Efficacy of seagrass <Emphasis Type="Italic">Cymodocea rotundata</Emphasis> beads on the removal of excessive nutrients in shrimp aquaculture wastewater

The aim of present study is to ascertain the effects of pH, retention time, biomass dosage in beads and beads density on nutrients (Phosphate and Nitrate) uptake efficiency of seagrass Cymodocea rotundata beads in aquaculture effluent. This study was carried out in shake flask at different pH viz. 5; 6; 7; 8 and 9, and different retention time such as 30; 60; 90 and 120 min. The seagrass biomass dosage was tested with 0.1; 0.5 and 1.0 g and beads density of 25; 50; 75; 100; 125 and 150 nos. These results revealed that the optimum pH for maximum uptake of phosphate and nitrate was 7. The overall maximum nutrient uptake was noticed in 50 number beads density where the nitrate concentration decreasing from 2.05 to 0.51 μmol/L and phosphate 1.203 to 0.31 μmol/L. On considering the effects of pH, biomass and retention time, the maximum nitrate reduction (3.85 μmol/L) was found at pH 7 in 120 min at 0.1 g biomass dosage. The high phosphate removal (0.68 μmol/L) was found at pH 7 in 120 min at 0.1 g biomass dosage. Whereas in case of biomass dosage in beads, the maximum nutrients removal were noticed at 0.1 g among the dosage tested.     

Influence of FCA Welding Process Parameters on Distortion of 409M Stainless Steel for Rail Coach Building

The influence of flux cored arc welding (FCAW) process parameters such as welding current, travel speed, voltage and CO2 shielding gas flow rate on bowing distortion of 409M ferritic stainless steel sheets of 2 mm in thickness was discussed. The bowing distortions of the welded plates were measured using a simple device called profile tracer. An experimental regression equation was developed to predict the bowing distortion and with this equation, it is easy to select optimized process parameters to achieve minimum bowing distortion. It is revealed that the FCAW process parameters have significant influence on bead profile and the bowing distortion.     

Scattering-matrix elements of coated infinite-length cylinders

The angular variations of scattering-matrix elements of coated cylindrical particles are presented. The sensitivity of different elements for a number of physical parameters are discussed, including size parameter, real and imaginary parts of the refractive index of the outer coat, and the inner core. The numerical predictions are presented for typical index-of-refraction values of cotton fibers. These results show that the physical structure of coated cylinders can be determined from carefully conducted light-scattering experiments.