Search Results (59)

The application of drones has contributed to automated herbicide spraying in the context of precision agriculture. Although drone technology is mature, the widespread application of agricultural drones and their numerous advantages still demand improvements in battery endurance during flight missions in agricultural operations. This issue has been addressed by optimizing the path planning to minimize the time of the route and, therefore, the energy consumption. In this direction, a novel framework for autonomous drone-based herbicide applications that integrates deep learning-based semantic segmentation and coverage path optimization is proposed. The methodology involves computer vision for path planning optimization. First, semantic segmentation is performed using a DeepLab v3+ convolutional neural network to identify and classify regions containing weeds based on aerial imagery. Then, a coverage path planning strategy is applied to generate efficient spray routes over each weed-infested area, represented as convex polygons, while accounting for the drone’s refueling constraints. The results demonstrate the effectiveness of the proposed approach for optimizing coverage paths in weed-infested sugarcane fields. By integrating semantic segmentation with clustering and path optimization techniques, it was possible to accurately localize weed patches and compute an efficient trajectory for UAV navigation. The GA-based solution to the Traveling Salesman Problem With Refueling (TSPWR) yielded a near-optimal visitation sequence that minimizes the energy demand. The total coverage path ensured complete inspection of the weed-infected areas, thereby enhancing operational efficiency. For the sugar crop considered in this contribution, the time to cover the area was reduced by 66.3% using the proposed approach because only the weed-infested area was considered for herbicide spraying. Validation of the proposed methodology using real-world agricultural datasets shows promising results in the context of precision agriculture to improve the efficiency of herbicide or fertilizer application in terms of herbicide waste reduction, lower operational costs, better crop health, and sustainability. Full article

Fusarium head blight (FHB) is an important disease throughout the world due to its strong association with yield reduction, quality deterioration, and mycotoxin contamination in wheat. The use of FHB-resistant genotypes in wheat production can significantly reduce damage. The current study screened a panel of bread wheat from CIMMYT and South Asian countries for FHB resistance to identify promising genotypes useful for wheat breeding and to map the associated genomic regions and linked molecular markers through a genome-wide association study (GWAS). Spray-inoculated field experiments were conducted at CIMMYT, Mexico, over three years, and a wide range of phenotypic variations was observed. Four lines, CIM-39, CIM-29, CIM-9, and CIM-3, exhibited consistent resistance across experiments, with FHB indices ranging from 6.5 to 8.1. Genotyping was conducted using the Illumina Infinium 15 K Bead Chip, and 11,184 high-quality SNP markers were obtained and used for GWAS. Nineteen significant marker-trait associations (MTAs) were detected, among which MTAs at Ra_c58315_265 on 1A and Tdurum_contig102328_129 and Ku_c20136_198 on 7B showed reproducible results, with phenotypic effects on FHB resistance of 6.05%, 3.54%, and 3.92%, respectively. Several genes associated with disease resistance were found near the significant SNPs. The identified resistant genotypes and markers may be useful in future marker-assisted breeding in wheat. Full article

In this study, the authors carried out a multiparametric assessment of the influence of swirl patterns during aerosol flow on the shape of the interfacial area that forms the cone based on data obtained from experimental measurements using the PIV and LLS methods. The results were correlated with the disinfection process occurring in the near and far fields of the aerosol (direct surface disinfection and volume fogging). In this study, parameters such as turbulent kinetic energy (TKE), swirl strength (SS), pressure fields, and Sauter mean diameter (d₃₂) are used to investigate the relationship between aerosol spray morphology and flow dynamics under different operating conditions. Three different geometrical settings of the aerosol-generating system and two different pressures corresponding to the air supply to the spray nozzle have been adopted. By evaluating the results obtained, the influence of each parameter on the formation of the aerosol displacement trajectory, the stabilization of the spray cone, and its degradation was identified. The shape of the boundary between the dynamically moving aerosol and the surrounding air was also evaluated. The conditions for swirling and straight-line flows within the aerosol cone, and, thus, the conditions for the volumetric development of swirling phenomena, were further clarified. Full article

