مجله پژوهش های مکانیک ماشین های کشاورزی
سال هشتم شماره 1 (بهار و تابستان 1398)

One of the steps in potato harvesting is to separate potato from clod and stone that cannot be entirely done by the harvester machines based on the friction and vibration and must be completed by labors. In the present study, image processing technique was used to detect the potato tubers and separate them from clod and stone. Four hundred potato, 100 stone and 100 clod specimens were randomly selected. After selecting the optimum imaging condition, the image of all specimens was individually acquired. An image processing algorithm was designed for preprocessing and extracting different color and texture features in MATLAB. From the features extracted, nine useful features were selected for classification. To classify the specimens, the support vector machine was used by considering two strategies: 3-way (potato, clod and stone) and 2-way (potato and non-potato). The correct classification rate of 3-way and 2-way strategies was obtained 98.67 and 99 %, respectively with the same mean square error (0.0017). According to this result, a machine vision system can be implemented for separating potato from clod and stone.

Site-specific spraying is a new method to weed exclusion. For this reason, a machine vision system is suggested in this study based on video processing and meta-heuristic classifier for online identification of potato plant and two types of weeds PortulacaOleracea, and Xanthium strumarium. In order to train the suggested machine vision system, 5 hectares of lands of Marfona potato in Kermanshah province were selected for filming. After extracting some features in fields of color features and spectral descriptors of texture using two methods of hybrid artificial neural network - ant colony (ANN-ACO) and hybrid artificial neural network - Particle swarm optimization (ANN-PSO), the effective features were selected. Finally, by analyzing the results of selected features set by each of the two mentioned methods, the selected features were selected using method of artificial ANN-PSO in order to use in machine vision system. Selected features were color index for vegetation cover in YCbCr color space, the extra second component index in HSV color space, the first and second component contrast in HSV color space, the mean of first component in HSI color space and the mean of S(r). The results of classification showed that method of hybrid artificial neural network - Differential Evolution (ANN-DE) with high accuracy of 99% is able to identify potato plant and two different types of weeds.

In this study, changes in the mechanical and rheological properties of potato (Agria) were assessed by examining the elastic and viscoelastic characteristics. Mechanical and rheological parameters were examinated by uniaxial compression and creep tests during six months storage. According to the results, curve fitting procedure of third-degree polynomial on the load-displacement in the compress test (R2 = 0.98) and Burger's model on the response of creep test (R2 = 0.99) was well done. During storage, the modulus of elasticity (10.47 %), maximum failure force, toughness and retardation time decreased. Also, Initial and retarded compliance has followed an increasing trend during storage (13.33 % and 10 %, respectively). The rest of the parameters obtained did not show a certain continuous process.

Peach, being one of the most important Iranian horticultural products, produce a considerable amount of post-harvest wastes. Product processing is one of the ways to reduce waste. For many years, the use of ultrasound has been considered as a novel pre-treatment in the drying of food. The purpose of this study was to investigate the effect of high-power ultrasound pre-treatment on the drying of peach and its quality. For this purpose, the ultrasound treatment (70 Watts and 28 kHz) was performed for 10, 20 and 60 minutes at two different temperatures of 65 and 105 C. The results showed that the application of ultrasound, as a pre-treatment before drying, decreases the drying time. In addition, it reduced the force required for shear and compression of the samples with no negative effect on the color of the samples. Furthermore, it was shown that the use of ultrasonic waves in drying of peach slices will reduce costs and energy consumption and increase the product quality.

Forest machinery is one of the sources of danger in forest logging. Considering the ergonomic factors of these machines plays an important role in reducing occupational injuries. In this study, the ergonomic factors of primary wood transportation machines in Hyrcanian forests including Timberjack 450C and HSM 904 were evaluated. In order to evaluate, some of the indicators of ergonomic and European safety guidelines for forestry machines were used. These indicators include: sound level, cabin access, driver's seat, cabin ventilation, which were selected based on the potential interface with the risks involved in the operation. Based on the results, the duration of exposure to the sound level for Timberjack 450C and HSM 904 was calculated to be 4 and 5 hours per shift, respectively, which was less than standard rate. Also, in the cabin access 120 and 62 negative points, in driver's seat 170 and 41 points and in the cabin ventilation 101 and 71 negative points were scored, respectively. The HSM 904 had a more ergonomic standard in all of the indicators. By making some changes, such as increasing the number of stairs, cabin insulating, replacing the air filter by on right time, can improve the ergonomic condition and reduce the risk and potential damage.

