Rotational drilling was a revolution in drilling technology. It made the drilling process more efficient and faster and more depth of well could be achieved through rotation method. Besides all of its advantages, the rotation approach induced some problems like pipe sticking and downhole cleaning to the drilling procedure. Hole cleaning and reduction of torque and drag seems to be vital in incl...

Multistage hydraulic fracturing is one of the most prevalent approaches for shale reservoir development. Due to complexity constructing environments experiments, numerical simulation a vital method study flow behavior under conditions. In this paper, we propose model that considers multistage fractured horizontal well with hilly-terrain trajectory in presence natural fractures. The was construc...

The time-optimal trajectory for an airplane from some starting point to some final point is studied by many authors. Here, we consider the extension of robot planer motion of Dubins model in three dimensional spaces. In this model, the system has independent bounded control over both the altitude velocity and the turning rate of airplane movement in a non-obstacle space. Here, in this paper a g...

The optimal barbell trajectory for snatch weightlifting has been achieved empirically by several researchers. They have studied the differences between the elite weightlifters’ movement patterns and suggested three optimal barbell trajectories (type A, B, and C). But they didn’t agree for introducing the best trajectory. One of the reasons is this idea that the selected criterion by researchers...

trajectories generally used to describe the space and time required to perform a desired motion task for a mobile robot or manipulator system. in this paper, we considered a cubic polynomial trajectory for the problem of moving a mobile robot from its initial position to a goal position in over a continuous set of time. along the path, the robot requires to observe a certain acceleration profil...

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...