BACKGROUND Sinus fungus ball, an accumulation of fungal dense concretions, is a common disease in practice, and might cause fatal complications or lead to death once converted into invasive type. Early preoperative diagnosis of this disease can lead to appropriate treatment for patients and prevent multiple surgical procedures. Up to now, the diagnostic criteria of sinus fungus ball have been d...

Baseball and softball pitch types are distinguished by the path and speed of the ball which, in turn, are determined by the angular velocity of the ball and the velocity of the ball center at the instant of release from the pitcher’s hand. While radar guns and video-based motion capture (mocap) resolve ball speed, they provide little information about how the angular velocity of the ball and th...

Kicking for distance in Australian Rules football is an important skill. Here, I examine technical aspects that contribute to achieving maximal kick distance. Twenty-eight elite players kicked for distance while being videoed at 500 Hz. Two-dimensional digitized data of nine body landmarks and the football were used to calculate kinematic parameters from kicking foot toe-off to the instant befo...

The 3D trajectory of the ball is one of the most important performance indicators in ball games. However, it often cannot be measured because of the requirements: synchronized cameras and control points within the playing field. Thus, this paper proposes a method that reconstructs the 3D trajectory of a ball with unsynchronized cameras. The proposed method consists of ball detection, camera cal...

A ball is propelled through a random environment of obstacles oo which it rebounds with perfect reeection. What is the behaviour of the trajectory of the ball? We summarise known mathematical results concerning this model, which we calìstochastic pin-ball', and which is known also as a `Lorentz lattice gas' and a version of which is sometimes termed thèEhrenfest wind{tree model'. The rigorous t...

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....

Leaded solder ball was replaced by leadfree solder ball which is now widely used in semiconductor industries, due to the hazardous effects of lead to human’s health and toxicity for environment. Due to this, poor solder joint strength for Ball Grid Array (BGA) packages on leadfree devices is a reliability concern when subjected to reliability stress test. With a polymer core in the solder ball ...

The objective of this study was to investigate the factors affecting ball velocity at the final instant of the impact phase (t1) in full instep soccer kicking. Five experienced male university soccer players performed maximal full instep kicks for various foot impact points using a one-step approach. The kicking motions were captured two dimensionally by a high-speed camera at 2,500 fps. The th...

The purpose of this study is to construct a finite-element (FE) model of golf balls with hyperelasticity and viscoelasticity and to devise a method for construction of FE ball models by investigating the relationship between the material properties and the behaviour of the golf ball during and after impact. As for the material model of the FE ball model, the Mooney–Rivlin model and the three-el...

The goal of the study was to analyse with which ball the 9-11-year-old participants achieved higher shot accuracy and efficacy during real basketball games. The participants were 54 children from six basketball teams. Three situations were established in which the participants played four games with each of the following balls: (a) a regulation ball (485 g, 69-71 cm), (b) a lighter ball (440 g,...