Energy survey is always a critical stage of the management in the process engineering facilities. As the first and crucial step toward technical, thermo engineering and economic improvement and optimization of sugar production process, energy audit is conducted experimentally and analytically in the evaporation line of Urmia sugar factory. To yield such a purpose, based on the thermodynamic analysis and measurements, the share of each equipment in energy and exergy loss is precisely determined. Moreover, detail parameters have been monitored in the different surfaces of each equipment. Thermography method is applied to study the insulation condition and heat loss level. Maximum energy and exergy loss is assigned to top view surfaces. Lateral surfaces dissipated much energy compared to bottom view surfaces. Results show that the heat loss is occurred mostly through radiation transfer by 67 % and the rest is experienced by convection transfer as 33 %. Total thermal power dissipation of the evaporation line to the medium is estimated to be 186.03 kW which is calculated on the basis of heat convection coefficient and heat radiation. Results prove that the dominant heat loss is respectively related to first evaporator, the second and third shell and tube heat exchangers. Furthermore, the maximum exergy loss is occurred in pre heating section, where more than half of the total exergy loss belongs to shell and tube heat exchangers. Accumulated exergy through the evaporation line is estimated to be 30.86 kW stating the energy effectiveness gap of the whole system comprising subsystems such as individual evaporators or heat exchangers. The research results would be implemented in the future management decisions on sugar production cost reduction. The research methodology and obtained technical details can be used in the future investigations on sustainable development policies in governmental section.

The economic importance of wheat and its contribution to the diets of humans and livestock cannot be disputed. Wheat is grown in most parts of the world, from near-arctic to near-equatorial latitudes. It is the most important crop among the cereals by area planted and is followed in importance by corn, barley and sorghum. The amount of wheat traded internationally exceeds that of all other grains. Furthermore, the protein and caloric content of wheat is greater than that of any other food crop. Most wheat is consumed in the form of baked goods, mainly bread; therefore, wheat grains must be milled to produce flour prior to consumption. Wheat is also used as an ingredient in compound feedstuffs, starch production and as a feed stock in ethanol production. The wheat flour is produced during the mechanized process at the factory. Therefore, increasing the productivity of this mechanized process is most important. The maintenance unit is one of the best opportunities to increase productivity of a mechanized system. For many systems, the category of human resources is considered to be the most important system capital, which has a significant impact on system performance. Since, The manpower productivity of the Shoale flour factory during the last ten years was evaluated taking into account the reliability of the system. The results indicated that the winnower and mill of flour factory included 44.59% and 55.41% of total failures, respectively. The results indicated that the spiral (22.7%), feeder (16.8%) and elevator (11.2%) caused the majority of recorded failures in winnower parts. Furthermore, the roller mill (21.9%), spiral (11.8%) and sieve (9.8%) parts of mill were more prone to failure than the rest. The manpower efficiency and factory equipment failure rate showed a positive relationship as well as there is a positive relationship between the manpower effectiveness and the factory equipment reliability.

This study was carried out to evaluate the energy efficiency of safflower production units using data envelopment analysis technique in Jolgeh district of Isfahan province in 2016. Data were collected from a total of 30 safflower farms using questionnaires and face to face interviews. The results showed that the input and output energy were 30843.1 and 6775.71 megajol/ha, respectively. The highest share of energy consumption was allocated to chemical fertilizers (48.18%), fuel (24.55%) and water (12.44%) respectively. The average technical efficiency, net technical efficiency and efficiency of Safflower product scale were 94.28%, 99.93% and 94.33%, respectively. According to the CCR model, the highest intakes of excessive intake units are related to the inputs of chemical fertilizers, especially urea (58%), diesel fuel (18%), water (12%) and seed consumption (8%). Fuels with 49% and then urea fertilizer with 35% have the largest share in the emissions of greenhouse gases in the production of safflower (Figure 4-16). Therefore, using managed mechanized systems, it is necessary to control the use of machinery to reduce fuel consumption and to reduce the consumption of urea crop by replacing livestock fertilizers in order to reduce the pollution caused by greenhouse gas emissions and pollution of the water resources of the area.This study was carried out to evaluate the energy efficiency of safflower production units using data envelopment analysis technique in Jolgeh district of Isfahan province in 2016. Data were collected from a total of 30 safflower farms using questionnaires and face to face interviews. The results showed that the input and output energy were 30843.1 and 6775.71 megajol/ha, respectively. The highest share of energy consumption was allocated to chemical fertilizers (48.18%), fuel (24.55%) and water (12.44%) respectively. The average technical efficiency, net technical efficiency and efficiency of Safflower product scale were 94.28%, 99.93% and 94.33%, respectively. According to the CCR model, the highest intakes of excessive intake units are related to the inputs of chemical fertilizers, especially urea (58%), diesel fuel (18%), water (12%) and seed consumption (8%). Fuels with 49% and then urea fertilizer with 35% have the largest share in the emissions of greenhouse gases in the production of safflower (Figure 4-16). Therefore, using managed mechanized systems, it is necessary to control the use of machinery to reduce fuel consumption and to reduce the consumption of urea crop by replacing livestock fertilizers in order to reduce the pollution caused by greenhouse gas emissions and pollution of the water resources of the area.

