Resumo em Inglês:

Abstract Tomato seedling stems can suffer mechanical damage during automatic grafting, reducing the quality of grafting. This study examined two sources of damage: compression damage to scion stems and bending damage to rootstock stems. Two damage tests were conducted. The test factors were determined based on the finite element simulation method. The four test indicators were established through a stress analysis method. Based on the damage test, for seedlings aged 33–35 days, when the diameter compression ratio was less than 40% or when the deviation distance of the rootstock emergence point in the longitudinal and transverse directions on the substrate bowl surface was less than 10 mm, the equivalent bending and buckling forces significantly exceeded the weight (0.0228 N) imposed by the graft clip and scion. Consequently, the deformation distance between the mass centre of the grafted seedling and the centre of the substrate bowl decreased to 0 mm, and the grafting success rate was 100%, with upright grafted seedlings and high–quality graft formation. This study provides a foundation for optimising clamping and alignment mechanisms in grafting machines.

Resumo em Inglês:

Abstract Accurate monitoring of reservoir water levels in urban and agricultural environments is essential but is often performed visually, a method that is both time-consuming and labor-intensive. This study describes the development and evaluation of a low-cost water level monitoring system based on the Internet of Things (IoT) concept. The system uses an ultrasonic sensor to continuously measure the distance to the water surface, incorporating automated data processing and real-time visualization through the ThingSpeak platform. Field tests were conducted in an open-air reservoir of 1,100 m3, and sensor readings were compared with manual observations from a limnimetric ruler, showing excellent agreement (R2 > 0.999). Results obtained under uncontrolled environmental conditions confirm the feasibility of ultrasonic sensing for continuous monitoring of water levels in open reservoirs. The system is inexpensive (approximately US$ 150), easy to assemble, install, and maintain, and provides accurate measurements both day and night.

Resumo em Inglês:

Abstract To address the problem of high rates of damage during automated apple harvesting, caused by uneven distribution in the filling of the apple bin, a device was designed with a bin that could rotate and move up and down autonomously. By analyzing the state of motion and the impact forces during the bin filling process, three factors influencing the rate of damage and the uniform distribution coefficient were identified: the conveyor belt speed, the rotational speed of the bin, and the angle of contact between the soft leather curtain and the bin. EDEM was used to simulate the process and to analyze the individual factors affecting the apple bin filling device, and to determine suitable value ranges for the influencing factors. The Box-Behnken response surface methodology was applied to study the interactive effects of these factors on the damage rate and uniform distribution coefficient. A quadratic regression model was established, in which the damage rate and uniform distribution coefficient were used as response variables, and the optimized values of the influencing factors were obtained as follows: a conveyor belt speed of 0.33 m/s, a rotational speed for the bin of 0.35 rad/s, and a contact angle between the soft leather curtain and bin of 30°. After optimization, the damage rate j was 4.07% and the uniform distribution coefficient S was 0.393. Bin filling experiments in an apple orchard yielded an average damage rate of 5.67% and an average uniform distribution coefficient of 0.408. The deviation between the experimental values and the optimized values was less than 5%. This study can provide a pertinent reference for the design of mechanized and automated bin filling equipment.

Resumo em Inglês:

Abstract Soil sampling for fertility mapping remains a challenge in agricultural management, mainly due to high costs. Several techniques have been employed to mitigate this issue, each with its own advantages and limitations. This study proposes an approach based on the delineation of management zones, considering soil classification, topography, and Apparent Magnetic Susceptibility (MSa). MSa was combined with each covariate to create two distinct sampling-zone configurations. We evaluated this methodology in a 107-ha area, assessing the representativeness of the zones for mapping potassium (K), phosphorus (P), and clay and seeking to determine the minimum number of subsamples required within each zone. We considered three error levels relative to the reference mean (10%, 20%, and 30%). The results indicated that zone-based sampling is effective for attributes with a well-defined spatial pattern, but limited for attributes with random distribution, such as phosphorus. Both zone configurations showed good capacity to represent variability. A 20% error level provided a balance between cost and accuracy, with about 12 subsamples per zone, which is considered feasible and consistent with field practice.

