River bed sediments typically fine downstream, where fining of median grain sizes are often described as exponential, except gravel abruptly transitions to sand. Across the gravel-sand transition, can reduce by more than 10 mm (>90%) over a distance only few channel widths. There several viable theories for why transition occurs, but they remain matter ongoing discussion in literature. Here, we...

The relation between the equivalent roughness and different grain size percentiles of the sediment in gravel-bed rivers was determined under the hypothesis that the vertical distribution of the flow velocity follows a logarithmic law. A set of 954 data points was selected from rivers with gravel size sediment or larger, with a non-sinuous alignment and free of vegetation or obstacles. According...

Abstract The size fractionation of magnetic nanoparticles is a technical problem, which until today can only be solved with great effort. Nevertheless, there an important demand for sharp distributions, example medical technology or sensor technology. Using chromatography, we show promising method respect to their and/or properties. This was achieved by passing through packed bed fine steel sph...

The radiative heat transfer in a high temperature granular bed of binary-size mixture was explored this paper. effective view factor between particles decreases exponentially with the increase particle interval, increases size absorption but is hardly affected by volume ratio mixture. thermal conductivity further deduced basing on characteristic factor. It indicated that proportional to and cub...

Fluidization of nanoparticle agglomerates is a promising technique to process nanoparticles. However, possible elutriation small may cause significant loss bed material. To obtain the behavior under stable operation, in this study fraction silica measured vibro-fluidized bed, which operated for several hours. Among conditions with different fluidizing gas velocities, Ug, and vibration strength,...

This study evaluates the size frequency distribution of 11 trees and shrubs in the cloud forest in Wadi Garziz, southern Oman, in order to assess their current situation, which is affected by cutting, overgrazing and other constraints. A size class distribution and a vegetation structure analysis were applied in order to analyze the dynamics of this forest using census data from 51 plots select...