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International audience; Crosstalk is considered as an undesirable phenomenon disturbing the electromechanical behavior of the ultrasonic transducer arrays used in medical imaging applications. Indeed, when one element of a transducer array is excited, it generates parasitic voltages and/or displacement fields on the adjacent passive elements. Consequently, these interactions between elements decrease the array's electroacoustic performance, which affects the obtained image quality. To overcome the crosstalk's problem, several research works propose active cancellation techniques. In this case, the correction voltages are determined by considering the array's elements grounded, contrary to the conventional crosstalk's definition which considers the array elements in Open-Circuit. The novelty of this paper is in one hand the study of the electrical limit conditions' effects on the physical behavior of a piezoelectric transducer array radiating in a fluid medium (water). On the other hand, a displacement method is proposed to evaluate the crosstalk level when the array elements are grounded. The limitations of the proposed method are also discussed. For this purpose, a piezoelectric transducer array is firstly modeled using a Two-dimensional Finite Elements Method (FEM), when the array elements are not grounded (open-circuit). Then, the results are compared to those obtained when the neighboring elements are grounded (as in the case of the crosstalk's active cancellation techniques). Finally, measurements are realized on a fabricated transducer array vibrating in air medium and are successfully compared to the results predicted using FEM.

ACT; International audience; The studied predictive model of behavior viscosimetric is the model of K.A. Petersen [1]. The dominant idea of this method is to characterize the viscosity of a fluid from two models taken as a reference in passing through a reduced pressure. The method is corresponding state with two references. This study shows that this method is dependent on the choice of reference and for each of the possibilities of C10/C6H6 and C1/C10 references . The results were investigated for four different weight ratios. It shows that the introduction of an adjusted coefficient does not improve significantly compared to results without adjustment factor, which appears to be the best choice. Regarding the influence of the choice of references, generally the two couples appear suitable but we noted that the choice is not necessary. In the case of mixtures containing at least one aromatic, the results are correct, especially if one takes the ratio of adjustment and our ratio without adjustment compared to that of K. A. PETERSEN[1]. The experimental results of the viscosity exhibit a good agreement with the calculated values. We can predict that the relative improvement is the finding that the introduction of the second body of reference (C10) from the model states corresponding to a reference (C1) of the authors. © Published under licence by IOP Publishing Ltd.