We present a novel control method achieving stable multiple-degrees-of-freedom electroacoustic resonators. Such broadband absorbers, composed of a feedback-controlled electrodynamic loudspeaker, have many practical applications to real-world acoustic engineering problems, such as low-frequency industrial noise reduction in the range of [20 200 Hz]. The proposed control architecture combines a c...

The effect of perforation impedance on the acoustic behavior of reactive and dissipative silencers is investigated using experimental and computational approaches. The boundary element method (BEM) is applied for the prediction of transmission loss of silencers with different perforation geometries. The variations are considered in the porosity (8.4 and 25.7%) and hole diameter (0.249 and 0.498...

The propagation of harmonic pressure waves through a Newtonian fluid contained within a thick-walled, viscoelastic tube is considered as a model of arterial blood flow. The fluid is assumed to be homogeneous and Newtonian, and its motion to be laminar and axisymmetric. The wall is assumed to be isotropic, incompressible, linear, and viscoelastic. It is also assumed that the motion is such that ...

The impedance and wakefield effects and higher order mode losses have been investigated for the Luminosity Upgrade Project at HERA for three regions where only minimal heating can be tolerated. These are two versions of the beam pipe configuration at the interaction region of the experiment Zeus and also for a region where superconducting magnets are to be installed. As the structures are very ...

Cross field amplifiers (CFA) h ave been used in many applications where high power, high frequency microwaves are needed. Although these tubes have been manufactured for decades, theoretical analysis of their properties is not as highly developed as for other microwave devices such as klystrons. % We have developed a simulation model for CFAs using the PIC code CONDOR. Our simulations indicate ...