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Saiedirad M.H.,Khorasan Agricultural and Natural science Research Center | Javadi A.,Iranian Agricultural Engineering Research Institute
Agricultural Engineering International: CIGR Journal | Year: 2011

Prior to developing a cumin thresher, the efficiency factors of cumin threshing was investigated. The effect of thresher variables including the moisture content, cylinder type and cylinder speed, feed rate and concave clearance on weight percentage of separated seeds, shattered stems and damaged seeds were studied in this research. The results showed that as moisture content increased from 7% to 13%, separated seed and damaged seed decreased from 92.8% to 90.4% and from 10.1% to 7.6%, respectively. However, increasing cylinder speed from 12.8 to 16.5 m/s, increased the percentage of separated seed, shattered stems and damaged seed. The cylinder type did not have significant effect on weight percentage of separated seed, while it had a significant effect on shattered stems and damaged seeds. It was concluded that the rub bar cylinder was better than the rasp bar cylinder. Thus, the rub bar cylinder, 16.5 m/s cylinder speed and 7% grain moisture content were the most suitable conditions for cumin threshing. Source

Ojaghloo H.,University of Tehran | Ojaghloo H.,Islamic Azad University at Tehran | Sohrabi T.,University of Tehran | Rahimi H.,University of Tehran | And 4 more authors.
ASABE - 9th International Drainage Symposium 2010, Held Jointly with CIGR and CSBE/SCGAB | Year: 2010

The necessity of the use of subsurface drainage envelopes (envelopes) is one of the major concerns which are brought up in the first stages of design and construction of a drainage project. Clay percentage of soil is the first index to predict this requirement. In this study, in order for the calculation of gradient ratio (GR) and the assessment of clogging potential and soil particles movement into the drainpipe, the permeameter test was carried out on three samples with clay and clay loam textures. Treatments in this experiment were drainage systems with and w/o envelopes. In system with envelope, two types of envelopes (granular and fiber) were used. Through conducting this experiment, discharge variation, system permeability, gradient ratio and exit gradient were investigated. The results showed that the values of gradient ratio in the systems without envelope in most cases were greater than one which indicates high particle movement potentials. Nevertheless, soil particles movement happened when the values of this index exceeded 3. The ratio of outflow from the systems with mineral and synthetic envelopes to the ones without envelope ranged 2.0-3.5 and 1.4-1.8, respectively. As hydraulic gradient was increased, system hydraulic conductivity decreased in a way that the greater decrease happened in the system without envelope. Furthermore, by the calculation of hydraulic failure gradient and its comparison to exit gradient at different hydraulic gradient values, the resistance of soil particles against flow pressure was analyzed. The results indicated that the system without envelope had the least and the most performance in samples No. 2 and 3, respectively. Source

Pishgar-Komleh S.H.,University of Tehran | Keyhani A.,University of Tehran | Mostofi-Sarkari M.R.,Iranian Agricultural Engineering Research Institute | Jafari A.,University of Tehran
Research Journal of Applied Sciences, Engineering and Technology | Year: 2012

This study evaluated the amount of machinery losses during seed corn harvesting operation and investigated the relationship between cylinder and ground speed of the grain combine on total harvesting losses. For this purpose data were collected from a representative seed corn field which harvested using the grain combine. All types of losses measured based on a standard method and gathered as total combine loss. Response surface methodology based on two variables (cylinder and ground speed), three levels and Central Composite Design (CCD) was applied to find the optimum level of harvesting loss. Different models (linear, 2FI, quadratic and cubic), were tested and the 2FI model was selected as the best model which describes the relationship between dependent and independent variables. The predicted values were compared with the actual values of total losses and it was evident that the actual values were distributed relatively near to the predicted line which indicated that there is a good correlation between the actual and predicted values (with R2 value of 0.88). The optimal condition in which the total combine harvesting losses was found the least at cylinder speed of 400 rpm and ground speed of 3 km/h. © Maxwell Scientific Organization, 2012. Source

Abbasi N.,Iranian Agricultural Engineering Research Institute | Nazifi M.H.,Shooshtar Azad University
Geotechnical and Geological Engineering | Year: 2013

Soil dispersion is a phenomenon in which soil particles become afloat when they are exposed to water, and are carried away by the force of seepage. In spite of that soil dispersion is due to its chemical composition, the results obtained from the chemical methods, especially from the most widely used, Sherard method does not match with the results of well-known Pinhole test. This study tries to evaluate and modify the Sherard diagram for determination of dispersion potential of clayey soils. For this purpose, several natural soil samples were collected from different regions of Iran and some artificial soil samples were made by adding different percentages of four chemical agents, including sodium chloride, sodium carbonate, sodium sulfate, and sodium polyphosphate to a natural soil. The physical, chemical and index properties of all samples were determined and for determination of dispersion potential, the commonly used chemical test (Sherard method) and Pinhole test were employed. The results obtained from the tests showed that the Sherard chemical method which is solely based on the amount and type of the existing cations, is not able to determine soil dispersion correctly since the role of some anions, especially chloride is neglected. It was also found that among the existing anions in the soil, the chloride on the contrary to sodium acts as a flocculating factor. The results showed that by converting the vertical axis of the Sherard chart from sodium% to (sodium chloride)%, its conformity to the results of Pinhole tests increases considerably. © 2012 Springer Science+Business Media Dordrecht. Source

Pishgar-Komleh S.H.,University of Tehran | Keyhani A.,University of Tehran | Mostofi-Sarkari M.R.,Iranian Agricultural Engineering Research Institute | Jafari A.,University of Tehran
Energy | Year: 2012

This study evaluated the energy balance and economic analysis between inputs and output of seed corn production in different harvesting systems in Iran. Data were collected from seed corn farms in Alborz province. The results indicated the total average energy input and output of 51.1 and 243.9GJha -1, respectively. The highest share in energy consumption belonged to chemical fertilizers (43%) followed by water for irrigation (19%) and diesel fuel (19%). The highest total energy input and output belonged to two stage harvesting system (using picker-husker) in comparison with other harvesting systems (combine and plot-harvester harvesting). The average energy use efficiency and productivity were calculated 4.78 and 0.05kgMJ -1, respectively. Combine harvesting had the highest energy ratio value (5.15) and followed by two stage harvesting system (4.78) and then plot harvester (4.40). Direct, indirect, renewable and non-renewable energies were 43%, 57%, 6%and 94% of total energy, respectively. Cost analysis revealed that total average cost of production and benefit-cost ratio were 3477 $ha -1 and 1.46, respectively. The benefit-cost ratio values for picker-husker, combine and plot harvester were 1.54, 1.53 and 1.32, respectively, that indicated harvesting by two stage harvesting system (using picker-husker) had more economic efficiency. © 2012 Elsevier Ltd. Source

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