مجله پژوهش های مکانیک ماشین های کشاورزی
سال نهم شماره 1 (بهار و تابستان 1399)

The use of diesel engines day by day increased because of their low fuel consumption and high performances. Common rail diesel engines with electronic fuel injection can accurately meter the fuel injection quantity and fuel injection pressure. Injection spray pressures in diesel engines play an important role for engine performance and emissions obtaining treatment of combustion. In this paper, effects of fuel injection pressure and spray cone angle on the exhaust emissions of a national diesel engine have been numerically investigated using a model verified by experimental data. In this study, four fuel injection pressures of 1000, 1400, 1600 and 1800 bar and three spray cone angle of 15, 25 and 35 degrees at 1400 bar injection pressure were investigated. The simulation results showed that by increasing the fuel injection pressure, the maximum pressure inside the combustion chamber increased from 144 to 162 bar and the temperature inside the combustion chamber increased by 8.2% and changed from 1607 to 1740 K. Subsequently, the amount of NOx produced also increased. But the amount of soot decreases with increasing fuel injection pressure due to better mixing of fuel and air. Changing the spray cone angle from 15 ° to 35 ° decreased the pressure inside the combustion chamber from 157 to 152 bar. One of the reasons for this decrease was the impact of fuel droplets against the walls of the combustion chamber at higher spray cone angles, this causes the fuel to not completely vaporize. An increase in the temperature of the combustion chamber was observed at a cone angle of 15 ° C relative to 35 ° C from 1654 to 1718 ° C. An increase in the temperature of the combustion chamber was observed at spray cone angle of 15 ° relative to 35 ° from 1654 to 1718 K.

In today’s modern world, in order to accelerate the work, it has been attempted to replace the human force with machines so that the jobs would not be dependent on certain people. Agriculture is no exception and today, image processing is used for mechanizing the methods and for replacing human beings with intelligent machines. One of the cases in which image processing is used is for identifying types of plants, their defects and the type of their diseases. The deficiencies of nutrients are one of a variety of physiological diseases of trees that its identification is very important. The common method for this is to review the leaf through human eyes, soil decomposition and laboratory methods, which needs experts and so much time and costs which makes it uneconomical. Thus, we have considered a method for solving this problem. In this study, few types of defect have been investigated. For this purpose, at first, the leaves were collected and their images were taken and after processing the image, leaf features were initially extracted and then, by using the chromatic features of each pixel of the leaf, their defects were identified. This method identifies the defects with an accuracy of 95%.

Loading and unloading of produced crop is one of the phases in traditional and semi mechanized agriculture in transporting it from farm to silo for selling it. Unfortunately, major part of transport and movement is done by man power, which in addition to high cost, excessive exhaustion of the workers viewed as its consequences. Pneumatic system is the best way of transportation with considered conditions. This system with low mass can transport granular materials without producing dust.The overall purpose of this research is design and manufacture of dilute-phase pneumatic conveying system for transporting corn seed and study of the effects of vertical pipe length (1, 2 and 3 m), speed of air supply (13, 17 and 20 m/s) and mass flow rate (200, 250 and 300 kg/hr) changes on pressure drop after transport. Machine's potency was acquired through empirical relationship. Transition pressure drop including air frictional pressure drop (ΔPL), corn accelerated pressure drop(ΔPA), corn frictional pressure drop(ΔPz*), corn suspension pressure drop (ΔPG) and total pressure drop of elbows (ΔPbend) are required to determine the required blower power. The total pressure drop carried out with summing up the individual contribution of air and solid by using theoretical equations which obtained 1265.60 Pa and required blower power was achieved 133.68 W. The experimental design was factorial based on completely randomized design with three replications. Analysis of variance (ANOVA) and mean comparisons and interaction between the parameters were performed using the SAS software. The results of the experiments showed that, by tripling the length of the vertical pipe, the pressure drop increased significantly (P≤0.01). Also, with increasing air velocity and mass flow rate, the pressure drop increased significantly (P≤0.01). It was also found that the increase of the pressure drop was directly related to the length of the pipe, and the length factor versus the speed factor was more effective in reducing the air pressure.

