Iranian Journal of Materials Science and Engineering

• Bentonite was firstly organo-modified by using three quaternary ammonium salts.
• Organo-modified bentonite (OMB) was then added to Portland cement.
• Adding 3.5 wt% OMB results in 11.43% increase in 28-day compressive strength.
• Adding 3.5 wt% OMB results in 20.78% reduction in total permeable porosity.
• Adding 3.5 wt% OMB results in 16.20% reduction in water absorption.

• Bias voltage has a significant effect on S/Mo in MoS2 films so that it decreases as bias voltage increases. The highest NS/NMo (1.59) ratio was reached with the lowest bias (0 V)
• Within the Ti content region of 0–5 wt.%, increasing the Ti content led to a significant increase in the coating’s critical load. 5. The MoSx/Ti coatings exhibited a stea state friction coefficient ranging from 0.13 to 0.19.
• Adding Ti to MoSx coatings improved their adhesion to the steel substrate and hardness as well as increased the wear performance ofMo x coatings under atmospheric conditions.
• Adding Ti to MoSx can significantly avoid humidity or tribo-chemical effects on the MoS 2 layer and hence significantly increase the wear life.

• Thickness of sol-gel derived nano-TiO₂ coatings were adjusted in two procedures.
• Single heat treated sample has thinner coating than multiple heat treated one.
• The increment of the heat treatment cycle led to roughness reduction of coating.
• There was optimum preparation procedure for the best anticorrosion performance.

AA2024 aluminum alloy reinforced with Al₂O₃/SiC different particle sizes (10, 20 and 40 μm) and weight fractions (upto 10 wt %) were fabricated by using squeeze casting technique.
AA2024/Al₂O₃ (5 wt%)/ SiC (5wt%) reinforced particle sizes showed maximum hardness and tensile strength.
Wear analysis revealed load followed by sliding speed is the most important factor that affects the coefficient of friction.
Al₂O₃/SiC 10 µm particle size reinforced AA2024 significantly enhanced the mechanical and wear properties

1-Mechanical activation and particle size reduction has a positive effect on gold extraction.
2- Leaching kinetics mechanism in the first two hours depending on activation time changed from diffusion through an ash layer to chemical reaction control.
3- Leaching kinetics mechanisms between of 2-16 hours depending on activation time changed from diffusion through an ash layer to liquid film diffusion control.
4- Mechanical activation of the ore for 60 minutes resulted in close to 100% of gold recovery during 16 hours of leaching.