pinene. More characteristics of the essential oil of seeds of Ridolfia segetum have been also proclaimed at the end of this paper.