Université François Rabelais de Tours, Laboratoire Imagerie et Cerveau FR CNRS 3110, Ecole Nationale d'Ingénieurs du Val de Loire, Rue de la Chocolaterie BP 3410, F-41034 Blois Cedex, France.
Ultrasonics. 2012 Jul;52(5):622-7. doi: 10.1016/j.ultras.2011.12.008. Epub 2012 Jan 24.
In many industrial processes where online control is necessary such as in the food industry, the real time monitoring of visco-elastic properties is essential to ensure the quantity of production. Acoustic methods have shown that reliable properties could be obtained from measurements of velocity and attenuation. This paper proposes a simple, real time ultrasound method for monitoring linear medium properties (phase velocity and attenuation) that vary in time. The method is based on a pulse echo measurement and is self-calibrated. Results on a silica gel are reported and the importance of taking into account the changes of the mechanical loading on the front face of the transducer will be shown. This is done through a modification of the emission and reception transfer parameters. The simultaneous measurement of the input and output currents and voltages enables these parameters to be calculated during the reaction. The variations of the transfer parameters are in the order of 6% and predominate other effects. The evolution of the ultrasonic longitudinal wave phase velocity and attenuation as a function of time allows the characteristic times of the chemical reaction to be determined. The results are well correlated with the gelation time measured by rheological method at low frequency.
在许多需要在线控制的工业过程中，如食品工业，实时监测黏弹性性质对于确保产量至关重要。声学方法表明，通过测量速度和衰减可以获得可靠的性质。本文提出了一种简单的、实时的超声方法，用于监测随时间变化的线性介质特性（相速度和衰减）。该方法基于脉冲回波测量，并且是自校准的。报告了硅胶的结果，并将展示考虑换能器前表面机械负载变化的重要性。这是通过对发射和接收传递参数进行修改来实现的。同时测量输入和输出电流和电压，可以在反应过程中计算这些参数。传递参数的变化在 6%左右，占主导地位的是其他影响因素。超声纵波相速度和衰减随时间的变化允许确定化学反应的特征时间。结果与低频流变法测量的凝胶时间很好地相关。
