Research

12 pages, 10035 KiB

Open AccessArticle

Inkjet Printing of Plate Acoustic Wave Devices

by Iren Kuznetsova, Andrey Smirnov, Vladimir Anisimkin, Sergey Gubin, Maria Assunta Signore, Luca Francioso, Jun Kondoh and Vladimir Kolesov

Sensors 2020, 20(12), 3349; https://doi.org/10.3390/s20123349 - 12 Jun 2020

Cited by 7 | Viewed by 2571

Abstract

In the paper, the results of production of Ag inkjet printed interdigital transducers to the acoustic delay line based on Y-cut X-propagation direction of lithium niobate plate for the frequency range from 1 to 14 MHz are presented. Additionally, morphological, structural, and electro-physical [...] Read more.

In the paper, the results of production of Ag inkjet printed interdigital transducers to the acoustic delay line based on Y-cut X-propagation direction of lithium niobate plate for the frequency range from 1 to 14 MHz are presented. Additionally, morphological, structural, and electro-physical characteristics of the obtained electrodes were investigated. Mathematical modeling of the excitation of acoustic waves by these electrode structures was carried out. Comparison of the theoretical results with experimental ones showed their qualitative and quantitative coincidences. It was shown that conventional inkjet printing can replace the complex photolithographic method for production of interdigital transducers for acoustic delay lines working up to 14 MHz. The resulting electrode structures make it possible to efficiently excite acoustic waves with a high value of electromechanical coupling coefficient in piezoelectric plates. Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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15 pages, 3821 KiB

Open AccessArticle

Sensor Based on PZT Ceramic Resonator with Lateral Electric Field for Immunodetectionof Bacteria in the Conducting Aquatic Environment †

by Irina Borodina, Boris Zaitsev, Andrey Teplykh, Gennady Burygin and Olga Guliy

Sensors 2020, 20(10), 3003; https://doi.org/10.3390/s20103003 - 25 May 2020

Cited by 4 | Viewed by 2204

Abstract

A biological sensor for detection and identification of bacterial cells, including a resonator with a lateral electric field based on PZT ceramics was experimentally investigated. For bacterial immunodetection the frequency dependencies of the electric impedance of the sensor with a suspension of microbial [...] Read more.

A biological sensor for detection and identification of bacterial cells, including a resonator with a lateral electric field based on PZT ceramics was experimentally investigated. For bacterial immunodetection the frequency dependencies of the electric impedance of the sensor with a suspension of microbial cells were measured before and after adding the specific antibodies. It was found that the addition of specific antibodies to a suspension of microbial cells led to a significant change in these frequency dependencies due to the increase in the conductivity of suspension. The analysis of microbial cells was carried out in aqueous solutions with a conductivity of 4.5–1000 μS/cm, as well as in the tap and drinking water. The detection limit of microbial cells was found to be 10³ cells/mL and the analysis time did not exceed 4 min. Experiments with non-specific antibodies were also carried out and it was shown that their addition to the cell suspension did not lead to a change in the analytical signal of the sensor. This confirms the ability to not only detect, but also identify bacterial cells in suspensions. Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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18 pages, 2785 KiB

Open AccessArticle

Ferroelectret-based Hydrophone Employed in Oil Identification—A Machine Learning Approach

by Daniel R. de Luna, T.T.C. Palitó, Y.A.O. Assagra, R.A.P. Altafim, J.P. Carmo, R.A.C. Altafim, A.A.O. Carneiro and Vicente A. de Sousa, Jr.

Sensors 2020, 20(10), 2979; https://doi.org/10.3390/s20102979 - 24 May 2020

Cited by 4 | Viewed by 2888

Abstract

This work focuses on acoustic analysis as a way of discriminating mineral oil, providing a robust technique, immune to electromagnetic noise, and in some cases, depending on the applied sensor, a low-cost technique. Thus, we propose a new method for the diagnosis of [...] Read more.