The aviculture industry is very important in terms of the protein requirements of the country. In this research, the energy efficiency and Greenhouse gas emissions of broiler chickens breeding centers in Kermanshah province was investigated. The total average input energy was 269242.84MJ, and the average total output energy was 30513.67 MJ Fuel (natural gas and gasoline) and feed with 46.82% and 28.36%, had the highest rate of energy consumption. The studied energy indexes were included in the energy ratio, energy efficiency, energy intensity, net energy added and respectively with 0.11, 0.01 kg /MJ, 48.16 MJ/kg, -1260369 MJ. To increase the energy efficiency index and the positive net energy value added, it is possible to reduce the amount of energy consumed by the correct management of high inputs and the use of renewable energies. Based on the obtained results using the Cobb-Douglas function, the coefficients of the inputs indicated that the stretch of the inputs include chicken, gas, manpower, corn, soybeans, minerals, fatty acid, calcium phosphate, water, and the disinfection was positive and smaller than one and their MP value was less than AP, so the use of these inputs by economic operators of poultry units of the region was economic and in the second area of production function were placed. The total emissions of greenhouse gases were equal to 2562.49 kg CO2eq, which the highest contribution was for fed with 37.12% and fuel and electricity 34.22 and 28.32 (kg CO2eq), respectively. The aviculture industry is very important in terms of the protein requirements of the country. In this research, the energy efficiency and Greenhouse gas emissions of broiler chickens breeding centers in Kermanshah province was investigated. The total average input energy was 269242.84MJ, and the average The aviculture industry is very important in terms of the protein requirements of the country. In this research, the energy efficiency and Greenhouse gas emissions of broiler chickens breeding centers in

One of the main issues in internal combustion engines is the reduction of the flow of air into the cylinder and, consequently, the reduction of engine efficiency. To solve this problem, the turbocharger can be used as a proper device in diesel engines to increase the efficiency and performance of the engine. The turbocharger is located in the direction of the exhaust gases to compress the air during the process and direct it into the cylinders to increase the volumetric efficiency as well as more complete combustion to reduce the exhaust emissions. The simultaneous use of turbochargers and intercooler in diesel engines reduces the temperature of the intake air into the cylinder and increases the volumetric efficiency. In order to investigate the effect of turbocharger and intercooler on the operation of the Ferguson 285 engine, a turbocharger with intercooler was used and installed on the engine, and then required tests carried out by hydraulic dynamometer in different speeds of 1000, 1500, 2000 and 2500 RPM at full load. The results showed that the engine torque at different speeds in the presence of turbocharger and intercooler increases by 27.22%. The results also indicated that the installation of turbocharger and Intercooler on a diesel tractor is meaningful in %1 level at speeds of 1500 until 2500 RPM in this engine, so that the presence of a turbocharger and intercooler in the range above 1500 increase the engine performance. Also, the difference in temperature between the intercooler input and output shows that during higher speeds, the temperature difference is higher than the lower speeds, which contributes to the increase and improvement of engine volumetric efficiency. Also, the difference in temperature between the intercooler input and output shows that during higher speeds, the temperature difference is higher than the lower speeds, which contributes to the increase and improvement of engine volumetric efficiency.

Precision Agriculture by managing in-farm variables and acquiring soil and product variable properties, mapping, analyzing variables, and accepting appropriate management practices lead to optimal use of inputs and increase performance with minimizing environmental effects. Therefore, in order to implement precision Agriculture, the first step is sufficient knowledge about the quantity of the yield. so, in this research, the pistachio yield monitoring system was designed and constructed and the machine performance was investigated in the laboratory tests. in this study the number of Connecting chains and height of the reservoir were selected as Variable factors. The number of chains at 3 levels (2, 3 and 4) and reservoir height at 3 levels (10, 20 and 30 cm) were investigated. The results showed that optimum values for the weighing of the product in the reservoir were not significant for the number of chains, so, in order to achieve better equilibrium in this study, four chains were used. Also, with the 20 cm height of the reservoir, the best results were obtained. The highest error value was 3.6%. After the laboratory tests, the system was transferred to the pistachio orchard and weight data were recorded associated with the location of each pistachio tree (by GPS). Among the methods of IDW interpolation, ordinary kriging, simple kriging, and general kriging, the ordinary Kriging method was introduced as the best method due to lower RMSE (1160.89). At the end, the yield map of the product was created by the usual Kriging method in the GIS software, which can be used along with other data as a prescriptive map for better management of the orchards. Among the methods of IDW interpolation, ordinary kriging, simple kriging, and general kriging, the ordinary Kriging method was introduced as the best method due to lower RMSE (1160.89). At the end, the yield map of the product was created by the usual Kriging method in the GIS software, which can be used along with other data as a prescriptive map for better management of the orchards.

