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United States Department of Agriculture

Agricultural Research Service

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Location: Crop Production Systems Research

2010 Annual Report

1a. Objectives (from AD-416)
Develop a new method based on control systems simulation for analysis of impact of various factors on in-swath and downwind deposition for improvement of efficiency in aerial chemical application.

1b. Approach (from AD-416)
A new method is proposed to provide valuable information about the significant level of the impact from many factors influencing spray deposition. The most significant factors will be identified using statistical analysis based on the simulation results. With this method the detailed relationship between the total deposition and impact factors such as wind speed, droplet size, and spray release height will be characterized. This characterization will not require actual field testing, but will subsequently be verified under field conditions. Robust results from the simulation will allow determination of optimal droplet size and spray release height that factors in wind speed and direction, providing guidelines for the applicator to achieve the best spray result. The method will be developed based on an existing prototype developed at Texas A&M University (TAMU), for simulation and robustness analysis of dynamic systems. The prototype was originally developed for control system design and analysis. A first principle or black-box model is used to build a simulation model. Based on the simulation result, the main factors that contributed to the system performance are identified using Design of Experiment (DOE). A robust solution can be derived to reduce system variation using Response Surface Method (RSM). The robustness of the new design can be verified using the simulation model. For system test and evaluation, the results of the developed method will be compared with actual field data, and could be used as a guideline for the applicators to achieve best spray result.

3. Progress Report
A statistical simulation was developed to analyze influencing spray deposition for aerial chemical application. A Design Of Experiments (DOE) test matrix was created, six variables were considered: release height; nozzle extent; droplet size; wind speed; temperature; relative humidity. The application efficiency, the total downwind drift, the cumulative downwind deposition between 30.48 m and 45.72 m, and the deposition at 30.48 m, 76.2 m, and 152.4 m are established as the performance metrics. Based on the DOE analysis, it was found that wind speed had significant impact on every outcome; nozzle extent, temperature, and their interactions with other factors had no significant impact on any of the outcomes; all significant interactions involved wind speed; the relative humidity had only a significant contribution to deposition a long distance downwind through the interaction with wind speed. This project has been monitored by the ADODR with visits to the Texas A&M University Research Lab; emails and phone calls.

4. Accomplishments

Last Modified: 06/23/2017
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