Research Article
Design and Construction
M. Tohri; D. Ghanbarian; O. Taki; M. Ghasemi-Varnamkhasti
Abstract
IntroductionIn recent years due to lack of water resources in our country, planting of bare root seedlings of onion has been welcomed by farmers. Considering the desired high dense planting of Iranian farmers, lack of proper transplanting machine has appeared as the main problem. To overcome this problem, ...
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IntroductionIn recent years due to lack of water resources in our country, planting of bare root seedlings of onion has been welcomed by farmers. Considering the desired high dense planting of Iranian farmers, lack of proper transplanting machine has appeared as the main problem. To overcome this problem, some researchers tested a few methods, but none of them reached to complete successfully. As the one of last efforts, Taki and Asadi (2012) developed a semi-automatic transplanting machine with 9 planting units. This machine requires to 9 men to separate and single out a bunch of seedlings. Usage of this machine is very time-consuming and labor intensive. In Iran, transplanting of bare root seedlings is practically performed by hand with a density of 700-800 thousand plants at hectare. The main purpose of this study was designed, manufacture, and evaluation of an automatic metering device that with the separation and singulars of bare root seedlings of onion could get a high density planting.Materials and MethodsFig. 1 shows the main employed idea of this research for separation and single out a bunch of seedlings.As shown in Fig. 1, the metering device consisted of two carrying and separating belts with different teeth forms. Placing seedling bunches between the two belts, the belts move at different speeds in opposite directions and separate seedlings from their bunch.For proper design of metering device system, measurement of some physical properties were necessary. The obtained information was used to select two belts form. A belt with flexible plastic teethes with a height of 6 mm and the distance of 4mm was selected as separator while for carrier, two types of belts were selected: the first was the same as a separator and the second was made of metal teethes. Based on the average thickness of seedling bunch and some pre-tests, the horizontal angle of separator belt determined as α=20 degrees. Theoretical calculations were done to computatingof the needed force of the system. In this section, seedlings were modeled as some solid cylinders with a length of 200 and a diameter of 10 mm. In the mentioned system, it was necessary that the speed of separator belt is more than the speed of carrier belt. Thus, ratio of two linear velocities ( ) of 1.67 and 2.32 were considered for evaluation of the system. For evaluation of manufactured metering device, the effects of three factors, i.e., carrier belt type, ratio of linear velocities of the belts, and number of seedlings in a bunch (n = 30 and n =60), on qualitative planting parameters were studied in a factorial experiment based on completely randomized design with three replications. The studied qualitative planting parameters were miss index, consumed seedlings, miss length, quality of feed index, multiple index, mean, and damaged seedlings.Results and DiscussionThe results of analysis of variance showed that, except of belt type, effects of the two studied factors and all interactions are statistically non-significant on consumed seedlings and miss length indexes. The results indicated significant differences between miss index (P<0.01), multiple index (P<0.05), and mean (P<0.05) as affected by belt type. None of the studied variable had a significant effect on damaged seedlings. Interactions of belt type and ratio of linear velocities significantly affected the quality of feed index (P < 0.01). An increase in ratio of linear velocities in plastic toothed belt lead to decrease of mean and miss indexes, whereas in case of metal toothed belt there is no significant effect on this two indexes. The results also showed that increase of linear velocities for the two types of carrier belt lead to increase of consumed seedlings and decrease of miss length. At the two ratios of linear velocities, miss length in metal toothed is less than plastic toothed belt. ConclusionsCommercial transplanting machines are not suitable for dense planting of onion. In this research an automatic metering device for separation and singularize of bare root seedlings of onion was manufactured and evaluated. The results indicated that the carrier belt with long and rigid teeth, having an angle of attack, could separate seedlings more efficiently. The results also showed a 80 percent increased in uniformity of plant seedlings distances is reachable using the metering system.
Research Article
Design and Construction
A. Mondani; S. H. Karparvarfard
Abstract
IntroductionMaximum efficiency of natural resources, reduced risk of production, improved fertility of soil, and increased production per area enjoyment have made intercropping a preferential practice compared with cropping. One of the fundamental problems in this kind of cropping is non-existence of ...
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IntroductionMaximum efficiency of natural resources, reduced risk of production, improved fertility of soil, and increased production per area enjoyment have made intercropping a preferential practice compared with cropping. One of the fundamental problems in this kind of cropping is non-existence of suitable machines. In this research, a new intercropping machine has been designed and built for intercropping of corn and bean with precise ratios and different planting patterns. Materials and MethodsThe experiments were conducted at the Badjgah Research Station, Shiraz University, located in NW Shiraz, Iran. The soil texture was clay loam (16% sand, 48% silt, and 35% clay). The plot size was 9 m wide and 12 m long. The total number of the plots were 9. The basic components of intercropping machine were an adjustable frame to adjust row spacing for each unit planter about 550 mm horizontally independently (the row spacing between corn and bean planting lines was considered 375 mm), a hinged frame for adjustment of seeding depth and possible poor emergence of plants due to very deep or shallow planting, metering case frames for installing the vacuum metering disk units around which the seed drums have a row of 36 holes of 4.5 and 5.5 mm diameter for corn and bean, respectively, seed delivery tubes, a suction fan, shovel openers used for bedder planting for corn and lister planting for bean, a knife covering attachment, seed-firming wheels, interchangeable gears which are mechanical chain drives for 43 varying seeding rates driven by carrying wheel drives, two metal seed hoppers whose lower side walls’ slope can be adjust at a maximum level of 45 . A front wheel assist, Massey Ferguson tractor (MF-399) (ITM, Tabriz, Iran) with a maximum engine power of 81 kW was used for field test of intercropping machine. Moldboard plow was used for primary tillage and the depth of plowing was 25 cm. Next, by an offset disk harrow, the field was disked twice for pulverizing lumps, mulching the surface and firming the underneath soil to provide a smooth uniform seedbed. In this study, the common bean seed (var. Derakhshan) and corn hybrid seed (SC-704) with 93 and 83 percent of germination and 97 and 98 percent of purity, respectively, were used. This machine was operated in five different distance patterns between corn and bean seeds on each row: 55 mm and 215 mm in the first pattern, 85 mm and 185 mm in the second pattern, 110 mm and 150 mm in the third pattern, 130 mm and 120 mm in the fourth pattern, and 160 mm and 100 mm in the fifth pattern for corn and bean, respectively. For all patterns, the depth of planting for corn and bean seeds was chosen as 20, 40, and 60 mm. In addition, the forward speed was assumed to be constant (4 km h-1). By using split plots with three replicates and SAS software (2002), the results were analyzed. Results and DiscussionThe multiple index, miss index, precision index, and quality of feed index was evaluated. The analysis of variance for bean planting unit showed that difference distance between seeds and various planting depth were significantly higher for multiple index (P< 0.01), but their interactions were not significant (P 0.05). Also, with decreasing the seeds distances, the multiple index was increased (P< 0.05). Moreover, comparing the results of the average multiple index in different levels of planting depth indicated that the multiple index was decreased when at higher depths of planting (P< 0.05). The seeds distance and planting depth were significantly higher for miss index and quality of feed index (P< 0.01), but their interactions were not significant for either index (P> 0.05). The precision index was significant was affected by different levels of seeds distance (P< 0.05) and was higher for different levels of seeds planting depths (P< 0.01), but their interactions were not significant. In corn planting unit, the results showed that the different distances between seeds and planting depths were significantly higher for multiple index, miss index, quality of feed index, and precision index (P< 0.01). Also their interactions were significant for multiple index (P< 0.05), but the other indices showed no significant interactions (P> 0.05). ConclusionsThe data suggested a higher quality index once corn and bean were respectively plated at 160 and 215 mm seed distance with a planting depth of 60 mm being optimum for each corn and bean.
Research Article
Design and Construction
I. Eskandari; N. Sartipi
Abstract
IntroductionResearchers frequently include multiple cultivars and fertility levels in field experiments. Therefore, the experiments sowing operation must represent a considerable saving in time and labor, compared to hand sowing. Greater flexibility in experimental design and setup could be achieved ...
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IntroductionResearchers frequently include multiple cultivars and fertility levels in field experiments. Therefore, the experiments sowing operation must represent a considerable saving in time and labor, compared to hand sowing. Greater flexibility in experimental design and setup could be achieved by equipment that enables quick changes in the cultivar and fertilizer rates from one plot to the next. A satisfactory seed drill must distribute a given quantity of seed evenly over a predetermined length of coulter row, the coulters must be spaced at exact intervals and depth of sowing must be uniform. In a self-propelled type of plot seeder, no coulter should run in a wheel track as the compaction of the soil can cause observable differences in vigor between plants in such a row and those in un-compacted rows. The machine should sow in succession from a try in which a series of seed pocket separated clearly and must be put into distributer funnel by an assistant operator. The length of gap being varied according to the nature and purpose of the plot.The objectives of this experiment were 1- to design and construct a local self-propelled plot seeder and 2- To compare it with the imported (Wintersteiger) plot seeder in cereal breeding programs.Materials and MethodsA small-plot seeder was designed and constructed to meet this objective. The unit consists of the following basic components: a toolbar for pulling a set of six blade coulter, an air compressor for lifting and putting down the openers and metering transmission drive wheel, an operators chair and work rack, one belt seed distribution. A cone-celled and rotor seed distributor is used for seed distribution to the openers. The cone system is connected to the gearbox and allows for great flexibility in changing cultivars, crop species, and plot length. This is driven by the separate drive wheel. The cone-celled distributor sows all the seed of the sample in making one complete turn. The spinner can be equipped with a 4 or 6 outlet delivery head, depending on row spacing. The planter is fitted with hoe openers. Alternatively, spear-point openers have sometimes been used under conventional tillage systems. Seeding depth control was achieved by an adjustment screw handle. The plot seeder is being moved by a 9.6 kW engine, and has been successfully used in applications. Field experiment established by using 4 plot length (2, 3, 4 and 6) with 4 replication by the constructed plot seeder and imported plot seeder. Crop measurements were planted height, spike m-2, seeds/spike, Thousand kernel weight, Biological and grain yield, harvest index and drill measurements were seeding depth, uniformity of row spacing in action, seed counter performance, power requirement, slippage evenly of rows after planting.Results and DiscussionResults showed that there were significant differences between the plant emergences. The emergencies were higher in plots, which planted by the new plot seeder. The differences between seed distribution of openers were insignificant, but the variances of new plot seeder and imported plot seeder were 0.267 and 1.05 respectively. Mean planting depth of plots planted by the Wintersteiger plot seeder was 0.8 cm shallower than the adjusted planting depth while mean planting depth in plots planted by constructing machine had only 0.01 cm variation.Results of variance analysis revealed that effect of treatments on wheat grain yield and yield components was significant. So that, highest grain yield (4216 kgha-1), biological yield (8704 kgha-1), number of spikes per square meter (649spike), obtained from a plot which planted by constructed plot seeder. Increasing yield of treatments which planted by constructed plot seeder might be because of increasing the number of spikes per square meter in those treatments. The mean of spike per square meter in plots of new planter was 691 spikes which were116 spike more than plots planted by imported plot seeder.ConclusionsThe constructed plot seeder had up to 18500$ cost reduction. The seeder was able to distribute the different type of seed to the seed tubes uniformly in laboratory tests, nevertheless it is necessary to test the constructed plot seeder in field condition by using different seed type and conducting new research project. Advantages of this planter include less variation of seed fall down in different coulters, perfect planting depth control, separate wheel for adjusting planting length, minimize the slippage of planter driven wheel and proper utility in different field condition. According to effects on crop parameters the constructed plot seeder had relative priority to imported one. In addition easily accessories supply and cheaper prime cost are profit of the designed and constructed plot seeder.
Research Article
Design and Construction
M. A. Rostami
Abstract
IntroductionNowadays, in a lot of farm land due to reasons such as high density, heavy textured soils, steep terrain and a large body of water at each irrigation, rapid and complete absorption of water in the soil does not happen and runoff will be accrued. Improvement of infiltration reduces runoff ...
