A kind of noise is dominated by broadband noise with low frequency tonal components. To achieve noise control on whole frequency band, it is necessary to implement hybrid control technique combining passive control and active control. There are three methods to combine passive control and active control, including active control in passive enclosures, active control outside passive enclosure an...

background: the adverse effects of noise are well known and noise problems due to industrialization of communities are increasing over the time. oil industries due to the process and nature of production; contain many noise sources such as compressors, turbines, and pumps, which cause excessive noise exposure. the objective of this study was to evaluate the noise characteristics of compressors ...

in this paper, free convection in an inclined stepped chamber has been studied. one wall of this enclosure is kept cold and the opposite wall equipped with constant heat source. the remaining walls are maintained adiabatic. there is one adiabatic step on the bottom wall. the aim of the present study is to forecast the effect of raleigh number, slope of enclosure, step dimension, and heat source...

a numerical investigation of laminar mixed convection heat transfer in a shallow two-sided lid driven rectangular enclosure of aspect ratio 5, (ar=5) is executed. the natural convection effect is sustained by subjecting the bottom wall to a higher temperature than its top counterpart. in addition, the two horizontal walls of the enclosure are moving in different directions and the two vertical ...

While there has been some research on the parliamentary enclosure of upland waste in England and Wales during the eighteenth and nineteenth centuries, this topic still receives little attention in some recent accounts of parliamentary enclosure. Many aspects of the processes involved, and their impact on the landscape, are also poorly understood. Much research has proceeded either at a very gen...

The theory of magnetic symmetry in quasicrystals, described in a companion paper [Lifshitz & Even-Dar Mandel (2004). Acta Cryst. A60, 167-178], is used to enumerate all three-dimensional octagonal spin point groups and spin-space-group types and calculate the resulting selection rules for neutron diffraction experiments.