## 2 Materials and Methods  
The subjects of the research were new standard flat fan nozzles RS11003 from the MMAT Agro Technology, Leszno, Poland. Seven copies were randomly selected from a batch of 75 pieces. According to the manufacturer's data, the nozzle produces a droplet spectrum ranging from fine to medium droplets with regard to ANSI/ASAE S572.1, 2009. The optimum fraction of the droplets produced is 100-250 \(\upmu\)m. Due to the reduction of the risk of drift of the finest droplet fraction (\(<\)100 \(\upmu\)m), it is recommended to use nozzles in the following conditions: wind speed up to 2 m/s, temperature 12-20 \({}^{\circ}\)C and relative humidity above 60%, maximum pressure range 1.5-5 bar [21]. Certification tests for this group of nozzles were carried out for a pressure of 3 bar, as a result of the tests obtaining a unit flow rate of 1.15 dm\({}^{3}\)/min, spray angle \(\alpha\) of 103\({}^{\circ}\), and a coefficient of uniformity of the transverse volume distribution (characterized by CV coefficient) of 7.6%. In the first stage of research, the nozzle quality was assessed based on the results of the lateral uniformity of volume distribution, characterized by the CV coefficient. Seven samples of the RS11003 nozzles and the reference TP11003-SS nozzle from Tejet were used in the tests. The CV coefficient was determined based on the results of measurements of liquid volume distribution on a standardized groove table with a groove width of 25 mm, carried out in accordance with ISO 5682-1-1996 standardsand applicable nozzle inspection procedures [15]. The stand used to test the lateral uniformity of volume distribution is shown in Figure 1[22]. Laboratory tests were carried out for the following parameters and accepted conditions:  
* The working medium was pure water and its temperature was 20 \(\pm\) 2 \({}^{\circ}\)C;
* During measurements, a constant value of the spraying boom height above the measuring table surface of 0.4 m and working pressure of 3 bar were maintained;
* The duration of each measurement was 120 s;
* The accuracy of liquid volume reading in a single measuring vessel was \(\pm\)1 mL;
* The ambient temperature during tests was 20 \(\pm\) 2 \({}^{\circ}\)C, with relative humidity of 40%-80%;
* The accuracy of the working pressure reading was \(\pm\)0.1 bar;
* The accuracy of the nozzle's height reading above the measuring table was \(\pm\)0.005 m;
* The accuracy of the nozzle's angle reading in relation to the horizontal was \(\pm\)1\({}^{\circ}\)[15]. The automatic monitoring and control system developed by the authors, which was equipped with a laboratory stand, allowed fluctuations in working pressure to be eliminated and the assumed spray dose to be obtained at a constant level during measurements. This system consisted of a precise flow meter, pressure sensor, and valves (including stepless, pressure control, and shut-off valves) that work with a measuring card and computer. During the measurements, the station operating values and the volume of liquid accumulated in individual grooving table measuring cylinders were recorded in the computer memory. The patented computer program equipped with the stand enabled the determination of the CV coefficient value for subsequent samples of tested nozzles, as well as a spraying boom composed of the appropriate number of tested samples. The volumes of liquids coming from adjacent nozzles were aggregated in such a way that the liquid streams overlapped and the axis of the nozzles were spaced every 0.5 m, which gave the same liquid distribution as for the actual field spraying boom [23]. Based on the results obtained in this way, the values of the CV coefficient for the spraying boom were calculated. In the main part of the research, measurements of the droplet spectrum in the liquid stream were performed using the 2D-LDA/PDA laser analyzer by Dantec Dynamics. The relevant elements of the Doppler analyzer are shown in Figure 2.  
Figure 1: View of the spraying process testing stand.