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IntroductionNowadays, in a lot of farm land due to reasons such as high density, heavy textured soils, steep terrain and a large body of water at each irrigation, rapid and complete absorption of water in the soil does not happen and runoff will be accrued. Improvement of infiltration reduces runoff and thus increases available water capacity. The main methods used to increase the infiltration area: The use of soil amendments, soil management by tillage and conservation farming. These methods may be used separately or together. Reservoir tillage is the process by which small holes or depressions are punched in the soil to prevent runoff of water from irrigation or rainfall. The objective of this study was to develop and evaluate a new reservoir tillage machine for runoff control in the fields. Materials and MethodsFabricated machine has four main units include three-point hitch, toolbar, frame and tillage unit. Tillage unit was a spider wheel with 6 arms that has 6 Wedge-shaped blades, mounted on them. Each tillage unit mounted on a frame and the frame is attached to the toolbar with a yoke. The toolbar was attached to the tractor by three-point hitch. The movement of tractor caused blades impact soil and spider wheel was rotating. Spider wheel rotation speed was depended on the forward speed of the tractor. Blades were created mini-reservoirs on the soil surface for "In situ" irrigation water or rainwater harvesting. Theoretically distance between basins, created by reservoir tillage machine, fabricated in this study was 57 and 68 cm for Arm's length of 30 and 40 cm respectively.For the construction of machine, first the plan was drawn with SolidWorks software and then the parts of the machine were built based on technical drawings. First tillage unit was constructed and its shaft was based in two bearings. Six of the arms were positioned at 60 degrees from each other around tillage units and connected by welding. For evaluation of machine performance, two factors contain of machine speed (in three levels of 5, 7.5 and 10 km h-1) and Arm's length (in two levels of 30 and 40 cm) were evaluated. The machine was evaluated based on a completely randomized block factorial design with three replications. Effects of these factors on depth, distance and volume of basins and runoff were evaluated. Results and DiscussionMean comparisons of depth, distance and size of reservoirs in different machine forward speed and different Arm's length are summarized in Table 1 and 2. The results showed that the effect of arm length and forward speed on changes in the depth and volume of the reservoirs were significant at the probability level of one percent but changes of the distance between the reservoirs was only affected by Arm's length. The results also showed that increasing the forward speed from 5 to 10 km h-1 and increase the Arm's length from 30 to 40 cm increased depth, distance and volume of reservoirs. Reservoir tillage practices were control runoff in all plots.ConclusionsIn this research project, a reservoir tillage machine was built and assessed. Tillage unit of this machine is similar to the spider wheel. By this machine the small holes generated in the ground periodically. For evaluation of machine performance, effect of two factors, including machine speed and arm's length on depth, distance and volume of the basins were evaluated. The results showed that increasing the ground speed from 5 to 10 km h-1 and increase the arm's length from 30 to 40 cm increased depth, distance and volume of reservoirs. Reservoir tillage practices were controlled runoff in all plots.
Research Article
Design and Construction
M. Zamani; M. Aboonajmi; S. R. Hassan Beigi Bidgoli
Abstract
IntroductionOne of the ways used for minimizing the cost of maintenance and repairs of rotating industrial equipment is condition monitoring using acoustic analysis. One of the most important problems which always have been under consideration in industrial equipment application is confidence possibility. ...
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IntroductionOne of the ways used for minimizing the cost of maintenance and repairs of rotating industrial equipment is condition monitoring using acoustic analysis. One of the most important problems which always have been under consideration in industrial equipment application is confidence possibility. Each dynamic, electrical, hydraulic or thermal system has certain characteristics which show the normal condition of the machine during function. Any changes of the characteristics can be a signal of a problem in the machine. The aim of condition monitoring is system condition determination using measurements of the signals of characteristics and using this information for system impairment prognostication. There are a lot of ways for condition monitoring of different systems, but sound analysis is accepted and used extensively as a method for condition investigation of rotating machines. The aim of this research is the design and construction of considered gearbox and using of obtaining data in frequency and time spectrum in order to analyze the sound and diagnosis.Materials and MethodsThis research was conducted at the department of mechanical biosystem workshop at Aboureihan College at Tehran University in February 15th.2015. In this research, in order to investigate the trend of diagnosis and gearbox condition, a system was designed and then constructed. The sound of correct and damaged gearbox was investigated by audiometer and stored in computer for data analysis. Sound measurement was done in three pinions speed of 749, 1050 and 1496 rpm and for correct gearboxes, damage of the fracture of a tooth and a tooth wear.Gearbox design and construction: In order to conduct the research, a gearbox with simple gearwheels was designed according to current needs. Then mentioned gearbox and its accessories were modeled in CATIA V5-R20 software and then the system was constructed.Gearbox is a machine that is used for mechanical power transition from a productive source of power to a consumer, for torque meeting and for rotating speed needed for the consumer. In fact, gearbox is an interfere between power source and power consumer which produces a flexible communication between power source and power consumer. Needing to a gearbox as a machine which can generate harmony as an interface is unavoidable due to lack of harmony of torque and rotating speed of production source of power. So necessary calculations in order to attain to technical characteristics of gearwheels, bearings, shaft dimensions and other accessories of gearbox were done. This gearbox is from kinds of simple gearwheel which its input and output shaft are parallel to each other. Main accessories of gearbox are: 1.crust 2.shaft 3.gearwheel 4.thorn 5.bearing 6.cover. All of the design parameters were calculated and considered in designing of all of the accessories of gearbox.Electromotor rotating calibration: For this aim, a light-contact telemeter in model of Lutron was used as contact.Acoustic module of electro motor: A module was constructed in order to prevent from sound waves interaction resulting from an electromotor function with waves of gearbox function. Three layers of sound absorbent including common felt with 1mm width, polyethylene foam with 15 mm width and shoulder foam egg with 35 mm width were used for the module insulation. Material used for the body of this module was MDF. Based on field measurement, level of electromotor sound decrement using the acoustic module was 20dB. Investigated malfunctions in this research are relevant to gearwheel with one tooth fracture, one worn tooth and one tooth fracture and other worn tooth.Collection and storage of acoustic data: In this research, an audiometer in model of HT-157 made in Italy in order to obtain acoustic data and a laptop with a model of Lenovo-G550 for data storage and processing was used. Cool Edit Pro 2.0 software was used for data processing. Data storage was in PCM format and MATLAB R2014a software used for data processing.Data processing: Signal processing method in the frequency domain is used in order to reveal the defects. Fast Fourier Transform: Fast Fourier Transform FFT for application in electronic equipment specially analyzers have great importance. In this condition, sampling number is chosen exponentially as 2N which decreases the calculation volume significantly. Determination of defect kind of gearwheel using frequency spectrum analysis: In mentioned gearwheel, errors were generated synthetically. Defect kind of these errors was generated in separate gearwheels in order to investigate the defects more precisely and a gearwheel was considered as control gearwheel. Despite of this, the sound of all of the gearwheels in correct condition was stored. Results and DiscussionComparison of processed acoustic signals from gearwheels of gearbox in two correct and incorrect conditions was indicative of gearwheel involvement, frequency, their harmony and the changes resulted from defects. Gearwheel defect detection tests showed that at the speeds of 1496, 1050 and 749 rpm, investigated defects are recognizable with a comparison of the frequency spectrum of obtained signals in correct and incorrect conditions and according to the involvement frequency of gearwheel, its harmony and sided spectrum. Results of the frequency spectrum of signal analysis in speed of 1496 rpm pinion showed the defect of one tooth fracture in involvement frequency of gearwheels by 489, 350 and 249 Hz respectively which became apparent with a mentioned frequency domain increment. A worn tooth defect in a gearwheel was completely determinable as sided bands with equal distance around gearwheel involvement frequency in the signal frequency determination of the speeds of 1496 and 105 rpm pinion, but became a bit harder in less speeds. Investigation of frequency spectrum of acoustic signal resulted from gearwheel, is indicative of the ability of this method in gearbox condition investigation with high precision and minimum time. So the gearbox condition investigation is reached by investigation of the frequency spectrum of acoustic signal resulted from gearwheel.ConclusionsIn current research, acquisitive signals resulted from produced sound waves of constructed gearwheel were used for investigation and diagnosis. Recorded signal in time domain and processed frequency and exploited characteristics of signal in frequency domain for diagnosis were analyzed. Obtained results of this research can be summarized as follow:1. Precision level in the diagnosis decreased by increasing in pinion speed.2. There will be a decrement in gearwheel diagnosis after defects integration and signal behavior won’t be completely similar to the defect as individual. 3. Proper placement of audiometer is effective in diagnosis trend.4. In frequency spectrum of obtained signals, particle velocity level is more efficient in diagnosis than the sound pressure level.
Research Article
S. F. Mousavi; M. H. Abbaspour-Fard; M. H. Aghkhani; E. Ebrahimi; A. Soheili Mehdizadeh
Abstract
Introduction
The diagnosis of agricultural machinery faults must be performed at an opportune time, in order to fulfill the agricultural operations in a timely manner and to optimize the accuracy and the integrity of a system, proper monitoring and fault diagnosis of the rotating parts is required. ...
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Introduction
The diagnosis of agricultural machinery faults must be performed at an opportune time, in order to fulfill the agricultural operations in a timely manner and to optimize the accuracy and the integrity of a system, proper monitoring and fault diagnosis of the rotating parts is required. With development of fault diagnosis methods of rotating equipment, especially bearing failure, the security, performance and availability of machines has been increasing. In general, fault detection is conducted through a specific procedure which starts with data acquisition and continues with features extraction, and subsequently failure of the machine would be detected. Several practical methods have been introduced for fault detection in rotating parts of machineries. The review of the literature shows that both Artificial Neural Networks (ANN) and Support Vector Machines (SVM) have been used for this purpose. However, the results show that SVM is more effective than Artificial Neural Networks in fault detection of such machineries. In some smart detection systems, incorporating an optimized method such as Genetic Algorithm in the Neural Network model, could improve the fault detection procedure. Consequently, the fault detection performance of neural networks may also be improved by combining with the Genetic Algorithm and hence will be comparable with the performance of the Support Vector Machine. In this study, the so called Genetic Algorithm (GA) method was used to optimize the structure of the Artificial Neural Networks (ANN) for fault detection of the clutch retainer mechanism of Massey Ferguson 285 tractor.
Materials and Methods
The test rig consists of some electro mechanical parts including the clutch retainer mechanism of Massey Ferguson 285 tractor, a supporting shaft, a single-phase electric motor, a loading mechanism to model the load of the tractor clutch and the corresponding power train gears. The data acquisition section consists of a data analyzer (PCA-40), a personal computer, a piezoelectric accelerometer (VMI-102, DT-2234B), a tachometer and two rubber vibration absorbing elements are located between the rig’s components and the plate holder. An evaluation function was employed in order to achieve the optimal structure of neural network models by selecting the number of layers, number of cells in the layers, transfer function, training function, learning functions, performance function, and number of epochs, in such a way that the MSE of the calculated output error was minimal. The data were collected by means of the accelerometer sensor attached on the clutch mechanism, with three different working conditions (normal condition, with worn bearing, and with worn shaft), and three rotational speeds including: 1000 rpm, 1500 rpm and 2000 rpm. The Wavelet Packet Transform (WPT) was applied on the data-set for features vector extraction and the principle component analyses (PCA) was applied for dimension reduction of the features vector. The signal processing and the features extraction are the most important characteristics of the monitoring methodology, by which the working condition of the machine can be determined. These characteristics may be acquired by transforming the signals from the time domain to the frequency domain and MATLAB software is used for this purpose. This software receives the vibration data (time series of output voltage) which are in Excel files format. To remove the noise a suitable filtering procedure was used and finally the statistical parameters of time - frequency were calculated.
