液压升降折叠宽幅喷杆喷架的结构设计     

许超  陈永成  李瑞敏 《农机化研究》2015,(8):96-99

针对目前植保机械中所使用的喷杆喷架稳定性差、折叠伸展需要人工辅助等问题,设计出了一种液压升降折叠宽幅喷杆喷架。对喷杆喷架的升降装置、90°液压油缸折叠机构、180°液压油缸折叠机构和整体宽幅喷架进行了理论分析和结构设计,并建立了关键部件的三维模型。通过田间试验验证了该装置设计方案的合理性,为研发先进适用、具有自主知识产权的液压升降折叠宽幅喷杆喷架奠定了基础。  相似文献   

Effect of dietary inclusion of spray‐dried porcine plasma on performance,some physiological and immunological response of broiler chickens challenged with Salmonella sofia          下载免费PDF全文

S. S. M. Beski  R. A. Swick  P. A. Iji 《Journal of animal physiology and animal nutrition》2016,100(5):957-966

This study was conducted to investigate the effect of spray‐dried porcine plasma (SDPP) in broiler chickens under Salmonella sofia disease challenge. The experiment comprised five starter diets: positive control (no supplement), diet supplemented with in‐feed antibiotics (IFA; salinomycin 0.05% + zinc bacitracin 0.033%) and diets supplemented with SDPP at 10 or 20 g/kg diet. All four of these groups were challenged with S. sofia, while a fifth group was unchallenged and used as the negative control. The experimental diets were fed to 14 days; then, the birds were switched to commercial‐type grower and finisher diets. Oral inoculation of the challenged groups with S. sofia occurred on day 8, 10 and 12. Body weight was significantly higher in the birds fed diets containing IFA and SDPP than in the challenged control group, but it was only significant in starter and grower phases. In general, there was an improvement in the weights of the immune‐related organs, but it was only significant for the weight of the bursa of SDPP‐fed birds at 13 days. At day 13, blood potassium content was lower and the concentrations of IgG and IgM tended to be lower in the birds fed on low‐SDPP starter diets than those of the other groups. There were significant differences in the concentration of lactic acid in the ileum and acetic acid, formic acid, butyric acid and propionic acid in the caeca. Inclusion of SDPP to the starter diets of broiler chicks had positive effects on broiler performance, immunity and gut health during exposure to highly pathogenic conditions.  相似文献   

Evaluation of the pattern of spray released from a moving multicopter     

Illia Chyrva  Mark Jermy  Tara Strand  Brian Richardson 《Pest management science》2023,79(4):1483-1499

BACKGROUND

Multicopters are used for releasing particulates seeds, fertilizer and spray. Their low cost and high manoeuvrability make them attractive for spraying in steep terrain and areas where overspray is undesirable. This article describes a model of multicopter wake and its influence on particulate dispersion, which is computationally economical compared to many computational fluid dynamics (CFD) approaches, yet retains reasonable accuracy.

RESULTS

A model was successfully implemented in OpenFOAM . It features source terms for the rotor wash, Lagrangian particle tracking, an evaporation model, and a porous medium approach to model the effect of the ground vegetation. Predictions were validated against the field tests of Richardson et al. which used a DJI Agras MG-1 multicopter in three different flights with airspeeds of 3.2–4.9 m s⁻¹, ground speeds of 2.1–2.9 m s⁻¹ and cross-wind speeds of 0.04–2.2 m s⁻¹. The effective swath width (30% line separation) was predicted to within one standard deviation. Sensitivity to a rotor rotational speed, flight height, flight velocity, multicopter roll and yaw angles, surface roughness length, plant height and leaf density was checked.

CONCLUSION

In all flight trials, the modelled swath was closest to the experimentally obtained swath when the surface roughness of the fetch was equal to 0.5 m (bushes) and the rotational speed of all rotors was equal to 2475 rpm with 0.75R (0.2 m) tall plant canopy (grass) introduced to the model. The model showed acceptable validity for flight velocities of ≤2.8–5 m s⁻¹ when flight parameters can be approximately estimated. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Assessment of microbial biocontrol agent (BCA) viability to mechanical and thermal stress by simulating spray application conditions     

Marco Grella  Fabrizio Gioelli  Paolo Marucco  Ingrid Zwertvaegher  Eric Mozzanini  Marco Pittarello  Paolo Balsari  Spyros Fountas  David Nuyttens  Monica Mezzalama  Massimo Pugliese 《Pest management science》2023,79(11):4423-4438

Background

In order to improve the biological control agent (BCA) efficacy, stress factors threatening the viability of microorganisms during spray application need to be determined. The effect of spray mixture temperature and exposure time on Trichoderma harzianum T 22 and Bacillus amyloliquefaciens QST713 viability were tested. Concurrently the combined effect of mechanical and thermal stress effect on BCA viability were tested at two initial spray mixture temperatures (14 and 25 °C) by simulating a spray application using airblast sprayers featured by different tank capacity and a spray liquid circuit (without and with hydraulic agitation system). To assess the BCA microorganism viability, spray mixture samples were collected at time intervals along trials and plated to count the colony forming units (CFU).

Results

The critical temperature threshold that inhibited BCA viability was 35 °C with 30 min of exposure. The sprayer type, the initial temperature of the spray mixture and the temperature increment during the trials significantly decreased the number of CFU recovered. When simulating a spray application, the spray mixture temperature increase rate was determined mainly by the residual amount of spray mixture in the tank. Even if the tank capacity does not substantially affect the final temperature reached by the spray mixture, the higher residual spray mixture in bigger tanks can expose the BCAs for a longer time to critical temperatures.

