Influence of surfactants and polymeric adjuvants on physicochemical properties, droplet size spectra and deposition of fenitrothion and Bacillus thuringiensis formulations under laboratory conditions

The effect of two surfactants and two polymeric adjuvants on droplet size spectra and deposition patterns of nine spray formulations was investigated following atomization in a laboratory chamber using a spinning disc atomizer that can produce a narrow droplet size spectrum. Spray droplets were sampled using Kromekote cards and deposit recoveries were examined on glass plates. Physicochemical properties studied were: viscosity-shear rate relationship, surface tension, volatility, pH, conductance, electrophoretic mobility and zeta potential. Formulations containing low surfactant concentrations provided Newtonian liquids with low viscosities. These liquids atomized into small droplets and provided low recoveries of spray deposits on sampling units. However, formulations containing polymeric adjuvants, and a high concentration of a non-ionic surfactant provided pseudoplastic liquids with high viscosities. These formulations resulted in large droplets with high recoveries of spray deposits on sampling units. Among the physicochemical properties studied, viscosity, surface tension, volatility and electrophoretic mobility, played important roles on liquid atomization and droplet deposition.     

Mathematical model for abrasive content estimation in a pulse-electroplated abrasive microtool

A mathematical model was developed to estimate the weight percent of diamond abrasive particles incorporated in nickel binder matrix during abrasive microtool fabrication by pulse-plating process. The proposed model is based on the hypothesis that, embedment of an inert micro abrasive diamond particle on the substrate will only occur when a few nickel ions from the adsorbed ionic cloud are chemically reduced at the cathode by hydrogen ions present in the diffusion layer. Experimental verification of the model developed was performed by pulse electroplating of diamond abrasive particles on tungsten micro tool shank using an in-house built experimental setup. The predictive model developed was found to estimate diamond abrasive content in nickel binder matrix within 1–7 wt% of experimental results for different pulse-plating conditions.     

Effect of depth of landfill on the characteristics of soil-like material of aged waste: a case study of Bhalswa dumpsite,India

Journal of Material Cycles and Waste Management - This study characterizes the municipal solid waste (MSW) accumulated for more than 25 years at Bhalswa dumpsite, Delhi, India. 50...