This work focuses on acoustic analysis as a way of discriminating mineral oil, providing a robust technique, immune to electromagnetic noise, and in some cases, depending on the applied sensor, a low-cost technique. Thus, we propose a new method for the diagnosis of the quality of mineral oil used in electrical transformers, integrating a ferroelectric-based hydrophone and an acoustic transducer. Our classification solution is based on a supervised machine learning technique applied to the signals generated by an in-home built hydrophone. A total of three statistical datasets entries were collected during the acoustic experiments on four types of oils. The first, the second, and third datasets contain 180, 240, and 420 entries, respectively. Eighty-four features were considered from each dataset to apply to two classification approaches. The first classification approach is able to distinguish the oils from the four possible classes with a classification error less than 2%, while the second approach is able to successfully classify the oils without errors (e.g., with a score of 100%). Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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11 pages, 4701 KiB

Open AccessArticle

Influence of Humidity on the Acoustic Properties of Mushroom Mycelium Films Used as Sensitive Layers for Acoustic Humidity Sensors

by Iren Kuznetsova, Boris Zaitsev, Larissa Krasnopolskaya, Andrey Teplykh, Alexander Semyonov, Anastasia Avtonomova, Mayya Ziangirova, Andrey Smirnov and Vladimir Kolesov

Sensors 2020, 20(9), 2711; https://doi.org/10.3390/s20092711 - 09 May 2020

Cited by 15 | Viewed by 3521

Abstract

The influence of humidity on the density, shear elastic module, viscosity, and thickness of the mushroom Pleurotus eryngii and Ganoderma lucidum mycelium films was studied. These data were obtained by comparing the theoretical and experimental frequency dependencies of the complex electrical impedance of [...] Read more.

The influence of humidity on the density, shear elastic module, viscosity, and thickness of the mushroom Pleurotus eryngii and Ganoderma lucidum mycelium films was studied. These data were obtained by comparing the theoretical and experimental frequency dependencies of the complex electrical impedance of bulk acoustic wave (BAW) resonator loaded by mycelium film using the least-squares method. This procedure was performed for the BAW resonator with pointed films for the relative humidity range of 17%–56% at the room temperature. As a result, the changes of the density, shear elastic module, viscosity, and thickness of the films under study, due to the water vapor adsorption, were determined. It has been established that the properties of mycelium films are restored after removing from the water vapor. So, these results show the possibility of using investigated mycelium films as sensitive layers for acoustic humidity sensors. Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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14 pages, 4494 KiB

Open AccessArticle

Evaluation of Elastic Properties and Conductivity of Chitosan Acetate Films in Ammonia and Water Vapors Using Acoustic Resonators

by Boris D. Zaitsev, Andrey A. Teplykh, Fedor S. Fedorov, Artem K. Grebenko, Albert G. Nasibulin, Alexander P. Semyonov and Irina A. Borodina

Sensors 2020, 20(8), 2236; https://doi.org/10.3390/s20082236 - 15 Apr 2020

Cited by 6 | Viewed by 2365

Abstract

Novel bio-materials, like chitosan and its derivatives, appeal to finding a new niche in room temperature gas sensors, demonstrating not only a chemoresistive response, but also changes in mechanical impedance due to vapor adsorption. We determined the coefficients of elasticity and viscosity of [...] Read more.

Novel bio-materials, like chitosan and its derivatives, appeal to finding a new niche in room temperature gas sensors, demonstrating not only a chemoresistive response, but also changes in mechanical impedance due to vapor adsorption. We determined the coefficients of elasticity and viscosity of chitosan acetate films in air, ammonia, and water vapors by acoustic spectroscopy. The measurements were carried out while using a resonator with a longitudinal electric field at the different concentrations of ammonia (100–1600 ppm) and air humidity (20–60%). It was established that, in the presence of ammonia, the longitudinal and shear elastic modules significantly decreased, whereas, in water vapor, they changed slightly. At that, the viscosity of the films increased greatly upon exposure to both vapors. We found that the film’s conductivity increased by two and one orders of magnitude, respectively, in ammonia and water vapors. The effect of analyzed vapors on the resonance properties of a piezoelectric resonator with a lateral electric field that was loaded by a chitosan film on its free side was also experimentally studied. In these vapors, the parallel resonance frequency and maximum value of the real part of the electrical impedance decreased, especially in ammonia. The results of a theoretical analysis of the resonance properties of such a sensor in the presence of vapors turned out to be in a good agreement with the experimental data. It has been also found that with a growth in the concentration of the studied vapors, a decrease in the elastic constants, and an increase in the viscosity factor and conductivity lead to reducing the parallel resonance frequency and the maximum value of the real part of the electric impedance of the piezoelectric resonator with a lateral electric field that was loaded with a chitosan film. This leads to an increase in the sensitivity of such a sensor during exposure to these gas vapors. Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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12 pages, 5024 KiB

