Effects of Formulated Glyphosate and Adjuvant Tank Mixes on Atomization from Aerial Application Flat Fan Nozzles
Abstract : This study was designed to determine if the present USDAARS spray-nozzle models, which were based on spray solutions of water plus non-ionic surfactant, could be used to estimate spray droplet-size data for different spray formulations through use of experimentally determined correction factors. Twelve spray-solution treatments were evaluated, ten of which contained a formulated glyphosate product and nine of these contained an additional tank-mix adjuvant. Droplet-size testing was conducted across multiple operational points (nozzle-orifice size, nozzle orientation spray pressure, and airspeed), in a high-speed wind tunnel, which corresponds to the response surface experimental model used to develop the present spray-nozzle models. The hypothesis that the different treatment solutions would respond linearly across a range of operational parameters and that a correction factor from relative to water plus non-ionic surfactant solution was proven false. When compared to water or the water plus non-ionic surfactant, the changes in atomization across the operation spectrum of the nozzle were not consistent and varied by formulation. Attempts to apply regression fits for a correction factor based on solution physical properties were not successful. With the formulated glyphosate tank mix used, none of the adjuvants tested, except the polymer, showed significant changes in droplet size under the high air shear regime. Whereas there is likely a need to develop formulated product-specific atomization models, the further addition of adjuvants do not significantly change the atomization characteristics and, as such, should not require a unique spray-nozzle model.
Experimental Study of Drop Size Distribution in the Bag Breakup Regime
The situation of a liquid drop exposed to a continuous air jet flow was investigated experimentally. The drop bag breakup of test liquids which included water, ethanol, and various glycerol mixtures was observed using a high-speed camera. The morphological change, such as drop deformation, was observed and analyzed. Mean fragment sizes were obtained, which were in good agreement with those reported in the literature. Big fragments formed from the ring contained the great mass of the initial drop and were studied in detail, and correlations on fragment mean size and number were obtained. Mean size decreased with the Weber number and increased with the Ohnesorge number; fragment number was in contrast to mean size. Fragment size distribution was another useful parameter. Our results showed that fragment size distribution based on the number formed from the ring was a gamma distribution. Fragment size distribution based on the number formed from the whole drop was an exponential distribution. We also investi...
Toluene degradation via a unique metabolic route in indigenous bacterial species
Tanneries are the primary source of toluene pollution in the environment and toluene due to its hazardous effects has been categorized as persistent organic pollutant. Present study was initiated to trace out metabolic fingerprints of three toluene-degrading bacteria isolated from tannery effluents of Southern Punjab. Using selective enrichment and serial dilution methods followed by biochemical, molecular and antibiotic resistance analysis, isolated bacteria were subjected to metabolomics analysis. GC–MS/LC–MS analysis of bacterial metabolites helped to identify toluene transformation products and underlying pathways. Three toluene-metabolizing bacteria identified as Bacillus paralicheniformis strain KJ-16 (IUBT4 and IUBT24) and Brevibacillus agri strain NBRC 15538 (IUBT19) were found tolerant to toluene and capable of degrading toluene. Toluene-degrading potential of these isolates was detected to be IUBT4 (10.35 ± 0.084 mg/h), IUBT19 (14.07 ± 3.14 mg/h) and IUBT24 (11.1 ± 0.282 mg/h). Results of GC–MS analysis revealed that biotransformation of toluene is accomplished not only through known metabolic routes such as toluene 3-monooxygenase (T3MO), toluene 2-monooxygenase (T2MO), toluene 4-monooxygenase (T4MO), toluene methyl monooxygenase (TOL), toluene dioxygenase (Tod), meta- and ortho-ring fission pathways. But additionally, confirmed existence of a unique metabolic pathway that involved conversion of toluene into intermediates such as cyclohexene, cyclohexane, cyclohexanone and cyclohexanol. LC–MS analysis indicated the presence of fatty acid amides, stigmine, emmotin A and 2, 2-dinitropropanol in supernatants of bacterial cultures. As the isolated bacteria transformed toluene into relatively less toxic molecules and thus can be preferably exploited for the eco-friendly remediation of toluene.