The phenomenon of dispersion (transverse and longitudinal) in packed beds is summarized and reviewed for a great deal of information from the literature. Dispersion plays an important part, for example, in contaminant transport in ground water flows, in miscible displacement of oil and gas and in reactant and product transport in packed bed reactors. There are several variables that must be con...

In this paper, the Al2O3-water nanofluid flow in laminar and turbulent flows inside tubes fitted with diamond-shaped turbulators is numerically modeled. The nanofluid flow is modeled by employing a two-phase mixture method and applying the constant heat flux boundary condition at tube walls. In the results, the effects of different parameters such as the geometry of turbulators, volume fraction...

abstract in the present article, effective parameters of the buoyant jets have been evaluated in the stagnant ambient fluid. the jet parameters, geometry parameters and environmental parameters are investigated. using dimensional analysis, a set of dimensionless functions was obtained. to achieve the exact functions, a physical model was built in the hydraulic laboratory of shahid chamran unive...

The examination of variation of elastic modules in single wall carbon nanotubes (SWCNTs) is the aim of this paper. Full nonlinear spring-like elements are employed to simulate specific atomic structures in the commercial code ABAQUS. Carbon atoms are attached to each node as a mass point using atomic mass of carbon atoms. The influence of dimensions such as variation of length, diameter, aspect...

The purpose of this study was to compare total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) with regard to the amount of acetabular bone stock removed and the ability to restore leg length and offset. Anteroposterior pelvis radiographs of 153 consecutive THAs and 84 consecutive HRAs were compared. Excluded patients were those with prior hip surgery, those in which a best-fit ci...

the goal of this study was to define the normal range of diameter in the deep vein of the lower limb and to compare this range with diameter of the veins with acute thrombosis and of veins with chronic thrombosis by using color doppler sonography. the study was cross sectional. the vein diameter and vein to artery ratio in different levels were measured and the following results were obtained. ...

The mass flow of granular particles in an aerial spreader duct was regarded as a sequence of cluster passage events. At low flow densities, the total mass per time unit could be estimated by measuring the diameter (length) of each individual particle passing a sensor and accumulating the associated masses. At higher flow densities, the lengths of clusters would be measured rather than the lengt...

Cobitis faridpaki Cobitis faridpaki (Mousavi-Sabet, Vasil'eva, Vatandoust and Vasil'ev, 2011) is found in streams of the Siahrud River in the southeastern Caspian Sea basin, and this is the first report on reproductive parameters of the newly described endemic loach. Reproductive conditions are key parameters of fish populations, and their assessment is very important for endemic fishes. To stu...

background: vascular access (va) is an important aspect for blood circulatory in hemodialysis (hd). arteriovenous fistula (avf) is a suitable procedure to gain va. maturation of the avf is a status of avf, which can be cannulated for hd. this study aimed to discover the parameters that effectively reduce the duration between va and start of hd, which symbolizes the maturation time (mt).   metho...