Resumo em Inglês:

Abstract Double-disc centrifugal fertilizer spreaders are widely used because of their high operational capacity and low cost for applying granular fertilizers. However, achieving adequate application uniformity remains a challenge. This study evaluated fertilizer distribution by examining transverse application uniformity and the intensity of particle-size segregation. The variables included fertilizer type, application rate, disc rotation speed, and vane shape, totaling sixteen treatments arranged in a factorial design. Transverse distribution data were analyzed to determine the coefficient of variation (CV) and the granulometric spread index (GSI). Results showed that effective application width depended on the interaction between fertilizer type and disc rotation speed. The fertilizer with the most homogeneous particle-size distribution (GSI = 16) produced wider effective spreading widths, exceeding 30 m. In contrast, the fertilizer with a higher initial GSI exhibited greater segregation across the spreading width, with the GSI increasing from 34 to 47. The surface area of fertilizer particles deposited along the spreading width also varied, and this effect was more pronounced for the product with initially higher quality. This study provides a detailed quantification of how fertilizer–machine interactions influence spreading performance, offering insights to improve broadcast fertilization accuracy and mitigate segregation-driven nonuniformity in precision agriculture.

Resumo em Inglês:

Abstract This paper analyzes the effects of the parameters of a symmetrical spiral anti-blocking and row-sorting device (SSARD) on the quality of no-tillage wheat sowing. The discrete element method was used to simulate the operating process of the SSARD in the soil bin. The effects of the outer diameter of the symmetrical row-sorting blade, the type of additional stubble-cutting and soil-breaking mechanism (ASSM), the radius of the side baffle notch, the length between the material hopper and the ground, and the width between the opener and the straw baffle on the straw removal rate and the blockage rate were studied. The analysis showed that the straw removal rate of the SSARD improved after optimization, and that the ASSM could cut and chop straw alternately at different rotary velocities. The ASSM could also cut the clods that accumulated on the straw baffle inside with support. The blockage rate was reduced. The response surface method was then used to determine the optimal combination of parameters for the SSARD. The results of a field verification test showed that the straw removal rate of the SSARD could reach 93.35% after optimization, representing an increase of 27.7% compared with a no-till planter without SSARD.

Resumo em Inglês:

Abstract Cotton (Gossypium hirsutum L.) is one of the world's most economically important crops, providing a major source of natural textile fiber, vegetable oil, and biofuel. This study aimed to map and evaluate the correlation between cotton lint productivity and the key agronomic traits, including boll number and the height of the first boll insertion, as well as other plant characteristics. Spatial variability was assessed through the interpretation of simple and cross-semivariograms, along with their respective kriging and cokriging maps. A regular geostatistical sampling grid consisting of 100 points, spaced at 9.9 m x 9.9 m, was established for data collection. The phenological indices evaluated included cotton lint productivity (PR), number of bolls per plant (NBO); height of the first boll insertion (HB); total fresh weight of the cotton plant (TF); plant height (HE); plant width (WI); number of branches per plant (NBR); and stem diameter (DS). Among these variables, most of them showed spatial dependence, except for total fresh biomass (TF) and plant height (HE), which showed a pure nugget effect, indicating the absence of spatial dependence among the sampled points. Cotton lint productivity showed a strong and positive correlation with the number of bolls per plant (R2=0.667), indicating the potential of this attribute as a strong indicator of crop productivity. In contrast, the height of the first boll insertion exhibited a strong negative relationship with cotton lint productivity (R2=0.820), indicating that higher boll insertion is associated with reduced crop productivity.

Resumo em Inglês:

Abstract Using an improved NSGA-II (non-dominated sorting genetic algorithm II) algorithm, a multi-objective optimisation approach is developed here for the pickup device of a square baler, in an attempt to significantly increase its work efficiency and to effectively reduce the missed pickup rate of a traction-type square baler. First, a thorough kinematic study of the pickup mechanism is carried out, and a model of the missed pickup region area is then created. The area of the missed pickup region and the contact speed between the spring teeth and the straw are found to be the two main elements affecting the picking efficiency. The optimisation goals are carefully established based on the results of this analysis. The NSGA-II method, which is well-known for its superiority in regard to multi-objective optimisation, is used for the optimisation task, in view of the high number of optimisation parameters and the significant computing burden involved. In order to overcome the inherent limitations of the NSGA-II algorithm, a population generation method based on linear parental ranking and the good point set is implemented. To further improve the NSGA-II algorithm, the NDX (normal distribution crossover) operator is included. To verify the efficacy and superiority of this approach, the enhanced algorithm is compared against the conventional NSGA-II algorithm, and the ZDT1 and ZDT2 functions are used for testing. A field comparison test is conducted using a 4YZK-4 type square baler in response to the optimisation findings of the enhanced algorithm. The experimental findings show that the output from the optimised revised algorithm is more dependable, and that the optimised parameters are superior. The proposed modification can significantly increase the productivity of a straw baler. The results of this study may provide a useful reference for further investigation into the picking mechanism of a straw baler.

