introduction: in recent decades, several monte carlo codes have been introduced for research and medical applications. these methods provide both accurate and detailed calculation of particle transport from linear accelerators. the main drawback of monte carlo techniques is the extremely long computing time that is required in order to obtain a dose distribution with good statistical accuracy. ...

Background: Neutron contamination is produced in electron beams of linac when tooth or dental materials are located in the path of beam. Objective: This study aims to determine the neutron dose contamination from different dental restoration materials in electron mode of a linac. Material and Methods: In this experimental study, the neutron dose contamination was calculated in the p...

Figure 1: Schematic experimental set up. Squeezed film damping (SFD) is a common phenomenon that occurs in many microdevices when a surface moves normally to another solid surface in close proximity. In microelectromechanical systems (MEMS), SFD is often one of the largest sources of parasitic losses. Therefore, an accurate evaluation of hydrodynamic forces due to the SFD effect is critical in ...

This work gives sequence to the study on the measurement of the electrostatic charges in aerosols. The particle charge classifier developed for this purpose and presented in the previous paper (Marra and Coury, 2000) has been used here to measure the particle charge distribution of a number of different aerosols. The charges acquired by the particles were naturally derived from the aerosol gene...

We present the nondiffracting spatially accelerating solutions of the Maxwell equations. Such beams accelerate in a circular trajectory, thus generalizing the concept of Airy beams to the full domain of the wave equation. For both TE and TM polarizations, the beams exhibit shape-preserving bending which can have subwavelength features, and the Poynting vector of the main lobe displays a turn of...

This paper presents two time methods to identify weak non-linearities on damping and stiffness of a free vibrating system. Only the displacement is known. The first method is a direct parameter estimation method : using the measured displacement data of the system we obtain by numerical differentiation velocity and acceleration. A linear system containing the parameters is then derived. A least...