The takraw ball is a very unique interwoven ball used in the action game of sepak takraw. To date there has been no studies on the dynamic behavior and mechanical properties of the takraw ball. The purpose of this study is to predict the dynamic behavior and mechanical properties of the takraw ball in particular of normal impact on flat surfaces at low speeds. Two methods are employed to measur...

Electroless nickel-boron coatings were deposited from a novel deposition bath that was stabilizer-free. Those analyzed by DSC to determine the crystallization temperature of nickel-boride phases, and then best heat treatment conditions for new selected using Knoop hardness test XRD. The results analysis XRD coherent with findings previous studies, which shows coating has boron content lower tha...

A strict theory of reciprocal influence of the contact deformation and molecular attraction of a ball and a plane has been developed. It has been shown that despite the van der Waals' forces being capable of increasing the elastic contact area between the ball and the plane, the force that is required to overcome the molecular forces arising when the contact is broken does not increase thereby....

A ball bouncing repeatedly on a vertically vibrating surface constitutes the famous "bouncing ball" problem, a nonlinear system used in the 1980s, and still in use nowadays, to illustrate the route to chaos by period doubling. In experiments, in order to avoid the ball escape that would be inevitable with a flat surface, a concave lens is often used to limit the horizontal motion. However, we o...

Identifying the trajectory and spin of the ball with speed and accuracy is critical for good performance in table tennis. The aim of this study was to analyze the ability of table tennis players presenting different levels of training/experience to identify the magnitude of the ball spin from the sound produced when the racket hit the ball. Four types of "forehand" contact sounds were collected...

the aim of this research work was to investigate on the ball filling estimation of miduk semi-autogenous (sag) mill via an utilized method. miduk copper concentrator is located in kerman province, iran, and its size reduction stage includes one gyratory crusher which feeds one sag mill (9.75 dia.(m)*3.88 length(m)) following two parallel ball mills (5dia.(m)*7lenght(m)). after sag mill, a tromm...

A skilled golfer hitting a drive can accelerate his club head from zero to 120 miles per hour in the quarter of a second before making contact with the ball. As a result, the ball leaves the tee with a typical speed of 175 miles per hour and at an angle of 11◦ to the ground. From that moment the golfer no longer exercises control. The trajectory of the ball is determined by the laws of physics....