Resumo em Inglês:

Abstract Bell pepper (Capsicum annuum L.) is a widely cultivated vegetable with substantial economic and nutritional relevance worldwide. This crop comprises several cultivars, primarily distinguished by green, yellow, and red coloration, which correspond to different maturity stages and phytochemical profiles. Dehydration represents an effective preservation strategy for bell peppers, as it promotes concentration of bioactive compounds such as carotenoids, flavonoids, and capsaicinoids. Moreover, dehydration constitutes a key processing step in paprika production, a condiment with high added value. This article addresses major bell pepper varieties, examines effects of dehydration on fruit bioactive composition, and explores relationships between processing and production of derived products such as paprika. A comparative analysis of physicochemical characteristics of green, yellow, and red bell pepper varieties was conducted in fresh form and after dehydration. Physical, biochemical, and sensory parameters were assessed, along with effects of thermal processing on concentrations of bioactive compounds, pigments, sugars, and antioxidant activity. Results indicate that thermal processing, particularly dehydration, increases concentration of several beneficial compounds, thereby enhancing nutritional value and potential health benefits of final products.

Resumo em Inglês:

Abstract The aim of this study was to address the problems of physical damage and soil contamination associated with the traditional scallion harvesting process by designing a portable hand-guided harvester and evaluating it through field experiments. The drawbacks of the traditional manual harvesting method were studied and analysed, with the aim of achieving efficient and low-loss harvesting of scallions through mechanical means, and reducing the breakage rate and soil content. The stability of scallions during the harvesting process and the reduction of damage are ensured by adopting a single-row one-time hand-guided mode of harvesting operation, which includes the four core steps of loosening soil, conveying the plants, removing debris, and collecting the plants. Several key components are designed, such as a support feeding device, a clamping conveying device, and a soil screening and debris removal device. This research involved indoor simulation conveying tests and field performance tests. The results indicate that the proposed scallion harvester meets all expected performance metrics, with a miss rate of 3.03%, a qualified debris removal rate of 96.08%, a qualified conveying rate of 96.98%, a damage rate of 3.65%, and a total loss rate of 6.67%. Furthermore, its operational efficiency is significantly higher than that of manual harvesting, as it substantially reduces labour costs and improves the overall productivity of scallion harvesting. Statics and computational modal analyses of the frame structure show that it can meet the strength requirements of normal working conditions, while avoiding the phenomenon of resonance and ensuring the stability and reliability of the harvester. The single-row hand-guided scallion harvester described in this study has good scope for application and practical value, and represents an efficient, low-loss solution for the mechanised harvesting of scallions. Particularly in large areas of planting, it can effectively alleviate the problem of labour shortage and promote the transition towards mechanisation of the scallion industry.

Resumo em Inglês:

Abstract The rate of damage to tobacco leaves during harvesting serves as a critical performance indicator for tobacco leaf harvesters. Real-time monitoring of the damage rate for freshly harvested leaves can provide essential guidance for dynamically adjusting harvester parameters to ensure optimal harvesting quality. To address this challenge, this study proposes a novel real-time detection method for assessing the rate of damage to fresh tobacco leaves. The methodology consists of the following steps: (1) a dataset of damaged and complete tobacco leaves is established; (2) an improved damage detection model YOLO-TL is developed based on YOLOv5, with its backbone network replaced by MobileNetV4 and GIoU loss function implemented; (3) the accuracy and efficiency of the model is validated through ablation and comparative experiments, which indicate an average precision of 0.959 and a processing speed of 123 frames per second. A real-time damage rate detection system is also developed, in which YOLO-TL is used as the detection module with ByteTrack for object tracking. The system determines the status of tobacco leaves by aggregating detection results across multiple frames, ultimately achieving a recognition accuracy rate of 92.9% and a missed detection rate of 6.7%, thereby meeting operational requirements for accurate damage assessment.

