The pure hydroxyapatite (HAp) and antibacterial co-doped hydroxyapatite [(Cu, Mg) HAp] nano-powders were synthesized by Wet chemical precipitation method. Calcium hydroxide (CaOH 2 ) and phosphate acid (H 3 PO 4 ) were utilized as starting materials, magnesium oxide (MgO) and copper oxide (CuO) represent the doping elements . The ratio (Ca/P) kept at 1.67 and PH value maintained to10 at room temperature. Pure HAp [Ca 10 (PO 4 ) 6 OH 2 ] and three stoichiometric compositions of the codoped HAp were prepared which were [(Mg 0.25 ,Cu 0.75 )Ca 9 (PO 4 ) 6 OH 2 ],[(Mg 0.5 ,Cu 0.5 )Ca 9 (PO 4 ) 6 OH 2 ] and [(Mg 0.75 ,Cu 0.25 )Ca 9 (PO 4 ) 6 OH 2 ]. All the prepared powders were calcinated at 800 °C for 2hrs . The structure, antibacterial activity, and toxicity with cell viability have been investigated using several characterization techniques . XRD results showed that the fabricated undoped-HAp and co-doped HAp has one (hexagonal) phase , and the FT-IR results shows functional group that confirm the results of XRD. The TEM images indicated that incorporation of Cu 2+ and Mg 2+ has altered the size and morphology of the resulting HAp crystals which appears elongated with dissimilar sizes. Antibacterial test indicated that co-doped HAp [(Mg 0.25 ,Cu 0.75 )Ca 9 (PO 4 ) 6 OH 2 ] showed high activity versus E.coli and S.aureus bacteria. The MTT assay for the [(Mg 0.75 ,Cu 0.25 )Ca 9 (PO 4 ) 6 OH 2 ] has shown superior positive role on cell viability as appears in the fluorescent image, and has acceptable antibacterial activity.

This paper study the effect of the calcium carbonate (CaCO3) nanoparticleson mechanical and physical properties of virgin and waste polypropylene (pp.). 3, 5, 7 and 10 (wt. %) of CaCO3nanoparticles are mixed with each of virgin and waste pp.These mixture are blended in co-rotating twin screw extruder at 190 °Cand different screw speed (25 and 50 rpm). Different mechanical and physical technique are used to evaluate the characteristics of polymer nanocomposites ex: Tensile strength , elastic modulus , impact strength , hardness and density. The results of virgin pp./(CaCO3) showed that The tensile strength decreasing with nano(CaCO3) concentration for virgin pp. , while for waste increasing at 5% and then decreasing gradually. The impact strength increasing with nanoCaCO3concentration increasing. The hardness and density increasing with the increasing of the nanoCaCO3concentration for two type of pp.Nearly all the mechanical properties were found to increase with the processing speed of 25 rpm. In this studies, it was seen that the highest processing speed of 50 rpm does not give the material performance enhancements due to higher shear intensity which causes defect points in the structure. Also the time is smaller at high screw speeds, so there is not enough time for good dispersion to occur.

This work deals with studying the mechanical properties specially fatigue behavior for high performance composite materials of poly ether ether ketone (PEEK)/glass fiber, which are used in Aircraft Industry. Two materials have been used: (PEEK natural) and (PEEK+30% glass fiber).To identify the type of (PEEK), infrared (FTIR) test has been conducted. X-ray test has been used to measure the (PEEK) crystalline ,also the tensile properties, impact strength and the fatigue test are performed.The results show that FTIR test peaks are for standard PEEK polymer and that GFRP increases the crystalline of (PEEK) material , while the tensile , impact and fatigue properties of (PEEK) decreases by adding GF to PEEK .

In present paper a new composite materials of (polyester/ (GF, SiC, PVC, Cu)) was prepared and studied to be used in gear applications. Samples were prepared with range of short length fiber (0.02-0.08 mm) and the weight fraction of E-glass fiber varying from (0-25)% . The best sample according to the wear resistance criterion was selected and some additives were used to improve impact, tensile, hardness, and thermal conductivity . These additives are 5% SiC, 6% PVC and 4% Cu. Samples properties were evaluated by using standard mechanical and physical testing. The results show improvement in all mechanical and thermal properties. Although the tensile strength decreases with increasing volume fraction of fiber content.

In present work, the influences of TiO2 nanoparticles addition on the tribological and mechanical behavior of polyphenylene sulfide (PPS) were investigated. The composites samples containing TiO2 nanoparticles at various percentages (0, 1, 3, and 6 wt. %) were prepared by melt mixing process using single screw extruder at 325 °C and 20 rpm. A pin-on-disc sliding test machine was used for measurement of wear volume and the friction coefficient. The counterface was made of steel carbide with roughness 0.1 μm Ra. The tests were run at a sliding speed of 0.4 m/s and 1 m/s, the contact pressure 0.65 Mpa with different sliding distances (5, 10, 15 and 20 km). Mechanical properties of PPS nanocomposites were studied to evaluate the influence of the nanoparticles addition, as well as examined the relation between the tribological and mechanical behavior. It was found that nanoparticles could further enhance the tribological properties. The lowest wear volume and friction coefficient was observed at 1 m/s was PPS+1wt. %, and for 0.4 m/s was observed in PPS+6wt. %. The results indicate that the mechanical of PPS nanocomposites have been improved, the impact strength and hardness increased with the incorporation of TiO2 nanoparticles. The density was also increased with TiO2 nanoparticles.