introduction: the aim of this study was to evaluate the effect of dental surface treatment with erbium-doped yttrium aluminum garnet(er: yag), neodymium-doped yttrium aluminium garnet(nd: yag) and carbon dioxide laser  (co 2 ) lasers and sodium ascorbate to recently home bleached enamel by scanning electron microscope (sem). methods: thirty extracted human third molars were selected for this in...

among various practical measures used for restriction of the ground surface settlement in such tunnels driven in soft ground, selection of an appropriate excavation method plays a significant role. in this paper, employing suggested diagram by yu & chern, corresponding values of niayesh tunnel has been inserted into the diagram. later, two excavation methods namely: central diaphragm and si...

A practical application of the spherical involute surface to the forged straight bevel gears is provided and demonstrated in this work. Conjugate (pure involute) theoretical surfaces are developed from the input design parameters. The surfaces are modified to suit the actual application (automotive differential). The unloaded (or low load) tooth contact analysis of modified surfaces is performe...