Resumo em Inglês:

Abstract Increasing crop productivity relies on techniques such as irrigation; however, drip irrigation systems face recurrent challenges related to dripper clogging, particularly in continuous emitters used in annual crops. Among these challenges, obstruction by solid particles is a major concern. In this context, this study evaluated sensitivity of continuous emitters to clogging by solid particles at two installation positions (upward and downward) using two procedures. Procedure 1 (P1) adopted particle size and concentration based on the test protocol proposed by the National Research Institute of Science and Technology for Agriculture and Environment (IRSTEA), whereas Procedure 2 (P2) used particle sizes corresponding to the minimum filtration level (120 mesh) recommended by irrigation equipment manufacturers. Clogging occurred primarily at the emitter inlet, even with particle diameters smaller than 125 µm, and was intensified by increasing concentrations up to 500 mg L-1. Particles close to 500 µm caused obstruction in emitters with channel depths below 50 mm. Under P1, increasing particle size was one of the main factors increasing susceptibility to obstruction. Under P2, even with particle sizes up to 125 µm and concentrations up to 500 mg L-1, conditions remained favorable for emitter clogging.

Resumo em Inglês:

Abstract To overcome the limitations of traditional fixed-speed threshing, this study applied a variable-speed pulley transmission to a threshing device, with the aim of systematically investigating the coupling relationships between working performance, vibration characteristics, and the mechanism of speed variation during threshing. Using a cross-flow threshing unit, bench tests were used to compare fixed-speed and three variable-speed modes (T/2, T/3, T/4), in terms of threshing performance (impurity rate, loss rate, broken stems) and axial vibration characteristics across feed rates of 0.0–2.5 kg/s. The results indicate that variable-speed threshing reduces the loss rate by 0.45–1.79%, compared to fixed-speed operations. Among these, T/2 and T/4 modes exhibited better adaptability to varying feed rates; whereas, T/3 was prone to clogging at high feed rates. Vibration analysis revealed that non-circular pulleys introduced significant periodic excitation, whilst feeding significantly increased the vibration acceleration and prolonged its duration; the duration increased, almost linearly, with the feed rate. Notably, variable-speed threshing, especially T/2 and T/4 modes, enabled faster recovery of vibration acceleration to a stable state after threshing, indicating a superior dynamic response. This study clarifies the intrinsic "speed–performance–vibration" relationship in non-circular pulley variable-speed threshing, providing a theoretical and data foundation for developing intelligent threshing equipment that balances high efficiency and low vibration.

Resumo em Inglês:

Abstract To overcome the issues of low operating efficiency and high losses in domestic fresh corn harvesting, a 4YZ-6 type combined harvester designed for fresh corn was developed. The structural design and operating mechanisms of the main components of the harvester are explained in detail. Stalk pulling roller speed, fan speed, and forward travel speed were chosen as experimental variables, while impurity rate and ear loss rate were used as performance evaluation indices. Based on the experimental results, an optimal set of operating parameters was identified, followed by additional validation tests to confirm the findings. The results showed that the impurity rate was 1.37% and the ear loss rate was 1.98%, which fully met the expected requirements. This study provides an effective technical approach for overcoming shortcomings in the field of mechanized fresh corn harvesting in China.

Resumo em Inglês:

Abstract The ability to recognise fruit tree trunks is essential to allow orchard operation robots to perform various intelligent tasks. However, dynamic changes in natural lighting, mutual occlusion of branches and leaves, and various weather-related factors pose severe challenges for target detection algorithms. To address these problems, this paper proposes a recognition method based on YOLOv9c for target objects such as fruit tree trunks, people, and obstacles in complex orchard environments. Orchard images were collected on site and augmented using weather-related factors such as fog, rain, and strong light to enrich the dataset. The YOLOv9c model was improved by integrating a spatial-channel synergistic attention (SCSA) mechanism into the backbone network to enhance its anti-interference capability in complex environments. The Slim-Neck-by-GSConv network structure was introduced to modify the neck network, and to reduce the number of model parameters. The improved YOLOv9c target recognition model was trained and validated on the experimental dataset, and the results showed that it achieved a precision of 97%, a recall rate of 95.4%, and an mAP@0.5 of 97.3%, thus demonstrating that the model exhibits superior detection precision and speed in complex orchard environments.