Greenhouses should provide a controlled environment to produce plants with sufficient sunlight, temperature, and humidity. Better growth conditions in the greenhouses are mainly achieved by maintaining the optimum indoor temperature compared to the outdoor temperature of the greenhouse. The objective of this study is design, construction and evaluation of a fuzzy control system for a research greenhouse with capability of measuring, control and monitoring of greenhouse environmental conditions. Greenhouses control variables are air temperature, ambient relative humidity, light intensity, CO2 levels which are monitored and controlled by operators (heating system, cooling system, carbon dioxide regulation system, ventilation and humidity regulation system). In this study, hydroponic greenhouse was first designed and constructed. Heating and cooling equipment as well as needed sensors were installed. Then, a fuzzy control system was designed. Finally, by considering information on the appropriate environmental conditions of the hydroponic greenhouse of cucumber, the values of temperature, humidity, light and carbon dioxide are considered as fuzzy system inputs and the rules of the fuzzy system were adjusted so that the environmental conditions of the greenhouse were also fuzzy defined according to the input data. The results of the system evaluation showed that fuzzy control can well control the greenhouse environmental conditions.

Iran is the highest producer of pistachio worldwide and has an annual production of about 500,000 tons of fresh pistachio by-product. Due to its high organic and phenolic content as well as high solids concentration, pistachio processing wastes create significant waste management problems unless they are properly managed. Anaerobic digestion is one of the acceptable environmental and economic technologies to control the pistachio wastes and produce energy and enrich fertilizer for soil. Good digestion for different wastes needs suitable mixture for co-substrates and pretreatments. Therefore, effect of different mixture of pistachio waste: cow manure and pretreatment factors of NaOH and H2O2 was studied in this research. Co-digestion was done in the 250 mL digesters for mesophilic condition using a combined D-optimal design. Their CH4 production were measured for 24 days. Then a model was developed among the CH4 production and amounts of pistachio waste, cow manure, NaOH and H2O2 to determine the effects of these parameters on the CH4 production. Model P-value was lower than 0.0001 and its lack of fit was 0.27, predicted R2 was 0.53 in reasonable agreement with adjusted R2 of 0.63. Adequate precision was 9.7 indicated an adequate signal for the model. Further, standard error of the model equaled to 0.4 which was very low, model R2 equaled to 0.69 and adjusted R2 was 0.63 which were high, indicating that the model was suitable for CH4 estimation. By illustrating the model in 3D graphs, it was shown that the use of NaOH had negative effect on the CH4 production while H2O2 had positive effect on the CH4 production. Higher amounts of cow manure improved the CH4 production while higher amounts of pistachio wastes decreased the CH4 production. These may happen because of the high amounts of phenolic and antioxidant compounds in the pistachio waste which are harmful for anaerobic microbes.

Many citrus fruits, such as tangerines in the country, are abandoned in orchards every year due to their low prices, causing great damage to the gardeners. On the other hand, the supply of homogeny product in terms of the amount ripeness, to the market, will be welcomed by the consumer and will stimulate the market for product sales. Tangerine has different varieties that in this research, Unshiu variety of Tangerine has been studied and image processing and artificial neural networks (ANN) were used for classification of tangerines into three degrees of ripe, half - ripe and unripe. 120 Tangerine fruit samples that graded by Expert Grading person, were selected And then their images were obtained using an imaging system. After taking pictures of tangerines, pre - processing operations, Segmentation operations and Classification of images were done and Images' attributes transferred to different color channels Specified such as RGB, HSV, YCbCr and CMY and the statistical characteristics of the images were extracted. Average of second component of YCbCr color space, standard deviation of third component of YCbCr color space, standard deviation of third component of CMY color space, average of first component of HSV color space, average of third component of HSV color space and standard deviation of second component of HSV color space were selected as input of proposed system. In total 6 × 4 Characteristics were extracted from each sample. Overall, the percentage of the correct classification of the three classes was 97.22 %. The results of this study indicated that the proposed system is capable to detect tangerines ripe, half - ripe and unripe carefully fit it had. Therefore, it can be concluded that modern methods such as image processing and artificial intelligence are used to classify tangerines.

