the aim of this study was to determine the monthly dtr mass load of amphetamine-type compounds in poland as well as an investigation of cyclical behaviour by using time series analysis and especially trends analysis.amphetamine, methamphetamine and mdma (ecstasy) were detected in wastewater samples collected from the main wastewater treatment plant in the city of poznan using liquid chromatogra...

Dynamic response of multispan viscoelastic thin beams subjected to a moving mass is studied by an efficient numerical method in some detail. To this end, the unknown parameters of the problem are discretized in spatial domain using generalized moving least square method (GMLSM) and then, discrete equations of motion based on Lagrange’s equation are obtained. Maximum deflection and bending momen...

Recently, a large amount of studies have been related to nonlinear systems with multi-degrees of freedom as well as continuous systems. The purpose of this paper is to optimize passive vibration absorbers in linear and nonlinear states for an Euler-Bernoulli beam with a nonlinear vibratory behavior under concentrated moving load. The goal parameter in the optimization is maximum deflection of t...

1.1 Ultra-precision moving positioning stage A typical ultra-precision moving positioning stage is often used in ultra-precision manufacturing system for its nanometer displacement and fast linear moving speed. Usually, such platform consists of electric amplifiers, piezoelectric actuators and loads. As hysteresis is inherent in piezoelectric actuator, the amplifier and load can be considered a...

In this paper, the dynamic response of a viscoelastic beam subjected to a moving distributed load has been studied. The viscoelastic properties of the beam have been considered as linear standard model in shear and incompressible in bulk. The stress components have been separated to the shear and dilatation components and as a result the governing equations in viscoelastic form has been obtaine...