Fluctuations of a swarm of Brownian bees.

The "Brownian bees" model describes an ensemble of N independent branching Brownian particles. When a particle branches into two particles, the particle farthest from the origin is eliminated so as to keep the number of particles constant. In the limit of N→∞, the spatial density of the particles is governed by the solution of a free boundary problem for a reaction-diffusion equation.

Effect of different types of organic compounds on the photocatalytic reduction of Cr(VI).

The effect of different types of organic compounds (humic acid, oxalate, ethylenediaminetetraacetic acid, nitrilotriacetic acid, phenol) on the photocatalytic reduction of Cr(VI) with illuminated TiO2 was studied in this work with variation of the solution pH, contact time, initial Cr(VI) concentration and type of organic compounds. As the pH increased, the removal efficiency for Cr(VI) decreased. The increase in Cr(VI) removal by UV/TiO2 with decreasing solution pH was due to the increased potential difference between the conduction band of TiO2 and Cr(VI)/Cr(III) as well as the anionic-type adsorption of Cr(VI) on to the TiO2 surface.

Photocatalytic reduction of Cr(VI) and Ni(II) in aqueous solution by synthesized nanoparticle ZnO under ultraviolet light irradiation: a kinetic study.

Photocatalytic removal of Cr(VI) and Ni(II) from aqueous solution using synthesized nanoparticle ZnO under ultraviolet (UV) light irradiation was studied in this work. Firstly, nanoparticle ZnO was prepared by the chemical method with an organic chemical inhibitor. Then removal efficiency of Cr(VI) and Ni(II) by nanoparticle ZnO was investigated with variation of the solution pH, ZnO dosage, contact time and initial Cr(VI) and Ni(II) concentration.

Photocatalytic removal of cyanide with illuminated TiO(2).

Effects of TiO(2) dosage, pH and initial cyanide concentration on the removal efficiency of cyanide from aqueous solutions with illuminated TiO(2) have been investigated. Adsorption and oxidation were recognized as significant processes for the elimination of cyanide. From the Langmuir isotherm, the maximum adsorption capacity was determined as 17.

[Pseudo-tumor form of bladder scleroderma: unusual cause of hematuria].

The bladder is a rare site of scleroderma. The frequency of bladder involvement is difficult to estimate, as only about thirty cases have been reported in the literature. Scleroderma bladder involvement usually presents in the form of frequency and burning, but may sometimes cause urgency or recurrent urinary tract infections.