فهرست مطالب m. h. aghkhani

On the field and in the paddy milling factory dryer losses have always been challenging issues in the rice industry. Different forms of losses in brown rice may occur depending on the field and factory conditions. To reduce the losses, proper management during pre-harvest, harvesting, and post-harvest operations is essential. In this study, different on-field drying and tempering methods were investigated to detect different forms of brown rice losses.

The present study was conducted on the most common Hashemi paddy variety during the 2019-2020 season in Talesh, Rezvanshahr, and Masal cities in the Guilan province, Iran with 0.2 hectares and 5 paddy milling factory dryers. On the fields, the method and date of tillage, irrigation, and transplanting used in all experimental units were the same. Moreover, the same amount of fertilizer and similar spraying methods were used across all experiments. For the pre-drying process on the fields, the following three pre-drying methods were applied on the harvest day: A1) The paddies were spread on the cut stems for insolating, A2) The paddies were stacked and stored after being placed on the cut stems for 5h, and A3) The paddies were covered with plastic wrap and stored after 5h of insolating. The first method (A1) is the most common in the area and was chosen as the control treatment. For the second step of the process, the time interval between the on-field pre-drying and threshing was considered: B1) 14 to 19h post-harvest; B2) 20 to 24h post-harvest, and B3) 25 to 29h post-harvest. Afterward, methods A1 to A3 were combined with methods B1 to B3 and feed into an axial flow-thresher at 10 kg min-1, 550 rpm PTO, and two levels of moisture content at 19 and 26 percent (% w.b). The third process was two-stage or three-stage tempering for 10 or 15 hours resulting in four levels (C1 to C4) and was done in the conventional batch type dryer under temperatures of 40 and 50 ˚C and airspeeds of 0.5 and 0.8 m s-1 in paddy milling factories. At the end of each process, a 100g sample was oven-dried for 48h and a microscope achromatic objective 40x was used to detect incomplete horizontal or vertical cracks, tortoise pattern cracks, and immature and chalky grains. The equilibrium moisture content was determined to be 7.3 percent. Losses properties were analyzed using a completely randomized factorial design with a randomized block followed by Tukey's HSD test at the 5% probability and comparisons among the three replications were made.

Results demonstrated that the stack and plastic drying methods significantly increased the percentage of losses. In the plastic drying method, the percentage of chalky grains and tortoise pattern cracks was higher than other forms of loss. In the first process, irrespective of the pre-drying method, the losses were reduced at a lower level of moisture content. At the end of the first stage, losses in the spreading method were significantly lower at 19% moisture content. Threshing the plastic-wrapped paddies after 14 to 19 hours at 19% moisture content resulted in the maximum threshing loss of 8.446% and over half of the grains were chalky or had tortoise pattern cracks. The threshing loss was halved (4.443%) for paddies threshed 25 to 29h after spreading at a moisture content of 26%. The mean of losses in the second step of the process were 7.229, 5.585, and 5.156% for the time interval between the on-field pre-drying and threshing of 14 to 19h, 20 to 24h, and 25 to 29h, respectively. In the last step of the process in paddy milling factory dryers, there was no significant difference in the minimum percent of losses between 10 and 15 hours of three-stage tempering at 40 °C and with 0.5 m s-1 airspeed. Furthermore, maximum total losses with the most incomplete horizontal and vertical cracks occurred in the two-stage 10h tempering at 50 °C and with 0.5 and 0.8 m s-1 airspeed.

Food security has always been a critical matter in developing countries. Furthermore, identifying the source of losses in the fields and the factories is one way to reduce losses and achieve food security. Stacking or wrapping the paddies in plastic after pre-drying on the fields for 5h is not recommended in terms of its effect on increasing the percentage of brown rice losses. Additionally, due to the importance of factory dryer scheduling in the management of the losses, it is recommended to use a three-stage 10h tempering at 40 °C and with 0.5 m s-1 airspeed.

