in the present work an attempt has been made to study the effect of the twisted tapes as bed internals, on the performance of the gas-solid fluidized beds. experimental investigation has been carried out in cylindrical column with and without twisted tapes. twelve numbers of twisted tapes of three different widths with four values of the twist ratios for each width were studied at different sta...

We theoretically study the optical activity in a doped system and derive tensor from light wavevector-dependent linear conductivity. Although light-matter interaction is introduced through velocity gauge minimal coupling Hamiltonian, we find that well-known ``false divergences'' problem can be avoided practice if electronic states are described by finite band effective such as few-band tight-bi...

background: the aim of the present study was to evaluate how left ventricular twist and torsion are associated with sex between sex groups of the same age. materials and methods : twenty one healthy subjects were scanned in left ventricle basal and apical short axis views to run the block matching algorithm; instantaneous changes in the base and apex rotation angels were estimated by this algor...

In nature of the transmission medium the broadcast, Wireless sensor networks are vulnerable to security attacks. The nodes are placed in a hostile or dangerous environment where they are not tangibly safe in the MANETs. In many application, the data obtained from the sensing nodes need a false, or malicious node could intercept private information or could send false messages to nodes in the ne...

background: in oil refinery plants, shift working is inevitable . shift work is associated with depression; therefore this prospective study was carried out in tehran shahid tondguyan oil refinery in order to determine the prevalence of depression in shift workers and to assess the effects of associated factors with depression among shift workers. in the present study, the shifting work system ...