Due to the importance of the use of reduced tillage systems to reduce energy crops, an experiment was conducted as completely randomized block design with 6 treatment and 3 replications in 2011-2012 growing season in the khuzestan province. Treatments includeing conventional tillage using moldboard plow, conventional tillage without using moldboard plow, reduced tillage, no-tillage with 100% crop residue retained, no-tillage with 60% crop residue retained, no-tillage without crop residue retained. In this research, fuel consumption, time of any operation and total time of tillage and planting wheat, tillage and planting energy, emergence of wheat, weed density, the number of ears per square meter, operation of biological and wheat grain yield, harvest index, the weight of one thousand seeds, inpout energy, outpout energy, net energy, productivity energy, specific energy and effeciency energy are measured. The results show that the maximum and the minimum amounts of fuel were obtained in traditional culture treatment (93.67 L/ha) and in no-tillage treatment (14.57 L/ha), respectively. The maximum and minimum of efficiency energy is in reduced tillage (2.53%) and conventional tillage using moldboard plow (2.27%) treatments, respectively, and also the maximum and minimum of energy intensity is in conventional tillage using moldboard plow and reduced tillage treatments, respectively.Totally, the most expensive (12 million Rial/ha) and highest revenue generating (27.4 million Rial/ha) is obtained in conventional tillage using moldboard plow treatment than other treatments.Totally, the most expensive (12 million Rial/ha) and highest revenue generating (27.4 million Rial/ha) is obtained in conventional tillage using moldboard plow treatment than other treatments.Totally, the most expensive (12 million Rial/ha) and highest revenue generating (27.4 million Rial/ha) is obtained in conventional tillage using moldboard plow treatment than other treatments.Totally, the most expensive (12 million Rial/ha) and highest revenue generating (27.4 million Rial/ha) is obtained in conventional tillage using moldboard plow treatment than other treatments.Totally, the most expensive (12 million Rial/ha) and highest revenue generating (27.4 million Rial/ha) is obtained in conventional tillage using moldboard plow treatment than other treatments.

Sugarcane with 110,000 hectares is one of the most important agricultural-industrial products in the country. Currently, a significant part of the sugarcane production process, such as cuttings, planting and harvesting, is done manually. Musculoskeletal complications are among the most commonly occurring complications in cane and other traditional agricultural environments. Among the various problem found in agriculture mentioned above, a problem commonly reported in agricultural workers in particular farmers in a rural area is work-musculoskeletal symptoms (MSS) in a different part of a body. A low level of knowledge about the correct condition of the body during work is one of the problems of farmers. Therefore, body status assessment methods are considered as the basis and basis for assessing the risk of musculoskeletal disorders associated with work. The aim of this study was to determine the prevalence of musculoskeletal disorders and risk assessment in the organs of sugarcane production workers in Khuzestan province. This cross-sectional study was carried out on 300 workers during the 2018-2019 crop year. The RULA method was used to determine the prevalence of musculoskeletal disorders and to assess the risk of these disorders. Data analysis was performed by Ergo Intelligence-UEA software. According to the RULA method, the cuttings, planting and harvesting were 28.69%, 20.56%, and 52.34% of workers' postures, respectively, in the most critical group. The need for ergonomic interventions in the RULA method is felt in sugarcane fields. A high percentage of musculoskeletal disorders in workplaces occur due to awkward posture and non-ergonomic design of the work stations for lifting and carrying of materials. To avoid these injuries, jobs should be designed in a way that ergonomics risk factors are controlled properly. These interventions primarily involve changing the production process from manual to mechanized, and further changing the work postures by considering access to work and proposing the right tools for doing work.

