Granular ratchets are well-known devices that when driven vertically produce a counterintuitive horizontal transport of particles. Here we report the experimental observation of a complementary effect: the striking ability of circular ratchets to convert their vertical vibration into their own rotation. The average revolution speed shows a maximum value for an optimal tooth height. With no spec...

in this work we solve the set of hydrodynamical equations for accretion disks in the spherical coordinates (r,θ,ϕ) to obtain the explicit structure along θ direction. we study a two-dimensional advective accretion disc in the presence of thermal conduction. we find self-similar solutions for an axisymmetric, rotating, steady, viscous-resistive disk. we show that the global structure of an advec...

We discuss the trajectory of a fast revolving solid ball moving in a fluid of comparable density. As the ball slows down owing to drag, its trajectory follows an exponential spiral as long as the rotation speed remains constant: at the characteristic distance L where the ball speed is significantly affected by the drag, the bending of the trajectory increases, surprisingly. Later, the rotation ...

Ninety-five high school baseball players (16 ± 1 years; 75 ± 13 kg; and 178 ± 20 cm) threw from flat-ground at distances of 9 m, 18 m, 27 m, 37 m, and 46 m while wearing a motusBASEBALL sensor (Motus Global, Massapequa, NY USA). Linear mixed-effects models and likelihood ratio tests were utilized to estimate the within-subject relationship between throwing distance and arm slot, arm speed, shou...

Purpose: Due to the paucity of the information regarding the lower limb biomechanics in slow speeds running as well as  concentration of the majority of previous studies in a single movement plane, aim of the present study was investigation on a kinetic based analysis of lower limb’ joints with increasing running speed. Methods: 28 runners asked to stay on the belt speed of treadmill that was ...

The numerical controlled oscillator has wide application in radar, digital receiver, and software radio system. Firstly, this paper introduces the traditional CORDIC algorithm. Then in order to improve computing speed and save resources, this paper proposes a kind of hybrid CORDIC algorithm based on phase rotation estimation applied in numerical controlled oscillator (NCO). Through estimating t...