It is well-established that wool and glass fibers are good absorbers for noise-control in air. However, inadequate levels of stiffness and strength have limited the range of the use of such fibers. The emergence of fibrous metal foams has meant rethinking of these limitations. Fibrous metal foams can be filled, not just with air, but also with other types of fluids. This means that altering bot...

Abstract In this paper a broadband active shunt technique for controlling vibration in piezoelectric laminated structures is proposed. The effect of the negative capacitance controller is studied theoretically and then validated experimentally on a piezoelectric laminated simply supported plate. The ‘negative capacitance controller’ is similar in nature to passive shunt damping techniques, as a...

This paper extends the theory of the diffraction of sound on 1D corrugated surfaces to 2D corrugated surfaces. Such surfaces, that are egg crate shaped, diffract incoming sound into all polar directions, which is fundamentally different from 1D corrugated surfaces. A theoretical justification is given for extending the classical grating equation to the case of incident inhomogeneous waves, for ...

A path integral formulation is developed for the dynamic Casimir effect. It allows us to study small deformations in space and time of the perfectly reflecting (conducting) boundaries of a cavity. The mechanical response of the intervening vacuum is calculated to linear order in the frequency– wavevector plane, using which a plethora of interesting phenomena can be studied. For a single corruga...

This paper describes comparative experiment on corrugated steel pipe culverts with different stiffness. The two culverts both with 1.2m span and 4m backfill height but with different corrugation pattern and plate thickness were constructed side by side. Displacement, strain and soil pressure at critical points were tested during construction. Two-dimensional (2D) finite element (FE) models were...

A solar absorption icemaker was designed. It is an intermittent system and uses Calcium Chloride and Ammonia as absorbent and refrigerant respectively. The single glazed collector/absorber/generator unit uses a plane glass sheet as the outer cover. Overall collector plate exposed area is 1.0m. A thermodynamic simulation of the icemaker has been performed in order to investigate the effect that ...

Abstract Most numerical research on thermoacoustic devices with a stack made of parallel plates has considered rectangular form for the plate. However, variety plate shapes can improve heat transfer and performance stack. In this paper, 2D model based computational fluid dynamics (CFD) analysis is used to examine efficiency couples using diversity surfaces. For investigation, flat others profil...