poor stand establishment of canola (brassica napus l.) under flatland mechanized planting and crust-forming soil is a major problem for farmers in central iran. previous research there showed that irrigated cotton emergence on crust-forming soils under flatland planting can be significantly improved using a double-disk planter with zero-pressure press wheel tires and no crust-breaking. in that ...

Fatigue crack growth can be strongly influenced by crack closure, i. e., the contacting of the opposing faces of a fatigue crack above the minimum load in a loading cycle. This crack closure shields the crack tip from the full stress field, but different views are held regarding the extent of this shielding. The type of closure, whether it be plasticity-induced, or roughness-induced may also pl...

background: the trajectory of marital quality over the life course assumes a curvilinear pattern and declines over time. however, most studies to date have been conducted in developed societies, leaving the generalizability of their findings open to skepticism. in this study, we aimed to delineate the trajectory of marital satisfaction in iran. methods: using cluster-sampling method, representa...

* Corresponding author; Email: [email protected] ABSTRACT Crack tunneling is a crack growth feature often seen in stable tearing crack growth tests on specimens made of ductile materials and containing through-thickness cracks with initially straight crack fronts. As a specimen is loaded monotonically, the mid-section of the crack front will advance first, which will be followed by crack growth ...

In this study, the problem of finding the complete trajectory of propagation in plates with internal straight cracks is extended to the non-linear field. In particular, results concerning concrete plates in bi-axial tensile loading are shown. The concrete constitutive law adopted for this purpose is monotonically non-decreasing, as following according to previous studies of the Authors on monot...

planning robot trajectory is a complex task that plays a significant role in design and application of robots in task space. the problem is formulated as a trajectory optimization problem which is fundamentally a constrained nonlinear optimization problem. open-loop optimal control method is proposed as an approach for trajectory optimization of cable parallel manipulator for a given two-end-po...

Planning robot trajectory is a complex task that plays a significant role in design and application of robots in task space. The problem is formulated as a trajectory optimization problem which is fundamentally a constrained nonlinear optimization problem. Open-loop optimal control method is proposed as an approach for trajectory optimization of cable parallel manipulator for a given two-end-po...

Theories of toughness of materials depend on an understanding of the characteristic instabilities of the crack tip, and their possible interactions. In this paper we examine the effect of dislocation emission on subsequent cleavage of a crack and on further dislocation emission. The work is an extension of the previously published Lattice Greens Function methodology[1, 2, 3]. We have developed ...