In order to gain a better understanding of the chemistry of methanl-to-hydro-carbon conversion, it is necessary to determine the nature of the primary reaction products. Experiments carried out in this work on H-ZSM-11, using a continuous flow reactor linked to an on-line gas chromatograph demonstrated that ethylene and methane are the primary reaction products. The results obtained using s...

CaCO3 nanoparticles have been synthesized via heat-treatment of a new precursor and solid state reaction. Effect of calcinations temperature and quantity of surfactant on particle size has been investigated. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT–IR) spec...

this study aimed to evaluate enamel roughness after adhesive removal using different burs and an er:yag laser.the buccal surfaces of forty human premolars were sealed by two layers of nail varnish, except for a circular area of 3 mm in diameter on the middle third. the enamel surfaces were initially subjected to profilometry analysis and four parameters of surface irregularity (ra, rq, rt and r...