Resumo em Inglês:

Abstract Accurate monitoring of crop growth at the field scale is essential for the development of farm management measures for plant protection, machine harvesting, and other agricultural processes. In this study, 17 vegetation indices and four texture features were gathered from canopy spectral data collected by a UAV. Using the recursive feature elimination method, redundant variables were removed. Four regression algorithms, namely SVR, RF, GBDT, and XGBoost, were used to build inverse models of the silique dehiscence force, seed compression force, and seed moisture content of rapeseed based on vegetation indices, texture features, and their fusion, and the differences between them were compared. The results showed that the seed moisture content had a higher sensitivity and was superior when used to estimate inversion compared to the silique dehiscence force and seed compression force. The seed moisture content estimation model developed with XGBoost achieved the highest accuracy (R2=0.847, RMSE=0.025). Of the 12 inversion models, the XGBoost/seed moisture content model based on the fusion of vegetation indices and texture features yielded increases in accuracy of 26% and 10% compared to the vegetation indices and texture features models, respectively. In summary, a seed moisture content inversion model based on the fusion of UAV spectral and texture information offers a feasible and accurate solution for timely machine harvesting of rapeseed.

Resumo em Inglês:

Abstract The well-cellar style transplanting (WCST) method has been shown to offer benefits in terms of improving the nutrient absorption capacity of tobacco plants, but conventional well-cellar devices tend to compact the soil, restricting the growth of tobacco roots. To address this issue, the discrete element method was applied in this study to investigate the impact of different soil drillers on the torque requirements and the profile characteristics of well-cellar holes. The performance of an auger with three rod diameters (20, 40, 60 mm), three values for the spiral lead (30, 60, 90 mm) and three rotation speeds (200, 400, 600 r/min) was evaluated, and the results showed that a lower mean torque was required as the auger rod diameter decreased and the rotation speed increased. The soil disturbance was 73.10% higher for an auger with a rod 20 mm in diameter than for a rod 60 mm in diameter. The weight variation in the auger trials was primarily affected by the rotation speed. Compared with a 200 r/min cylinder-cone bit, an optimized auger with a rod diameter of 40 mm, spiral lead of 90 mm, and rotation speed of 200 r/min had a lower peak torque and caused less soil disturbance, with looser soil around the well-cellar hole wall. The optimized design for the auger enhanced the formation of the well cellar, thereby promoting improved root growth and nutrient uptake in tobacco plants.

Resumo em Inglês:

Abstract Beef tallow is the second major feedstock used for biodiesel production in Brazil; however, studies on its performance and emissions in diesel engines remain limited. This study evaluates the performance and emissions of a single-cylinder diesel engine operating on beef tallow biodiesel blends (B10, B20, B30, and B100) under varying load conditions. Engine tests were conducted using a hydraulic dynamometer at loads ranging from 1 to 5 Nm. The specific fuel consumption (SFC), exhaust gas temperature (EGT), nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), and carbon dioxide (CO2) were measured. The biodiesel blends exhibited higher SFC than diesel due to their lower energy content, although SFC decreased at higher engine loads. Beef tallow biodiesel consistently produced lower NOx emissions than diesel fuel across all operating conditions, indicating a potential environmental benefit associated with its higher degree of saturation. In general, the B10 and B20 blends exhibited the most balanced overall performances, combining moderate fuel consumption and controlled emissions. These results demonstrate that beef tallow biodiesel is a technically viable alternative for small diesel engines, supporting its use as a renewable substitute for fossil fuels in practical applications.

Resumo em Inglês:

Abstract Efficient and consistent formation of transplanting holes (pits) is essential for the mechanized transplanting of tobacco plants, but the design of earth auger devices has traditionally relied on empirical selection and repeated trials. In this study, a systematic approach based on a combination of kinematic derivation, DEM–MBD coupled simulation, and orthogonal regression analysis was applied to optimize the geometry and operating parameters of an earth auger bit. Simulation results showed that the geometry of the bit primarily determined the depth of the transplanting hole, while the rotational speed exerted a significant quadratic effect on the hole’s diameter. Diameter and depth correction factors were also found to influence the stability of pit formation. Field experiments confirmed the feasibility of the optimized parameters, with an average diameter for the transplanting hole of 303 mm, an average depth of 127 mm, and a qualification rate of 98.2%, exceeding the 95% threshold set out in agronomic requirements. The close agreement between the simulation and experimental results validated the reliability of the DEM–MBD model. This study not only provides a theoretical reference for the design of tobacco transplanting using earth auger devices but also offers a practical methodology for improving agricultural engineering equipment involving interaction between soil and tools.