Results and Discussion
To verify the accuracy of the Genetic Algorithm model, the required data were collected from the training and testing steps of the Neural Network. For this purpose, the statistical parameters such as mean squared error (MSE), mean absolute error (MAE) and correlation coefficient (r) were used. The optimal parameters of the neural network obtained for the family of Db4. A trial and error procedure was used to minimize the mean square error of the network output and the desired amount of training step. During the training step, four neural networks including Db4, Db30, Db35 and Db40 achieved a gradient descent weight in the learning bias and four neural networks including Db9, Db15, Db20 and Db25 achieved a gradient descent with momentum weight in the learning bias. The two of the achieved neural networks including Db4, Db20 have circular logarithm function and the remaining networks have annular hyperbolic tangent transfer function. The most appropriate networks configuration was acquired when the network exhibited the minimal error with the training and testing data sets. The results show that the highest accuracy of the GA-ANN Artificial neural networks for all rotational speeds (1000, 1500 and 2000 rpm), and working conditions (intact gear and shaft, damaged bearing and worn shaft) observed for the network family of Db4. The highest error observed for the family of Db20 with MSE of 0.011.
Conclusions
Artificial neural networks can somewhat think and make decisions similar to an expert person. In this project in order to predict the occurrence of a failure of the clutch mechanism of MF 285 tractor, the experimental data were obtained using some sensors, and the data were transferred to a computer by means of a data analytical. By training of the neural networks, the errors were identified separately. The output data from the combined Neural Network and Genetic Algorithm shows that the performance of the prediction model is enhanced. Based on the experiments and calculations, the best data set belongs to the family of Db4 network with the least MSE equal to 4.09E-07 and r equal to 0.99999, indicating that the model could precisely detect the faulty bearings or shafts.
Research Article
Modeling
A. R. Tahavvor; Sh. Heidari; P. Zarrinchang
Abstract
IntroductionAutomation of agricultural and machinery construction has generally been enhanced by intelligent control systems due to utility and efficiency rising, ease of use, profitability and upgrading according to market demand. A broad variety of industrial merchandise are now supplied with computerized ...
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IntroductionAutomation of agricultural and machinery construction has generally been enhanced by intelligent control systems due to utility and efficiency rising, ease of use, profitability and upgrading according to market demand. A broad variety of industrial merchandise are now supplied with computerized control systems of earth moving processes to be performed by construction and agriculture field vehicle such as grader, backhoe, tractor and scraper machines. A height control machine which is used in measuring base thickness is consisted of two mechanical and electronic parts. The mechanical part is consisted of conveyor belt, main body, electrical engine and invertors while the electronic part is consisted of ultrasonic, wave transmitter and receiver sensor, electronic board, control set, and microcontroller. The main job of these controlling devices consists of the topographic surveying, cutting and filling of elevated and spotted low area, and these actions fundamentally dependent onthe machine's ability in elevation and thickness measurement and control. In this study, machine was first tested and then some experiments were conducted for data collection. Study of system modeling in artificial neural networks (ANN) was done for measuring, controlling the height for bases by input variable input vectors such as sampling time, probe speed, conveyer speed, sound wave speed and speed sensor are finally the maximum and minimum probe output vector on various conditions. The result reveals the capability of this procedure for experimental recognition of sensors' behavior and improvement of field machine control systems. Inspection, calibration and response, diagnosis of the elevation control system in combination with machine function can also be evaluated by some extra development of this system.Materials and MethodsDesigning and manufacture of the planned apparatus classified in three dissimilar, mechanical and electronic module, courses of action. The mechanical parts were computer-generated by engineering software in assembled, exploded and standard two-dimensional drawing required for the manufacturing process. Carrier and framework of control unit and actuator mainly designed to have the capability to support and hold the hardware and sensor assembly in an easy mountable fashion. This arrangement performed feasibility of the movement and allocating of control unit along the travel length of belt above the conveyor unit.In this work a multilayer perceptron network with different training algorithm was used and it is found that the backpropagation algorithm with Levenberge-Marquardt learning rule was the best choice for this analysis because of the accurate and faster training procedure. The Levenberg-Marquardt algorithm was an iterative technique that locates the minimum of a multivariate function that was expressed as the sum of squares of nonlinear real-valued functions. It has become a standard technique for non-linear least-squares problems, widely adopted in a broad spectrum of disciplines. LM can be thought of as a combination of steepest descent and the Gauss-Newton method. When the current solution was far from the correct one, the algorithm behaves like a steepest descent method: slow, but guaranteed to converge. When the current solution is close to the correct solution, it becomes a Gauss-Newton method. The Levenberg algorithm is:1. Do an update as directed by the rule above.2. Evaluate the error at the new parameter vector.3. If the error has increased as a result the update, then retract the step (i.e. reset the weights to their previous values) and increase l by a factor of 10 or some such significant factor, then goes to (1) and try an update again.4. If the error has decreased as a result of the update, then accept the step (i.e. keep the weights at their new values) and decrease l by a factor of 10 or so.Results and DiscussionThe study of multi artificial neural network learning algorithm by using base Levenberg–Marquardt was the best choice to estimate function experimental data convergence. Artificial neural networks databases were generated by experimental measurement data condition scales.It has been observed that the artificial neural networks could be used in height control. The function estimation problem with parameters in Levenberg–Marquardt algorithm showed a high performance and has a high speed, the error in the most cases were decrease and show a high convergence. Sum square error between ANN predictions and experimental measurements was less than 0.001 and correlation coefficient is above 0.99.ConclusionsANN method was capable to predict and capture the behavior of experimental measurements.ANN method can easily be used to determine new results with considerably less computational cost and time. Results show that the back-propagation method with Levenberg-Marquardt learning rule was suitable for training the networks.The Sum square error between ANN predictions and experimental measurements was less than 0.001 and the correlation coefficient is above 0.99.Replacement of the identity matrix with the diagonal of the Hessian in Levenberge-Marquardt update equation has great advantages in convergence and computation time.
Research Article
Image Processing
H. Asaei; A. A. Jafari; M. Loghavi
Abstract
IntroductionIn conventional methods of spraying in orchards, the amount of pesticide sprayed, is not targeted. The pesticide consumption data indicates that the application rate of pesticide in greenhouses and orchards is more than required. Less than 30% of pesticide sprayed actually reaches nursery ...
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IntroductionIn conventional methods of spraying in orchards, the amount of pesticide sprayed, is not targeted. The pesticide consumption data indicates that the application rate of pesticide in greenhouses and orchards is more than required. Less than 30% of pesticide sprayed actually reaches nursery canopies while the rest are lost and wasted. Nowadays, variable rate spray applicators using intelligent control systems can greatly reduce pesticide use and off-target contamination of environment in nurseries and orchards. In this research a prototype orchard sprayer based on machine vision technology was developed and evaluated. This sprayer performs real-time spraying based on the tree canopy structure and its greenness extent which improves the efficiency of spraying operation in orchards. Materials and MethodsThe equipment used in this study comprised of three main parts generally: 1- Mechanical Equipment 2- Data collection and image processing system 3- Electronic control systemTwo booms were designed to support the spray nozzles and to provide flexibility in directing the spray nozzles to the target. The boom comprised two parts, the vertical part and inclined part. The vertical part of the boom was used to spray one side of the trees during forward movement of the tractor and inclined part of the boom was designed to spray the upper half of the tree canopy. Three nozzles were considered on each boom. On the vertical part of the boom, two nozzles were placed, whereas one other nozzle was mounted on the inclined part of the boom. To achieve different tree heights, the vertical part of the boom was able to slide up and down. Labview (version 2011) was used for real time image processing. Images were captured through RGB cameras mounted on a horizontal bar attached on top of the tractor to take images separately for each side of the sprayer. Images were captured from the top of the canopies looking downward. The triggering signal for actuating the solenoid valves was initially sent to the electronic control unit as the result of image processing. Electronic control unit was used to adjust the right time of spraying based on the signals received from the encoder to precisely spray the targeted tree. The distance between the camera and spraying nozzles was considered in the microcontroller program. The solenoid would be turned off and stop the spraying when the vision system realized that there was a gap between the trees.Water sensitive papers (WSP) were used to evaluate the sprayer performance in prompt spraying of the trees and cutting off at hollow spaces between the trees. Water sensitive papers were attached to three ropes extended along the movement direction of the tractor at top, middle, and bottom of the trees so that each tree comprised 9 WSPs whereas other 9 WSPs were placed at each gap between two successive trees. Three levels of forward speed of 2 km h-1, 3.5 km h-1and 5 km h-1 was tried in these experiments to evaluate the effect of forward speed on spraying performance. Experiments were conducted in three replications. Liquid consumption of the sprayer designed in this research was compared with the conventional overall spraying.Results and DiscussionAnalysis of variances of data gained from water sensitive paper corresponding to the sprayed areas showed a significant effect of forward speed on prompt spraying.Comparison of means of spraying coverage on WSPs at different forward speeds with four replications showed that the maximum amount of targeted sprayed pesticide has been achieved at the lowest speed (2 km h-1) while the lowest amount of sprayed was seen at the maximum speed. Although higher forward speed is preferred because it increases the operation capacity of the sprayer, increasing the forward speed of the sprayer reduces the coverage density of the liquids on WSPs because the output rates of the nozzles are constant. Therefore, in cases that higher forward speed is demanded, more nozzles should be added to the sprayer booms Comparison between the liquid consumptions of the proposed system and conventional overall spraying showed that in this study, up to 54% less material has been used for the experiment in olive orchard. ConclusionsThe sprayer designed in this study was able to detect the gap between the trees in orchards using a machine vision system to stop the spraying on places where no tree exists. Results showed that employing the new sprayer decreased a significant amount of spray liquids which can be important both economically and environmentally. Considering to lack of pesticide spraying in the hollow spaces between the trees, certainly, more significant reduction is expected to achieve in young orchards where trees are small and there are larger gaps between the trees
Research Article
F. Amirshaghaghi; M. Safari
Abstract
Introduction
The efficiency and cost effectiveness of orchard pest management programs are influenced by the skills of managers and sprayer operators who evaluate orchard conditions and alter machine settings and operating techniques to optimize performance of sprayers. A combination of operational ...
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Introduction
The efficiency and cost effectiveness of orchard pest management programs are influenced by the skills of managers and sprayer operators who evaluate orchard conditions and alter machine settings and operating techniques to optimize performance of sprayers. A combination of operational skill, equipment performance, timing and chemical selection is necessary for optimal results. Research and development of electrostatics, air-assisted, low-volume spraying and other technologies for agriculture and horticulture was studied by biological and agricultural engineering in order to decrease of pesticide consumption. The main objective of charged liquid or powder form of the pesticide spread is increasing the percentage of poison meeting on plant surfaces. The first sprayer with rotary plate became available in 1970. The amount of solution was less and had uniform spray droplets. Apple orchards in West Azerbaijan province, Iran, are sprayed mainly with tractor-mounted lance sprayers but there is large national, regional and farm to farm variation in spray volumes applied with such sprayers. Traditionally, high spray volumes (> 2000 l.ha-1) were used in many places. Reduction in spray volume has been driven largely by the need to improve spraying equipment. West Azerbaijan province has 117000 hectare fruit orchards and 1.2 million ton fruit production that the most of them are apple and grape. However, it is necessary for reduction of pesticide application in order to produce economic and safe fruits.
Materials and Methods
In the present study the tractor-mounted lance sprayer in control of apple pest (Carpocasa pomonella L) was evaluated and compared with electrostatic and Micronair sprayers. This research was implemented in an apple orchard (Golden Delicious variety) with row spacing of 66 meter. The experiment was conducted as a randomized complete block design (RCBD) with three replications. Statistical analysis was performed using MS-TATC software and mean comparisons were conducted by Duncan’s multiple range test. The location of the research was in an orchard around the city of Urmia with geographical coordinates of 10-45' and 24-37' north latitude and east longitude, average rainfall of 380 mm, average temperature of 10°C, relative humidity of 60% and an average wind speed of 3.4 m.s-1. Average altitude of 1450 meters above sea level and has very high soil fertility and texture of silt loam class was the first class. In this experiment the following variables were measured: solution consumption, droplet distribution uniformity, pest control and economical comparison. Distribution uniformity was evaluated by use of water sensitive papers with dimension of 7×3 centimeter that installed in front and behind of leaves.
