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Farid Eltom A.E.,Nanjing Agricultural University | Farid Eltom A.E.,Key Laboratory of Intelligent Agricultural Equipment of Jiangsu Province | Ding W.,Nanjing Agricultural University | Ding W.,Key Laboratory of Intelligent Agricultural Equipment of Jiangsu Province | And 5 more authors.
Journal of Terramechanics | Year: 2015

Abstract Draught requirement is an important parameter for tillage tool performances. This study investigated the influence of trash board on the performance of moldboard plough and the system optimization. Draught and vertical forces acting on the plough were measured with and without a trash board under two straw conditions, i.e. with only stubbles and with dense straw cover. Field soil moisture content was kept at 30%. The study also used the finite element method (FEM) to simulate stress distribution on the plough. Results showed that draught significantly increased without trash board under dense straw cover as compared with only stubbles. The trash board attachment reduced draught significantly. Similar trend was also true for vertical force. FEM results were found to be compatible with the experiment. The simulated maximum equivalent stress acting on the mouldboard plough was 279.43 MPa, while the material's yield stress was 250 MPa. Attaching trash board with the moldboard plough is important where straw cover was dense. © 2015 ISTVS. Published by Elsevier Ltd. All rights reserved. Source

Zhang C.Y.,Nanjing Agricultural University | Zhang C.Y.,Key Laboratory of Intelligent Agricultural Equipment of Jiangsu Province | Jian X.L.,Nanjing Agricultural University | Jian X.L.,Key Laboratory of Intelligent Agricultural Equipment of Jiangsu Province | And 2 more authors.
EPL | Year: 2012

The influence of polarization on the two-dimensional structure of heterogeneous dumbbells is studied by Monte Carlo simulation. The dumbbell consists of two fused hard spheres whose centers are embedded with point dipoles μ → a and μ → b, respectively. The axis of the dumbbell can rotate freely in the x-y plane but μ → a and μ → b are always along the x-axis which is the polarization direction. When the dipolar strength μa is much larger than μb, the dumbbells are perpendicular to the polarization direction and form zigzag chains; when μa and μb are comparable, the dumbbells will form end-to-end chains if μ → a and μ → b are parallel, or side-by-side chains if μ → a and μ → b are antiparallel. All the chains are along the polarization direction and the detailed information about them is given through extracting the radial and angular distributions from the simulation results. Finally, we calculate the energies of four kinds of ideal chains to explain structural transition. Our simulation results can explain the very recent experiment by Nagao D. et al. (Langmuir, 28 (2012) 6546) which studied the assembly of dumbbells with inducible dipoles, where magnitude of the dipoles was frequency-dependent and by changing frequency, different assemblies could be obtained. Copyright © EPLA, 2012. Source

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