E. Chavoshgoli; Sh. Abdollahpour; H. R. Ghasemzadeh
Abstract
IntroductionThe nut sunflower is usually cultivated in small farms and is harvested with a low capacity of harvester at high moisture content. For the rigid threshing components, impact and knead force are so large as it leads to crushing of the grain or inner stress. This reduces marketability and the ...
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IntroductionThe nut sunflower is usually cultivated in small farms and is harvested with a low capacity of harvester at high moisture content. For the rigid threshing components, impact and knead force are so large as it leads to crushing of the grain or inner stress. This reduces marketability and the germination rate of seeds. The mechanical damage degree of sunflower grain is influenced by the material of the threshing beaters, the velocity of impact, moisture contents, etc. Traditional manual methods, that separate grain from the sunflower head, take a lot of time, require large manpower, have high grain damage, and low efficiency. The objective of the present work was to develop and optimize a threshing unit for nutty sunflower that would combine safe impact velocities with appropriate adjusting of its variable to maximize threshing efficiency whilst minimizing grain damage resulting from shearing, cracking, or crushing.Materials and MethodsThe nutty Sunflower heads were procured from the Experimental Orchard of University of Tabriz, Iran at the moisture content of harvesting. Axial threshing units using kinematic equation and properties of the grain, designed and constructed that the variables of its components are adjustable. The beater of the thresher is flexible, which the deformation and vibration undergoing the overall rotation and impact process becomes larger with increasing speed and prevents grain damage. The power required for threshing and separation grain from heads was calculated at about 4.5 kW. Diameter and rotational drum speed value estimated using relation (V= and study of other researches as considering critical impact velocity of sunflower grain. The length of the thresher was 1.2 m that estimated by determining the capacity and the number of beaters. Threshing efficiency (%), separation efficiency (%), and grain damage (%) were parameters of performance for study. The experimental design by the Response Surface Methodology in Design Expert software 11 with central composite experiment design developed and the affecting parameters on accuracy analyzed and optimized. The threshing unit was evaluated against three threshing drum speeds of 380, 280, and 180 (rpm), feed rates 4000, 3000, and 2000 (kg (head)h-1), moisture content of 60%, 45%, and 30 (%w.b).Results and DiscussionThe results showed that the models and effect of variables were statistically significant at the 95% confidence level. The moisture content on threshing efficiency and grain damage had the greatest effect followed by drum speed and feed rate. While for separation efficiency, the feed rate had the most influence. With reducing feed rate and moisture content the threshing efficiency increased, although the decrease in drum speed reduced it. This might be due to sunflower grains adhering loosely to the head at the low moisture contents. The maximum (99.81) and minimum (96.12) percentage of threshed heads was at the moisture content of 30 and 60, respectively. The separation efficiency increased with reducing of feed rate and moisture content. Though, drum speed had insignificant efficacy statistically. The sunflower heads with high moisture content are fragile and brittle, also at high feed rates, the number of impact forces and collisions of heads rises in the condition of threshing. Therefore, the extra MOG is produced and passed from the separator grille. The feed rate of 2000 kg h-1 and moisture content of 30% was the maximum point of separation efficiency that obtained 69.82%. The grain damage decreased significantly with reducing drum speed (380 to 180) and moisture content (60 to 30). This result may be due to the reasons that at higher moisture content the husk of grains becomes soft. The goal of optimization is maximizing threshing and separation efficiency and minimizing grain damage that the optimized values of variables were determined 292.134 rpm for drum speed, 2000 kg h-1 for feed rate, and 30.7406% (w.b) for moisture content.Conclusion A threshing unit of sunflower, using properties of grains and kinematic equation, was designed and constructed. The models and effect of the variable were statistically significant on performances. The moisture content had a greater effect than other factors on threshing efficiency (%) and grain damage (%). Also, the feed rate of crops in thresher had the most influence on separation efficiency (%). With decreasing the moisture content, threshing and separation efficiency increased and grain damage reduced. The threshing efficiency (%), separation efficiency (%), and grain damage (%) were reported in the range of 96.12 to 99.81, 57.34 to 68.55, and 0.49 to 1.25, respectively. The optimized points were determined at the drum speed of 292.134 m s-1, feed rate of 2000 kg h-1, and moisture content of 30.7406% (w.b).
Design and Construction
P. Pashaee; H. R. Ghasemzadeh; H. Behfar
Abstract
Introduction According to reports on trends in the agricultural industry, demand for more precise and affordable machinery is rising and precision farming methods used by farmers are expanding. Damping vibration of the boom sprayer is one of the challenges for researchers when crossing the surface roughness. ...
