Prediction of mechanical behavior of friction stir welded joints of AA3003 aluminum alloy

Friction stir welding (FSW) is an extremely complex process because it depends on the intrinsic and extrinsic factors of the material under consideration. The purpose of the present work is to formulate a set of recommendations concerning the choice of the different factors that are likely to influence the quality of the FSW joint and to find a mathematical model that allows predicting the mechanical behavior of the junction. An experimental design was therefore used to highlight the effect of the welding parameters on the behavior of the aluminum alloy  FS-Welded joint. The most influential parameters were shown to be in the order of rotational speed, feed rate and tool tilt angle. The study of the interactions between these different parameters made it possible to establish a number of combinations of the different factors for the purpose of achieving the quality optimization of the FSW joint by obtaining a tensile strength of the weld joint equal to  of that of the base metal

Fast, Efficient and Environmentally Friendly Extraction of Cu(II) and Zn(II) by Hybrid Silicas Impregnated with Acidic Organic Extractants

The extraction of copper and zinc by mesostructured silicas impregnated with organic acidic chelators, an acylisoxazolone 3-phenyl-4-benzoyl-5-isoxazolone (HPBI), an acylpyrazolone 1-phenyl-3-methyl-4-stearoyl-5-pyrazolone (HPMSP) and an organophosphoric acid di-(2-ethylhexyl)-phosphoric acid (DEHPA) was performed in a sulfate medium. Various factors such as the pH of the aqueous phase, the chelators concentration in the silica matrix, the extraction equilibrium time and the extraction capacity of the two cations on silica were studied. The cations were extracted at very acidic pH with very high extraction rates. The stripping of cations was achieved at pHs that were more acidic than those utilized for the extraction by maintaining the structure intact. Finally, their separation was successfully conducted in the cases of the three chelators

Prediction and optimizing residual stress profile induced by cold expansion in aluminum alloys using experimental design

Cold expansion by hardening is a common process used in the aerospace industry to extend the fatigue lifetime of assembly holes, through a field of high compressive tangential residual stresses. The understanding and the control of the residual stresses are thus important, since it can be beneficial to improve lifetime of the structures. The main objective of this work is to establish and validate a predictive model of residual stresses generated by cold hardening. This technique can be an effective ways for industrials allowing an estimation of the fatigue lifetime of parts according to the process parameters or to determine the optimal parameters to maximize fatigue lifetime. An experimental setup was used to highlight the effect of expansion degree, thickness of the part and yield strength on the residual stresses profiles. Moreover, the proposed mathematical models were used to determine the optimal values of the various factors for the residual stress profiles prediction at any factor values, in order to achieve maximum service life after repair of a cracked structure or to delay crack initiation and growth in riveted or bolted structures. Besides, the modelling permits us to highlight the effect of interaction of these factors on the residual stresses profiles

Optimization of the geometrical parameters of bonded composite wrap for repairing cracked pipelines

In this study the finite element method is used to analyze the performances of bonded composite wrap repair of  cracked steel pipelines. Parametric analysis was performed in order to highlight the effects of the geometrical properties on the repair efficiency. The experimental design method is used to explore the effects of wrap dimensions (length, angle and thickness) in order to optimize  the repair process. We showed in using the MOODE.5 software the most dominant geometrical parameters on  stress intensity factor at the crack front which  to determine the most important parameters on the repair efficiency. This  optimization  can help the composite wrap designers to improve the repair performance and rehabilitation

Small iron pieces effect on the output of single slope solar still

Solar distillation is an environmental technique that uses solar energy to treat polluted water. In this context, two solar stills of the same size (0.5 x 0.5 m) were exposed to the sun i.e., under the same weather conditions to see the effect of small iron parts on the production of pure water. The results showed that the modified solar still SSM which contained iron pieces had an improvement rate of 23.46% compared to the reference solar still SSR

Preparation of silicas impregnated with HPBI, HPMSP and DEHPA and their application in the solid–liquid extraction of Cu(II) and Zn(II)

International audienc

Study on the extraction of lanthanides by a mesoporous MCM-41 silica impregnated with Cyanex 272

International audienc