This paper focuses on key engineering issues, particularly the overall turbulent transport of paint spray and coating film distribution characteristics, in the process of airless spraying film formation. By deeply considering the geometric features of spherical surfaces and their impact on the near-wall region of the flow field, an airless spraying film formation model consisting of the Eulerian multiphase model, the realizable k–ε turbulence model, and the Eulerian Wall Film model was established. Through numerical simulations of static spraying on the inner and outer walls of spherical surfaces with different radii, the influence of geometric features on the spray flow field and film formation characteristics on spherical surfaces was investigated. Subsequently, based on numerical simulations of dynamic spraying on different nozzle trajectories, the film formation characteristics were analyzed, and the optimal spray trajectory planning method was determined. Additionally, this study examined the coating distribution characteristics during dynamic spraying on spherical surfaces with varying geometric dimensions. Finally, a kind of chlorinated rubber anti-corrosion primer was chosen to carry out spraying experiments, which validated that the airless spray coating model and the corresponding numerical simulation methods established in this paper were reasonable and feasible for investigating the film formation characteristics on spherical surfaces. This work is expected to further promote the application of airless spray techniques in machinery, automotive, shipbuilding, and aviation industries. Full article

In view of the current situation where research on the dust diffusion laws of different dust source points is limited and the gap with the actual field situation is too large; this study employs an innovative gas–liquid–solid triphase coupling method to investigate how dust moves and spreads in the fully mechanized excavation face 431305 at the Liangshuijing Mine; focusing on both the dust field and the dust–fog coupled field. The results indicate that using the long-pressure short-suction ventilation method; dust movement in the roadway is primarily influenced by the airflow; which can be classified into vortex; jet; and return flow regions. The analysis reveals that different dust source points affect dust distribution patterns. Dust source 1 generates the highest dust concentration; primarily accumulating on the duct side and return air side of the roadway. By contrast; dust source 2’s dust mainly gathers at the heading and the front of the cutting head. Dust sources 3 and 4 show lower dust concentrations near the top of the roadway. Dust source 5 achieves the most effective dust removal; aided by airflow and a suction fan; showcasing superior dust performance. A comprehensive comparison indicates that dust source 1 has the highest overall dust concentration. Therefore; further simulation of the distribution law of dust generated at dust source 1 under the action of water mist reveals that the dust concentration near the heading face is reduced from 2000 mg/m³ under the action of single air flow to about 1100 mg/m³. At t = 5 s; the spray droplets almost cover the entire tunneling face; leading to a significant decrease in dust concentration within 10–25 m from the tunneling face. Within 40 s; both coal dust and spray droplets are significantly reduced. The field measurement results verify the accuracy of the simulation results and provide certain guidance for promoting the sustainable development of the coal industry. Full article

To effectively combat the re-infestation of boll weevils (Anthonomus grandis L.) in cotton fields, it is necessary to address the detection of volunteer cotton (VC) plants (Gossypium hirsutum L.) in rotation crops such as corn (Zea mays L.) and sorghum (Sorghum bicolor L.). The current practice involves manual field scouting at the field edges, which often leads to the oversight of VC plants growing in the middle of fields alongside corn and sorghum. As these VC plants reach the pinhead squaring stage (5–6 leaves), they can become hosts for boll weevil pests. Consequently, it becomes crucial to detect, locate, and accurately spot-spray these plants with appropriate chemicals. This paper focuses on the application of YOLOv5m to detect and locate VC plants during the tasseling (VT) growth stage of cornfields. Our results demonstrate that VC plants can be detected with a mean average precision (mAP) of 79% at an Intersection over Union (IoU) of 50% and a classification accuracy of 78% on images sized 1207 × 923 pixels. The average detection inference speed is 47 frames per second (FPS) on the NVIDIA Tesla P100 GPU-16 GB and 0.4 FPS on the NVIDIA Jetson TX2 GPU, which underscores the relevance and impact of detection speed on the feasibility of real-time applications. Additionally, we show the application of a customized unmanned aircraft system (UAS) for spot-spray applications through simulation based on the developed computer vision (CV) algorithm. This UAS-based approach enables the near-real-time detection and mitigation of VC plants in corn fields, with near-real-time defined as approximately 0.02 s per frame on the NVIDIA Tesla P100 GPU and 2.5 s per frame on the NVIDIA Jetson TX2 GPU, thereby offering an efficient management solution for controlling boll weevil pests. Full article

