Pesticide spray drift has been a worldwide concern in terms of potential environmental pollution and ecosystem damage. This study defined the main drift reduction agent (DRA) characteristics that help to understand the drift formation process in agricultural spraying. Seven various DRAs and water were evaluated. Three solutions were created based on the following materials: calcium dodecylbenzenesulfonate, benzenesulfonic acid, C10-13-alkyl derivatives, and calcium salt. Drift measurements were performed by means of the open circuit-type wind tunnel and in the field under conditionally controlled conditions. Air-injector flat spray nozzles and standard flat spray nozzles were used during trials. The spray pressure was 4.0 bar. Solutions were sprayed at different wind speeds (from 2 m s⁻¹ to 10 m s⁻¹, increasing every 2 m s⁻¹). Studies have shown that wind speed and nozzle design have the greatest influence on spray drift. For all DRA solutions studied, the standard flat spray nozzles resulted in ground spray drift, both in the wind tunnel and in the field, which was about two times higher than that of air-injector flat spray nozzles. The spraying of water and all DRA solutions with the air-injector flat spray nozzle showed that all new solutions statistically significantly reduced the drift both in the tunnel and in the field. Ground-drift studies in the wind tunnel showed a trend towards a less intense drift reduction in DRA droplets with increasing wind speed. With DRA7e, the drift can be reduced by up to 56% (at a wind speed of 4 m s⁻¹) and up to 30% (at 10 m s⁻¹). The effect of the solutions on the reduction in spray drift is significantly lower when spraying with standard flat spray nozzles. Spray drift can then be reduced by up to 30% (at a wind speed of 4 m s⁻¹) and up to 12% (at 10 m s⁻¹) for DRA7e.

Soil compaction (SC) is one of the most damaging degradation processes. The effects of compaction are closely related to crop losses and GHG emissions due to additional fuel use. It is therefore important not only to correctly monitor the condition of the soil and the restoration of damaged soil but also to understand the costs of excessive exploitation of soil and individual risks in different countries and continents. A model of equations has been developed to assess the effects of compaction that can be used on a national or even single farm scale. However, for its further application, more data should be collected. Based on the data available in the public domain, the damage caused by compaction was compared between Ukrainian (UA) and Lithuanian (LT) scenarios as these countries have a similar situation but different levels of soil resource management. Soil characteristics, such as soil types and predisposition to compaction, depending on its type, were assessed in both countries. The main parameters used to estimate the damage due to SC were: yield loss; additional fuel consumption; losses of N, P, K fertilizers, water pollution, and flooding; erosion; and GHG emissions. The results reveal potential annual losses due to compaction of around EUR 27 million for Lithuania and around EUR 1.6 billion for Ukraine. Expected potential average losses per hectare of arable land are about EUR 49 ha⁻¹ y⁻¹ for Ukraine (33.9 million ha or 56.76% of the total area) and about EUR 13 ha⁻¹ y⁻¹ for Lithuania (2.11 million ha or 33.77%). Potential crop losses are one of the costliest consequences of compaction. They could cost about EUR 1 billion annually for Ukraine and about EUR 10.7 million for Lithuania. Moreover, the additional use of fuel and the associated GHG emissions can probably take away EUR 180 million (UA) and about EUR 4 million (LT) each year.

Corn ear feed rate variations in the threshing-separation unit of a combine harvester have a significant impact on the dynamic indicators of the threshing process. In this study, we conducted experiments using a stationary tangential threshing device and measured the forces acting on the rear part of the concave as well as the torque of the rotating cylinder during a threshing process. The ThreshLab software was developed for this purpose. We found that increasing the corn ear feed rate made the threshing process more even, due to decreasing the fluctuation of forces acting on the rear part of the concave and torque of the rotating cylinder. The corn ear threshing process may be more stable if the threshing cylinder is fitted with filler plates (FP-II). A comparison of the results obtained for variations in the forces acting on the rear part of the concave with those obtained for variations in the total torque of resistance and the speed of the threshing cylinder revealed a linear correlation between these parameters at varied feed rates. DOI: http://dx.doi.org/10.5755/j01.mech.24.4.20721

Corn Ear Threshing Performance of Filler-Plate-Covered Threshing Cylinders

The appearance, evolution, and proliferation of electric-vehicle motors have introduced new challenges for lubricants. The appearance of electric currents in the shafts of electric motors can dramatically change the original properties of lubricated contacts, leading to mechanism failure. Understanding and controlling this phenomenon can be advantageous for lubrication, but investigating the lubricants requires specific equipment and conditions. Therefore, in this study, we introduced a ball-on-plate reciprocating tribometer capable of applying electric voltage to the elements of the friction pair and measuring the electric contact resistance (ECR) as feedback. Mineral-based paraffin oil was used as a lubricant in this study. The coefficient of friction (COF), wear, surface morphology, and composition were analysed. It was found that high-speed ECR measurement could give valuable information regarding the lubrication conditions in reciprocating friction pairs. This study shows that even tiny currents flowing through the tribo contact can alter the lubricating conditions. Moreover, the polarity of the applied voltage is also of great importance. Applying negative voltage to the harder surface can significantly increase wear if the tribo-film is based on surface oxidation.