Robots have been used for material handling for many years, and their applications have greatly expanded with the integration of intelligent technologies. While numerous researchers have proposed various robots for this field, it is crucial to design customized configurations that are suitable for agricultural farms. However, research in our country has been limited to a few mobile agricultural robots. The main focus of this paper is to design and model workspaces and analyze the kinematics of manipulators in agricultural settings.

This article investigates the workspace and kinematics of a robot manipulator to design and manufacture a four-DOF manipulator for farming. This manipulator will be capable of performing a variety of tasks, but the goal of this project is to enable it to load and unload materials and products on the farm as an auxiliary force for the farmer.
When designing and analyzing a manipulator, the first step is to determine the specific task that the robotic arm will perform. For example, consider a scenario where the task involves loading or unloading forage packages from a trailer at a designated location. This task specification forms the basis for further design and analysis, ensuring that the manipulator is appropriately designed to meet the requirements of the task.
An intelligent robotic arm that is attached to a tractor can perform this operation in the shortest possible time without the intervention of human workers. Otherwise, a large number of laborers would be required to move boxes weighing 10 kg over distances of 3 to 4 meters and heights of 1 to 2 meters, which would require a great deal of torque.
At this stage, the design of the arm kinematics model, direct kinematic equations, velocity kinematics, and Jacobian matrix solving were performed. The calculations were carried out using two methods manual calculation and kinematic modeling in MATLAB software for three arm configurations in two simulation tests. The results of both methods were compared.
The workspace analysis of the selected manipulator configurations, as well as the use of arm kinematic performance evaluation indices, were illustrated in graphs.

The issue of moving forage packages on the farm is described below. If a farmer were to move 48 packages of fodder weighing about 10 kg manually (using human workers) in the workspace modeled in Figure 10, each package would take an average of 30 seconds to be moved reciprocally along an unobstructed path. Hence, it would take approximately 24 minutes to move all the packages. However, the linear speed of the final operator of the robot arm during the first test was found to be 1 meter per second, which is 3.7 times faster than the manual work scenario, and the total movement of the packages can be completed in about 6.5 minutes.
Upon analyzing the velocity diagrams of the final performer in both tests, it becomes evident that there is not much variation in speed and acceleration due to the change in configurations. The evaluation of robot workspace indicators was conducted using two methods workspace index and structural length index. These indicators were calculated for all three configurations, and the results indicated that Configuration Type 1 was the most suitable option. Furthermore, the manipulability index of the robot arm was assessed based on the obtained diagrams for all three configurations in the two tests. It was observed that Configuration Type 1 outperformed the other two types in terms of score, indicating its superior performance. This aligns with the suggestion made by Yoshigawa for the first three joints of the Puma robot.
Overall, the results suggest that Configuration Type 1 is one of the most favorable options, ensuring better performance for the final performer.

One of the main considerations when using robots in agriculture is the appropriate kinematic design of joints and links for work operations. Using the example of robots assisting with moving products on the ground, it can be seen that using robots significantly reduces the time required compared to manual labor. Furthermore, in terms of energy consumption and cost within a certain period, the use of robots has economic justification.
Based on the studies conducted, Configuration Type 1 passed the kinematic path in both tests with a higher manipulability index and a more suitable workspace index based on both calculated criteria. Therefore, this configuration is recommended for the design of robots for the operation of moving products on the ground.

Pistachio production has been adversely affected by Psylla, which is a devastating insect. The primary goal of this study was to select sensitive spectral bands to distinguish pistachio leaves infected by Psylla from healthy leaves. Diagnosis of psylla disease before the onset of visual cues is crucial for making decisions about topical garden management. Since it is not possible to diagnose psylla disease even after the onset of symptoms with the help of color images by drones, hyperspectral and multispectral sensors are needed. The main purpose of this study was to extract spectral bands suitable for distinguishing healthy leaves from psylla leaves. For this purpose, in this paper, a new method for selecting sensitive spectral properties from hyperspectral data with the high spectral resolution is presented. The intelligent selection of sensitive bands is a convenient way to build multispectral sensors for a specific application (in this article, the diagnosis of psylla leaves). Knowledge of disease-sensitive wavelengths can also help researchers analyze multispectral and hyperspectral aerial images captured by satellites or drones.

