Technical Papers and Presentations

Amplitude of acoustic waves can be magnified by conical or concave waveguides, like in ear trumpets or fjords (surface waves). The simplest way realizing a capable device is a conical waveguide with a target to be treated in the top of the cone, and a spherical actor or acoustic exciter ... Read More

It is known that photoacoustic spectroscopy shows the highest signal-to-noise ratio compared to other spectroscopy techniques. This is due to an orthogonal detection scheme: while exciting with light we monitor soundwaves. In gaseous phase, the use of an acoustic chamber called cell ... Read More

There are several industrial applications, like food dehydration, atomization and textile washing among others, that are enhanced by the use of power ultrasonic transducers with flat rectangular plate radiator. These transducers are composed by three main parts, the piezoelectric ... Read More

Flexible and semi-rigid polyurethane foams are widely used as noise and vibration damping materials. Their porous random microstructure is composed of a visco-elastic frame structure with an interstitial fluid, normally air, filling the voids. The viscoelasticity of the foams is due to ... Read More

For non-imaging wearable ultrasound applications Novioscan is developing piezoelectric MEMS transducers. These transducers consist of a large array of micromechanical silicon membranes with piezoelectrically actuated regions to generate an out-of-plane displacement causing a pressure ... Read More

Large centrifugal compressors, which are commonly applied in the oil and gas and in the process industry, may fail due to vibrations of the impeller. These vibrations are induced by pressure pulsations in a compressor stage. These vibrations can be especially strong in so-called dense ... Read More

Functionally graded materials (FGM) are those that contain chemical, phase or structural gradients. Whilst the design of functionally graded structures is well researched in areas such as shape optimisation and topology optimization, their manufacture is still in development. One ... Read More

When acoustic applications include small geometries, i.e. mm/submillimeter range, so-called thermoviscous effects can greatly affect the pressure response. This paper deals with acoustic topology optimization of such miniature structures with thermoviscous effects taken into account. ... Read More

Seismic evaluation of existing dams is a major issue that has been even more highlighted by the recent events in Italy. In this regard, researchers and engineers need a reliable and quick tool to assess the complex behaviour of the structure – fluid – soil system. In this paper the soil ... Read More

COMSOL analysis of the acoustic modes of two different Combustion Wind Tunnel Facility’s test sections was conducted in this project. The test sections are rectangular ducts, therefore the mathematical expressions to predict the longitudinal and transverse modes inside a tube were used ... Read More