Several methods have been proposed to determine the engineering properties of agricultural products based on empirical knowledge or statistical relationships between properties. Therefore, the purpose of this study was to construct a system to measure stress and forces applied to sour orange as well as to design a graphical interface to quickly measure mechanical properties (Elasticity module, stress and Poisson's ratio in x, y and z directions) during loading using image processing. The effective contact area of the compressed fruit was determined by image analysis and compared in x, y and z directions using three webcams with other methods (capsule, fix volume, ASABE and bounding-box). According to the results, the contact area in ASABE method at 6% strain with 7% error had no significant difference with the image processing method. According to the results, the contact area in ASABE method at 6% strain with 7% error had no significant difference with the image processing method. The Poisson's ratio and the strength of the samples increased and decreased in the strain steps, respectively. The Poisson's ratio and the strength of the samples increased and decreased in the strain steps, respectively. There was no significant difference between ASABE and image processing methods in Ex and Ey at strain of 3% and 6%, respectively. There was no significant difference between ASABE and image processing methods in Ex and Ey at strain of 3% and 6%, respectively. In addition, there was no significant difference in Ez at 3% strain between capsule, image processing, and bounding-box methods. Moreover, there was no significant difference in the amount of stress at 3% strain between capsule, image processing, ASABE and bounding-box methods. Moreover, there was no significant difference in the amount of stress at 3% strain between capsule, image processing, ASABE and bounding-box methods. Among the mentioned methods, the ASABE method with the lowest error at 6% strain was the most appropriate method in comparison with image processing.

In recent years, the role of robotics technology in the management of poultry conditions and the welfare of livestock has led to increase of production rate and reduce of production costs. The purpose of this research was to construct a robot to measure and plot the distribution of temperature, humidity, ammonia and oxygen parameters in the poultry house, and to apply the commands necessary to optimize the poultry conditions in different parts of the building. For this purpose, an experiment was carried out using 700 laying hens for 20 days from age of 20 days. The robot made in this study includes 3 hardware components, a set of sensors (ammonia, carbon dioxide, temperature and humidity), data storage unit, displays, mechanical components (wheels, gearboxes and chassis) and the software sector. The robot made in this study includes 3 hardware components, a set of sensors (ammonia, carbon dioxide, temperature and humidity), data storage unit, displays, mechanical components (wheels, gearboxes and chassis) and the software sector. The robot made in this study includes 3 hardware components, a set of sensors (ammonia, carbon dioxide, temperature and humidity), data storage unit, displays, mechanical components (wheels, gearboxes and chassis) and the software sector.In order to control the local environment of each cage, due to the variability of the amount of excrement, birds activity, and also the remoteness and proximity to poultry conditioning, a control circuit was constructed to optimize the conditions of each cage. By calculating the directional error, the angular difference between the orientation of the path and the actual orientation of the robot, the speed of the motors was adjusted automatically. The amount of robotic deviation from the predetermined path in the direct path and bypass was calculated and the mean error of the robot in the seven points examined was 1.34 and 4.5 cm, respectively. In addition, according to the distribution diagrams, the parameters of temperature, humidity, ammonia and oxygen were determined and the required action was taken.

Production and use of biogas, as an alternative renewable fuel, along with increasing energy security, can reduce the use of fossil fuels and thus reduce the environmental impact of these fossil fuels. Biogas production is subject to certain conditions and is influenced by some parameters such as pH, Hydraulic Retention Time (HRT), Solid Retention Time (SRT), temperature, agitation and so on. The existence of a laboratory digester to control and identify the best conditions of these effective parameters is of great importance. Therefore, three types of anaerobic digester, were built to digest liquid wastes, considering the advantages and disadvantages of various digesters, factors affecting biogas production and also considering the cost issues. In these digesters, it was possible to control the parameters affecting biogas production (temperature, pH, concentration and retention time) and were also equipped with a system to measure the amount of gas produced. These digests were batch type and the feasibility of experimental designs to study the effect of parameters affecting biogas production was predicted. Batch digests are more suitable than continuous ones to study raw materials that require longer retention time, such as lignocellulosic biomass. Due to the transparent body of these digesters, it was also possible to study optical treatments. The most important and difficult part of the construction was the possibility of sealing the joints. Glass digester, if properly sealed, is the best one and meets almost all requirements for testing the factors affecting biogas production. Its main problem is the possibility of air leakage and liquid penetration into the mixer electromotor. Due to the flexibility of polyethylene digesters, it is easy to extract air and provide an anaerobic environment. The disadvantage was the requirement of manual or magnetic mixing and a possible error in measuring the volume of gas produced. Use of the Erlen vacuum, rubber cap, needle and heparin locker were appropriately meet the requirements of an anaerobic digester, but steel mixing in the digester is done manually or by magnetic stirring.