Design and Construction
M. Rezaei; J. Khodaei; B. Astinchap
Abstract
IntroductionDue to the increasing need for agricultural products, protection of products against pathogens and preventing them from being wasted is important. Studies on droplet charging systems result in the reduction of chemical usage and an increase in the deposition of droplets on the target. Conventional ...
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IntroductionDue to the increasing need for agricultural products, protection of products against pathogens and preventing them from being wasted is important. Studies on droplet charging systems result in the reduction of chemical usage and an increase in the deposition of droplets on the target. Conventional sprayers used in Iran have numerous disadvantages such as drift, environmental pollution, lack of complete and homogeneous coverage of the spraying surface, phytotoxicity, and crop losses. Therefore, evaluation of new spraying methods and using a variety of electrical sprayers as alternatives to conventional spraying is essential. This study aims to design, construct, and optimize the performance of the electrodynamic head of an atomizer motorized knapsack sprayer, and study the effects of the angle of the target position, spraying distance, and wind speed on the performance of the electrodynamic sprayer.Materials and MethodsExperiments were performed in an agricultural machinery workshop at The Department of Biosystems Engineering, the University of Kurdistan, Iran, with an atomizer motorized knapsack sprayer equipped with an electrodynamic head. The effect of some factors including wind speed, spraying angle, and spraying distance on deposition, coverage percentage, and uniformity of spraying were investigated. These effects were investigated to determine the uniformity coefficient of total spraying. Design Expert 8.0.6 Trial software was used to design the experiments based on central composite design and to analyze the data. The investigated factors and levels were: the distance of nozzles from the target (at three levels of 2, 4, and 6 m), the angle of the target position (at three levels of 0, 45, and 90 degrees), and wind speed (at three levels of 2.5, 3, and 3.5 m s-1). Water-sensitive paper cards were used to evaluate the quality of the spraying. The cards were scanned and magnified with an Olympus SZX12 Stereo Microscope equipped with an objective lens of X1 and a total magnification of 7X. The characteristics of droplet size were determined using Mountains Map Trial and Deposit Scan software.Results and DiscussionThe maximum value of the total spraying uniformity coefficient was equal to 1.95 for the spraying angle of 0 degrees, the distance of 6 meters, and the speed of 3.5 meters per second. Meanwhile, the lowest value of the spray uniformity coefficient of 1.18 was obtained for the test conditions of 90 degrees, distance of 2 m, and speed of 2.5 m s-1, respectively. Based on analysis of variance for the two-factor interactions model (P-value less than 0.0001, explanation coefficient 0.9383, absolute explanation coefficient 0.910, standard deviation 0.0590, and coefficient of variation 3.790%). It can be stated that this model is highly accurate in predicting the uniformity of the total spraying, and the linear components of spraying angle and spraying distance, as well as the interaction of spraying angle × spraying distance and spraying distance × wind speed, significantly affect the uniformity of the total spraying (p<0.05). Nevertheless, the linear component of wind speed and the interaction between wind speed and spraying angle had no significant effect on the changes in the uniformity coefficient of the total spray. According to the variance analysis table (F-values), spraying distance has a far greater effect on the spraying uniformity coefficient than the spraying angle.It has been observed that the spraying uniformity coefficient will increase by increasing the spraying distance and decreasing the spraying angle. It can also be stated that the linear components of spraying angle and spraying distance, the interaction component of spraying angle × spraying distance, and the square power of the components of spraying distance and wind speed have a significant effect on surface coverage. The values of R2, Adj-R2, CV, and PRESS for the model adapted to the test data of leaf surface coverage percentage were obtained as 0.9929, 0.9865, 4.87%, and 188.61, respectively.Among the three input variables, the spraying distance has the greatest effect on the coverage of water-sensitive papers. At larger spraying angles, especially 90 degrees, the coverage decreased with the increasing distance. At spray angle of 90 degrees, by increasing the distance from 2 to 4 m, the spray uniformity coefficient increased from 1.18 at a wind speed of 2.5 m s-1 to 1.84 at a wind speed of 3.5 m s-1. However, at smaller spraying angles (for example zero-degree angle), at first, the spraying coverage increases with the increase of the spraying distance from 2 to 3 m and then sharply decreases afterward. According to the contours of spray coverage, in the spray distance range of 4 to 6 m and regardless of wind speed, the spray coverage does not vary with the increase of the spraying angle (p< 0.05). Meanwhile, in the spray distance range of 2 to 4 m, with the increase of the spraying angle, the spraying coverage increases significantly (p<0.05). Overall, increasing the distance between the sprayer and the target decreased the surface coverage on the target, and in electrodynamic spraying, the uniformity of particle deposition on the underside of the target was relatively the same as on the upper side.ConclusionTo improve the performance of the atomizer motorized knapsack sprayer, an electrodynamic spraying head was designed and built, and its performance was optimized using the response surface method (RSM) with a central composite design. During the research process, the influence of the independent parameters such as the distance between the nozzle and the target, the angle of the target position, and the wind speed on the variables including spraying uniformity, the percentage of the spraying coverage, and the percentage of changes in the total spraying coefficient were discussed and investigated. The results of the research led to the determination of the 3.5 m s-1 wind speed, 2.5 m sprayer distance, and 90 degrees spraying angle with 0.792 desirability, which were considered as the optimal performance conditions of the electrodynamic spraying head. The results of laboratory validation for optimal conditions show that the uniformity of total spraying indicated by the total relative span factor (RSFT) and the percentage of spraying coverage (Cov) are equal to 1.65 and 28.27%, respectively.
