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Hybrid laminate composites based on two natural long fiber combinations as jute/coir and jute/doum fibers at different layers stacking were successfully manufactured by using illite clay particles at various content (5−20 wt%). Mechanical and rheological tests were conducted on the elaborated composite in real-time and after aging in order to investigate the effects of clay incorporation, natural fiber hybridization, and long-term aging on mechanical, physical, and morphological properties. The properties of the laminate composites were mainly influenced by the use of hybrid matrices at different clay content and hybrid fibrous reinforcement (jute/coir and jute/doum), fiber orientations ([0] and [45]), and fiber architecture (canvas and matt). The mechanical properties of realized hybrid laminate composites increased with the addition of clay up to an optimum value at 15 wt%. The complex modulus G* confirms that the laminates have an elastic behavior. The long-term aging of laminates has also been investigated by choosing 5 years as long-term duration. This choice, not random, represents moderately the period of maturity of the functional composite parts used in different industrial sectors. The results of aged laminates show an abyssal decrease of rigidity (54%), tensile strength (20%) and complex modulus (97%) and a highly considerable increase of strain at yield up to 54%. This decrease is mainly attributed to the relaxation phenomenon of polymeric chains of epoxy and deterioration of natural fibres.

This study aims to develop a new low carbon composite material using illite clay and titanium dioxide as a stabilizing and whitening agent. It investigates the effect of the inclusion of titanium dioxide nano-powder and illite particles on optical, thermal, and mechanical performances of polypropylene (PP) matrix. The composite samples based on binary (PP-illite) and ternary (PP-illite-titania) composites at various particle contents of illite-titania have been manufactured by using a melt-compounding technique. The results showed that the low loading of titania has a significant effect on the whiteness index of the composites. The comparative analysis also demonstrated that the thermal stability was increased by approximately 7% in the case of the composites reinforced by the illite-titania at 18:2 wt%. Moreover, the addition of titania powder leads to ensure stabilization of tensile strength properties for all composites and also allowing Young’s modulus to gain increase of 83% for the composites reinforced by 2 wt% of titania powder. As for the addition of titanium dioxide until 5 wt%, an improvement in the aesthetic appearance of the composites is well noted by slightly decreasing the other specific properties. By combining the useful with the pleasant, and from different results obtained, it is proposed to use an optimal percentage of titania is less than 2% without impacting the hygroscopic and resistance of ternary composites and enhancing the rigidity of polymer products.

The structural, elastic, and electronic properties of rare earth intermetallic R2Ni2Pb (where R = Ho, Lu, and Sm) compounds were investigated with the density functional theory (DFT) calculations. The calculations are performed using the full potential-linearized augmented plane wave (FP-LAPW) method within the framework of local density approximation (LDA). The calculated values of the equilibrium lattice constants were in agreement with the available experimental values. The elastic constants (C i j ) were also calculated to understand the mechanical properties and structural stability of the compounds. Furthermore, the density of states and the charge density distributions of the compounds were calculated to understand the nature of the bonding in the material. The calculated results are in accordance with the available data in the literature.

Germanium implantation into silicon substrate is currently used to preamorphisize the crystalline structure in order to avoid boron channeling effects in shallow P+N junction manufacturing. Nevertheless, after boron doping and rapid thermal annealing, different defects are formed within the structure, such as end of range defects which are created at the amorphous/crystalline interface. Our study concerns two types of shallow P+N junctions. These junctions were fabricated using low energy boron implantation at 3 KeV with a dose of 2×1015 cm-2 into high-energy germanium preamorphized n-type crystalline silicon substrates at 2.2 MeV with a dose of 1015 cm-2. In the first type, the preamorphization was performed at ambient temperature. In the second, the preamorphization was performed at liquid nitrogen temperature. Boron doping was followed by a Rapid Thermal Annealing (RTA) step for 15 s at 950 °C. Deep Level Transient Spectroscopy (DLTS) technique was used to characterize the defects formed in each structure. The impact of an ac magnetic field on the reverse current has been studied at a given bias, when sweeping the sample temperature. The measurements were performed under a low frequency (less than 1 kHz) magnetic field of a Vrms value of 2000 G, with sample temperature varying between 80 and 260 K. The results show a high activity of defects at low frequencies (1 and 10 Hz) for the nitrogen preamorphized sample. Moreover, this activity is observed at about 200 K which corresponds to the peak of the DLTS spectra of such sample. However, the ambient preamorphized sample characterized by a lower concentration of defects seems to be insensitive to the ac magnetic field. Therefore, it appears that the preamorphization-induced defects influence strongly the response of the junction to an applied ac magnetic field.