background: a substantial part of the public’s natural radiation dose is due to the inhalation of radon gas. most of the exposure occurs indoors where the airborne concentration of radon and its decay products is usually higher than outdoors. materials and methods: radon activity concentration has been measured twice in 50 classrooms in 5 levels (10 each) during summer and winter using solid-st...

Solid state chemical reaction is attributed to the chemical reaction performed at temperature which reactants are solid. In most solid state chemical reactions the reaction volume continually diminishes as the reactants become spatially separated by the products. As a result, the kinetics of solid state chemical reactions are limited by the rate at which reactant species are able to diffuse acr...

the reaction mechanism between (h2c) and (7, 0), zigzag single-walled carbon nanotubes(zswcnts) on two different orientation of c-c have been studied by semi empirical am!method. the activation barriers of (h2c) adding to (7, 0) zswcnt are computed and compared.the effects of diameters of zigzag swcnt on their binding energies were studied