Characterization of wheat-flour-water doughs: a new method using ultrasound.

In this paper, an original method of evaluating the physical properties of wheat-flour-water systems using high-frequency low-power ultrasound is presented. Most of the experiments were performed with a reflectance technique measuring the acoustic impedance of doughs. The velocity of propagation, attenuation and viscoelastic moduli have been evaluated for both compressional and shear ultrasonic waves in the interval 2-10 MHz for doughs of different hydrations. The 53% water content was found to be critical with respect to the presence of free water. The influence of the mixing and rest times on the longitudinal ultrasonic parameters is also studied.

[Limits of auditory evoked potentials of the brain stem in the diagnosis of deafness in children]. / Limites des potentiels évoqués auditifs du tronc cérébral dans le diagnostic des surdités de l'enfant.

117 children were examined in Gatien of Clocheville during 13 months. In the same session behavioural audiometry and brainstem auditory evoked response audiometry were performed. With the click technique: BSAER do not identify tonal notchs. The BSAER threshold is higher than the behavioural threshold because low frequencies are not explored in profound deafness. It is difficult to differentiate conductive and perceptive deafness when wawe I is missing. Within these limits BSAER is powerful test in babies and children with behavioural disorders.