Results and Discussion
During the two-years study, results showed that uniform droplets on leaves in electrostatic and micronair sprayers with 30 drops per square centimeter were better than lance sprayer and in behind of leaves and electrostatic sprayer with 16 drops per square centimeter had better coverage. In lance type, large droplets and non-uniform distribution on the front and back of the leaves were observed. The mean comparison of solution consumption of treatments showed that electrostatic and microner sprayers with 157 and 134 liters per hectare, respectively, were in the range of low volume spraying (from 50-200 liters per hectare) and lance sprayer with 1629 liters per hectare was in the high volume spraying (more than 200 liters per hectare). Economically, the results showed that the micronair sprayer with high cost-benefit ratio (315.7) was recommended. Low volume spraying of apple trees is achievable by the use of spray technology such as micronair sprayers and provides considerable advantages in spray volume reduction.
Conclusions
Pesticides are active substances and instead of drenching of targets with lance sprayers we can change this poor and high expensive method with effective and environmental friendly methods. The technical evaluation showed that electrostatic and micronair sprayers were significantly better with more spray uniformity, higher performance, and lower consumption of solutions. Replacing the traditional methods with minimal use of chemicals and new equipment can improve the quality of agricultural and horticultural crops in national production contribution.
Research Article
N. Tarabi; H. Mousazadeh; A. Jafari; J. Taghizadeh Tameh
Abstract
Introduction
Calotropis is an evergreen and perennial shrub that grows in tropical areas of Iran and has valuable fibers in the bark of its stem. Fibers obtained from Calotropis stem have 75% cellulose. Tensile strength and modulus of the fibers is more than Cotton and elongation of the fibers is higher ...
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Introduction
Calotropis is an evergreen and perennial shrub that grows in tropical areas of Iran and has valuable fibers in the bark of its stem. Fibers obtained from Calotropis stem have 75% cellulose. Tensile strength and modulus of the fibers is more than Cotton and elongation of the fibers is higher than Linen fibers. Calotropis stem fibers are researched for paper pulp applications and also has been evaluated for some applications such as their fiber characteristics for cloth making.
However, there are no more studies on Calotropis bark fibers and very limited information is available about fibers extraction methods. In traditional methods of extraction, the stems were wetted for a period of 8 days and then the fibers were separated manually. In another method that was common in south region of Iran, the dried stems were threshed by hand and the fibers were separated from the crushed stems manually. These methods need cumbersome works, and require long times for processing. Therefore the aim of this study is to develop an extraction method for Calotropis bark fibers based on mechanical ways. Investigation of some importance characteristics, e.g. moisture content and rotational speed on the performance of extraction machine is another objective of this study.
Materials and Methods
Considering that the fibers are in the bark of the stems, extracting principle is based on bark separation by pushing of stems against some pairs of sharp blades. Since diameter of stems is variable, it is essential that the designed system to be capable of auto-adjusting for different diameters. So the stems were fed through the blades, via two serrated rollers. The roller, blade and other parts of a separated unit were tightened to a yoke, so when thick stems are inserted, the roller compresses the spring and moves up, as a result, the blade was pulled up. The Yoke was connected to the frame through two long screws. For complete debarking and fibers extraction, three separation units were arranged in series at the final design. For complete debarking from all sides, the second unit was attached while 90o rotated in relation to the first unit.
To evaluate the machine performance, the test specimens were provided from the south region of Iran, Kerman. Approximated length of test specimens was 150 cm. Firstly, petioles and leaves were removed at the nodes of the stems. Extraction efficiency of the machine was evaluated with three moisture contents (75% w.b., 65% w.b. and 55% w.b.) and six rotational speeds (30, 35, 40, 45, 50 and 50 rpm). Stems with a moisture content higher than 75% w.b. and lower than 55% w.b. were not suitable for fiber extraction by the machine. Because latex flows from the stem at moisture content of higher than 75% w.b. and also the bark was being stuck on the stem at moisture content of lower than 55% w.b. The stem feeding capacity was evaluated at different moisture content and speeds as well. In order to investigate the power consumption due to moisture content and rotational speed, the consumed power per stem mass unit was calculated at three moisture contents and three speeds (35, 45 and 55 rpm).
Analysis of variance (ANOVA) technique was used to evaluate effect of different speeds and moisture contents. The study was planned as factorial experiments based on a completely randomized design and each treatment was replicated five times.
Results and Discussion
Based on the analysis of variance for extraction efficiency at different three moisture contents and six rotational speeds, it is obtained that the effect of moisture contents (at P≤0.01) and rotational speeds (at P≤0.05) were significant on the extraction efficiency. Comparison extraction efficiency at six speeds and three moisture content levels showed that the maximum extracting efficiency occurs at rotational speed of 40 rpm with the moisture content of 75% w.b. The average efficiency in this case was 95% approximately. Extraction efficiency at moisture contents of 65 and 55 % w.b. were 78-90% and 60-82% respectively. As the moisture content decreased, the bark was being bonded and stuck on the stem so the fibers were torn while debarking. It is found that the effect of speeds on the capacity was not significant. Average stem feeding capacity into the machine at rotational speed of 45 rpm and at three moisture contents of 75% w.b., 65% w.b. and 55%w.b. were respectively 46, 37 and 28 kg hr-1.
The effect of moisture content and rotational speed on the consumed power per stem mass unit was significant at 0.01 probability level. However, the consumed power per mass unit increased with decrease in moisture content and increase in rotational speed. The average of maximum consumed power per unit mass at moisture contents of 75%, 65% and 55% w.b. were 1.46, 1.70 and 1.85w g-1, respectively. Also 1 kg fibers were obtained from 22kg stems at a moisture content of 75% w.b. Finally, it is concluded that the fiber length varied from 10 cm to 80 cm by the mechanical method.
Conclusions
In this study, a machine that would be capable to extract fibers from stems of Calotropis was developed. Comparison of extracting efficiency at six speed levels and three moisture contents indicated that the maximum extracting efficiency (95%) is at rotational speed of 40 rpm with the moisture content of 75% w.b. Average stem feeding capacity into the machine at three moisture contents of 75% w.b., 65% w.b. and 55% w.b. were 46, 37 and 28 kg hr-1, respectively. Results showed that consumed power per unit mass is increased when moisture decreased. Also 1 kg fiber was obtained by 22kg stems at moisture content of 75% w.b.
Research Article
S. Kamgar; F. Noori Gushki; H. Mustafavand
Abstract
Introduction
The main producers of lentil are Canada, India, Nepal and China, respectively and Iran is the ninth producer in the world. The hand pulling is the usual method of lentil harvesting. Use of conventional combine because of short leg varieties, wide combine head in dry land and grain losses ...
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Introduction
The main producers of lentil are Canada, India, Nepal and China, respectively and Iran is the ninth producer in the world. The hand pulling is the usual method of lentil harvesting. Use of conventional combine because of short leg varieties, wide combine head in dry land and grain losses by cutter bar vibrations is impossible. So a mechanism should be designed to harvest the lentil plants with minimum damage. This mechanism should be evaluated under different tests of crop and machines such as forward speed (FS), grain moisture content (GMC), different varieties and other parameters. Some researchers studied the effects of GMC (Andrews and et al., 1993; Huitink, 2005; Adisa, 2009; Abdi and Jalali, 2013) and FS on grain losses (Geng et al., 1984; Swapan et al., 2001; Mostafavand and Kamgar, 2014; Hunt, 1995). Field tests were conducted at three levels of FS 1.5, 3 and 4.5 km.h-1; three levels of cutting height (CH) 4, 8 and 13 cm and two levels of GMC, 8 and 14% on two varieties of lentils including Flip and Shiraz with three replications.
Materials and Methods
The feeder and cutter mechanism for chickpea harvesting that was the base design of device which is notched wheel and counter shear, was used. The other components of device were dividers, slat and chain feeders, belt and pulleys, chassis, elevator conveyor and storage. Two split plot design based on a randomized complete design was used to determine the effects of above treatments on lentil losses.
Results and Discussion
The ANOVA results indicated that the all studied factors; FS of feeder and cutter mechanism, CH and GMC had significant effect on losses of Shiraz variety (P0.05). The ranges of losses of Flip variety at 8% GMC were 8.6 to 10% for FS of 1.5 km.h-1, 9.1 to 10.4% for FS of 3 km.h-1and 10.4 to 11.4% for FS of 4.5 km h-1. These ranges at 14% GMC were 7.9 to 8.9% for FS of 1.5 km.h-1, 8.4 to 9.2% for FS of 3 km.h-1and 8.5 to 10% for FS of 4.5 km h-1. The ranges of losses of Shiraz variety at 8% GMC were 8.3 to 10.9% for FS of 1.5 km.h-1, 9 to 12.4% for FS of 3 km h-1and 10.7 to 13.6% for FS of 4.5 km h-1. These ranges at 14% GMC were 8.3 to 9.1% for FS of 1.5 km h-1, 8.3 to 9.9% for FS of 3 km h-1and 9.2 to 11.5% for FS of 4.5 km h-1. The comparison between two varieties at different levels of FS, GMC and CH indicated that the lentil losses of Shiraz variety were more than the other variety at 8 cm CH at 8 and 14% GMC. The difference of losses between two varieties was 0.8% at FS of 4.5 km.h-1 at 14% GMC where this value was 2% at 8% GMC and same FS and at 14% GMC and 8 cm CH from FS of 3 to 4.5 km h-1 was 0.3% and 1% for Flip and Shiraz varieties, respectively. Also at 14% GMC and 13 cm CH, the differences within group were 0.8 and 1.4% where at 8% GMC and 13 cm CH were 1 and 1.2% for Flip and Shiraz varieties, respectively. The results of the study of field evaluation of cutter and feeder mechanism of chickpea harvester for lentil harvesting showed that FS, CH and GMC at 1% probability for Shiraz variety and FS and GMC at 1% probability had significant effect on lentil losses but CH at 5% probability for Flip variety had no significant effect. The lentil losses were increased by increase in FS, CH and decreasing of GMC for both varieties. There was no significant difference from 1.5 to 3 km.h-1 and 4 to 8 cm CH in Flip variety while significant difference was at all levels of FS and CH in Shiraz variety.
Conclusions
At studied varieties, Flip variety because of more performance and minimum of losses was better than Shiraz variety. Also to achieve the lowest of losses by feeder and cutter mechanism, FS of 3 km h-1, GMC of 14%, CH of 8 cm and variety of Flip was recommended.
Research Article
S. Zareei; Sh. Abdollahpour
Abstract
Introduction
The noticeable proportion of producing wheat losses occur during production and consumption steps and the loss due to harvesting with combine harvester is regarded as one of the main factors. A grain combines harvester consists of different sets of equipment and one of the most important ...
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Introduction
The noticeable proportion of producing wheat losses occur during production and consumption steps and the loss due to harvesting with combine harvester is regarded as one of the main factors. A grain combines harvester consists of different sets of equipment and one of the most important parts is the header which comprises more than 50% of the entire harvesting losses.
Some researchers have presented regression equation to estimate grain loss of combine harvester. The results of their study indicated that grain moisture content, reel index, cutter bar speed, service life of cutter bar, tine spacing, tine clearance over cutter bar, stem length were the major parameters affecting the losses.
On the other hand, there are several researchswhich have used the variety of artificial intelligence methods in the different aspects of combine harvester.
In neuro-fuzzy control systems, membership functions and if-then rules were defined through neural networks. Sugeno- type fuzzy inference model was applied to generate fuzzy rules from a given input-output data set due to its less time-consuming and mathematically tractable defuzzification operation for sample data-based fuzzy modeling. In this study, neuro-fuzzy model was applied to develop forecasting models which can predict the combine header loss for each set of the header parameter adjustments related to site-specific information and therefore can minimize the header loss.
