Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 6 Articles
Primary tillage parameters and their effects on tractor efficiency, fuel consumption management and cost reduction\nare very important in mechanization. The main goal of this study was to determine some performance parameters in three\nconventional tractors Massey Ferguson 285(MF 285), Universal 650 (U650) and John Deer 3140 (JD3140) to primary tillage\npractices in some area of Iran. These parameters are important for selecting tractors to set up mechanization program in a\nlarge scale. The sampling method was random in 10 regions with seven replications. After data gathering, results were\nanalyzed using SPSS software. Results indicated that average drawbar power for plowing without considering of area and\ntractor type was 15 kW. The maximum and minimum drawbar powers were 19.20 kW and 11.10 kW for Esfahan and Fars\nareas respectively at 1% level significance. There were significant differences between values of rolling resistance of JD3140\ntractor with other tractors at 1% level of significance. Besides, no significant differences were observed between tractors of\nU650 and MF285. Slippage percentage was similar for most areas. The maximum and minimum slippage was recorded for\nMF285 tractor in Moghan area and JD3140 tractor in Esfahan area respectively. The optimum soil moisture was 15% for\nslippage reduction. Average Power Delivery Efficiency (PDE) was 25.5%. It was low in comparison with world standards\nand requires improvement. Tractor of JD3140 had maximum fuel consumption (0.012 m3 h-1) as compared to other types of\ntractor. Use of the U650 tractor was recommended to farmer and other data can be used for mechanization programs....
To design a sunflower machine for removing seeds from sunflower head (SH) based on air-jet impingement,\npreliminarily model of such machine was designed, constructed and evaluated. Effects of the seed location, angle of\nimpingement, distance between nozzle outlet and sunflower head, and rotational velocity of sunflower head on percentage of\nextracted seeds were examined. In order to examine the effects of air-jet parameters on percentage of removed seeds in\ndifferent locations of seed on sunflower head, sunflower heads were divided into three regions, namely central region, middle\nregion and side region. Results indicated that in all three regions, with increasing rotational velocity from 10 to 30 rev/min,\npercentages of removed seeds from the SH decreased. Results also indicated that in all three regions, with increasing distance\nbetween nozzle outlet and SH surface from 10 to 20 mm and decreasing distance between nozzle outlet and SH surface from 40\nto 20 mm, percentage of removed seeds from the SH by air-jet increased. Results indicated that in side region, with\ndecreasing angle of impingement from 90% to 30%, of removed seeds from the SH by air-jet increased and in middle and\ncentral regions, with increasing angle of impingement from 30�º to 60�º and decreasing angle of impingement from 90�º to 60�º,\npercentages of removed seeds from the SH by air-jet increased. Also in all tests, no seed damaged due to air-jet impinging\nwas observed....
In this study, characterization of an automatic greenhouse spraying system containing a full cone spray nozzle is\npresented. Spray flow rate of the nozzle as a function of incoming pressure to the nozzle, together with distribution of mean\ndrop size, two components of drop velocity and uniformity of the generated spray are given in this study. Based on the results\nobtained, mean droplet size at the centreline of the spray is much smaller than dose in the outer side of the full cone spray.\nUniformity of the generated spray by a given nozzle should be examined before application, especially if the nozzle is not new.\nThe average generated drop size by the examined nozzle is less than 60 �µm which is suitable for the insecticide or fungicide\napplications....
In this study, an experimental investigation regarding the influence of three independent variables including tillage\ndepth (10, 15, 20 cm), angle of attack (60, 75, 90 degrees) and forward speed (0.5, 1, 1.35, 1.7 m/s) on draft force of a thin\nblade is presented. Chisel plow in this research was constructed in two furrows with a blade width of 3 cm and a maximum\ndepth of 25 cm (the distance between two blades was 1 m). Some changes were made in the chassis of the chisel plow in\norder to obtain different attack angle of the blade. The experimental work was then complemented with a new theoretical\nmodel for predicting the blade force using dimensional analysis method. The final expression for estimating the pull\nresistance is as a function of several soil engineering properties (soil bulk density, soil adhesion and cohesion coefficients),\nblade parameters (blade width and blade rake angle) and operational conditions (tillage depth and forward speed). Finally\nconstants of the model were computed based on obtained experimental data. The proposed model properly estimated the draft\nforce of a thin blade. Results obtained in this study indicate the stronger influence of tillage depth on the pulling force of a\nthin soil-working blade compared to the penetration angle and forward velocity. The average error for the vertical blade with\ndepth of 20, 15 and 10 cm were obtained equal to 4.5%, 4% and 1.5%, respectively....
The objective of this study was to find optimizing moisture content and cutting area of sugarcane stalk cutting\nparameters using multiple regressions and to verify the optimum levels of the variables. The effect of moisture content and\ncutting section area on mechanical cutting properties of sugarcane stalks was studied using a linear blade cutting and UTM\n(Universal Testing Machine) size reduction device. Data obtained in the laboratory were divided into four different groups in\norder to determine the peak force, cutting energy, ultimate stress and specific energy. Additional criterions were also proposed\nand used as an indicator of the cutting performance. These were the marginal cutting parameter (MCP) and return to scale\n(RTS). The data obtained in the laboratory were then used to develop functions in polynomial form that allowed the\ncalculation of the optimum level of each independent variable considered in the study. Moisture content had the highest effect\non peak force, ultimate stress and specific energy with an impact of -15.936, -0.147 and -0.179, respectively. Also cutting\nenergy affected with cutting section area with a 36.06 coefficient. The high moisture content level compared to low moisture\ncontent level produced a significant reduction in the peak force, ultimate stress and specific energy. Cutting parameters were\nrelatively insensitive to moisture content of sugarcane stalk more than cutting section area of that....
This study evaluated effects of crosswind on the variable rate sprayer application treatments spray coverage and\ndeposition on different citrus canopy sizes. The axial-fan airblast sprayer retrofitted with variable liquid- and air-assist rates\nwas field-tested with different crosswind conditions on small (about 2 m tall and < 1.5 m wide) and medium-sized (about 3 m\ntall and < 2.5 m wide) canopies. Crosswinds of 1.3, 2.7, and 4.0 ms-1 on the canopies being sprayed were generated using the\nstationary conical air shaker as the air blower unit. Water sensitive papers (WSPs) were used to collect droplet deposits and\nimage processing software was used to analyze the WSPs scanned at 600 dpi. Percent spray coverage on the WSPs was found\nto be one of the most suited parameters to evaluate the effectiveness of spray application treatments. Overall, the variable rate\nspray application treatments had comparable spray coverage on respective canopies (front, middle, and across WSP locations in\nthe canopy) during all crosswind conditions. For both types of canopies, spray coverage was higher on the canopy front and\ndecreased as the spray penetrated inside (i.e. canopy middle) and across. Due to coalescing, larger droplets (Dv,0.5 [volume\nmedian diameter] = 838 to 2,624 �µm) were formed on the WSPs located on canopy front, whereas coalescing reduced as the\nspray penetrated inside (Dv,0.5 = 391 to 1,625 �µm on canopy middle) and across the canopy (Dv,0.5 = 307 to 508 �µm)....
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