Modeling
Z. Zibahoosh; J. Khodaei; S. Zareei
Abstract
IntroductionThe most costly part of poultry breeding is feeding. Due to the noticeable developments in animal husbandry and agricultural sectors, it is necessary to use the mechanized methods to reduce the casualties, increase the productivity as well as reduce the time and cost in each of these sectors. ...
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IntroductionThe most costly part of poultry breeding is feeding. Due to the noticeable developments in animal husbandry and agricultural sectors, it is necessary to use the mechanized methods to reduce the casualties, increase the productivity as well as reduce the time and cost in each of these sectors. Reducing the particle size is one of the ways to process cereals which improves the mixing and also the nutritional value of the feed and the quality of the pellet feed. Optimizing the performance of hammer mill with the aim of reducing the size of different materials for poultry feed, would be very beneficial for obtaining the minimum cost of food, maximum quality and capacity. The main objective of this research was to optimize the operational variables, including sieve size, grain moisture content, feed rate and the number of hammers, each of them at three levels, on a hammer mill during the process of poultry food production from wheat, corn, barley and soybean grains. Materials and MethodsThe seeds used in experiments were wheat (Azar2 variety), corn (Brazilian variety), soybean (Danpars variety) and barley (Aras variety). A laboratory hammer mill was used to perform experiments. The treatments including sieve diameter (2, 2.3and 4.4 mm), grain moisture content (10, 14 and 18%), seed input rate to milling compartments (one-third, two-thirds and fully openness of tank gate) and the number of hammer (12, 18 and 24) were investigated. In order to measure the working capacity of the hammer mill, the required time for milling was recorded. The amount of final milled crop in each experiment was weighed and divided into the needed time for milling. Sieve analysis was used to determine the distribution and dispersion of the milled material which works according to the standard of ASTM E-11-70 Part 41 (Anonymous, 2004). In this study, the effects of input variables were investigated using the response surface method focusing on the central composite design approach to optimize the fineness degree and working capacity of the mill. The Design Expert 8.0.6 software was applied for statistical analysis, modeling and optimization. Results and DiscussionThe results indicated that sieve size and the number of hammers have been affected by the fineness degree of wheat grains, significantly. In addition, all four factors and interaction effects between sieve size and moisture content and also moisture content and number of hammers influential working capacity at the significant level of 1%. In the case of corn, the influence of moisture content and its interaction with sieve size on grain fineness, and the effect of sieve size, moisture content, feed rate and interactions between sieve size and moisture content and moisture content and feed rate of working capacity were significant at the level of 1%. For barley, moisture content at the level of 1% and interaction between sieve size and moisture content at the probability level of 5% were effective on barley fineness degree. Meanwhile, the moisture content at the level of 1% and sieve size and its interaction with moisture content at the level of 5% influenced working capacity, significantly. Soybeans were not able to respond the required moisture level for the experiments due to their soft and brittle texture, whereas unreliable results were obtained by changing its moisture levels. The best size of sieve holes, grain moisture content, feed rate and the number of hammers were determined to minimize the fineness degree and maximize the working capacity of the hammer mill. ConclusionIn this research, the response surface method considering a central composite design was used to optimize the operational variables of a hammer mill, including sieve hole size, grain moisture, feed rate and the number of hammer to produce poultry feed with the aim of achieving a minimum fineness degree (more grain crushing) and maximum milling capacity. The results of variance analysis were presented for wheat, corn, barley and soybean. Regression models could represent the relationship between the independent variables and the outputs with high confidence coefficient, and the best values of input variables were determined to optimize grinding operation.