Materials and Methods
The field experiment was conducted during the harvesting season of 2011 at the research station of the Faulty of Agriculture, Shiraz University, Shiraz, Iran. The wheat field (CV. Shiraz) was harvested with a Claas Lexion-510 combine harvester. The factors which were selected as main factors influenced the header performance were three levels of reel index (RI) (forward speed of combine harvester divided by peripheral speed of reel) (1, 1.2, 1.5), three levels of cutting height (CH)(25, 30, 35 cm), three levels of the horizontal distance of reel tine bar from cutter bar (Hd)( 0, 5, 10 cm) and three levels of vertical distance of reel tine bar from cutter bar (Vd)( 5, 10, 15 cm) which are taken as the input variables for neuro-fuzzy model and only combine header loss is output of the model.
Some frames with the dimensions of 50 × 50 cm2 were randomly used to determine the amount of header loss. In order to determine the header loss, the frame was placed on the ground in the vacant place behind the cutter bar, where output material from the back of the combine was not allowed to pour on the ground. Grains and ears found inside the frame were gathered, weighed and then the amount of pre-harvest loss was subtracted from it. A fractional factorial design based on a completely randomized design was used to determine the header loss. Each test was repeated three times and for each repetition.
The structure of neuro- fuzzy model for this study has four inputs and each input variable as mentioned and three Gaussian membership functions (mf), result in 81 rules.
Results and Discussion
A neuro- fuzzy model was developed for predicting the combine header loss based on reel index, cutting height, the horizontal distance of reel tine bar from the cutter bar and vertical distance of reel tine bar from cutter bar as input variables. The Model has three membership functions for each input. Gaussian membership functions and rules were defined for knowledge representation of header loss.
Predicting header loss is an important issue for minimizing the amount of harvest grain losses. Neuro-fuzzy model presented a satisfactory application to describe header loss of a combine harvester. It showed R² equal to 0.95 which is superior to multiple regression method with 0.71. In fact, the amount of coefficient of determination is a good indicator to check the prediction performance of the model. Based on developed neuro-fuzzy system model, levels of reel index, cutting height, the horizontal distance of reel tine bar from cutter bar and vertical distance of reel tine bar from cutter bar could be recommended according to minimize header loss.
Conclusions
In the final step, the designed controller was simulated in SIMULINK. The Controller can change setting of header components in order to their impaction gathering loss and in each step, compare gathering loss with optimal value and If it was more than optimum then change the settings again. The simulation results were evaluated satisfactory.
Research Article
A. Rezaei; M. Loghavi; S. Kamgar; Y. Mehdipour
Abstract
Introduction
Olive (Oleo europaea) includes about 20 species of small trees from Oleaceae family. This point should be considered that Iran has allocated only a small universal market to its olive products in spite of having high production potentials; so that about 23 provinces of this country can ...
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Introduction
Olive (Oleo europaea) includes about 20 species of small trees from Oleaceae family. This point should be considered that Iran has allocated only a small universal market to its olive products in spite of having high production potentials; so that about 23 provinces of this country can produce olive products. Therefore mechanizing of olive production and encouraging to develop olive trade are among the effective methods for development of this market. On the basis of IOOC report, the production of olive oil in 2008-2009 in Iran and all over the world has been 3 and 2866.5 thousand tons, respectively. Currently, harvesting olive product is done by hand in Iran. The expensiveness of work force and providing the needed workers are considered as the biggest problem in olive harvesting. While harvesting the tall trees, the workers use beating method by wood sticks which causes the fruits to be damaged and their quality to be decreased. The harvesting method which the quality and quantity of the olive final products is under its effect and also high expenses of harvesting by hand are considered as the two important factors in developing the mechanical harvesting of olive. For this purpose, the mechanized harvesting of olive should be considered for producing olive conserve and olive oil and decreasing expenses of harvesting. Considering the conducted studies on one hand and shortage of informational resources in the country on the other hand, a research was designed and performed with the following purposes:
Designing and fabricating of a portable pneumatic branch shaking system.
Determining the best frequency and oscillation duration for harvesting olive by the constructed system.
Materials and Methods
The branch shaking system is made of two general parts:
(a) The set of branch shaker driving unit.
(b) The portable vibration arm.
For constructing the set of vibrating arm, two experiments “elasticity and inflectionˮ of tree branches were conducted and the maximum force of 362.40 N was registered and it was considered as the base of computations. Then a double-action pneumatic jack with the internal diameter of 32 mm and the rod diameter of 12mm with the stroke length of 200 mm was selected. An electronic circuit was designed and developed for ordering the solenoid valve to control the flow. The system was transferred to one of the olive garden’s located in kilometer 5 of Sarvestan – Fasa road in Fars province in order to be evaluated. The effects of three oscillation frequencies of 12, 16 and 20 Hz and three oscillation durations of 5, 10 and 15 seconds at constant amplitude of 5 cm on detachment percentage of olive fruit was investigated through a factorial 3×3 experiment based on completely randomized design with four replications. Then the most suitable frequency and vibration duration was selected for harvesting olive by this system.
For measuring the static detachment force of the fruits, a tensile force dynamometer system model FG-5100 made by Lutron Company was used with the accuracy of 0.1 N and a maximum capacity of 980 N.
Results and Discussion
The variance analysis of the investigated features on the basis of the factorial experiment based on completely randomized designs was conducted through using SPSS software. The results showed that both frequency of vibration and oscillation duration had significant effect on the shaker performance; with no significant interaction effects which implies the independence of the debated variables. Comparing the means by using Duncan test at 1% significance level for features of oscillation frequency and duration of shaking showed that at any constant duration of oscillation, increasing of oscillation frequency significantly increases the percentage of the olive fruit detachment. This increase is due to the increase of dynamic force with the second power of oscillation frequency compared to the static separating force (Murphy, 1950).
It was observed that the calculated dynamic force is larger than the static force for separating the fruit in frequencies of 16 and 20 Hz, but since the dynamic force is variable at each point of the branch, 84.50 percent of fruits are separated from branches at frequency of 16 Hz and 87.25 percent of the fruits are separated from branches at frequency of 20 Hz.
Conclusions
At the end, the frequency of 20 Hz with 5 second duration of oscillation was selected as the most suitable treatment for this branch– shaker in harvesting oil-type olives.
Research Article
Modeling
M. Ostad Hoseini; A. Ghazanfari Moghaddam; H. Hashmipour-Rafsanjani; A. Ataei
Abstract
IntroductionThe lignocelluloses materials have high potential for producing various types of biofuels. These materials include various parts of plants, especially leaves and stems that are left without a specific usage after annual pruning. These residues can be used through slow or fast pyrolysis process ...
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IntroductionThe lignocelluloses materials have high potential for producing various types of biofuels. These materials include various parts of plants, especially leaves and stems that are left without a specific usage after annual pruning. These residues can be used through slow or fast pyrolysis process for production of liquid and gaseous biofuels. The slow pyrolysis is taking place at temperatures below 500°C while fast pyrolysis process takes place at a temperature above 700°C. Various studies on production of biofuels from plant residues have shown that the temperature, heating rate and the resident time of pyrolysis process are the main factors that affect the final product quality. At present time, in Iran, there are more than 360 thousands hectares of pistachio growing fields which annually produce over 215 thousands metric tons residues which are mainly leaves and stems. The main objective of this study was to measure the heating properties of the powders prepared from the leaves and the stem of pistachio trees. These properties include higher heating value (HHV), lower heating value (LHV) and thermal gravimetric analysis (TGA) of the powders. Then the powders were separately pyrolysed and the kinetic of the pyrolysis process for producing charcoal from them was investigated. Materials and MethodsIn this research, leaves and stems of pistachio trees were initially analyzed to determine their chemical constituents including moisture content, volatile compounds, carbon (C), hydrogen (H), nitrogen (N), sulfur (S) and oxygen (O) content. Using these constituents the height heating value and low heating value for the leaves and the stems were determined. The thermal gravimetric analysis (TGA) of the powders was made to select a proper heating temperature for pyrolysis of the powders. In each experiment about 10 g of powder powders were pyrolyzed to produce char. Based on TGA results, the pyrolysis experiments were performed at 350, 400, 450 and 500°C with 30 minutes residence time. The instantaneous amount (in decimal) of the produced gas (M) and char (Ms) as a function of time (t) was modeled using the following equations: For each experiment B is a constant value and is represented by:Where Ea is the activation energy, R is universal gas constant, T is the temperature of the experiment and A is the pre-exponential constant. By having M or Ms at different times (t), the parameters of A, B and Ea were estimated using the curve fitting tool box of the MATLAB® software. Results and DiscussionThe results of chemical analysis indicated that the leaves powders contained 1.5% N, 42.1% C, 5.5% H, 0.4% S and 48.3% O while the stem samples contained 0.5% N, 46.5% C, 6.1% H, 0.2% S and 44.6% O. Higher amount of carbon and hydrogen in the stem leaves indicates that the stem should have higher energy content. In fact, the calculated high and low heating values for leaves were 17.23 and 16.03 MJ.kg-1, and for the stems were 18.91 and 17.59 MJ.kg-1, respectively which comply with the predicted results from chemical analysis of the powders. The TGA test results indicated that the initial weight loss took place up to 270°C for the stems powder and up to 220°C for leaves powders. This weight loss was due to loss of moisture and volatile compounds. The actual degradation temperature for the stem powders ranged from 300 to 500°C while for the leaves was from 350 to 600°C. The results of pyrolysis experiments indicated that the pyrolysis of stems took place faster than leaves. The pyrolysis time was 10 to 15 min for leaves and 5 to 10 min for stems. The resulting char for pyrolysis of stem was 30% and for stems were 40% of the original materials. The kinetic of pyrolysis was modeled using one-step global model for production of char and gas. The experimental data were fitted to the used model with high degrees of accuracy (R2>0.99). The model parameters, namely activation energy and frequency factors were 10.70 kJ.mol-1, and 0.047 s-1 for stems and 21.72 kJ.mol-1 and 0.312 s-1, respectively. ConclusionsIn general, both HHV and LHV of the stems were higher than those of leaves due to higher carbon content of the stems. The TG curves indicated the pyrolysis time of stems was shorter than that of leaves. The leaves yielded 40% char while the stem yielded 30%.
Research Article
B. Hosseinzdeh Samani; E. Fayyazi; B. Ghobadian; S. Rostami
Abstract
Introduction
Biodiesel is a promising renewable substitute source of fuel produced from tree born oils, vegetable based oils, fats of animals and even waste cooking oil, has been identified as one of the key solutions for the alarming global twin problems of fossil fuel depletion and environmental degradation. ...
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Introduction
Biodiesel is a promising renewable substitute source of fuel produced from tree born oils, vegetable based oils, fats of animals and even waste cooking oil, has been identified as one of the key solutions for the alarming global twin problems of fossil fuel depletion and environmental degradation. One of the sources for biodiesel production is mastic which is often grown in mountains. Its kernel contains 55% oil which makes it as a valuable renewable resource for biodiesel production. The objective of this research was to study of the feasibility of biodiesel production from Atlas mastic oil using ultrasonic system and optimization of the process using Response surface methodology.
Materials and Methods
In order to supply the required oil for the biodiesel production process, the oil should be prepared before the reaction. Hence, the purified oil was methylated using Metcalf et al (1996) method, and the prepared sample was injected into Gas Chromatography device to determine fatty acids profile and molecular weight of the used oil. An ultrasonic processor (Hielscher Model UP400S, USA.) was used to perform the transesterification reaction.
All the experiments were replicated three times to determine the variability of the results and to assess the experimental errors. The reported values are the average of the individual runs. The different operating parameters used in the present work, to optimize the extent of conversion of Atlas pistache oil, include methanol to oil molar ratio (4:1, 5:1 ,6:1), amplitude (24.1, 62.5 100%), pulse (24.1, 62.5 100%), reaction time (3, 6, 9 min).
Results and Discussion
Results of analyses showed that the independent variables, namely molar ratio, vibration amplitude, pulse and reaction time had significant effects on the amount of produced methyl ester.