Open AccessArticle

Feasibility Study on Shear Horizontal Surface Acoustic Wave Sensors for Engine Oil Evaluation

by Saya Kobayashi and Jun Kondoh

Sensors 2020, 20(8), 2184; https://doi.org/10.3390/s20082184 - 12 Apr 2020

Cited by 8 | Viewed by 2252

Abstract

On site monitoring of engine oil is required. The features of a shear horizontal surface acoustic wave (SH-SAW) sensor include simultaneous detection of mechanical and electrical properties of liquids (such as viscosity, relative permittivity, and conductivity) and loaded mass on the sensor surface. [...] Read more.

On site monitoring of engine oil is required. The features of a shear horizontal surface acoustic wave (SH-SAW) sensor include simultaneous detection of mechanical and electrical properties of liquids (such as viscosity, relative permittivity, and conductivity) and loaded mass on the sensor surface. In this paper, the used engine oil extracted from a motorbike was measured using the SH-SAW sensor. The degradation factors of the used engine oil were experimentally discussed. Especially, the influences of the particles in the engine oil, heating effect, and water contained in the engine oil were considered by comparing the differences between new and used engine oils. The results indicate that the influence of the water contained in the engine oil is the primary cause of the degradation of the used engine oil. Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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15 pages, 4912 KiB

Open AccessArticle

Experimental and Theoretical Study of Multifrequency Surface Acoustic Wave Devices in a Single Si/SiO₂/ZnO Piezoelectric Structure

by Cinzia Caliendo and Farouk Laidoudi

Sensors 2020, 20(5), 1380; https://doi.org/10.3390/s20051380 - 03 Mar 2020

Cited by 19 | Viewed by 3271

Abstract

The propagation of surface acoustic waves (SAWs) along a ZnO/SiO₂/Si piezoelectric structure is experimentally and theoretically studied. Six surface acoustic modes were experimentally detected in the 134 to 570 MHz frequency range, for acoustic wavelength λ = 30 μm, and for [...] Read more.

The propagation of surface acoustic waves (SAWs) along a ZnO/SiO₂/Si piezoelectric structure is experimentally and theoretically studied. Six surface acoustic modes were experimentally detected in the 134 to 570 MHz frequency range, for acoustic wavelength λ = 30 μm, and for SiO₂ and ZnO layers with a thickness of 1 and 2.4 μm. The numerical and three-dimensional (3D) finite element method analysis revealed that the multilayered substrate supports the propagation of Rayleigh and Sezawa modes (R_m and S_m), their third and fifth harmonics at λ/3 and λ/5. The velocity of all the modes was found in good agreement with the theoretically predicted values. Eigenfrequency, frequency domain, and time domain studies were performed to calculate the velocity, the electroacoustic coupling coefficient, the shape of the modes, the propagation loss, and the scattering parameter S₂₁ of the SAW delay lines based on the propagation of these modes. The sensitivity to five different gases (dichloromethane, trichloromethane, carbontetrachloride, tetrachloroethylene, and trichloroethylene) was calculated under the hypothesis that the ZnO surface is covered by a polyisobutylene (PIB) layer 0.8 µm thick. The results show that the modes resonating at different frequencies exhibit different sensitivities toward the same gas. The multi-frequency ZnO/SiO₂/Si single device structure is a promising solution for the development of a multiparameters sensing platform; multiple excitation frequencies with different sensing properties can allow the parallel analysis of the same gas with improved accuracy. Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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15 pages, 6044 KiB

