background: noise is one of the most important harmful agents in work environment. noise pollution in oil refinery industries is related to workers' health. this study aimed to determine the overall noise pollution of an oil refinery operation and its frequency analysis to determine the control plan for a vent noise in these industries. methods: this experimental study performed in control unit...

background: noise pollution is currently a major risk factor in industries in both developed and developing countries . the present study assessed noise pollution in the knitting industry in iran in 2009 and presented a control method to reduce the rate of noise generation. methods: the overall noise level was estimated using the network environmental noise assessment method in sina poud textil...

This paper is concerned with the analysis and design of an integrated passive and active control system for reducing the haul truck noise. By using a passive enclosure with two open ends and fiberglass inner surface, a three-dimensional noise radiation problem of the engine noise is shaped to a simple problem of noise radiation from the open ends above 200 Hz. Below 200Hz where the transmission...

Ventilation systems installed in buildings usually generate low-frequency noise because the passive silencers commonly used to attenuate the ventilation noise are not effective in the lowfrequency range. A method proven to effectively reduce low-frequency noise in a wide variety of applications is active noise control (ANC). A feedforward ANC system applied to duct noise normally uses a referen...

results according to the study results, noise levels in a co2 plant’s house and control room ranged from 88 to 102 db and 79 to 82 db (a), respectively. in order to reduce the amount of emitted noise in the co2 plant house and control room, a noise control plan was implemented in each part of the facility; it was met with effective results. conclusions the findings of this investigation have cl...

introduction hippocampus is a well-defined brain region involved in learning and memory. in spite of the existing reports on hippocampal-dependent memory impairment due to noise stress, to our knowledge, there is no study on the effect of noise stress on the size of hippocampus. the present study aimed to investigate the likely effects of chronic noise exposure on learning and the size of rat h...

This paper proposes a novel optimization framework in passive control techniques to reduce noise pollution. The geometries of the structures are represented by Catmull-Clark subdivision surfaces, which able build gap-free Computer-Aided Design models and meanwhile tackle extraordinary points that commonly encountered geometric modelling. acoustic fields simulated using isogeometric boundary ele...

A research programme to investigate the feasibility of using active control systems to control the radiated noise of a naval platform due to the on-board machinery was first setup in the late 1970s at the Defence Evaluation and Research Agency. The programme covers the development of control algorithms, development of the hardware for the controller, a trial on a naval platform, analysis of the...

piezoelectric actuators are widely used in micro manipulation applications. however hysteresis nonlinearity limits accuracy of these actuators. this paper presents a novel approach utilizing a piezoelectric nano-stage as slave manipulator of a teleoperation system. the prandtl-ishlinskii (pi) model is used to model actuator hysteresis in feedforward scheme to cancel out this nonlinearity. a pas...