By increasing the amplitude and pulse, the methyl ester content increased. Increase in amplitude and pulse cause to increase the mixing effect and physical interface. Increasing the ratio of ultrasonic working time to its idling time caused to an increase in the conversion percent. Because the treating time of the samples by ultrasound in limit time durations is increased, while this increase becomes lower at higher ratios. This is due to the fact that the initial vibrative shock acted on the samples after ultrasonic restarting, finds an identical effect with uniform wave. However, the idling phase of ultrasound caused a decrease in the amount of consumed energy. Similar results have been reported by Chand et al. (2010) for the effect of pulse on conversion percent of methyl ester. Trend of reaction time and molar ratio were different with trend of amplitude and molar ratio on methyl ester content so that they were divided to two sections. It should be mentioned that the increase in biodiesel yield because of molar ratio has some limitations. If the ratio is increased more than a certain extent, biodiesel conversion percent will decrease. The main reason for this result can be related to the amount of methanol increase in the mixture, which leads to more dissolution of glycerin and alcohol in biodiesel which considerably influences its purity.
Optimization was carried out based on Response Surface Methodology (RSM) using Design Experts software. The obtained results from optimization were as follow: 5.45 molar ratio, 0.89 amplitude, 0.71 pulse and 5.99 minutes of time. The conversion percentage obtained as 94.96. It is worthy to note that the experiment was iterated at suggested point by the optimization software and the conversion percent was 94.02. As well as 34792.37 J at the obtained point to be acceptable (1%) difference from the model.
Conclusions
The increase in the ultrasound amplitude resulted in an increase in the conversion percentage which tends to ascend. Also, the increase of reaction time by 5 to 7 minutes increased the conversion percentage, following which is the descend trend. The obtained results from optimization were as follow: 5.45 molar ratio, 0.89 amplitude, 0.71 pulse and 5.99 minutes of time. The conversion percentage and consumed energy obtained as 94.96 and 32421.5 J, respectively. It is worthy to note that the experiment was iterated at suggested point by the optimization software and the conversion percent was 94.02.
Research Article
H. Samimi Akhijahani; A. Arabhosseini; M. H. Kianmehr
Abstract
Introduction
Drying is one of the most common methods for storing food and agricultural products. During drying process, free water that causes the growth of microorganisms and spoilage of products is removed from the product. There are several methods for drying of agricultural products. one of the ...
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Introduction
Drying is one of the most common methods for storing food and agricultural products. During drying process, free water that causes the growth of microorganisms and spoilage of products is removed from the product. There are several methods for drying of agricultural products. one of the most important methods of investment is drying by using sunlight. Iran is situated at 25- 43oE longitude and mean solar radiation is about 4.9 kwh.m-2.d-1. Because of the proper solar radiations in 95% of the agricultural areas in Iran, solar drying is widely used for drying of fruits and vegetables. The use of solar dryer causes saving in energy consumption and processing costs for drying of products in farms and gardens. Several researchers investigated heat transfer and heat flow in dryers. Selection of appropriate method was carried out for drying of agricultural products using heat pump. Experiments were done and mathematical relationships were estimated to obtain correlation parameters between Reynolds number and Nusselt number for the three cases of solar dryer (cabinet, indirect and combination).The best working conditions were determined for three types of solar collectors (flat, finned and corrugated). In this study, the process of heat transfer and heat transfer coefficient of a solar dryer with and without rotation of absorber plate was compared.
Materials and Methods
The experiments were conducted in Azarshahr, East Azarbayjan province, Iran in September 2014. Newton's law of thermodynamic was used to analyze the working condition of solar absorber. For this purpose the absorber plate was divided into four equal parts. According to the thermal equations and related boundary conditions as well as the relationship between heat transfer coefficient and the temperature gradient, equation 1 for the Nusselet number obtained:
1
Beside the relationship between Nusselt number and heat transfer coefficient is defined as equation 2:
2
Finally variation of total heat flow over the time at different surfaces of the collector is determined by using equation 3:
3
Two cases (solar panel with rotation and without rotation) were considered for testing. Data measuring was carried out for 9 hours from 8 to 17. The fluid flow rate was 0.0185m3.s-1. The dryer was installed in an environment with air temperature of 31.6 oC and 31.8 oC, with the air velocity of 0.58 m.s-1 and 0.54 m.s-1 and with the relative air humidity of about 21%and 21.5% at the first and second days, respectively. The dryer had an automatic temperature controller to fix the air temperature with an accuracy of ±0.1 oC. An anemometer Yk-2005AM model was used to regulate the required air velocity. The output data of the thermocouples was recorded by a digital thermometer (DL-9601A, Lutron) that was connected to a computer using RS232 cable and recorded the temperature at required point every an hour. The relative humidity of the ambient was measured every hour with a digital hygrometer (HT.3600, Taiwan), accuracy of 3%. By assembling controlling system with a DC motor, a precious photocell and a proper mechanism, the frame would rotate by the sun and followed solar radiation, therefore more solar energy produced in solar panel.
Results and Discussion
The results of the experiments showed that the heat transfer process increased in both cases from the early morning and reached to its maximum value around 12 to 14 o’clock. The trend was more homogeneous in the dryer by absorber plate without rotation due to the decline of the heat accumulation. The mean temperature rise in the solar dryer without rotation was 37oC and in the solar dryer with rotation was 54oC. Because of the rotation of solar plate, variations of solar radiation were low. Therefore, by rotation of the solar dryer panel the temperature rise was 27oC. The values of heat transfer coefficient in the solar dryer with rotation were decreased by the time. This reduction in the hours before noon is more than after noon. This is due to the reduction of the temperature gradient in the solar absorber plate. Also the results showed that heat transfer coefficient in the lower levels (S1 and S2) is more than higher levels (S3 and S4). Variations of the heat flow for the solar dryer with rotation is more than the other. Because in the first one, the absorber plate was followed the solar radiation and generated heat in the plate increases and the fan does not have the ability to discharge the generated heat. The total amount of heat transfer in absorber plate with rotation was 36.1% higher than the absorber plate without rotation. To increase the heat transfer from the dryer, design of the system to change air flow rate by increasing temperature, can increase the efficiency of the dryer.
Conclusions
In this study the performance of the absorber plate in a solar dryer in two cases with rotation and without rotation were compared. The results showed that by rotation of the solar absorber plate the output temperature of the collector rises about 27oC. Thermal fluctuation in the rotation solar plate is lower than the solar plate without rotation.
Research Article
N. Hafezi; M. J. Sheikhdavoodi; S. M. Sajadiye; M. E. Khorasani
Abstract
Introduction
Potato (Solanumtuberosum L.) is one of the unique and most potential crops having high productivity, supplementing major food requirement in the world. Drying is generally carried out for two main reasons, one to reduce the water activity which eventually increases the shelf life of food ...
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Introduction
Potato (Solanumtuberosum L.) is one of the unique and most potential crops having high productivity, supplementing major food requirement in the world. Drying is generally carried out for two main reasons, one to reduce the water activity which eventually increases the shelf life of food and second to reduce the weight and bulk of food for cheaper transport and storage. The quality evaluation of the dried product was carried out on the basis of response variables such as rehydration ratio, shrinkage percentage, color and the overall acceptability. Drying is the most energy intensive process in food industry. Therefore, new drying techniques and dryers must be designed and studied to minimize the energy cost in drying process. Considering the fact that the highest energy consumption in agriculture is associated with drying operations, different drying methods can be evaluated to determine and compare the energy requirements for drying a particular product. Thermal drying operations are found in almost all industrial sectors and are known, according to various estimates, to consume 10-25% of the national industrial energy in the developed world. Infrared radiation drying has the unique characteristics of energy transfer mechanism. Kantrong et al. (2012) were studied the drying characteristics and quality of shiitake mushroom undergoing microwave-vacuum combined with infrared drying. Motevali et al. (2011) were evaluated energy consumption for drying of mushroom slices using various drying methods including hot air, microwave, vacuum, infrared, microwave-vacuum and hot air-infrared. The objectives of this research were to experimental study of drying kinetics considering quality characteristics including the rehydration and color distribution of potato slices in a vacuum- infrared dryer and also assessment of specific energy consumption and thermal utilization efficiency of potato slices during drying process.
Materials and Methods
A laboratory scale vacuum-infrared dryer, developed at the Agricultural Machinery and Mechanization Engineering Laboratory of Shahid Chamran University of Ahvaz has been used. The dryer consists of a stainless steel drying chamber; a laboratory type piston vacuum pump, which was used to maintain vacuum in the drying chamber; an infrared lamp with power of 250 W which was used to supply thermal radiation to a drying product; and a control system for the infrared radiator.
Sample Preparation
Fresh potatoes were purchased from a local market in Hamadan province. Potatoes were peeled, washed, and cut into sliced with thickness of 1, 2 and 3 mm by a manual slicer. Drying experiments of potato slices were performed in a vacuum chamber with absolute pressure levels of 20, 80, 140 and 760 mmHg; and radiation intensity of infrared lamp was 0.2, 0.3 and 0.4 W cm-2. The mass change of the sample during drying was detected continuously using an electronic weight scale (Lutron, GM- 1500P, Taiwan) with the accuracy of ±0.05 g.
Evaluation of rehydration capacity of dried potato slices
The rehydration tests measured the gain in weight of dehydrated samples (~5 g), dehydrated samples were rehydrated in 200 cc of distilled water at 100°C for 3 minutes.
Evaluation of color
The color of potatoes was measured on five slices selected randomly, and was described by three coordinates in the RGB color space using computer vision.
Evaluation of specific energy consumption
Energy consumption of dying process came from the electrical energy consumed by the operation of the vacuum pump and the infrared lamp. Specific energy consumption was defined as the energy required for removing a unit mass of water in drying the potato slice.
Evaluation of thermal utilization efficiency
Thermal utilization efficiency is defined as the latent heat of vaporization of moisture of sample to the amount of energy required to evaporate moisture from free water. The latent heat of vaporization of water at the evaporating temperature of 100°C was taken as 2257 kJkg-1.
Results and Discussion
The results of the evaluation of rehydration capacity of potato slices during drying process are shown in Table 1. Statistical analysis (ANOVA, post-hoc Duncan) showed that thickness at probability level of 1% had statistically significant influence on rehydration capacity values of dried potato slices. Moisture of dried slice of potato compared to its fresh was obtained nearly 80% in boiling water (at temperature 100°C) for 3 min. The most color changes of slice after drying was related to green color. According to Table 2 and statistical analysis results showed that factor of thickness was not statistically significant on specific energy. The effect of absolute pressure (p<0.05) and radiation intensity (p<0.01) parameters also interaction of absolute pressure and radiation intensity (p<0.05) had statistically significant influence on specific energy of dried potato slices. According to Table 3 and statistical analysis the factor of absolute pressure had statistically significant at probability level of 5% on thermal utilization efficiency. Also the effect of interaction of absolute pressure and radiation intensity had statistically significant at probability level of 5% on thermal utilization efficiency of dried potato slices. The drying efficiency of potato slices varied between 2.13% to 31.01%.
Conclusions
Dried potato slices at a thickness of 1 mm put in boiling water for three minutes; showed the most amount of water absorption ratio that it was able to absorb the value of 86% more than the initial moisture. The lowest rate of color change before and after the drying process is related to the thickness of the thinnest sliced potatoes. Comparison of energy consumption showed that the radiation intensity of 0.4 W cm-2, absolute pressure level of 80 mmHg and slice thickness of 1 mm had shorter drying time in experimental conditions.
Research Article
M. Safari; R. Abdi
Abstract
Introduction
Seventy million tons of agricultural crops are produced from 18 million hectares of agricultural lands in Iran every year. Since 80% of the crops (wt. basis) ends up as residues, therefore, about 50 million tons of crop residues are generated annually the majority of which is burnt on field ...