Conclusions

Experimental trials allowed us to identify the effect of factors affecting the viability of tested BCAs, providing information about the actual chance to guarantee the biological efficacy of BCA treatments. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

Challenges and opportunities of unmanned aerial vehicles as a new tool for crop pest control     

Ruirui Zhang  Andrew J Hewitt  Liping Chen  Longlong Li  Qing Tang 《Pest management science》2023,79(11):4123-4131

The application of pesticides is not simply delivering chemicals to the target area. It also involves considering the negative aspects and developing strategies to deal with them during the application process, to ensure the maximization of pesticides use efficiency and the maintenance of the ecosystem. Unmanned aerial vehicle (UAV) sprayers demonstrate unique advantages compared to traditional ground sprayers, particularly in terms of maneuverability and labor intensity reduction, showed great potential for chemical application in pest control. It is undeniable that there exist challenges in the practice of UAV spraying, such as higher potential risks of pesticide drift or pathogen transmission, uncertainty canopy deposition for different crops, and unexpected leaf breakage induced by downwash flow. Maximizing the utilization of downwash flow while avoiding lateral air movement outside the intended target crop area is a major issue for chemical application with UAV sprayers, particularly in light of the increasingly apparent consensus on the need for enhanced environmental protection during the chemical application process. It must be considered that the operation strategy in different scenarios and for different crop targets is not the same, unique requirements should be given on nozzle atomization, flight parameters, adjuvants and aircraft types in specific working situations. In future, the implementation of spray drift prediction, technical procedures development, and other solutions aimed at reducing pesticide drift and improving deposition quality, is expected to promote the adoption of UAV sprayers by more farmers. © 2023 Society of Chemical Industry.  相似文献   

Ineffectiveness of applying additional insecticide sprays at the border of the citrus block for the control of Huanglongbing     

Isabela Vescove Primiano  Fabiano Parra Asato  Renato Beozzo Bassanezi 《Pest management science》2023,79(3):1113-1122

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PWM变量喷雾系统动态雾滴分布均匀性实验   总被引：4，自引：0，他引：4  

蒋焕煜  周鸣川  李华融  蒋卓华 《农业机械学报》2015,46(3):73-77

由于PWM变量喷雾作业过程中喷头不连续作业,喷雾的均匀性特别是喷雾机运动方向上的均匀性较难控制,为此通过高速电磁阀、不锈钢压力罐、压力传感器、气泵、调速输送带等构建了一套动态PWM变量喷雾实验平台,并对该平台动态喷雾雾滴分布特性进行实验研究。采用水敏试纸作为获取动态雾滴分布状态手段,通过图像处理技术以区域内雾滴覆盖率的变异系数作为动态雾滴分布均匀性判定指标,评估了在不同PWM控制信号频率、不同PWM控制信号占空比及不同喷雾压力下的单个喷头动态雾滴分布均匀程度。经实验表明,变异系数随控制信号占空比的增大而减小,控制信号频率对动态喷雾雾滴分布均匀性有较大影响,变异系数随控制信号频率增大而减小,喷雾压力对变异系数影响较小,喷雾压力越大变异系数越大。  相似文献   

喷嘴雾化特性的PDPA实验研究进展   总被引：1，自引：1，他引：1  

魏琪  岑旗钢 《排灌机械》2003,21(4):27-30

喷嘴雾化在能源动力、化工、农业和环境工程中有非常广泛的应用，研究喷嘴雾化的流动特性是两相流研究中一个重要课题。对粒度分布等雾化特性的研究，有助于对喷嘴雾化机理的了解以及雾化结构的优化。本文简要介绍了PDPA基本原理和研究状况，综述了应用PDPA测量喷嘴雾化特性的实验研究进展，并提出了对此研究的展望。  相似文献   

螺旋型喷嘴雾化及流量特性实验   总被引：3，自引：1，他引：3  

刘乃玲  张旭 《农业机械学报》2006,37(9):79-82

分析了几种常用的表征液滴尺寸的参数以及喷嘴的流量及雾化特性,用因次分析的方法建立并回归了TF型喷嘴的雾化准则关系式。通过实验研究了TF6喷嘴的几种雾化液滴直径随喷雾压力变化的规律,建立了TF6喷嘴的流量与喷雾压力之间的关联式。实验表明,随着喷雾压力的升高,喷嘴的流量增大,雾滴的各种直径均降低,但喷雾压力对雾滴直径的影响是有限度的。  相似文献   

等离子体脉冲荷电喷雾装置   总被引：7，自引：1，他引：7  

储金宇  吴春笃  杨超珍  何雄奎  张波  杜彦生 《农业机械学报》2004,35(6):98-101

设计了一套用于荷电喷雾的高压脉冲电源和等离子发生环 ,详细介绍了脉冲电源电路、电极结构和脉冲荷电喷雾系统 ,分析了脉冲电源的荷电原理 ,检测了系统的荷质比。理论分析和试验结果表明 :在同样试验条件下 ,脉冲电源优于普通直流高压电源 ,具有起晕电压低、能耗省、工作平稳、结构紧凑等特点 ,可靠、经济、实用  相似文献