Coupled Particle Transport and Pattern Formation in a Nonlinear Leaky-Box Model

Effects of particle-particle coupling on particle characteristics in nonlinear leaky-box type descriptions of the acceleration and transport of energetic particles in space plasmas are examined in the framework of a simple two-particle model based on the Fokker-Planck equation in momentum space. In this model, the two particles are assumed coupled via a common nonlinear source term. In analogy with a prototypical mathematical system of diffusion-driven instability, this work demonstrates that steady-state patterns with strong dependence on the magnetic turbulence but a rather weak one on the coupled particles attributes can emerge in solutions of a nonlinearly coupled leaky-box model. The insight gained from this simple model may be of wider use and significance to nonlinearly coupled leaky-box type descriptions in general

Removal of cationic pollutants from water by xanthated corn cob: optimization, kinetics, thermodynamics, and prediction of purification process

The removal of Cr(III) ions and methylene blue (MB) from aqueous solutions by xanthated corn cob (xCC) in batch conditions was investigated. The sorption capacity of xCC strongly depended of the pH, and increase when the pH rises. The kinetics was well fitted by pseudo-second order and Chrastil’s model. Sorption of Cr(III) ions and MB on xCC was rapid during the first 20 min of contact time and, thereafter, the biosorption rate decrease gradually until reaching equilibrium. The maximum sorption capacity of 17.13 and 83.89 mg g-1 for Cr(III) ions and MB, respectively was obtained at 40 °C, pH 5 and sorbent dose 4 g dm-3 for removal of Cr(III) ions and 1 g dm-3 for removal of MB. The prediction of purification process was successfully carried out and the verification of theoretically calculated amounts of sorbent was confirmed by using packed-bed column laboratory system with recirculation of the aqueous phase. The wastewater from chrome plating industry was successfully purified, i.e. after 40 min concentration of Cr(III) ions was decreased lower than 0.1 mg dm-3. Also, removal of MB from the river water was successfully carried out and after 40 min removal efficiency was about 94 %

Assessment of trace metal contamination in a historical freshwater canal (Buckingham Canal), Chennai, India

The present study was done to assess the sources and the major processes controlling the trace metal distribution in sediments of Buckingham Canal. Based on the observed geochemical variations, the sediments are grouped as South Buckingham Canal and North Buckingham Canal sediments (SBC and NBC, respectively). SBC sediments show enrichment in Fe, Ti, Mn, Cr, V, Mo, and As concentrations, while NBC sediments show enrichment in Sn, Cu, Pb, Zn, Ni, and Hg. The calculated Chemical Index of Alteration and Chemical Index of Weathering values for all the sediments are relatively higher than the North American Shale Composite and Upper Continental Crust but similar to Post-Archaean Average Shale, and suggest a source area with moderate weathering. Overall, SBC sediments are highly enriched in Mo, Zn, Cu, and Hg (geoaccumulation index (Igeo) class 4– 6), whereas NBC sediments are enriched in Sn, Cu,Zn, and Hg (Igeo class 4–6). Cu, Ni, and Cr show higher than Effects-Range Median values and hence the biological adverse effect of these metals is 20%; Zn, which accounts for 50%, in the NBC sediments, has a more biological adverse effect than other metalsfound in these sediments. The calculated Igeo, Enrichment Factor, and Contamination Factor values indicate that Mo, Hg, Sn, Cu, and Zn are highly enriched in the Buckingham Canal sediments, suggesting the rapid urban and industrial development of Chennai MetropolitanCity have negatively influenced on the surrounding aquatic ecosystem