Grain size distribution of quartz isolated from Chinese loess/paleosol

Grain size distribution of bulk loess-paleosol and quartz chemically extracted from the loess/paleosol shows that mean size of the bulk samples is always finer than that of the quartz, The original aeolian depositions have been modified to various degrees by post-depositional weathering and pedogenic processes. The grain size distribution of the isolated quartz should be close to that of the primary aeolian sediment because the chemical pretreatment excludes secondary produced minerals. Therefore, the grain size of the quartz may be considered to more clearly reflect the variations of winter monsoon intensity.

Templateless synthesis of catalysts with narrow mesoporous distribution

In this study, amorphous silica-alumina nanomaterials with narrow mesoporous distribution can be obtained by two novel sol-gel processes, without the use of any templates. The results of our experiments show that the preparation method has a great influence on the precursor sol structure as well as the specific surface area and mesopore volume of the final product, but has no effect on the pore size distribution.

On the Size Distribution of Autonomous Systems

This paper explores reasons for the high degree of variability in the sizes of ASes that have recently been observed, and the processes by which this variable distribution develops. AS size distribution is important for a number of reasons. First, when modeling network topologies, an AS size distribution assists in labeling routers with an associated AS. Second, AS size has been found to be positively correlated with the degree of the AS (number of peering links), so understanding the distribution of AS sizes has implications for AS connectivity properties. Our model accounts for AS births, growth, and mergers. We analyze two models: one incorporates only the growth of hosts and ASes, and a second extends that model to include mergers of ASes. We show analytically that, given reasonable assumptions about the nature of mergers, the resulting size distribution exhibits a power law tail with the exponent independent of the details of the merging process. We estimate parameters of the models from measurements obtained from Internet registries and from BGP tables. We then compare the models solutions to empirical AS size distribution taken from Mercator and Skitter datasets, and find that the simple growth-based model yields general agreement with empirical data. Our analysis of the model in which mergers occur in a manner independent of the size of the merging ASes suggests that more detailed analysis of merger processes is needed.

Effect of biodiesel oil composition on droplet size distribution

Droplet size distribution of biodiesel oil with various compositions was investigated in this work. The droplets generated by a two-fluid atomizer were measured by a commercial PDA. It was found that viscosity of the fuel has a strong effect on the drop size distribution. Additionally, effect of air injection pressures applied to atomize the spray was taken into account. Shear force induced by flow field exerts an effect on distribution of biodiesel droplets in atomized spray.

Transient Crystal Size Distribution in DTB and FC Crystallizers

This work deals with the transient analysis of crystal size distribution (CSD) for imperfectly mixed draft tube baffled (DTB) and forced circulation (FC) crystallizers. The DTB and FC crystallizers are described by the Compartmental and Mixed models respectively. Monte Carlo (MC) scheme has been employed for simulation purposes. The simulation results have been compared with the available experimental data of BENNETT and VAN BUREN for continuous urea crystallizers.