With widespread use of pesticides in modern agriculture, the impacts of spray drift have become a topic of considerable interest. The drifting of sprays is a highly complex process influenced by many factors. The paper presents results of experimental research on a drifting cloud of droplets dispersing from aircraft. Experiments were conducted to quantify spray drift from aerial applications of pesticide. Parallel to the blowing wind, the measurement line 800 m long was disposed. The relationships between the relative dose and the distance of drift as well as spray density and its structure on the measuring length have been established.
Improving application efficiency is crucial for both the economic and environmental aspects of plant protection. Mathematical models can help in understanding the relationships between spray application parameters and efficiency, and reducing the negative impact on the environment. The effect of nozzle type, spray pressure, driving speed and spray angle on spray coverage on an artificial plant was studied. Artificial intelligence techniques were used for modeling and the optimization of application process efficiency. The experiments showed a significant effect of droplet size on the percent area coverage of the sprayed surfaces. A high value of the vertical transverse approach surface coverage results from coarse droplets, high driving speed, and nozzles angled forward. Increasing the vertical transverse leaving surface coverage, as well as the coverage of the sum of all sprayed surfaces, requires fine droplets, low driving speed, and nozzles angled backwards. The maximum coverage of the upper level surface is obtained with coarse droplets, low driving speed, and a spray angle perpendicular to the direction of movement. The choice of appropriate nozzle type and spray pressure is an important aspect of chemical crop protection. Higher upper level surface coverage is obtained when single flat fan nozzles are used, while twin nozzles produce better coverage of vertical surfaces. Adequate neural models and evolutionary algorithms can be used for pesticide application process efficiency optimization.
In this study T6 heat treated 6063 aluminum alloys were used as substrate material. In order to form a bond between the substrate and the
main coating, all samples were coated with Ni-Cr-Al powders. 8 wt% Yttria Stabilized Zirconia powders (YSZ) were coated with plasma
spray technique. Thickness of YSZ was 150 m and bond coating was 36 m. XRD and SEM-EDS analyses were performed to characterize
the coating layers. These YSZ coated and uncoated samples were subjected to wear testing under different spindle speed, loading and
working distance. Wear test results were compared with the kinetic friction coefficients and weight loss values. Wear marks on YSZ
coated and uncoated samples were investigated by SEM analysis. By coating with plasma spray technique, the wear resistance of Al alloys
was increased without changing the friction coefficient. It was found that spindle speed had significant effect over the wear properties than
the load applied. By YSZ coating, wear properties were increased 10 times.
As in many thermal processing technologies, there is a delicate balance between productivity and quality during ingot cooling process. Higher cooling velocities increase productivity but also create higher temperature gradients inside the ingot. Such a fast cooling does not leave sufficient time to establish the equilibrium within the solid, thus the final metal structure is strongly affected by the set up cooling mode throughout the liquid metal solidification. The first intention in this paper is to compare between three cooling modes in order to identify the required mode for a continuous casting process. Then, we study the influence of heat transfer coefficient on metal liquid-to-solid transition through the spray-cooled zone temperature and the metal latent heat of solidification. A gray iron continuous casting process subjected to water-sprays cooling was simulated using the commercial software for modeling and simulating multiphysics and engineering problems. The primary conclusions, from the obtained results, show the forcefulness of water spray cooling regarding standard cooling. Afterward, we highlight the great influence of heat transfer coefficient on the location of transition region as well as the relationship between heat transfer coefficient, wall outer temperature, latent heat dissipation, and the solidification time.
It is challenging to obtain proper leaf wetting. An angled spray could overcome this impediment, but which spray angle is best suited to droplet size is still unknown. In an outdoor pot experiment, seven doses of cycloxydim and sethoxydim were sprayed with single-orifice standard, anti-drift, and air induction (having a fine, medium, and extremely coarse spray quality, respectively) flat fan nozzles, using spray angles of 10°, 20° backward, 0° (vertical), 10°, 20°, 30°, 40°, 50°, and 60° forward relative to the direction of nozzle trajectory on wild barley at the three-leaf stage. Generally, the forward angled spray was better than the backward angled spray. With a standard flat fan nozzle, the forward angling of spray from 0° to 20° reduced the ED50 from 60.24 to 39.85 g a.i. ⋅ ha−1 for cycloxydim and from 150.51 to 81.13 g a.i. ⋅ ha−1 for sethoxydim. With an anti-drift flat fan nozzle, the forward angling of spray from 0° to 30° reduced the ED50 from 72.57 to 50.20 g a.i. ⋅ ha−1 for cycloxydim and from 181.94 to 104.51 g a.i. ⋅ ha−1 for sethoxydim. With an air induction flat fan nozzle, the forward angling of spray from 0° to 40° reduced the ED50 from 102.96 to 45.52 g a.i. ⋅ ha−1 for cycloxydim and from 209.91 to 92.80 g a.i. ⋅ ha−1 for sethoxydim. More angling did not improve the efficacy of these herbicides. Our results revealed that larger spray droplets needed more spray angle than smaller spray droplets to achieve an equal control.
Ice formed on radome surfaces causes communication disruption due to radio-frequency interference (RFI), which reveals the importance of de-icing systems for radomes. As a radome de-icing application, in this work, carbon nanotube (CNT) thin films were fabricated using a spray-coating method, and influence of process parameters on RF transmittance and electrothermal properties was investigated. With the increase of spraying time, sheet resistance of the fabricated film decreases, which results in a decrease of the RF transmittance and improvement of the heating performance. Also, the de-icing capability of the fabricated CNT film was evaluated at –20oC, and efficient removal of ice under cold conditions was demonstrated.
In the summer 1980-1981, in the Antarctic areas, in the coastal zone of Admiralty Bay (King George Island), complex measurements were carried out in order to investigate the proportion of wind gustiness in the processes generating marine spray systems and stimulating aerosol mass exchange between the sea and the atmosphere.