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Introduction
Seventy million tons of agricultural crops are produced from 18 million hectares of agricultural lands in Iran every year. Since 80% of the crops (wt. basis) ends up as residues, therefore, about 50 million tons of crop residues are generated annually the majority of which is burnt on field leading to vast emissions of greenhouse gases (GHG) due to the incomplete combustion process. These residues could potentially be transformed into heat energy directly by adopting a burning process or indirectly by first transforming them into secondary fuel as hydrogen, bio-methane, methanol or ethanol.
Materials and Methods
The present study was conducted using, wheat and rapeseed straws dried at ambient temperature co-digested with fresh cow dung while the total solid content and detention time were kept constant. To conduct the Anaerobic Digestion (AD) experiments, cylinder reactors (13 L) were constructed and placed in a water bath equipped with a heater and sensor to maintain the temperature at 35±2 oC. The biogas produced in the digester was investigated by measuring the displacement of the water in a measuring tube connected to the reactor. Gas samples were obtained from the sampling port and were analyzed gas chromatograph. The temperature for detector, injector and oven were 170, 110 and 50 oC respectively. Before the test, the first CH4 and CO2 net gases, peaks corresponding percentage was determined with respect to the retention time of the area. Then sample was compared with standard gas and samples gas percentage was determined. The residues were mechanically pretreated using a mill in order to increase the availability of the biomass to enzymes. After the pre-treatment, the material (<2 mm) was mixed with a different proportion of fresh cow dung, Initial Total Solids (TS) content in the reactor was adjusted at 9%. Factors such as PH, Volatile Solids (VS) were determined by the standard method.
Results and Discussion
A decrease in the process pH was observed in the first few days of the digestion and this is due to high volatile fatty acid (VFA) formation. These results were compatible with sanaee moghadam et al. (2013). The results obtained showed that, the highest rate of VS reduction belonged to rapeseed residues at 52.22%.The lowest rate of VS reduction attributed to wheat residues at 36.79%. The rapeseed residues with 311.45 Lit.kg-1 VS had the highest accumulated methane followed by wheat straw with 167.69.28 L.Kg-1 VS in probability level of 5%. The average percentages of methane production for rapeseed straw and wheat straw during the 140 days experiment under mesophilic condition were 66% and 55%, respectively. Production of methane had delay and started after 46th day. Much reason may be possible. Inoculums used in this study were only fresh cattle dung. The mixture of fresh cattle dung and effluent of anaerobic digester or fresh rumen fluid may be decrease retention time and increase biogas production. According results of Budiyono the rumen fluid inoculated to biodigester significantly affected the biogas production. Rumen fluid inoculums caused biogas production rate and efficiency increase more than two times in compare to manure substrate without rumen fluid inoculums (Budyono et al., 2010). The other reason was pretreatment. This study applied just mechanical pretreatment. According to Cecilia studies, different pretreatment combined with mechanical pretreatment decrease retention time and increase biogas production efficiency (Cecilia et al, 2013). However, Zhang et al. claimed that it is hard to say which method is the best because each has its own strong point and weak point. Yet, until now, none of the pretreatment technologies has found a real breakthrough.
Conclusions
According to this study, rapeseed residues had the highest level of methane production in comparison with wheat residues. The rapeseed residues combine with cattle dung had suitable potential to methane production. The 140 days, Biomaethane Potential (BMP) of rapeseed residues combine with cattle manure had 311. 45 Lit/kg vs. add. Moreover, it had high percentage of VS content reduction (52.22%). The high retention time was observed (140 day). One reason was lack of suitable inoculums and pretreatment. Furthermore, the lingo-cellulose nature of the crop residues, lower will be the biodegrade ability. Furthermore, the anaerobic co-digestion of rapeseed straw with cattle manure is feasible for production of methane.
Research Article
M. Javidi Gharache; M. Khojastehpour
Abstract
Introduction
People in different jobs may face skeletal problems in their body due to poor physical conditions as a result of poor working conditions and inappropriate equipment. Harvesting tea is one of those jobs that are known as a very vigorous process and it requires hard work and perseverance. ...
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Introduction
People in different jobs may face skeletal problems in their body due to poor physical conditions as a result of poor working conditions and inappropriate equipment. Harvesting tea is one of those jobs that are known as a very vigorous process and it requires hard work and perseverance. Moreover, after water, tea is the most widely consumed beverage in the world. This fact highlights the great importance of jobs related to tea. The most prevailing method used for tea harvesting in Iran is manual harvesting, although this job in some regions is mechanized. Manual harvesting intensifies the hardness of this job.
Materials and Methods
This study was launched and aimed to find harmful postures in tasks related to tea plucking in order to reduce the intensities in this job. To obtain this goal workers’ postures were needed while working. Different postures should be attained by filming during a working day. Films were recorded from 30 workers in tea farms at the different parts of Lahijan region, Iran, and were analyzed by modeling tea harvesters’ bodies by CATIA software. Then, the modeled postures were analyzed by three methods: OWAS, REBA and RULA.
Results and Discussion
According to OWAS analysis, 30% of postures placed at the first level, that means the postures have not harmful effects on musculoskeletal system, and the corrective action is not required. 10% of the tea harvest labors population was placed at level 2 so the posture has harmful effects on musculoskeletal system and the corrective action is necessary in the near future. This situation is not critical, only needs more attention. The corrective actions require soon in the third level. 33% of analyzed and modeled postures were in this level. In the fourth level which is absolutely critical and has biomechanical strain with very traumatic effect on musculoskeletal system and it is necessary to exert corrective action immediately, 27% of postures were observed.
The results of REBA analysis showed that 24% of workers’ postures in tea farms and under this study were at level 1 where the risk level is low and the corrective action may be necessary to them. 53% of workers are at level 2 who are at the average risk and corrective action is necessary for them. 23% of tea harvesters are in level 3 with high level of risk, therefore the corrective action must be performed immediately. Finally, similar to results obtained from the analysis of OWAS, no posture placed at level 4. The results of RULA analysis show that there is no posture in positions 1 or 2 and all positions need to be investigated. According to this analysis, 2% of tea harvesters' postures are in position 3 and no posture in position 4. Therefore, in total, 2% were in second level. According to RULA analysis, 16% of workers' postures were in position 5. 44% of postures of tea harvesters working in different parts of Lahijan region were in position 6. Accordingly, 38% of the postures were in position 7.
Conclusions
The findings from this study showed that the highest prevalence rate of musculoskeletal pain or discomfort was in the trunk region (92%), following by the neck and upper arm (38%), lower arm (23%) and wrist (15%). For men the most frequent disorders were trunk (89%), upper arm and neck (33%), lower arm and wrist (22%). The results from this study also revealed that all women in this occupation faced musculoskeletal problems in the trunk region (100%). After trunk, neck and upper arm (57%) and lower arm (25%). No disorder was seen in wrist region in this analysis, which is consistent with female labors’ report. After this analysis finding uncomfortable postures in each duty and making changes in simulated bodies in CATIA software in order to reach a lower grand score can be helpful to improve working conditions. Reanalyzing new posture is the stage to obtain new grand score. Final step in this case is reporting harmful and improved postures to employees and employers. Notice that improved postures are not valid unless workers can have acceptable access to their work. Similarity between the results of OWAS and RULA methods and the difference from the results of REBA method could come to conclusion of not using REBA method for jobs similar to tea plucking.
Research Article
R. Rahimzadeh; Y. Ajabshirchi; Sh. Abdollahpour; A. Sharifi Malvajerdi; N. Sartipi; A. Mohammadi
Abstract
Introduction
Direct planting becomes more common in the recent years, because it conserves soil and water as well as it saves energy and time. However, this technology needs special implements such as seed planter. Given that direct planting is practiced in undisturbed lands, so it was needed to design ...
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Introduction
Direct planting becomes more common in the recent years, because it conserves soil and water as well as it saves energy and time. However, this technology needs special implements such as seed planter. Given that direct planting is practiced in undisturbed lands, so it was needed to design a special furrow opener. In order to obtain a suitable furrow opener this experiment was conducted in rain-fed Agricultural Research Institute in Maragheh.
Materials and Methods
Most of seed planters that are used for cultivation in rain fed conditions are equipped by hoe-type furrow opener. Hoe-type furrow openers have good penetration in hard and dry soils. However, they do not have the ability for direct planting. Hoe-type furrow opener was chosen as a model. Then by changing the geometric form of the depth to width ratio (d/w), the two openers were designed. In the first design, which was called O1 two wings and a narrow blade acting as a coulter were added in front of the hoe-type furrow opener. In the second design, which was called O2, in addition to the O1 modification, furrow opener width was decreased and a disk blade was added for seed sowing (Fig. 1).
The performance of O1 and O2 openers were compared with the conventional hoe-type furrow opener (check) in soil bin and in field conditions. At three different forward speeds (1, 1.5 and 2 m.s-1) with 3 replications, the effects of the openers designs of vertical and horizontal soil forces were evaluated in soil-bin conditions. In order to evaluate the performance of the furrow opener in field conditions, an experiment was conducted using a split plot design based on RCBD at 4 replications. Furrow openers formed the main plots and forward speeds formed the sub plots. Each plot size was 22 meters long in two rows for each treatment. After germination of wheat crop, the numbers of seedlings in two rows were counted (along a one meter). After crop maturity, all plots were harvested by hand and grain and biological yield was measured. ANOVA test, uniformity test and mean comparison were conducted by using Genstat software.
Results and Discussion
The soil bin test results showed that opener design and forward speed both have significant influences on the horizontal force (p<0.01). Horizontal force was increased with increasing of forward speeds. The same result was reported by Wheeler and Godwin, 1996 and Astafford, 1979. The lowest horizontal force (average 1.66 kN) occurred at 1 m.s-1 and the highest (average 1.94 kN) occurred at 2 m.s-1 forward speeds. Horizontal force increased in O2 (2.8%) and decreased in O1 (3.4%) compared with the control (average 1.77 kN). Moreover, openers had significant influence on the vertical force (p<0.01). Vertical force values were negative in O1 (average -0.05 kN) and O2 (average -0.07 kN) in comparison with positive value in the control (average +0.01 kN). The effect of forward speed on vertical force was not statistically significant. The field results showed that there were significant differences among the openers in the numbers of seedling, grain and biological yield (p<0.01). The O2 opener (with the average of 48 seedlings per one meter row) had 33% and 24% more seedlings in comparison with O1 and check furrow openers, respectively. Probably, using dick bald in O2 design leads to increased seed germination. Increasing of seed germination by using disk furrow opener as an advantage is reported by Kushwaha and Foster, 1993. The O2 furrow opener would also increase grain yield about 36% compared with both O1 and check furrow openers.
Conclusions
It can be concluded that the newly designed furrow opener (O2) could improve the energy efficiency with increasing crop yield. Hence, O2 furrow opener could be recommended for direct planting in rain-fed farming.
Research Article
A. Sharifi Malvajerdi; H. R. Sadeghnezhad; A. Faraji
Abstract
Introduction
Nowadays, agricultural systems are seeking economic, ecological and bioenvironmental goals for production of agricultural crops with protection and sustainability of the environment. Therefore, there is need to extend sustainable agricultural systems such as conservation agriculture. One ...
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Introduction
Nowadays, agricultural systems are seeking economic, ecological and bioenvironmental goals for production of agricultural crops with protection and sustainability of the environment. Therefore, there is need to extend sustainable agricultural systems such as conservation agriculture. One of the principles of conservation agriculture is conservation tillage. Conservation tillage is a kind of tillage that retains crop residues on the soil surface or mixes it with soil using related machines. It could also affect on machine performance parameters. Energy consumption for producing one kilogram crop could be studied for conservation tillage. Several researchers have conducted studies on this issue for production of different crops including wheat, sunflower and forage crops. This study conducted to assess machine performance parameters and energy indices of conservation tillage systems for soybean cultivation in Golestan province.
