Assessment of Ultrasound Velocity Application for Chemical Process Monitoring

Abstract

Study on the accuracy of the ultrasound velocity application for chemical process monitoring is presented. Cure degree of epoxy resins was monitored in order to establish the percentage of the final cure based on ultrasound velocity of longitudinal waves. Time of flight estimations by correlation processing were used to estimate the velocity. Sources of error in the velocity measurement and their influence in the sensitivity and accuracy of the results have been studied. In order to improve the accuracy and reliability of the measurements, the use of Spread Spectrum instead of conventional excitation signals have been evaluated. Experimental results indicate that random errors of propagation time estimation are lower than velocity fluctuation over the chemical process. Spread spectrum signals provide more reliable measurements.

Reaction Monitoring by Ultrasounds in a Pseudohomogeneous Medium: Triglyceride Ethanolysis for Biodiesel Production

“…The measurement of the sound velocity can also be applied for process monitoring, being remarkable for its use in the following processes, among others: alcoholic fermentation [12,13], kinetics of crystallization of palm fats [14], or epoxy curing processes [15]. Our research group demonstrated in a previous study that the real-time monitoring of the methanolysis of vegetable oils for obtaining fatty acid methyl esters (FAME) (biodiesel) is possible [16], with synthesis focused on the production of a biofuel for direct injection compression ignition engines [17][18][19][20].…”

Model Based Ultrasonic Measurement Technique for Evaluation of the Adhesive Properties

“…Adhesive bonding is widely used in vehicles manufacturing [1], aircraft industry [2], civil infrastructure such as bridges, buildings renovation or manufacturing instrumentality [3], [4]. Despite the advantages of widely used adhesives, they have drawbacks related to the need of surface preparation, necessity to avoid contaminations [5], time needed for curing the adhesive layer [6], aging and complexity of material characterization of the adhesive layer after gluing. The gluing defects can be divided into the two classes, such as adhesive and cohesive.…”