A total number of 160 healthy and diseased leaves were scanned in 64 spectral bands between 400-1100 nm with 10 nm spectral resolution. A random forest algorithm was used to identify the importance of features in classifying the dataset into diseased and healthy leaves. After computing the importance of the features, a clustering algorithm was developed to cluster the most important features into six clusters such that the center of clusters was 50 nm apart. To transfer the hyperspectral dataset into a multispectral dataset, the reflectance was averaged in spectral bands within ±15 nm of each cluster center and achieved six broad multispectral bands. Afterwards a support vector machine algorithm was utilized to classify the diseased and healthy leaves using both hyperspectral and multispectral datasets.

The center of clusters were 468 nm, 598 nm, 710 nm, 791 nm, 858 nm, and 1023 nm, which were calculated by taking the average of all the members assigned to the individual clusters. These are the most informative spectral bands to distinguish the pistachio leaves infected by Psylla from the healthy leaves. The F1-score was 90.91 when the hyperspectral dataset (all bands) was used, while the F1-score was 88.69 for the multispectral dataset. The subtle difference between the F1-scores indicates that the proposed pipeline in this study was able to select appropriately the sensitive bands while retaining all relevant information.

The importance of spectral bands in the visible and near-infrared region (between 400 and 1100 nm) was obtained to identify pistachio tree leaves infected with psylla disease. Based on the importance of spectral properties and using a clustering algorithm, six wavelengths were obtained as the best wavelengths for classifying healthy and diseased pistachio leaves. Then, by averaging the wavelengths at a distance of 15 nm from these six centers, the hyperspectral data (64 bands) became multispectral (6 bands). Since the correlation between the wavelengths in the near-infrared region was very high (more than 95%), out of the three selected wavelengths in the near-infrared region (710, 791, and 1023), only the 710-nm wavelength, which was closer to the visible region, was selected. The results of classification of infected and diseased leaves using hyperspectral and multispectral data showed that the degree of classification accuracy decreases by about 2% and if only 4 bands are used, the degree of accuracy decreases by about 3%.The results of this study revealed that the proposed framework could be used for selecting the most informative spectral bands and accordingly develop custom-designed multispectral sensors for disease detection in pistachio. In addition, we could reduce the dimensionality of the hyperspectral datasets and avoid the issues related to the curse of dimensionalitylity.

Today, maximizing the efficiency of fuels and increasing the output power of diesel engines is considered inevitable due to the increasing need for energy resources, the reduction of fossil fuel resources, the need to maintain the environment, reduce air pollution, and limit the electricity supply and fuel supply. In the large cities of Iran, the problem of vehicle pollution is one of the main problems. The lack of proper fuel, soot filters, and absence of requirement for a technical inspection of diesel vehicles have led to an increase in mortality and the growth of lung cancer due to pollution. All of studies indicate that fossil fuels, despite the low cost of production, will increase the cost of both living and environment. A solution for this crisis is to reduce the sources of pollutant-producing sources from the source of these pollutants. In the internal combustion engines, the compression ratio and alternative fuels are two important factors affecting engine performance and exhaust emission.

In this research, a one-dimensional computational fluid dynamics solution with GT-Power software was used to simulate a six-cylinder diesel engine to study the performance and exhaust emissions with different compression ratios and alternative fuels. The compression ratio was chosen to be 15:1 to 19:1 with an interval at unity. Alternative fuels such as (as base diesel), methanol, ethanol, diesel and ethanol, biodiesel and decane were selected. To modeling engine, first, all parts of the engine were introduced as a real six-cylinder engine, and then the required data were entered according to the actual engine conditions at the atmospheric pressure of one atmosphere. Before this investigation was carried out, a validation model for evaluation was done by experimental and simulation data. The validation results showed that software model error is acceptable and the model has a good capability of fitting and predicting.