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Introduction According to reports on trends in the agricultural industry, demand for more precise and affordable machinery is rising and precision farming methods used by farmers are expanding. Damping vibration of the boom sprayer is one of the challenges for researchers when crossing the surface roughness. The lack of uniformity of the nozzle spray pattern and the reduction of the precision and quality is the result of an uncontrolled vibration of the boom sprayer. So far, many efforts have been made to decrease the vibration of the long sprayer boom. Using active and passive methods, researchers have achieved great success in reducing the spray boom vibration. Many of these methods are based on the use of external force as a controlling force. Expensive equipment, the use of tractor hydraulic power, and high energy costs are the main disadvantages of these methods. In the present work, a new system called "variable support" was designed and built. The boom rests on a round bar at its midpoint; as the boom tends to oscillate, a minute amount of rotation of the bar activated by a servomotor in an appropriate direction, alters the position of the resting point of the boom on the supporting bar, bringing the boom back to its initial balanced position as a result.Materials and Methods To carry out experiments, the universal tractor U650 and a mounted tractor sprayer model tms500 with 8 m boom and a 500-liter tank, was used in this research by making changes to the design of the simple tractor sprayer a new active sprayer designed and built with intelligent online balancing system that in addition to balancing the boom angle, it reduced the fluctuations that occur during work. Electronic control was used to control the position of the boom. The microcontroller programming codes were developed and uploaded in the microprocessor to execute instantaneous commands to the mounted activator due to the need for boom positional data for analyzing experiments, a data logger was also designed in conjunction with the controller circuit and the algorithm was loaded after coding with C++. To compare the new sprayer with the conventional, a field test was conducted. Tests were carried out according to manufacturer's instructions at three-speed levels of 3 (low), 5 (medium), and 8 km h-1 (high), with three bumps heights of 10, 15, and 20 cm with three replications. For the acquisition of vertical acceleration as well as axial rotation data in the conventional sprayer, a data logger with an accelerometer and gyroscope was used. The data logging rate and the accuracy of the accelerometer and gyroscope measurement were set to 50 Hz, 0.1 m s-2 and 0.1°, respectively.Results and Discussion To compare the behavior of the active and the conventional spray booms in terms of vibrations, the univariate analysis was used. The results showed that there was a significant difference between the performances of two sprayers at 5% probability level with the sig. number of 0.000.To compare the behavior of the active and the conventional spray booms in terms of axial rotation, also the Univariate analysis was used. The results showed that there was significant difference between the performances of two sprayers at 5% probability level with the sig. number of 0.000. Also, comparing the marginal mean values of the data obtained from the data logger showed that the active boom compared with the conventional boom had less axial rotation and less vertical acceleration.Conclusion Results of experiments showed that the new sprayer with variable support system, relative to the conventional sprayer in terms of controlling boom acceleration and the angular balance of the boom with a significant difference had relative superiority and can be considered as an appropriate alternative to increase the accuracy of spraying, although more research on large scale booms are necessary before coming to final conclusion.
Kh. Mohammadi; H. R. Ghasemzadeh; H. Navid; M. Moghaddam; H. Ghaffari
Abstract
In this research the quality of walnut kernels under impact loading were studied. Due to unavailability of specific varieties of walnut in Iran, the tests were carried out on the available genotypes. Three different genotypes from walnut orchards of Azarshar region were selected and were collected in ...
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In this research the quality of walnut kernels under impact loading were studied. Due to unavailability of specific varieties of walnut in Iran, the tests were carried out on the available genotypes. Three different genotypes from walnut orchards of Azarshar region were selected and were collected in 2009. A drop test device was designed and constructed to perform the experiments. The impact tests were performed considering five factors in a factorial experiment using completely randomized design with five replications. The factors were genotype, moisture content, geometrical mean diameter, load direction with three levels and the hammer drop height (five levels). The effect of these factors on kernel quality was examined. Walnut cracking assessments and kernel quality were evaluated by well-defined criteria. Generally, by increasing the moisture content, the percentage of broken kernels decreased while the number of unbroken kernels increased and the quality grade of the kernels improved. The percentage of broken kernels increased as hammer drop height increased. Soaking the walnuts in water for 3 hours, with transverse loading (in Y direction) and hammer drop height of 35cm were formed the best set of walnut cracking parameters for obtaining quality kernels.
S. Aliasgarian Najafabadi; H. R. Ghasemzadeh; M. Moghaddam
Abstract
In the present research, susceptibility of two strawberry cultivars (Selva and Gavita) to bruising was studied. Individual fruits were subjected to impact and compressive forces. Impact forces were applied through dropping the fruits from predetermined heights as well as pendulum. Bruising volume was ...
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In the present research, susceptibility of two strawberry cultivars (Selva and Gavita) to bruising was studied. Individual fruits were subjected to impact and compressive forces. Impact forces were applied through dropping the fruits from predetermined heights as well as pendulum. Bruising volume was considered as damage index. In both methods bruising severity was increased as a function of impact energy. Dropped fruits were showed higher bruising volume than those of fruits impacted by pendulum for similar energy levels. Increasing energy level by a factor of four (from 0.022 to 0.082 J) caused the bruise volume to increase by a factor of three (from 46 to 134.5 mm3). Increasing drop height from 18 cm (0.026 J) to 54 cm (0.079 J) caused the bruise volume to increase up to 35%. Bruise severity due to compression force was higher than those of obtained from other tests. Doubling the loading time from 2 to 4 seconds showed no significant difference in bruise volume. Although Gavita variety had greater sensitivity to bruising than Selva variety, the effect of variety was significant only in impact test with pendulum tester.
