the radionuclides 226ra, 232th and 40k concentrations measured as well as radiological parameters, for 14 granite samples that use in iran as building material were calculated. the measurements of the radioactivity concentrations were carried out at nuclear physics laboratory university of tabriz. this subject is important in environmental radiological protection, since granites are extensively...

filter is one of the main components of embankment dams. by a simple but effective performance, filter protects the dam against erosion and soil scouring in impervious core caused by leakage (piping) and makes it safe. interaction between filter and erodible base soil is a complex phenomenon which is dependent upon several factors, and has challenged researchers for better understanding the fil...

We study analytically and numerically a model describing front propagation of a KPP reaction in a fluid flow. The model consists of coupled one-dimensional reactiondiffusion equations with different drift coefficients. The main rigorous results give lower bounds for the speed of propagation that are linear in the drift coefficient, which agrees very well with the numerical observations. In addi...

objective: in this study, we aimed to validate the accuracy of computed tomography-based attenuation correction (ctac) using the bilinear scaling method.methods: the measured attenuation coefficient (μm) was compared to a theoretical attenuation coefficient (μt ) using four different ct scanners and an rmi 467 phantom. the effective energy of the ct beam x-rays was calculated, using the aluminu...