Resumo em Inglês:

Abstract In this paper, a digging device was developed to address the difficulty of digging peanuts in saline soil. The device first cuts the ridge and then performs the digging operation. The key factors affecting peanut digging resistance, including the digging shovel blade angle, cutting knife edge angle, and tilt angle of the digging shovel, were identified through theoretical analysis. A discrete element model of peanut ridges in saline soil was established in EDEM based on the ridge dimensions and the distribution characteristics of peanut roots and fruits. The optimum structural parameters of the digging shovel were determined through simulation analysis and bench tests. The working resistance of the digging device was minimized when the digging shovel blade angle was 11°, the tilt angle of the digging shovel was 27°, and the cutting knife edge angle was 25°. The device reduced the working resistance by 15.5% compared with that of existing digging devices. Finally, a field trial was conducted, and the results revealed that the average working resistance of the digging device was 434.4 N, with the relative error between the field test and the bench test being less than 5.34%. These findings indicate that the structural parameters are well designed.

Resumo em Inglês:

Abstract In recent decades, agricultural practices and urbanization, combined with inadequate conservation measures, have likely intensified soil erosion in the headwaters of the Córrego Rico watershed (HCRW), located in northeastern São Paulo State, Brazil. The HCRW represents an important water source for Jaboticabal and surrounding municipalities; however, it remains vulnerable to erosion driven by intensive agricultural use. This study aimed to estimate soil erosion and its spatial distribution in the HCRW using the Revised Universal Soil Loss Equation (RUSLE) integrated with a geographic information system (GIS). Spatial layers were developed in GIS for each RUSLE factor: average annual soil loss (A), rainfall erosivity (R), soil erodibility (K), slope length and steepness (LS), cover-management (C), and support practice (P). Estimated average annual soil loss (A) reached 68.61 t ha⁻1 year⁻1, with values ranging from 22.82 to 414.15 t ha⁻1 year⁻1. Approximately 77.40% of the watershed exceeded the tolerable soil loss limit of 8.6 t ha⁻1 year⁻1, indicating significant risks to soil productivity and ecosystem services, with potential implications for food and water security in the HCRW.

Resumo em Inglês:

Abstract Given the increasing use of shipping containers for housing, this study evaluates the thermal performance of a 20-ft container (6.05 × 2.43 × 2.59 m) in Cascavel, Paraná, Brazil through short-term monitoring and comparative analysis of internal and external temperatures relative to local climatic conditions. A TempU 07B data logger is used for continuous monitoring over seven days. The hygrothermal performance of the container is characterized and compared to thermal comfort limits defined by NBR 15575, ASHRAE 55, and ISO 7730. The internal temperature of the container showed strong correlation with solar irradiance, reaching 27.22 °C on sunny days and dropping to 10–11 °C on cloudy days, exceeding thermal comfort limits defined by NBR 15575 and ASHRAE 55. Linear regression (R2 = 0.77) indicated an average increase of 7.1 °C for every 100 W m−2 of irradiance. The thermal performance was insufficient to guarantee habitability without air conditioning.

Resumo em Inglês:

Abstract The analysis of energy generation variation throughout the year reveals a geometric structure intrinsically linked to the solar analemma, whose patterns resemble the Möbius strip and Klein bottle. This behavior suggests that the global effective incident energy and the energy converted by solar panels do not follow a trivial linear relationship, but a distribution influenced by unconventional topological properties. Modeling this system in a Riemannian space—using the analemma’s metric and scalar curvature—allowed the formulation of a differential equation governing the generated energy, incorporating seasonal variations and dependencies on panel inclination and orientation. From an exergy perspective, a correspondence between exergy destruction, owing to system irreversibilities, and geometric effects, described by scalar curvature, was identified. The resulting equation, expressed through the Laplace–Beltrami operator, indicated that energy variation can be described in a space with non-orientable properties, supporting the hypothesis that the energy distribution behaves analogously to complex topological surfaces. This approach enhances the understanding of the relationship between solar energy generation and spatiotemporal geometry while providing a mathematical framework to optimize energy harvesting throughout the year. By linking the curvature of the analemma with exergy principles, this study proposes a new paradigm for modeling energy efficiency based on geometric and topological analysis.