The engine performance was evaluated in terms of engine power, engine torque, and specific fuel consumption at different engine compression ratio and fuel. The results showed that with increasing the compression ratio, brake power and brake torque increased. Among the fuels used in this engine, the maximum brake power and brake torque in the compression ratio of 19 with the decane fuel were 3.86% higher than that the base fuel and the lowest value was awarded in the compression ratio of 15, with methanol fuel and it was equal with 56.04%. The results indicated that by increasing compression ratio, the brake specific fuel consumption was reduced due to more power than the fuel consumed in the engine. A fuel with lower heating value should be injected more mass to the engine. This will increase the brake specific fuel consumption. In this research, the decane fuel with a compression ratio of 19 with a reduction of 3.72% had the lowest brake specific fuel consumption among other fuels. The CO emission from the engine largely depended on the fuel's properties, the availability of oxygen, the fuel mix with air, temperature, and turbulence inside the combustion chamber. The results highlighted that by increasing compression ratio, CO emission increased and CO emission in biodiesel fuel, with a compression ratio of 15, was decreased by 82.37% compared to the base. CO2 emissions are not too harmful to humans, but they increase the potential for ozone depletion and global warming. With increasing compression ratio, CO2 and HC emissions increased for all fuels, CO2 emissions have risen up the base. The fuel heating mechanism, combustion temperature, oxygen content, and gas fuel availability are the most important factors in the formation of NOx. With increasing the compression ratio, the amount of NOX increases, which is due to the high temperature in the cylinder at a higher compression ratio. The viscosity and density of fuels have an effect on NOX emission, and because of the larger droplets of the fuel, it released NOX. The highest NOx emissions from biodiesel fuel are due to the high oxygen content of this fuel and the lowest NOx emissions from decane fuel, due to the low density of the fuel compared to other fuels.

The results of this study showed that the decane fuel with a compression ratio of 19 in total had the best functional and pollutant characteristics among the six fuel used in this study. Therefore, this fuel can be the best alternative for diesel fuel.

The eggshell of birds, as a natural shield and package, protects the tissues inside it from microbial and mechanical damages. Proper intake of calcium, as an important and effective factor in increasing the strength and quality of the eggshell, could reduce complications. In this paper, the effect of dietary calcium at five different levels on engineering features of Japanese quail eggs in a in their first laying period was investigated. The values for an average of mass, volume, specific mass, shell thickness, major diameter, central diameter and rupture force along the longitudinal and transverse axes were measured. Rupture energy or toughness, slope of the rupture curve (hardness), deformation along the longitudinal and transverse axis to the point of rupture as well as longitudinal and transverse deformation of 450 tested quail eggs (3 period of time, 5 treatment of calcium, 5 replication, 6 observation) were measured. The characters of the specific mass, shell thickness, rupture force, and slope of the rupture curve of quail eggs indicate the strength of quail egg. In this study, variations in all parameters indicating shell strength at different levels of dietary calcium were consistent with each other. Five different treatments with 1.5%, 2%, 2.5%, 3%, and 3.5% calcium content were supplied for the study. By increasing the calcium content of the quail diet from 1.5 to 3 wt%, the volume and weight of quail eggs dropped and shell thickness was reinforced. According to the results, the shell strength of quail eggs along the transverse axis was slightly less than the longitudinal axis, but the flexibility and energy required for quail egg rupture were much greater across the longitudinal axis.

This study aimed to compare the effects of practices of protective agriculture and conventional methods of farming on soil compaction and the amount of plant residues. The experiments included 9 treatments based on split plot design in a randomized complete block with three replications in Mashhad Agricultural Research Station of Torogh, Iran. The treatments were consisted of three different tillage practices at three levels (1- conventional tillage, 2- reduced tillage, 3- No-tillage) and crop residue management at three levels (1- without residue, 2- retains 30% residue, 3- preserved remains 60%). Some physical parameters of soil such as cone index, bulk density, mean weight diameter and aggregate soil moisture content were measured in this study. The results showed that the effect of various tillage methods on all of the studied indices was significant. The effect of management methods on plant residues were also significant on cone index and moisture content of the soil. The effect of interaction of two factors on cone index for some depths of the soil and soil moisture content was significant.

