background: noise pollution is currently a major health risk factor for workers in industries. the aim of this study was to investigate noise pollution and implement a control intervention plan for blast furnace in a steel industry. methods: the measurement of sound pressure level (spl) along with frequency analysis was done with the sound-level-meter cell-450 . personal noise exposure was perf...

Both axial and centrifugal fans are used to cool information technology (IT) equipment. These fans generate noise that can be annoying to their users, particularly the tonal noise that can be radiated. Work has focused on developing a method to attenuate the tonal noise associated with both of these types of fans. A compact system is used, whereby control sources are placed in close proximity t...

We introduce a new method for reducing phase noise in oscillators, thereby improving their frequency precision. The noise reduction is realized by a passive device consisting of a pair of coupled nonlinear resonating elements that are driven parametrically by the output of a conventional oscillator at a frequency close to the sum of the linear mode frequencies. Above the threshold for parametri...

We have researched on the rational design method of active noise barrier based on the boundary surface control principle. This active noise barrier is composed of a conventional barrier, multiple secondary sources and multiple error sensors. The secondary sources and the error sensors are located on a surface in parallel with the barrier. By using this, we can control noise not only at the erro...

Agricultural machines generate a complex noise field with significant low-frequency components. The demands for good sound comfort of the driver inside cabins of these machines are continuously growing. Since passive control techniques are not able to efficiently reduce the low-frequency noise in the cabin, active noise control techniques are being explored. A zone of quiet around the ears of t...

Active noise control has been used in a variety of applications where it is impractical to achieve significant levels of noise control using traditional passive noise control treatments, for example, at low frequencies. In recent years, a similar performance benefit has been gained through the use of acoustic metamaterials, which achieve levels of noise control performance that are not achievab...

this paper addresses the signal processing principles in passive bistatic radar (pbr) systems. in this case, the detection problem in the presence of system noise, clutter/multipath, direct signal and interfering target signals is investigated. to this light, two types of detectors are studied. in the first one, which is based on intuitive sense, we examine two detectors. in the second type det...

Currently, sound quality control using Active Noise Control (ANC) and Passive (PNC) has been used as noise reduction methods. ANC an effect on the low-frequency noise, PNC affects high-frequency noise. However, in case of control, our previous study revealed that individual preference impression strongly to each. In recent years, automobiles is developing day by day, driving become essential fa...