Materials and Methods
This study was conducted to investigate the effects of conservation tillage systems on machine performance and energy indices in soybean production at the Gorgan research station of Golestan Agricultural and Natural Resource Research Center in 2012. The precipitation was 450 mm. Soil texture was silty clay loam. Treatments were four tillage methods, including no-till using row crop direct planter, no-till using grain direct drill, conventional tillage usin a disk harrow with working depth of 10-15 cm and minimum tillage using chisel packer with a working depth of 20 cm. Machine performance parameters and energy indices studied in a farm covered by wheat residues in a randomized complete block design (RCBD) with four treatments and four replications. Machine performance parameters consisted of field efficiency, field capacity, total field capacity and planting uniformity index were measured. Energy indices such as energy ratio, energy productivity, energy intensity and net energy gain were also calculated.
Results and Discussion
The results showed that no-tillage methods by grain drill and row crop planter had the lowest field efficiency (56% and 58.9%, respectively), but had the highest field capacity (0.76 and 0.71 ha h-1, respectively), as the passage of implements in the field was less than that of conventional tillage. Peruzi et al., (1996) also reported that required time for minimum tillage and no-till was 80% less than conventional tillage. No-till using grain drill with the total field capacity of 0.76 ha h-1 and conventional tillage with 0.33 ha h-1 had the highest and lowest field capacity among the treatments, respectively. Minimum tillage had the best horizontal distribution uniformity for seed placement on the row. No-till using seed drill had the highest energy ratio of 4.5 and yield of 3612 kg ha-1, which were higher than the other treatments. No-till also produced 0.19 kg crop per each MJ energy consumption. It consumed the lowest amount of energy with 5.3 MJ for production of 1 kg soybean and had the highest net energy gain among treatments. Minimum tillage had the lowest consumption of energy with 2030.2 MJ ha-1 among the treatments. It had the lowest amount of net energy gain because of having lowest yield (2794 kg ha-1). Zentner et al., (2004) and Razzaghi et al., (2012) also concluded that conservation tillage systems had the lowest amount of energy consumption compared to the conventional tillage.
Conclusions
The study of energy indices is important for producing agricultural crops to decrease energy consumption. Among the tillage methods, no-till method had the best indices about reducing energy consumption. Although the size of no-till grain drill will increase the weight and energy consumption of machine, but it well penetrates on the soil. Results showed that minimum tillage and no-till methods are proper alternatives for replacement of conventional method for producing soybean, according to the precise of planting and improvement of energy indices. However, the existing planters can be modified for row crops and increasing of planting accuracy indices with correct management of no-till methods at crop protection stages. It can also help to localize conservation tillage implements and speeding up new methods for reaching to sustainable energy and production resources.
Research Article
M. Shabanzadeh; R. Esfanjari Kenari; A. Rezaei
Abstract
Introduction
While the world's population is growing, agricultural production is still based on the use of limited and non-renewable resources. In addition to the scarcity of resources, their continuous using over the long term, causes the widespread pollution, loss of soil fertility and low agricultural ...
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Introduction
While the world's population is growing, agricultural production is still based on the use of limited and non-renewable resources. In addition to the scarcity of resources, their continuous using over the long term, causes the widespread pollution, loss of soil fertility and low agricultural production capacity, eventually. The main causes of the increase in energy consumption include the increase of world population, limited arable land, low price of fuel and fertilizer and noted increased levels of human life. Attention to limited resources and adverse effects resulting from the appropriate use of different energy sources on human health and the environment, has been required examining the energy consumption patterns and the flows of energy in the agricultural sector. Checking the share of input and output energy in different agricultural ecosystems, with attention to the type of product and the type of materials used in production, can help to identifying defects and play a fundamental role in the sustainable production, optimization of economic system, maintaining reserves of fossil fuels and mitigate air pollution. With this approach, in this present study energy consumption and energy indices for tomato production in Khorasan Razavi were studied.
Materials and Methods
The energy efficiency of units was analyzed using the stochastic frontier technique (SFA). Energy inputs from two perspectives have also been divided. In the first view of energy inputs, including inputs that have a direct energy (DE) and indirect energy (IDE). The second approach as well includes inputs that have renewable energy (RE) and non renewable energy (NRE).The data for this study was collected through interviews and completing 156 questionnaires using two-stage random sampling from tomato producer of Khorasan Razavi province in 2012.
Results and Discussion
The results showed that the energy consumption for tomato production in Khorasan razavi province of Iran were 43.2 GJha-1. Water for Irrigation was attributed the greatest share of energy inputs (30%). The average amount of diesel fuel consumption was 152 lha-1, Human resources and machinery were 987 hha-1 and 44.6 hha-1 respectively. The average amount of water needed for irrigation was 12,596 m3ha-1. Average energy output of the system was determined to be 35.3 GJha-1. The share of different forms of energy inputs such as direct energy was 53.9 %, indirect energy was46.1renewable energy was 50.5, and renewable energy was49.5%. According to the results, the share of indirect energy was higher than direct energy and the share of renewable energy was higher than renewable energy. Also the result of the study revealed that energy productivity and efficiency in the investigated units were 0.68 and 0.82MJha-1, respectively. The results show that the Cobb-Douglas function to calculate the efficiency has more consistency and adaptation with the data. In other words, Cobb-Douglas function is superior to the translog function. Average of technical efficiency was calculated 57%.
Conclusions
The results indicated that although a significant percentage of the investigated farms are inefficient, farmers with higher acreage have favorable energy consumption and technical efficiency of these farms was higher than that the other ones. Considering the obtained results, the main drawback associated with the technical efficiency of energy use and production of tomato in Khorasan Razavi is inappropriate use of inputs due to mismanagement, lack of information and also the small size of the farms. Based on the results the better management in the use of inputs and the enlargement of the size of agricultural land can improve energy efficiency in the region. Also, for improving the measures of energy flows in growing tomatoes, determining the appropriate amount of fertilizer (particularly phosphates) to grow tomatoes, conducting classes and printing the brochures for farmers to implement correct procedures in the use of inputs and the use of machines, correction of the system to reduce water consumption and cultivation of new varieties of tomato seeds in the region are recommended.
Research Article
A. Kosari Moghaddam; H. Sadrnia; H. Aghel; M. Bannayan Aval
Abstract
Introduction
The working day is an important component in selection and analysis of farm machinery systems. The number of working days is affected by various factors such as climate, soil characteristics and type of operation. Daily soil moisture models based on weather long-term data and soil characteristics ...
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Introduction
The working day is an important component in selection and analysis of farm machinery systems. The number of working days is affected by various factors such as climate, soil characteristics and type of operation. Daily soil moisture models based on weather long-term data and soil characteristics were almost used for calculating probability of working days. The goal of this study was to develop a simulation model to predict the number of working days for secondary tillage and planting operation in fall at 50, 80 and 90% probability levels.
Materials and Methods
A Simulation model was developed using 21 years weather data and soil characteristics for calculate daily soil moisture content in Research Station of Ferdowsi University of Mashhad. So soil moisture was calculated using daily soil water equation for top 25 centimeter of soil depth. Moisture equal or lower than 85% of soil field capacity and precipitation lower than 4 millimeter (local data) were considered as soil workability criteria. Then the working days were determined for secondary tillage and planting operation at 50, 80 and 90% probability levels in falls. The number of days at 50% probability was the mean over 21 years and the number of days at 80% and 90% were determined for each two weeks period as the average number of working days minus the product of t value and standard deviation of those numbers.
Model Evaluation
Evaluation of model included a comparison of predicted and the observed the number of working days in Research Station of Ferdowsi University of Mashhad during 2002-2010 and sensitivity analysis was implemented to test the effect of changes in soil workability criterion (80, 90, 95 and 100% of soil field capacity), drainage coefficient (25 % decrease and increase) and soil field capacity (40% increase) on simulation results.
Results and Discussion
Comparison of predicted and observed days showed that correlation coefficient was 0.998 and the difference between the simulated data and observed data was not significant at the 5% level.
Results from sensitivity analysis in Table 3 showed that when soil workability, drainage coefficient and field capacity increased, the number of working days increased, but model sensitivity was very low to drainage coefficient and soil field capacity. In general, the most important factor is precipitation in this weather conditions.
The number of working days for secondary tillage and planting operation for each period in fall are shown in Table 4.
Conclusions
A simulation model was developed for predicting the number of working days for secondary tillage and planting operation in fall. This model was based on weather long-term data and soil characteristics for the Research Station of Ferdowsi University of Mashhad. The most important factor was precipitation and the model had low sensitivity to drainage coefficient and soil field capacity. The number of working days in 50%, 80% and 90% probability levels for period of ten days was on average 9.94, 9.21, 8.57 days for 23th September to 22th October and 9.77, 8.02, 6.41 days for 23th October to 21th November and 9.68, 7.48 and 5.24 for 22th November to 21th December, respectively.
Short Paper
Design and Construction
I. Ahmadi
Abstract
IntroductionMeasurement of the draft force exerted from agricultural machineries to the tractor and the calculation of the implement power requirements is important for agriculturalists in terms of machine design and tractor-machine matching . Therefore, studies about this issue have been started from ...
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IntroductionMeasurement of the draft force exerted from agricultural machineries to the tractor and the calculation of the implement power requirements is important for agriculturalists in terms of machine design and tractor-machine matching . Therefore, studies about this issue have been started from the 1950’s. Zoerbet al.,(1983) claimed that the first dynamometers have been made of spring and in reality, users had difficulties reading these dynamometers gauge due to the quick variations of the gauge pointer. Therefore the second stage was the development of the hydraulic-type dynamometers in which the oil pressure inside the hydraulic cylinder-piston set installed between machine and tractor that can be readable with a bourdontube gauge was considered as its indicator. From the first years of the 1960’s development of the strain-gauge pull-type dynamometers started. In this study, design, fabrication and evaluation of a pull-type tractor dynamometer is considered that can be used to measure and store tractor forward velocity, and horizontal component of draft force exerted from wheel-type towed implements to the tractor. Therefore, drawbar power needed to pull the machine through the soil can be calculated. This dynamometer can also be utilized to measure three-point-hitch implement’s draft force and power requirements in condition that the RNAM (1983) method was used. In addition to measure the tractor velocity with a GPS receiver instead of a fifth wheel, the other particular issue about this dynamometer is that a remote controller is used to order data acquisition commands such as starting, ending, pausing and time zeroing in the process of data gathering. Materials and MethodsIn this study an S-type strain gauge load cell (model: SS300) and a GPS receiver (model: Micro GPS antenna AGM-10 + NEO-6-M-0-001 ublox AG board) were utilized to measure the draft force and forward velocity, respectively. To calibrate the load cell sensor, in an iron material selling store, the load cell was placed between an external force with a known value and roof-type load lifter by steel cables, and external loads with the value of 1-5 ton applied to the load cell in ascending and descending order. In each loading stage, the system and measuring apparatus outputs were booked. After drawing the x-y scatter chart of paired values (system output, measuring apparatus output), regression equation between these two variables were obtained that can be utilized to calibrate this part of the system. Above-mentioned method was used to calibrate the velocity measuring part of the dynamometer with a difference that real velocity was used instead of external load and velocity output was used instead of the load cell output. After performing the calibration of the system, the developed dynamometer was utilized to measure the draft force and power requirements of a three-point-hitch moldboard plow using the RNAM method. Finally, the obtained results were compared with the other researcher’s results, and the ASAE prediction of the draft force of a moldboard plow.Results and DiscussionAccording to the results of this study, the estimated equation and its coefficient of determination for the calibration of the load cell sensor were , and respectively, and the estimated equation and its coefficient of determination for the calibration of the velocity were , and respectively. Moreover, according to the results of the field tests, draft force and the power requirements of a three-bottom moldboard plow in a silty clay loam soil with the forward velocity of was measured to be , and , respectively, that were in agreement with other studies. Furthermore, the draft force results of this study, and other studies were in the range of of the which is the moldboard plow draft prediction according to the ASAE standard.ConclusionsThis study suggests that with the aid of the RNAM method, and the developed dynamometer, the draft force and power requirements of the tillage implements can be calculated. These results can further be utilized to match the implements with the tractor or to design new tillage implements.