Coconut cultivation faces serious challenges caused by pests and diseases, whose targets are often not reached by conventional application methods such as spraying and soil application. New control strategies, such as vegetative endotherapy, have emerged, but knowledge gaps persist regarding many aspects, especially in pesticide translocation within palm trees, which is crucial for an efficient practical field application. This study investigated the translocation of a mixture of commercial insecticides and fungicides—difenoconazole, imidacloprid, thiabendazole, cyproconazole, thiamethoxam, spirodiclofen, and carbosulfan—applied via pressurized and nonpressurized endotherapeutic methods to coconut stems. This assessment aimed to quantify the concentrations of pesticide translocation through the stem, from the application site to the plant canopy. Due to the difficulty of applying the solution to the instrument used for pressurized endotherapy, the solution had to be diluted and used at a lower volume. In experimental field conditions, stem samples were assessed at 50 and 100 cm above the application point following endotherapy treatments conducted over a period ranging from 2 to 45 days. The analyses were performed using LC-MS/MS. In the pressurized method, the highest concentrations were observed for difenoconazole (1684 µg kg⁻¹), imidacloprid (1278 µg kg⁻¹), and thiabendazole (781 µg kg⁻¹). Conversely, in the nonpressurized method, the highest concentrations were recorded for imidacloprid (5803 µg kg⁻¹), followed by difenoconazole (3660 µg kg⁻¹) and thiabendazole (2598 µg kg⁻¹). To address the issue with formulation conditions in the pressurized method and to allow a comparison between the two application methods, we simulated extrapolated results for comparison with the nonpressurized method. This evaluation aimed to evaluate both methods under similar formulation conditions (volume and concentration). The results predicted that if the solution had not been diluted, the pressurized method would present the best translocations, mainly near the plant canopy, except for carbofuran. All pesticides were translocated independently of their physical–chemical properties or formulation. No pesticide residues were detected in the coconut water and pulp up to 120 days after the endotherapy application. Full article

A detailed experimental study of ethanol spray swirling flames was performed in an axial bluff body stabilized burner. The characteristics of the non-reacting and reacting sprays were recorded by particle imaging velocimetry (PIV) and planar laser-induced fluorescence (PLIF) of the OH radical. A few typical flames with different structures (outer-side-flame-lifting, stable, and near-blow-off) were compared and analyzed. The parameters of the spray, including the spray half-angle (α) and droplet number density (n_d), are quantified, and it has been found the flame structure and stability were strongly correlated with the droplet distribution. Several parameters of the flow field, such as velocity magnitude ($\left|U\right|$ vorticity (ω_z), and turbulent kinetic energy (TKE), are quantitively analyzed, and it is observed that the local strain rate rose as the air flow rate increased, which is not conducive to local flame stability. Regarding the flame, quantities such as progress variable (<c>), flame height (L_f), lift–off height (h_lf), and symmetry factor (S_nd and S_<c>) are calculated, and it can be observed that the flame symmetry keeps worsening when approaching blow–off, and the inner flame branch exhibits a worse stabilization than the outer one. Our comprehensive investigations offer a deeper understanding of stable combustion in such two–phase flames. Full article

When a curved target surface is coated in an electrostatic spray-painting process, the paint film pattern on curved targets will deform, and the thickness will change compared with the planar target due to the curvature characteristics of the target, the inhomogeneous electric field, and the flow field. Therefore, directly using the planar deposition distribution for painting the trajectory planning of curved surfaces causes large errors and low paint transfer efficiency. A study investigating the curved surface paint film thickness distribution characteristics is presented in this research to understand the relations among the target surface curvature, the electrostatic field, and the flow field distribution. Spray-painting process simulations were performed for conical surfaces of different curvatures. Moreover, the paint particle’ trajectories, electric potential, and film deposition distribution were computed using ANSYS Fluent. The paint transfer efficiencies of these targets were computed. The results show that when the generatrix curvature of the conical surface increases gradually, the electric field intensity near the wall increases, which enhances the deposition of charged droplets on the wall. Moreover, the airflow field velocity increases as the curvature increases, which leads to a large diffusions of the spray flow field, so the paint thickness decreases, and the transfer efficiency is low. Full article

