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New Surface-Plasmon-Polariton-Like Acoustic Surface Waves at the Interface Between Two Semi-Infinite Media

Kiełczyński Piotr

Archives of Acoustics

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2022

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Vol. 47, No. 3

363--371

EN

This paper presents theory of new shear horizontal (SH) acoustic surface waves that propagate along the interface of two semi-infinite elastic half-spaces, one of which is a conventional elastic medium and a second one an elastic metamaterial with a negative and frequency dependent shear elastic compliance. This new surface waves have only one transverse component of mechanical displacement, which has a maximum at the interface and decays exponentially with distance from the interface. Similar features are also shown by the acoustic shear horizontal Maerfeld-Tournois surface waves propagating at the interface of two semi-infinite elastic media due to the piezoelectric effect that should occur in at least one semi-space. The proposed new shear horizontal acoustic surface waves exhibit also strong formal similarities with the electromagnetic surface waves of the surface plasmon polariton (SPP) type, propagating along a metal-dielectric planar interface. In fact, the new shear horizontal elastic surface waves possess a large number of properties that are inherent for the SPP electromagnetic surface waves, such as strong subwavelength concentration of the wave field in the proximity of the guiding interface, low phase and group velocity etc. As a result, the new shear horizontal acoustic surface waves can find applications in sensors with extremely high sensitivity, employed in measurements of various physical parameters, such as viscosity of liquids, as well as in biosensors, chemosensors, or a near field acoustic microscopy (subwavelength imaging) and miniaturized devices of microwave acoustics.

2

SAW Sensor with Langmuir-Blodgett Layer for Detection of Benzene and its Derivatives

Balcerzak Andrzej, Kiełczyński Piotr, Szalewski Marek, Wieja Krzysztof

Archives of Acoustics

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2021

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Vol. 46, No. 1

25--30

EN

Vapors of benzene and its derivatives are harmful and toxic for human beings and natural environment. Their detection has fundamental importance. For this purpose authors propose surface acoustic wave (SAW) sensor with skeletonized layer deposited by Langmuir-Blodgett (L-B) method. This layer was obtained by depositing a binary equimolar mixture of 5-[[1,3-dioxo-3-[4-(1-oxooctadecyl) phenyl]propyl]amino]-1,3-benzenedicarboxylic acid with cetylamine. The skeletonized sensor layer has been obtained by removing cetylamine. Response of this sensor depends mainly of the electrical dipole momentum of molecule. Among the tested compounds, benzene has a zero dipole moment and gives the smallest sensor response, and nitrobenzene has the largest dipole moment and the sensor reacts most strongly to its vapor.

3

New Theoretical Model for Mass Sensitivity of Love Wave Sensors

Kiełczyński Piotr, Szalewski Marek, Balcerzak Andrzej, Wieja Krzysztof

Archives of Acoustics

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2021

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Vol. 46, No. 1

17--24

EN

In this work we analyse basic characteristics of Love wave sensors implemented in waveguide structures composed of a lossy viscoelastic surface layer deposited on a lossless elastic substrate. It has to be noted that Love wave sensors working at ultrasonic frequencies have the highest mass density sensitivity Sσvp among all known ultrasonic sensors, such as QCM, Lamb wave or Rayleigh wave sensors. In this paper we have established an exact analytical formula for the mass density sensitivity Sσvp of the Love wave sensors in the form of an explicit algebraic expression. Subsequently, using this developed analytical formula, we compared theoretically the mass density sensitivity Sσvp for various Love wave waveguide structures, such as: (1) lossy PMMA surface layer on lossless Quartz substrate and (2) lossy PMMA on lossless Diamond substrate. The performed analysis shows that the mass density sensitivity Sσvp (real and imaginary part) for a sensor with a structure PMMA on Diamond is five times higher than that of a PMMA on Quartz structure. It was found that the mass density sensitivity Sσvp for Love wave sensors increases with the increase of the ratio: bulk shear wave velocity in the substrate to bulk shear wave velocity in the surface layer.

4

Dispersion Curves of Love Waves in Elastic Waveguides Loaded with a Newtonian Liquid Layer of Finite Thickness

Kiełczyński Piotr, Szalewski Marek, Balcerzak Andrzej, Wieja Krzysztof

Archives of Acoustics

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2020

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Vol. 45, No. 1

19--27

EN

In this paper, the authors analyse the propagation of surface Love waves in an elastic layered waveguide (elastic guiding layer deposited on an elastic substrate) covered on its surface with a Newtonian liquid layer of finite thickness. By solving the equations of motion in the constituent regions (elastic substrate, elastic surface layer and Newtonian liquid) and imposing the appropriate boundary conditions, the authors established an analytical form of the complex dispersion equation for Love surface waves. Further, decomposition of the complex dispersion equation into its real and imaginary part, enabled for evaluation of the phase velocity and attenuation dispersion curves of the Love wave. Subsequently, the influence of the finite thickness of a Newtonian liquid on the dispersion curves was evaluated. Theoretical (numerical) analysis shows that when the thickness of the Newtonian liquid layer exceeds approximately four penetration depths 4δ of the wave in a Newtonian liquid, then this Newtonian liquid layer can be regarded as a semi-infinite half-space. The results obtained in this paper can be important in the design and optimization of ultrasonic Love wave sensors such as: biosensors, chemosensors and viscosity sensors. Love wave viscosity sensors can be used to assess the viscosity of various liquids, e.g. liquid polymers.

5

Application of Ultrasonic Methods for Evaluation of High-Pressure Physicochemical Parameters of Liquids

Kiełczyński Piotr, Ptasznik Stanisław, Szalewski Marek, Balcerzak Andrzej, Wieja Krzysztof, Rostocki Aleksander J.

Archives of Acoustics

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2019

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Vol. 44, No. 2

329--337

EN

An emerging ultrasonic technology aims to control high-pressure industrial processes that use liquids at pressures up to 800 MPa. To control these processes it is necessary to know precisely physicochemical properties of the processed liquid (e.g., Camelina sativa oil) in the high-pressure range. In recent years, Camelina sativa oil gained a significant interest in food and biofuel industries. Unfortunately, only a very few data characterizing the high-pressure behavior of Camelina sativa oil is available. The aim of this paper is to investigate high pressure physicochemical properties of liquids on the example of Camelina sativa oil, using efficient ultrasonic techniques, i.e., speed of sound measurements supported by paralel measurements of density. It is worth noting that conventional low-pressure methods of measuring physicochemical properties of liquids fail at high pressures. The time of flight (TOF) between the two selected ultrasonic impulses was evaluated with a cross-correlation method. TOF measurements enabled for determination of the speed of sound with very high precision (of the order of picoseconds). Ultrasonic velocity and density measurements were performed for pressures 0.1-660 MPa, and temperatures 3-30°C. Isotherms of acoustic impedance Za, surface tension σ and thermal conductivity k were subsequently evaluated. These physicochemical parameters of Camelina sativa oil are mainly influenced by changes in the pressure p, i.e., they increase about two times when the pressure increases from atmospheric pressure (0.1 MPa) to 660 MPa at 30°C. The results obtained in this study are novel and can be applied in food, and chemical industries.