The tissue of fruit varies at different stages of growth and storage and by determining its characteristics; the stage of fruit maturity can be found. Depending on the type of tissue, the ultrasonic waves will attenuate and its speed will change too while crossing the fruit tissue. Thus, by calculating the attenuation coefficient value and its speed in no destructive way, the characteristics of fruit tissue and the rate of its maturity will be determined. In this study, peach fruits -the Tabrizi variety- were classified in ripen, semi-ripen, large and small groups and the validity of ripen and semi-ripen groups were confirmed by taste panel. Then, in addition to measuring the attenuation coefficient and velocity of ultrasonic wave parameters, the physic-chemical parameters of fruit, including dimensions, mass, density, hardness, reducing sugar, acidity, pH, dry weight and soluble solids contents, which are the maturity indices of peach, were measured and compared with ultrasonic parameters. Results showed that fruit size and degree of maturity significantly affect on the wave attenuation and wave velocity, respectively. The correlation coefficients between attenuation coefficient and hardness (without skin) in ripen and semi ripen groups were higher than 0.8 and also the correlation coefficients of attenuation coefficient in relation with the hardness (by skin) in ripen and semi ripen groups were higher than 0.7. Also, the correlations for both attenuation coefficient and wave velocity in relation with the pH were higher than 0.8 as well as correlation between wave velocity and acidity.

The assessment of ripeness is a major part of quality evaluation and depends on several factors such as soluble solid content (SSC), acidity and firmness. Most of the methods THAT measure these qualities are destructive. So it is essential to develop an efficient and nondestructive method for measuring internal attributes of fruit. The objective of this study was to investigate visible and near infrared (Vis/NIR) spectroscopy method for prediction of SSC and pH of kiwi fruit. Near infrared spectroscopy is a fast and a nondestructive analytical technique. One of the main advantages of NIR spectroscopy is that IT allows several constituents to be measured at the same time. Transmittance determinations in the 400-1000 nm range were carried out on samples which WERE separated randomly into two groups: first group for making calibration models and second one for quality predictions. Different data preprocessing and spectra treatments such as standard normal variate transformation (SNV), multiplicative scatter correction (MSC), median filter and derivative were used to eliminate noise. Then calibration models were developed by using principal component analysis (PCA) and partial least squares (PLS). Performance of different models was assessed in terms of root mean square errors of prediction (RMSEP) and correlation coefficient (r) between the predicted and measured parameter values. The correlation coefficient and root mean square errors of prediction to soluble solids content and pH were 0.93, 0.952 and 0.259˚Brix, 0.236, respectively. The results indicated the feasibility of Vis/NIR transmittance spectral analysis to predict SSC and pH of kiwi fruit in a nondestructive way.

Annual medics seed have woody spiral pods that need to be threshed before planting. This can be done during harvesting. In order to design the harvester system, pod cutting force has to be determined. The required force for cutting the pods of two species of annual medics (M. scutellata, M. rigidula) was determined by conducting an experimental design. Independent variables were pods moisture, cutting speed and cutting direction of pod. In order to support the samples in tension-compression testing machine head, a special clamp was designed and developed. Results of statistical analysis of the data indicated that in most of the conditions, cutting force for M. scutellata increases with increasing moisture content. Cutting force had a significant relation with the direction of application and was lower when applied perpendicular to the pod axis as compared with the parallel condition. Increasing the cutting speed from 0.16 mm/s to higher speeds (10 or 100 mm/s) decreased the cutting force for the M. scutellata species. Cutting energy determined based on the area under the force- deformation curve, was used in calculation of power requirement for the threshing system of the annual medics seed combine harvester.