With respect to post-processing techniques in the field of surface engineering, it was recently found that machine hammer peening (MHP) represents a promising approach to functionalizing thermally sprayed coatings as the MHP contributes to a compression of the coating, enabling the potential to reduce the coating porosity as well as the protruding peaks of the rough as-sprayed coating surface. The MHP also has the potential to induce compressive residual stresses in the coating surface, which can positively affect the mechanical and tribological properties. Arc-sprayed tungsten carbide-reinforced Fe-based coatings pose an appropriate candidate to counteract the wear of tribologically stressed surfaces. Due to the inherent process characteristics, however, these coatings are mostly characterized by a heterogeneous lamellar microstructure with residual porosity and interstratified with a certain amount of oxides, as well as the presence of tensile residual stresses. To adjust their microstructural and mechanical coating properties, the applicability of a subsequent MHP was evaluated in this study. Therefore, arc-sprayed WC-W₂C reinforced FeCMnSi coatings are deposited using either argon or compressed air as atomization and shroud gas, providing different lamellar structures and oxide content. The effect of MHP on the surface integrity of the WC-W₂C-FeCMnSi coating is investigated with respect to its porosity, lamellar structure, hardness, and residual stresses, which are known as relevant influencing factors on the performance of tribologically stressed components. It was found that the MHP leads to reduced porosity and lamella thickness as well as increased hardness due to strain hardening effects. Furthermore, it was demonstrated that the MHP leads to the introduction of compressive residual stresses, which contribute to a decline in tensile residual stresses in the near-surface area. Full article

The homogeneous field measurement of internal flow and spray of internal combustion engine injector nozzles under high pressure has always been one of the difficulties in experimental research. In this paper, an actual-size aluminum alloy nozzle is designed, and the simultaneous measurement of internal flow and near-field spray is successfully realized with the help of synchrotron radiation X-ray phase contrast imaging technology under an injection pressure of 30~90 MPa. For a 0.25 mm aperture nozzle, different radii of the inlet corner can induce different cavitation layer thicknesses, and the measured flow section shrinkage ratio is 0.70. The flow characteristics in the nozzle are entirely connected to the jet characteristics, indicating a tight correlation between internal flow and jet morphology. Finally, the internal cavitation of the nozzle was studied by the CFD simulation, and the simulation results are in good agreement with the experiment. Full article

Understanding hydraulic fracturing in concrete super-high arch dams is vital for the implementation of safety measures on the bearing surface. In this study, we conducted tests on hydraulic fracturing for the Xiaowan arch dam (294.5 m) to analyze concrete behavior at cracks under various stress conditions. The risk of hydraulic fracturing near the dam heel was identified without compressive stress. Addressing this, we propose a flexible anti-hydrofracturing system using GB sealing material and a spray polyurea coating. Simulation tests on three schemes: ‘3 mm GB plate + 4 mm polyurea’, ‘1 mm GB glue + 5 mm polyurea’, and ‘7 mm polyurea’ showed effective prevention of hydrofracturing at concrete crack openings of 5 mm, 8 mm, or 10 mm under 300 m water pressure. Field tests supported ‘3 mm GB plate + 4 mm polyurea’ and ‘7 mm polyurea’ as optimal solutions for dam sections. Implementation involves a protective block layout with ‘3 mm GB plate + 4 mm polyurea’ on blocks and ‘7 mm polyurea’ in interval zones and corners. Since 2008, maximum leakage, including rock foundation, has remained minimal at 2.78 L/s under regular water levels. These insights aid similar concrete dams in optimizing safety systems. Full article

The footwear industry is moving towards automation and intellectualization. To overcome the drawbacks of the high-cost and low-efficiency traditional manual shoe sole gluing process, automatic methods were utilized for generating spray trajectories. Currently, most of the reported automatic methods for generating spray trajectories mainly rely on the outer contour bias method. However, the glue is only applied to the area near the edge/contour of shoe soles and the fixed offset distance in the outer contour bias method cannot adapt to the immense amount of shoe styles with high precision and achieve applicability for irregular and unique sole designs. An intuitive yet logical approach to fulfill the requirements is to utilize the deconvolutional neural network for generating shoe sole spray trajectories. In this work, we treated the glue trajectory prediction as an image-to-image prediction and established a novel deconvolutional neural network to generate shoe sole spray trajectories. The as-proposed deconvolutional neural network for generating spray trajectory offered significant advantages over the existing bias-based methods, including: (1) based on the novel deconvolutional neural network, the proposed method for generating shoe sole spray trajectories exhibits greater applicability to irregular shoe soles, which improves the spray accuracy without compromising the spray efficiency; (2) we discard all the pooling layers, which only consist of convolutional and deconvolutional layers, to preserve more spatial information and achieve higher spray accuracy through end-to-end mapping from shoe sole images to shoe sole spray trajectories, resulting in an improved spray accuracy without sacrificing spray efficiency. The Dice similarity coefficient and Hausdorff distance were used as the evaluation metrics to assess the performance of our approach. Our proposed method showed an ultra-high accuracy and precision with a Dice similarity coefficient over 99.25% and a Hausdorff distance less than 1.2 mm, which are ~10% higher than the spray accuracy of other reported traditional methods. Our findings would bring significant improvements to the field of automatic shoe sole spray trajectory generation, which has the potential to promote the utilization of intelligent technologies in the footwear industry. Full article