Open AccessArticle

A Langasite Crystal Microbalance Coated with Graphene Oxide-Platinum Nanocomposite as a Volatile Organic Compound Sensor: Detection and Discrimination Characteristics

by Ainan Leong, Tridib Saha, Varghese Swamy and Narayanan Ramakrishnan

Sensors 2020, 20(2), 334; https://doi.org/10.3390/s20020334 - 07 Jan 2020

Cited by 10 | Viewed by 3419

Abstract

We propose a novel langasite crystal microbalance (LCM) sensor with a graphene-based sensing medium to detect and discriminate volatile organic compounds (VOCs) at room temperature. A thin film of graphene oxide embedded with Pt nanostructures (GO-Pt nanocomposite) was deposited on the electrode surface [...] Read more.

We propose a novel langasite crystal microbalance (LCM) sensor with a graphene-based sensing medium to detect and discriminate volatile organic compounds (VOCs) at room temperature. A thin film of graphene oxide embedded with Pt nanostructures (GO-Pt nanocomposite) was deposited on the electrode surface of the LCM, a thickness-shear acoustic wave resonator. Ethyl acetate, acetic acid, and ethanol were chosen as typical VOCs for this study. Sensitivity and selectivity of coated LCM were investigated for different concentrations of the VOCs by analysing the resonant properties of the sensor. When exposed to VOCs, a negative shift in series resonance frequency was observed due to the mass loading of VOC molecules. Simultaneously, changes in equivalent resistance and parallel resonance frequency of the sensor were also observed due to the interaction of VOCs with charge carriers on the GO-Pt nanocomposite film surface. This dual measurement of both series and parallel resonance frequencies allowed for detection and discrimination of VOCs. Moreover, the high thermal stability of langasite makes the proposed sensor suitable even for harsh environmental conditions. Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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22 pages, 3740 KiB

Open AccessArticle

Arbitrary Microphone Array Optimization Method Based on TDOA for Specific Localization Scenarios

by Haitao Liu, Thia Kirubarajan and Qian Xiao

Sensors 2019, 19(19), 4326; https://doi.org/10.3390/s19194326 - 07 Oct 2019

Cited by 7 | Viewed by 3655

Abstract

Various microphone array geometries (e.g., linear, circular, square, cubic, spherical, etc.) have been used to improve the positioning accuracy of sound source localization. However, whether these array structures are optimal for various specific localization scenarios is still a subject of debate. This paper [...] Read more.

Various microphone array geometries (e.g., linear, circular, square, cubic, spherical, etc.) have been used to improve the positioning accuracy of sound source localization. However, whether these array structures are optimal for various specific localization scenarios is still a subject of debate. This paper addresses a microphone array optimization method for sound source localization based on TDOA (time difference of arrival). The geometric structure of the microphone array is established in parametric form. A triangulation method with TDOA was used to build the spatial sound source location model, which consists of a group of nonlinear multivariate equations. Through reasonable transformation, the nonlinear multivariate equations can be converted to a group of linear equations that can be approximately solved by the weighted least square method. Then, an optimization model based on particle swarm optimization (PSO) algorithm was constructed to optimize the geometric parameters of the microphone array under different localization scenarios combined with the spatial sound source localization model. In the optimization model, a reasonable fitness evaluation function is established which can comprehensively consider the positioning accuracy and robustness of the microphone array. In order to verify the array optimization method, two specific localization scenarios and two array optimization strategies for each localization scenario were constructed. The optimal array structure parameters were obtained through numerical iteration simulation. The localization performance of the optimal array structures obtained by the method proposed in this paper was compared with the optimal structures proposed in the literature as well as with random array structures. The simulation results show that the optimized array structure gave better positioning accuracy and robustness under both specific localization scenarios. The optimization model proposed could solve the problem of array geometric structure design based on TDOA and could achieve the customization of microphone array structures under different specific localization scenarios. Full article

(This article belongs to the Special Issue Acoustic Wave Sensors for Gaseous and Liquid Environments)

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