نشریه تحقیقات سامانه ها و مکانیزاسیون کشاورزی
پیاپی 82 (تابستان 1401)

The use of renewable energy is very important in meeting current and future needs. Vibrations are a good source of energy, especially through piezoelectric nanogenerators. Light, soft and flexible piezoelectric materials such as PVDF can be used to supply part of the electrical energy required by drones. This study was conducted to investigate the possibility of using PVDF / Zno-RGO piezoelectric polymer polymer nanofibers in supplying the required energy of different UAV components. In this study, first, polymer nanofibers were constructed through electrospinning process and then piezoelectric nanogenerator was constructed. Finally, the amount of electrical energy produced and its usability in multi-axis drones were evaluated. A plan was proposed to install a piezoelectric nanogenerator on the arm of a multi-axis drone. The highest output voltage in one of the samples of nanogenerators was 560 mV and in the larger sample was 1870 mV in laboratory conditions and at a frequency of 23 Hz for 5 minutes. The results of this study showed that by using piezoelectric nanogenerators, it is possible to supply part of the electrical energy used by drones and it can be upgraded.

Considering the problems of visual and human evaluation, machine vision, can be used as a suitable substitute for human vision. The purpose of this research was to build and evaluate a machine vision system to determine the breakage percentage and the number of wheat seeds. The system consists of three parts: suction box, sampling box and imaging box and evaluated for two cultivars Torabi and Azar wheat. In each type of wheat, the performance of the suction device was evaluated with two seed plates and four suction values. In each amount of suction, the number of singled seeds and the seeds of sticked together on each hole were counted and their percentage was calculated. The image prepared was transferred to MATLAB software and breakage determination algorithm and wheat seed number was coded and presented. The results showed that the most suitable treatment for wheat of Torabi cultivar, was seed plate with 1 mm hole and suction of -100 mm Hg with 95.31 percent singled seeds and 4.69 percent of sticked together seeds. For Azar cultivar, seed plate with 1 mm hole and suction of -120 mm Hg with a percentage of singled seeds of 91.6 and a percentage of sticked together seeds of 8.4 was the most appropriate treatment. The validation results of the algorithm showed that its accuracy for determining the percentage of breakage and the number of wheat seeds were 85.33 and 98.76%, respectively. It is suggested that this system be evaluated for seeds of different sizes.

This study aimed to design, perform static and dynamic analysis, manufacture, and evaluate an oleaster mill machine. It was designed from a crusher, anti-crusher, tray, body, chassis, inlet, and outlet. After the 3D design, static and dynamic analyses were performed to confirm the strength of the crusher. Then, the technical knowledge (drawings) was extracted and used to manufacture the machine through sheet metal and welding (body and its accessories) as well as casting-machining methods (crusher and anti-crusher parts). An electric motor (2.206 kW) was utilized to rotate the crusher. The manufactured machine was evaluated by measuring the amount of pulverization of oleaster fruit (particles smaller than 250 microns) at various moisture content of the fruit (close to 0% or no change in the moisture content of the sample at 70 C, 5%, and 10%), different speeds of the crusher (750, 1000, 1250, 1500 rpm) and different sizes of tray meshes (0.5, 0.75 and 1 mm) in the form of a factorial experiment based on a completely randomized design in three replications. Statistical analysis showed that the maximum amount of pulverization (80.16) was achieved at the highest rotating speed of the crusher, with the size of tray meshes of 0.75 mm, and samples at moisture content close to zero. By a similar setup, the pulverization was calculated at 79.33% and 55.12% at 5% and 10% moisture content of the samples, respectively. For the manufactured machine and samples at 5% moisture content, which is recommended, the total capacity was calculated at 30 kg/h.

In this study, the performance of the drone sprayer and conventional sprayers was evaluated for weed control in wheat fields. This project was conducted in a completely randomized experimental design with three replications. The studied parameters were: effective spraying width, spraying time per hectare and consequently the field capacity and field efficiency of sprayers, amount of herbicide solution per hectare, volume and number median Diameter of herbicide particles, spraying quality coefficient, drift, energy consumption, crushing rate of Wheat, sprayers effectiveness and economic evaluation. The results of analysis of variance showed a significant difference between the experimental treatments at 5% probability level. The results showed that the drone sprayer, boom sprayer and the turboliner sprayer had 11.14, 351.59, 249.14 liters solution per hectare, 16.76, 7.66 and 38.6% rate of drift, and 6.72, 5.92 and 7.66 hectar per hour field capacity, and energy consumption of 418, 2837.8 and 4796.2 kJ respectively. E was 72.6, 5.92 and 7.66 hectares per hour and energy consumption was 418, 2837.8 and 4796.2 Kjoules per hectar. Spray quality coefficient in drone sprayer and turboliner sprayer were 1.78 and 4.24, respectively. In 30 days after spraying, no significant difference was observed between treatments in terms of operation effectiveness. The cost per hectare of using drone sprayer was twice as much as conventional sprayers.

Soil compaction is a negative factor for plant growth. The purpose of this research is to investigate the effect of deep tillage (subsoiling) on potato yield using domestic and foreign studies with meta-analysis method. For this purpose, articles, research reports and student thesis between 1966 and 2021 were reviewed using key keywords related to subsoiling in the potato. Finally, after quality control, 23 studies were entered into the meta-analysis process to compare deep tillage (including conventional subsoiling, in row subsoiling before planting and inter-row subsoiling after planting) with conventional tillage without subsoiling using a random model. Based on the results, according to the total effect size value (SMD = 0.37), it can be concluded that subsoiling has had a positive effect on the increase of potato yield and has caused a 3.92% increase in potato yield. Conventional subsoiling, in row subsoiling before planting and inter-row subsoiling after planting increased potato yield by 1.23, 5.18 and 4.75%, respectively, compared to the control treatment (without subsoiling). It is recommended to use either inter-row subsoiling (to depth of 35-45 cm) after planting or in row subsoiling (to depth of 40-50 cm) before planting in the potato crop. Conventional subsoiling is not recommended due to low impact on potato yield and high cost.

Grain drill performance can be affected by creating clods during seedbed preparation in dry soil conditions. To increase performance of grain drill in dry soil conditions need to design the new opener for grain drills. This study has been carried out for the economic evaluation of the suitable tillage method for planting by grain drill equipped with a bent leg furrow opener and their effect on the yield of irrigated wheat. This study was a randomized complete block experimental design with four treatments and four replications. Treatments were seeding winter wheat by a grain drill with bent leg furrow opener in three tillage practices of no-tillage (T1), reduced tillage (T2), and conventional tillage (T3). Seeding wheat by conventional grain drill in the conventionally tilled plots was also used as control treatment (T4). In order to investigate the economic effects of tillage and planting methods by the bent leg grain drill on wheat yield, the income and cost of treatments were measured, and using the marginal net profit analysis method, the economic rate of return on investment of each method. The results of showed that the most suitable treatment from the economic point of view is the bent leg tillage treatment + planting with a grain drill equipped with a bent leg furrow opener. The findings showed that the bent leg tillage + the bent leg grain drill, as a new technology, has the potential to increase crop yield and can increase the farmer's net profit.