The study aimed to assess the quality of spraying of ornamental conifer using a multi-rotor drone. We examined how the speed of drone movement and the propellers’ spin speed can affect the deposition quality of the sprayed liquid in the crown of blue spruce (Picea pungens Engelm.). Due to the avoidance in the future of droplet drift by air movements, an air injector atomiser for liquid spraying was used, and a low altitude of 0.6 m of the drone flying above the tree was used in the study. The drone moved at two speeds: 0.57 m·s^–1 and 0.94 m·s^–1. The propellers’ spin speeds were adjusted based on the drone’s weight with the spray liquid tank filled and empty. The propellers’ zero-spin rate was also included to compare the drone to a field sprayer. The tests were conducted in a laboratory setting. Volume and uniformity of liquid volume settled on the levels of samplers positioned on a tripod within the tree canopy were assessed. The samplers were placed in two zones of the tree: near the tree trunk and at a distance of 0.21 m from the trunk. Airstream speed generated by drone propellers was also evaluated inside the tree. The findings indicated that the rotations of propellers and air speed significantly influenced the quality of liquid deposition on samplers located away from the trunk. The results also showed that using a drone instead of a field sprayer could benefit the quality of the spray application. The weight of the multi-rotor drone, determined by the spray liquid tank’s filling level, can significantly impact the quality of spray deposition in the tree. Based on the investigations, it can be recommended that low-altitude spraying drones be adopted for studies and future strategies in precision agriculture using autonomous inspection-spraying drones. Full article

Wind drift and evaporation loss (WDEL) of mid-elevation spray application (MESA) and low-elevation spray application (LESA) sprinklers on a center pivot and linear-move irrigation machines are measured and reported to be about 20% and 3%, respectively. It is important to estimate the fraction of WDEL that cools and humidifies the microclimate causing evapotranspiration (ET) suppression, mitigating the measured irrigation system losses. An experiment was conducted in 2018 and 2019 in a commercial spearmint field near Toppenish, Washington. The field was irrigated with an 8-span center pivot equipped with MESA but had three spans that were converted to LESA. All-in-one weather sensors (ATMOS-41) were installed just above the crop canopy in the middle of each MESA and LESA span and nearby but outside of the pivot field (control) to record meteorological parameters on 1 min intervals. The ASCE Penman–Monteith (ASCE-PM) standardized reference equations were used to calculate grass reference evapotranspiration (ET_o) from this data on a one-minute basis. A comparison was made for the three phases of before, during, and after the irrigation system passed the in-field ATMOS-41 sensors. In addition, a small unmanned aerial system (UAS) was used to capture 5-band multispectral (ground sampling distance [GSD]: 7 cm/pixel) and thermal infrared images (GSD: 13 cm/pixel) while the center pivot irrigation system was irrigating the field. This imagery data was used to estimate crop evapotranspiration (ET_c) using a UAS-METRIC energy balance model. The UAS-METRIC model showed that the estimated ET_c under MESA was suppressed by 0.16 mm/day compared to the LESA. Calculating the ET_o by the ASCE-PM method showed that the instantaneous ET_o rate under the MESA was suppressed between 8% and 18% compared to the LESA. However, as the time of the ET suppression was short, the total amount of the estimated suppressed ET of the MESA was less than 0.5% of the total applied water. Overall, the total reduction in the ET due to the microclimate modifications from wind drift and evaporation losses were small compared to the reported 17% average differences in the irrigation application efficiency between the MESA and the LESA. Therefore, the irrigation application efficiency differences between these two technologies were very large even if the ET suppression by wind drift and evaporation losses was accounted for. Full article