Current Issue : January - March Volume : 2013 Issue Number : 1 Articles : 6 Articles
The need for knowledge of coefficient of friction of agricultural materials on various surfaces has long been\r\nrecognized by engineers concerned with rational design of grain bins, silos and other storage structures. In the design of\r\nagricultural machinery, however, the need for this information has been recognized rather recently. Not finding this\r\ninformation in any handbook or published data, it became necessary to set up a friction test apparatus and obtain the\r\ninformation needed. We know that the internal friction angle metering devices in our laboratories have the low accuracy, thus\r\nwe decided to design an automatic internal friction angle metering device with high accuracy which the tangent of this angle is\r\nequal to the coefficient of friction that be measured and displayed. This device is made up of one frame, three hinges, one\r\nelectromotor with gearbox, one DC Adaptor, one wooden plate that can be changed, acceleration measuring sensor, laser\r\ntransmitter and LDR for detection of movement, electrical circuit, Microcontroller and monitor for display of the angle and\r\nother devices for moving of the wooden plate and carrying of the materials....
The objective of this study was to apply the precision metering on wheat seeding to overcome seed damage, seed loss\r\nand non-uniform distribution. Accordingly, a prototype of the pneumatic precision metering device for wheat was developed.\r\nThe performance of the device, including quality of feed index (QFI), multiple index (MULI), miss index (MISI) and seed rate\r\nexpressed in number of kernels per meter length (KPM), was investigated under laboratory conditions in Wuhan using a test\r\nstand with camera system. The results revealed that the rotating speed (RS) and negative pressure (NP) and their interactions\r\nhad a significant effect on these variables. The maximum QFI (92.98%) was obtained at rotating speed of 19.0 rpm and\r\nnegative pressures of 2.5 kPa with MULI and MISI of 2.01% and 5.09%, respectively. However, the seed rate (KPM) was\r\nless than the recommended compared to previous hypothesis. The best seed rate was 53 KPM producing QFI of 89.11% with\r\nMULI and MISI of 9.00% and 1.88%, respectively at rotating speed of 34 rpm and negative pressure of 4.5 kPa. The\r\nrecommended seed rates estimated at 40 KPM and 53 KPM for 12 cm and 15 cm row spacing respectively were achieved at a\r\nrange of RS and NP with QFI ranging between 84.57 to 89.11%. The study demonstrated that wheat could be seeding within\r\nan acceptable precisely range by pneumatic precision metering device....
Several physical and mechanical properties of Zucchini from Kermanshah province of Iran were determined. The\r\nphysical and mechanical properties of the zucchini are necessary for the design of automatic equipment for harvesting,\r\nprocessing, transporting, sorting and separating of samples. At the average moisture content of 94.65% w.b., average of mass,\r\nvolume, dimensions (big, medium and small diameters), geometric mean diameter, projected area (big, medium and small area),\r\ncriteria areas, arithmetic means diameter, sphericity, density and surface area were 80.81 g, 85 cm3, 111.7 mm, 34.58 mm,\r\n33.87 mm, 51.74 mm, 3,892.52 mm2, 3,792.07 mm2, 1,126.44 mm2, 2,937.02 mm2, 60.05 mm, 45.49%, 0.96 g/cm3 and\r\n8,268.20 mm2, respectively, and ratio of weight of rind per weight of fruit was 0.25. Mechanical properties that measured\r\nincluding elasticity modulus, maximum force which fruit can be supported, work which performed to this force under\r\ncompression loading, deformation at maximum force and penetration force, their averages were found 0.73 GPa, 167 N,\r\n762.82 N.mm, 8.81 mm and 1.26 N, respectively....
In order to solve the boredom involved in melon shelling operation which is one of the major factors militating\r\nagainst the large scale production, processing and the use of this important oil crop, a power-driven melon seed shelling\r\nmachine was designed, constructed and tested. The machine consists of a feed hopper, a shelling unit, a delivery chute, a\r\npower system and a tool frame. The shelling action was achieved by principle of a rotor that throws melon seeds against the\r\nshelling drum by centrifugal force and then the seeds were converged onto a spinning disc with vanes that provide impact force\r\nto remove the kernel from the shell. The results of the performance tests carried out showed that the machine shelling\r\nefficiency increased with the increase in moisture content and speed. Maximum shelling efficiency percentage of 95% was\r\nobtained at the seed moisture content of 26.6% d.b and at 2,190 rpm shelling speed. Percentage seed damage was found to\r\ndecrease with the increase in seed moisture content. Machine capacity and throughput capacity were 192 kg/h and 796 kg/h\r\nrespectively. The analysis of variance showed that moisture content and machine shelling speed have significant effect on\r\nboth shelling efficiency and percentage seed damage at 1% level. Regression models that could be used to express the\r\nrelationship among the performance indices, moisture content and machine speed were established....
Aim of this work was to investigate the influence of pretreatment on drying rates of chili pepper (Capsicum annum\r\nL.) at various air temperatures and pretreatment methods. Chilies were pretreated mechanically, chemically as well as by a\r\ncombined form before drying. The changes of moisture content were determined experimentally at temperatures of 35, 50, 60,\r\n70, and 90?? for pretreated and untreated red chilies. The total drying time required for each case was evaluated based on the\r\nacceptable value of moisture content (dry basis) for safe storage of vegetables and fruits obtained from literature. In this work,\r\na moisture content of 0.10 (kg water /kg dry chili) was taken as the final moisture content to determine the final drying time.\r\nThe results of this experiment showed that much shorter drying times were achieved with the application of pretreatments.\r\nIncreasing the drying air temperature from 35 to 50?? shortened the final drying time by 140 h, which is 72% reduction of the\r\noriginal drying time. The shortest drying time at lower as well as higher temperatures was achieved by making a number of\r\nsmall holes on the skin of chilies (mechanical pretreatment method). In this case, at a temperature of 60?? the final drying\r\ntime was shortened by 48% compared to the untreated method which was at the same temperature and in the same drying\r\nconditions....
Abstract: Design of unit operations for mechanical and pneumatic cleaning, transportation (conveying), processing and storage\r\nof cardamom seeds are dependent on moisture content. Some of moisture dependent physical properties of cardamom seeds\r\nwere studied at moisture contents 9.9%, 13.57%, 18.41%, and 23.29% wet basis (w.b.). The length, width, thickness,\r\ngeometric mean diameter, thousand seed mass, and sphericity increased from 17.01 to 17.30 mm, 5.68 to 6.57 mm, 5.02 to\r\n5.35 mm, 7.86 to 8.47 mm, 120.83 to 165.60 g, and 0.46 to 0.49, respectively, with the increase in the moisture content from\r\n9.9 to 23.29% w.b. As the moisture content increased from 9.9 to 23.29% the bulk density, true density, and porosity\r\ndecreased from 408.2 to 358.90 kg/m3, 926.57 to787.19 kg/m3, and 55.94 to 54.41%, respectively. The angle of repose\r\nincreased from 72.16o at 9.9% to 73.80o at 23.29% moisture content. Whereas, the static coefficient of friction increased with\r\nthe increase in moisture content from 9.9 to 23.29% on three different surfaces. The highest static coefficient of friction was\r\nrecorded when cardamom seed against plywood (0.47 to 0.56), and lowest static coefficient of friction against mild steel (0.41\r\nto 0.50). The static coefficient of friction between cardamom seeds and galvanized iron surface increased from 0.44 to 0.53\r\nwithin the studied moisture content range....
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