# The Impact of Incorporated Nonwovens on the Surface Roughness of Sport Pitches
## 3 Results  
For validation of the sensor frame, the measured profiles and the real profile of the trapezoidal bump are presented (Figure 4). The means of the measurements (\(n=5\)) recorded by the feeler wheel, the distance sensor and the ultrasonic sensor are shown. Using Equation (1), the \(RMS_{error}\) was calculated for the location of the trapezoidal bump. The \(RMS_{error}\) was 1.8 mm for the profile measured by the feeler wheel. The results of the distance sensor showed an \(RMS_{error}\) of 7.7 mm according to the profile of the trapezoidal bump. The ultrasonic sensor measured the highest variation to the real profile of the trapezoidal bump, with an \(RMS_{error}\) of 9.9 mm. The ultrasonic sensor showed a high amount of variation due to the low reflection. However, the error was lower than 10 mm. The presented profiles are the results of one measuring track of the first plot measured by the feeler wheel before and after the incorporation of the nonwoven (Figure 5). The changes in the roughness are obviously lower than 20 mm, and a direction of the variation is not visible in the presented data. Figure 4: The profile height in meters measured by the feeler wheel, the long-range sensor and the ultrasonic sensor in comparison with the real profile of the trapezoidal bump. The profile height is presented in relation to the driven distance in meters. Impact of Incorporating the Nonwoven in the Trial Area  
In the presented study, the impact of incorporating a nonwoven in relation to the surface roughness was also investigated. Figure 6 presents the variation in surface roughness caused by incorporation. The \(RMS_{roughness}\) calculated according to Equation (2) was used to compare the results of the feeler wheel. Each bar of the bar chart presents the mean \(RMS_{roughness}\) of 14 replications measured on each of the three plots. The error bars indicate a standard deviation of the \(RMS_{roughness}\) for the 14 replications. The black-colored bar describes the \(RMS_{roughness}\) before the incorporation of the nonwoven, whereas the grey bar stands for the mean \(RMS_{roughness}\) after the incorporation. A paired Tukey test for the roughness of all replications was performed. The p-value of 0.0375 indicates a significant change in the mean values of the \(RMS_{roughness}\) after incorporation. Figure 6 allows the conclusion to be drawn that the surface roughness has been increased, affected by the installation of the nonwoven. For example, the \(RMS_{roughness}\) in plot 3 increased from 0.008 to 0.011 due to the installation of the fleece. The high standard deviation in the repetitions indicates that the measured plots have a high heterogeneity of surface roughness. Figure 6 shows that the values for \(RMS_{roughness}\) in plot 1 are lower than those in plots 2 and 3. Data for the roughness of the three plots measured with the long-range sensor are presented in Figure 7. The results are shown as the mean \(RMS_{roughness}\) before and after the incorporation of the nonwoven, following Equation (2). Figure 7 describes that the incorporation of the nonwoven has increased the roughness of the surface in plot 1 and plot 2. Statistics performed by a paired Tukey test describe no significant difference between the means of all measurements before and after the incorporation. This is mainly caused by the high standard deviation of the first plot. The high standard deviation may result from measurement errors due to the reflection of the laser beam on the turf. From the calculated mean \(RMS_{roughness}\) presented in Figure 8 it is obvious that the profile measured by the ultrasonic sensor detects no changes in the roughness. A day before the incorporation of the nonwoven, the roughness was about 10 to 12 mm, presented as \(RMS_{roughness}\). After the device had incorporated the nonwoven into the sport pitch, the surface shows a higher roughness with an increase of about 3 mm.