Modeling
M. Mehrijani; J. Khodaei; S. Zareei
Abstract
Introduction Tillage as a preliminary step for agricultural production consumes large amounts of energy. Regarding the energy crisis and the greenhouse gas emissions caused by the indiscriminate use of fossil fuels, many efforts have been done to reduce energy consumption as much as possible. About half ...
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Introduction Tillage as a preliminary step for agricultural production consumes large amounts of energy. Regarding the energy crisis and the greenhouse gas emissions caused by the indiscriminate use of fossil fuels, many efforts have been done to reduce energy consumption as much as possible. About half of the energy used in the crop production has been dedicated to tillage operations; hence the optimization of tillage tools performance can lead to decrease the energy loss. Tillage operation in most regions of Iran is carried out by moldboard plow. The ability of this plow in turning the soil has made it impressively different from the other plows. The energy used in tillage operations depends on various factors such as soil type and its conditions (soil moisture and texture), plow depth and forward speed. The aim of this study is to investigate the effect of forward speed, plow depth and soil moisture on fuel consumption and required tensile force during tillage operation with a moldboard plow which uses three plows in clay soil. Materials and Methods The current study was carried out to optimize the tillage operation with a moldboard plow in the clay soil. Tillage experiments were performed to evaluate the effect of forward speed, plow depth and soil moisture content on the required tensile force and tractor fuel consumption. A moldboard plow with three single-sided plows was used to conduct experiments. Two tractors (MF285 and U650) and a dynamometer were used to measure the required tensile force. To measure the fuel consumption of the tractor during operation, the fuel level was measured in a separate tank system installed on the tractor's fuel system. Experiments were carried out using response surface method and central composite design (CCD) by taking three levels of forward speed (4, 5 and 6 kmh-1), three plow depth (20, 25 and 30 cm) and three levels of soil moisture content (12, 16 and 20%). Design Expert 8.0.6 software was used to analyze the experimental data. Results and Discussion The result of the analysis of variance showed that the effects of plow depth, forward speed and soil moisture, as well as the interaction between forward speed and moisture content on the fuel consumption during tillage operations with moldboard plow are significant. The results also indicated that the increase in forward speed decreased the fuel consumption. Also, fuel consumption decreased with increasing in moisture content at first, but then increased. The reason for this was probably because of the increased strength of soil particles due to the reduced moisture content (the stronger coherence force between the particles), which required more energy to shear the soil. According to the results of analysis of variance, it can be concluded that all three factors of forward speed, plow depth and soil moisture had a significant effect on the required tensile force of moldboard plow at %1 probability level. With increasing the plow depth and forward speed, required tensile force increased significantly. The dependent variables were modeled as second order regression equations and optimal values of independent variables were determined. Optimum performance with maximum desirability was determined at forward speed of 5.08 kmh-1, plow depth of 20 cm and soil moisture content of 16.41%. Conclusion With increasing plow depth, tensile force and fuel consumption increased. Also, tensile force increased with increasing forward speed, but this increase was not severely affected by the plow depth and reduced the fuel consumption. The quadratic regression models can well predict the required tensile force and fuel consumption. Using response surface method, optimum performance was determined at forward speed of 5.08 kmh-1, plow depth of 20 cm and soil moisture content of 16.41%.
J. Khodaei; H. Samimi
Abstract
Kurdistan Rasa grape is one of the delicious and sweet fruits with black color. It contains vitamins E, C and some protectors such as antioxidants. In order to design equipments and facilities for drying, preservation and processing of Rasa grape, it is necessary and important to know about its specific ...
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Kurdistan Rasa grape is one of the delicious and sweet fruits with black color. It contains vitamins E, C and some protectors such as antioxidants. In order to design equipments and facilities for drying, preservation and processing of Rasa grape, it is necessary and important to know about its specific heat and thermal conductivity. In this paper the specific heat and thermal conductivity of Rasa grape were studied. The method of mixtures and hot wire as a heating source was used for measuring the specific heat and thermal conductivity, respectively. The experimental variables were temperature at four levels of 40, 50, 60 and 70 °C and moisture content at four levels of 22.36, 37.56, 52.13 and 71.53%. The results showed that the specific heat and thermal conductivity of Rasa grape increased linearly from 1.6523 kJ kg-1°C-1 to 3.3253 kJ kg-1°C-1 and 0.1252 W m-1°C-1 to 0.4202 W m-1°C-1 respectively, with increasing moisture content and temperature. The results also showed that the effect of moisture content on increasing the specific heat and thermal conductivity was more significant than that from temperature rise.
