Surface acoustic waves application for gas leakage detection

Abstract

Surface Acoustic Waves (SAW) are by their nature very sensitive to changes in physical propagation conditions. This statement relates primarily to the properties of the substrate, i.e. the surface on which these waves propagate, but under certain conditions it also refers to the parameters of the gaseous environment directly in contact with the substrate. The influence of this environment on SAW parameters can be used to detect specific gases that are present in this environment and change its density. The basic research problem was to determine the dependence of the resonant frequency and attenuation of waves in a resonator with SAW on the parameters and concentrations of specific gases in the gaseous environment in which the resonator works. The secondary objective was to determine whether this dependence is strong enough to be used for the construction of sensors and whether it is possible to identify gases present in the environment based on such measurements. Two-port resonators from SAW and measuring stand of our own design were used for the research. The analyses conducted and laboratory measurements confirmed the existence of the abovedescribed dependence. It was found that it increases with the increase of the difference between the molar mass of the gas being tested and the average molecular mass of the gaseous environment. This fact makes the proposed method suitable for detection of gases of relatively low or high molar masses. In air it is possible to detect hydrogen, helium, krypton, xenon and vapour of volatile compounds with sufficiently high molar masses.

An Acoustic Emission Method for Assessing the Degree of Degradation of Mechanical Properties and Residual Life of Metal Structures under Complex Dynamic Deformation Stresses

“…During the operation of structures, periodic control of deformation deviations from the design values and static monitoring of deformations are performed [ 1 , 2 , 3 , 4 , 5 , 6 ]. There are several traditional methods for assessing stresses, e.g., the method of drilling holes, the method for determining stresses by measuring the surface hardness [ 7 ], methods using surface waves [ 8 , 9 ], the phenomenon of acoustoelasticity and interferometry [ 10 , 11 ], X-ray methods [ 12 ], electromagnetic methods [ 13 ], tensometric methods [ 14 ], magnetic resonance methods [ 15 ], and acoustic emission [ 16 ].…”

Infrared thermography as a method of diagnosing reproductive pathologies in animals

“…Thermal imaging diagnostics can be promising in this regard, which allows for characterizing specific features of the structure (morphology) or function of the organ under study (Stelletta et al 2013;Rekant et al 2016;Pasternak et al 2017). Thermography is a promising non-contact remote diagnostic express method.…”