Resumo em Inglês:

Abstract This study aimed to evaluate the use of three-dimensional (3D) modeling and virtual reality (VR) as tools for spatial optimization and emission reduction in an agro-industrial requalification project in Ibema-PR, Brazil. The methodology comprised digital modeling in SketchUp, immersive validation in a Meta Quest 2 headset, and quantification of the carbon footprint associated with the main construction inputs (concrete, steel, masonry, and zinc), which included transportation, on-site diesel consumption, and end-of-life (EoL) emissions. The inventory indicated a baseline carbon footprint of 1,052.5 tCO₂, and the application of 3D and VR modeling demonstrated mitigation potential of 105.3 tCO₂ (10% – conservative scenario), 210.5 tCO₂ (20% – moderate scenario), and 315.7 tCO₂ (30% – optimistic scenario). These reductions correspond to up to 1.26 million km traveled by car, 31.6 thousand trees in annual sequestration, or 16.3 thousand months of residential electricity, respectively. In financial terms, the carbon credits avoided represent values ranging from R$ 5.26 thousand to R$ 94, 700, depending on the reference market. The results demonstrate the relevance of digital modeling as a sustainability strategy, while reconciling constructive efficiency, resource savings, and academic awareness for environmentally responsible practices.

Resumo em Inglês:

Abstract Improving the efficiency and precision of pesticide application remains a major challenge in modern agriculture, particularly for oil-based emulsions with complex atomization behaviors. This study investigates the perforation fragmentation phenomenon that occurs in the liquid sheet during emulsion atomization, which differs from that observed in water sprays. A correlation between emulsion-induced properties and perforation morphology was observed. The formation, growth, and instability of perforations under flat-fan nozzles (Lechler 110-01) were characterized, and their effects on droplet kinematics and liquid sheet evolution were analyzed. Additionally, the spray pressure and spatial position were examined to evaluate their effects on perforation dynamics and initial droplet velocity. The results show that oil-based emulsions exhibited a shorter instability evolution process, with the perforation movement reflecting a velocity trend similar to that of the liquid sheet. As the spray pressure increased from 0.1 to 0.5 MPa, the liquid sheet velocity increased from 20 to 40 m/s, whereas the perforation center velocity increased from 13.5 to 28 m/s. A consistent relationship was observed between the perforation and liquid-sheet velocities, thus suggesting that sheet momentum critically governs perforation dynamics. Moreover, the average droplet velocity of emulsion atomization (20 m/s) was significantly higher than that of water sprays (15 m/s). These findings provide insights into the kinematic behavior of perforation-driven breakup in emulsion sprays and enhance understanding of atomization mechanisms in oil-based pesticide formulations.

Resumo em Inglês:

Abstract This study investigates how different chord and twist angle distributions: in ideal, linear, and elliptic forms, influence the performance of a micro horizontal wind turbine designed for low-intensity winds in the semi-arid region of Pernambuco. Using a code based on lifting line theory, validated with reference data, airfoils and geometric combinations were evaluated to maximize annual energy production. The results indicate that the GOE 222 airfoil and ideal distribution deliver the best performance, maintaining suitable angles of attack and high lift coefficients. The linear distribution showed intermediate performance, whereas the elliptic distribution was the least efficient because of increased drag. Additionally, twist was found to have greater influence than the chord on aerodynamic efficiency under weak wind conditions.