The cultivation of greenhouse crops is an advance in agricultural production technology that is increasing from temperate to warmer regions. However, greenhouse protects crops in a bad weather condition, but high temperature and humidity in the tropics have a converse effect on a production of crops. Therefore, in these regions, it is necessary to reduce the temperature inside the greenhouse. Since the design of the cooling system is highly dependent on environmental conditions, it is difficult to develop an appropriate system that provides local climate conditions for product growth. Therefore, in this research, the performance of fan-pad cooling system was studied in different climatic conditions. For this purpose, the greenhouse environment was first modeled using TRNSYS software. After verifying the model with experimental results, the system's ability to cool the greenhouse and system performance was evaluated relative to the parameters of air velocity, temperature and humidity ratio. The results showed that in ambient conditions with dry bubble temperature and humidity ratio less than 40˚C and 0.015 kg/kg, direct evaporative cooling system (fan-pad) at an air velocity of 1.25 m/s was a suitable method for cooling the greenhouse and provides suitable conditions for product growth. The cultivation of greenhouse crops is an advance in agricultural production technology that is increasing from temperate to warmer regions. However, greenhouse protects crops in a bad weather condition, but high temperature and humidity in the tropics have a converse effect on a production of crops. Therefore, in these regions, it is necessary to reduce the temperature inside the greenhouse. Since the design of the cooling system is highly dependent on environmental conditions, it is difficult to develop an appropriate system that provides local climate conditions for product growth. Therefore, in this research, the performance of fan-pad cooling system was studied in different climatic conditions. For this purpose, the greenhouse environment was first modeled using TRNSYS software. After verifying the model with experimental results, the system's ability to cool the greenhouse and system performance was evaluated relative to the parameters of air velocity, temperature and humidity ratio. The results showed that in ambient conditions with dry bubble temperature and humidity ratio less than 40˚C and 0.015 kg/kg, direct evaporative cooling system (fan-pad) at an air velocity of 1.25 m/s was a suitable method for cooling the greenhouse and provides suitable conditions for product growth. Also, the results showed that in the case of moisture content greater than 0.015 kg/kg, the evaporative cooling system alone could not cool the greenhouse.

The manual harvesting of chickpea is costly and tedious. Therefore, in this study a chickpea harvesting header was designed, constructed, and evaluated. This header has long stripper fingers and with forward movement of header, pods continuously jammed between the fingers and were separated from bushes. The following four points were considered in designing of header: geometry of fingers, angle of fingers to the horizontal surface (A), fingers length (L) and distance between fingers (S). In field evaluations, the effect of fingers angle (15°, 20° and 25°) and fingers distance (7 mm and 10 mm) on losses due to remained pods on bushes (Lp) and losses due to spilled pods on the ground (Lf) were evaluated. Furthermore, by measuring total losses (LT = Lf + Lp) in different configuration of header, the best combination of fingers’ angle and fingers’ distance was determined. The results demonstrated that, the effect of increasing the fingers angle and fingers distance on both types of Lp losses and LF losses was significant (P<1%) and incremental. However, the effect of the fingers angle (A) was greater on LF losses and the effect of the fingers distance (S) was higher on Lp losses. The lowest amounts in total losses (LT) (P< 0.05) were 57.4% and 24.7% in layouts of headers of number 1 (S =7mm and A=15°) and number 2 (S =7mm and A=20°), respectively. The manual harvesting of chickpea is costly and tedious. Therefore, in this study a chickpea harvesting header was designed, constructed, and evaluated. This header has long stripper fingers and with forward movement of header, pods continuously jammed between the fingers and were separated from bushes. The following four points were considered in designing of header: geometry of fingers, angle of fingers to the horizontal surface (A), fingers length (L) and distance between fingers (S). In field evaluations, the effect of fingers angle (15°, 20° and 25°) and fingers distance (7 mm and 10 mm) on losses due to remained pods on bushes (Lp) and losses due to spilled pods on the ground (Lf) were evaluated. Furthermore, by measuring total losses (LT = Lf + Lp) in different configuration of header, the best combination of fingers’ angle and fingers’ distance was determined. The results demonstrated that, the effect of increasing the fingers angle and fingers distance on both types of Lp losses and LF losses was significant (P<1%) and incremental. However, the effect of the fingers angle (A) was greater on LF losses and the effect of the fingers distance (S) was higher on Lp losses. The lowest amounts in total losses (LT) (P< 0.05) were 57.4% and 24.7% in layouts of headers of number 1 (S =7mm and A=15°) and number 2 (S =7mm and A=20°), respectively.