Parametric modeling with beamspread compensation and MIMO frequency domain inversion applied to fine saturated sands.

A system identification technique is applied to estimate the intrinsic absorption and dispersion of two fine sands. The method is based on the parametric modeling of the wave propagation through a Plexiglas tank filled with the sediment under investigation. The applicability of various porous models is discussed.

Experimental validation for the diffraction effect in the ultrasonic field of piston transducers and its influence on absorption and dispersion measurements.

The aim of this work was to study the diffraction effects in the ultrasonic field of piston source transducers and their importance for accurate measurements of attenuation and dispersion in viscoelastic materials. In laboratory measurements, the diffraction phenomena are mainly due to the beam spread of the ultrasonic wave propagating in viscoelastic materials. This effect is essentially related to the estimated attenuation and dispersion in the material.

Theoretical comparison of the SAR distributions from arrays of modified current sheet applicators with that of lucite cone applicators using Gaussian beam modelling.

The technical comparison of Current Sheet Applicator (CSA) and Lucite Cone Applicator (LCA) arrays covering an area of approximately 20 x 20 cm2 is investigated based on Gaussian beam (GB) predicted SAR distributions. The comparison is made in muscle equivalent tissue at 1 cm depth (maximum SAR normalized to 100%) and over a volume of 3 cm depth under the aperture of the antennae. The planar SAR distribution is tested on field sizes (FSx: area covering x% SAR), penetration depth (PD) and homogeneity coefficient (HC = FS75/FS25).

Quantitative evaluation of 2 x 2 arrays of Lucite cone applicators in flat layered phantoms using Gaussian-beam-predicted and thermographically measured SAR distributions.

SAR distributions from four different E-field-orientated 2 x 2 arrays of incoherently driven Lucite cone applicators (LCAs) were investigated. The LCAs operated at 433 MHz with an aperture of 10.5 cm x 10.

Effectiveness of the Gaussian beam model in predicting SAR distributions from the lucite cone applicator.

The Gaussian beam model (GBM) has been shown to be a successful tool in the development of the current sheet applicator. As a result, the effectiveness of the GBM is investigated in single and dual array applications of the lucite cone applicator (LCA). The LCA is a modified water-filled waveguide applicator with an improved effective field size (EFS > 64 cm2, aperture 10 cm x 10 cm).