introduction: the photoelectric attenuation coefficient of substances is known to depend upon the energy e of the photon and the effective atomic number of substances (zeff) as (zeff x /e y ).  no definitive values about these indices x, y are given in the literature. the index x is said to lie between, 3.0 and 4.0, while for ‘y’ different values have been assigned, between 3.0 and 4.0. methodo...

this research was conducted to determine the effect of gamma ray (gr) (100 and 150 kgy), sodium hydroxide (50 g/kg dm) and calcium oxide (160 g/kg dm) on gas production parameters and in vitro digestibility of soybean straw. all treatments, except for the gamma ray (100 and 150 kgy) did not have gas production up to 4 hours after incubation and there was a lag time. from 8 to 96 hours of incuba...

in this research, the effect of tension wood formation in populus nigra on its anatomical characteristics was studied. vessel element and ray frequency (n/mm²), vessel diameter and ray dimensions were measured in both normal and tension wood. furthermore, the formation of gelatinous layer (g-layer) in the fibers of tension wood was studied. the results showed that the vessel proportion and diam...

The ray effect in ray tracing method was analyzed and three new ray emitting methods for a surface element (method A, B and C) were presented. Numerical computations of viewfactors for three different typical configurations indicated that the proposed methods can significantly eliminate the ray effect. Compared with the conventional ray emitting method, the proposed methods, especially method C...

Introduction: To date, gold nanoparticles (GNPs) have been demonstrated to have great potential as contrast agent for CT imaging and therapeutics. This study was designed to evaluate any effect on X-ray attenuation that might result from using GNPs with a variety of size, surface chemistries and shapes.   Materials and Methods: Spherical GNPs and gold nanorod...