Resumo em Inglês:

Abstract This study analyzed changes in temperature extremes in Maputo, Mozambique, focusing on heatwave and cold-spell frequency and duration in the context of climate change and their direct impacts on agrometeorology and plant-soil-atmosphere relationships. Using daily maximum and minimum temperature data from the ERA5-LAND reanalysis database for the period 1984–2023, rigorously validated with an imputation RMSE of 0.05 °C and emphasizing the climatological normal for 1991–2020 computed through a mathematically robust 5-day moving window, the study applied indices recommended by the World Meteorological Organization (WMO) and the Expert Team on Climate Change Detection and Indices (ETCCDI). These indices include daily percentiles for hot days (TX90p) and cold nights (TN10p), as well as duration indices for heatwaves (WSDI) and cold spells (CSDI), assessed using Sen's slope estimator and the non-parametric Mann-Kendall test. Results indicate that over the last three decades, a non-significant increase occurred in the frequency of hot days (p = 0.144), accompanied by a decrease in the frequency of cold nights (p = 0.161), as well as a non-significant decline in the number of cold spells (p = 0.243). Although the trend in heatwaves was not statistically significant throughout the study period (p = 0.418), an apparent episodic intensification has occurred since 2010, particularly during years associated with El Niño events. These findings are essential for developing public policies focused on adaptation of climate change, urban planning, and resilience strategies, particularly in agricultural, health, and infrastructure sectors in Maputo. In addition, they reinforce the importance of continuous monitoring of temperature extremes to mitigate adverse impacts of climate change, not only in Maputo but also in other coastal cities across Southern Africa.

Resumo em Inglês:

Abstract Autonomous agricultural vehicles are gradually becoming more common in Brazil despite significant challenges. To enable the safe and efficient adoption of rural property, it is essential to update Brazilian laws and regulations. This requires a deeper understanding of both machines and existing regulatory frameworks. This study aims to address some of these gaps through applied research that gathers information on autonomous vehicles, legislation, and technical standards. The research involved the participation of industry companies, consultations with technical and regulatory standards, and analysis of bibliographic materials. Among other findings, the study identified that NR 31 is not fully capable of covering autonomous agricultural vehicles and that the current regulatory process directed at autonomous vehicles could be beneficial to autonomous agricultural vehicles (AAVs), highlighting the emerging importance of specific regulations related to intelligent embedded systems in AAVs.

Resumo em Inglês:

Abstract The conflict between operational efficiency and mechanical damage to tubers that arises during mechanical potato harvesting has become increasingly pronounced. This study investigated collision damage to potatoes using numerical simulation, and a damage prediction model was developed. We first conducted sampling and parameter determination through laboratory experiments, and a high-fidelity 3D geometric model was then reconstructed via reverse engineering. Following this, a multi-factor explicit dynamic simulation scenario was established in which the effects of the mass of the tuber, drop height, and impact angle on the damage characteristics were systematically analysed. Finally, a second-order response surface regression model incorporating three-factor interaction effects was developed using response surface methodology, based on the simulation data. Experimental results demonstrated that the quadratic response surface model achieved a high predictive accuracy for both the collision force and area of damage (R2 > 0.92), with prediction errors ranging from 1.54% to 25.22%. The optimal combination of parameters (a tuber mass of 320 g, an impact angle of 30°, and a drop height of 36.8 cm) was obtained through multi-objective optimisation, and reduced the collision force and area of bruising by 26.14% and 50.83%, respectively. The proposed damage prediction model was validated as reasonable and effective, and provides a theoretical basis for low-damage structural design and optimisation of separation systems in potato harvesters.

Resumo em Inglês:

Abstract The existing plug seedling transplanters that are used for large-scale vegetable cultivation in China are faced with three main issues: the poor reliability of electrical control systems in the harsh conditions in the field, low efficiency of single-row operations, and low success rates for the picking and depositing of seedlings. To address these issues, this paper presents a high-speed transplanter for plug seedlings equipped with a mechanical and pneumatic synergistic drive system. A kinematic analysis is conducted to determine the main parameters, including the numbers of teeth for the seedling supply ratchet and for the driving sprocket, and a mechanical analysis shows that the minimum clamping force for the seedling picking gripper is 2.0 N. Simulations with FluidSIM software verify that the cylinder action sequence meets the design requirements. The optimal values for the parameters are a picking frequency of 112 seedlings/min, a working pressure of 0.4 MPa, and a seedling height of 145 mm. Field tests of the transplanter with these values indicate that the average success rate for picking and depositing of seedlings, the average missed planting rate, and the single-row transplanting frequency of the transplanter are 96.48%, 3.65%, and 124 seedlings/min, respectively. This study provides theoretical guidance for the design and optimisation of high-speed transplanters.