The mapping method of Wisdom (1982) is generalized to encompass all gravitational n-body problems with a dominant central mass. The method is used to compute the evolution of the outer planets for a billion years, providing independent numerical confirmation of the result of Sussman and Wisdom (1988) that the motion of the planet Pluto is chaotic. The stability of the symplectic mapping method ...

air pollution in industrial and urban areas is one of the most important problems of environment which endangers humans' health; an example of these pollutants is the suspended particles in the air that with the increase of 10 in the air, the rate of mortality increases by 1 to 3 precent. this study was done during three seasons by determining ten sampling stations in each season and according ...

A vertical pendulum apparatus has been used to experimentally investigate the impulse and pressure applied by the impact of wet synthetic sand upon the flat surface of a back supported solid aluminum test block. The transferred impulse and maximum pressure applied to the sample were both found to decrease with increasing standoff distance between the bottom of the sand layer and the impact face...

Fertilizer spreaders are traditionally tested by using the collecting tray method . This method requires large indoor test facilities and is very expensive when applied on a large scale . A proposed alternative method is to measure the velocity and diameter of individual fertilizer particles emanating from the spreader and use a model to predict the landing spot of individual particles . The to...

We present a method for detecting collisions between a system of spherical particles and an environment composed of triangles. The proposed algorithm takes into account the particles’ volume and is based on an intersection test between a triangle and a cylinder with spherical caps (the trajectory of a particle). The algorithm also efficiently calculates a close estimate of the point of intersec...