Piezoelectric Detection Research Articles

Piezoelectric geophone: a review from principle to performance

Real-time monitoring of seismic information is important, a wide variety of geophones have emerged to achieve this goal. According to the principle of transforming seismic signals, the geophones can be classified into electromagnetic geophones, piezoelectric geophones, electrochemical geophones, fiber optic geophones and so on. Among them, piezoelectric geophones have been widely used in seismic detection. In this article, the piezoelectric material is briefly introduced at first, and then the piezoelectric seismic detector with piezoelectric ceramic and polyvinylidene fluoride as a sensitive material is involved. After analyzing the electrical equivalent model of the piezoelectric sensitive unit, the signal conditioning circuit of the piezoelectric geophone is summarized as well. After that, the promotion of MEMS technology to piezoelectric geophones is discussed. Finally, a summary of all the work listed in this article is given and an outlook of combining MEMS and PVDF to improve the performance of geophones is proposed.

Simplified detection of cavitation threshold in control valves

For industrial monitoring of fluid flows, the transition from a single-phase flow to a cavitation regime is most commonly determined by a microphone that measures the sound emitted in the vicinity of critical constrictions such as in the opening of the control valves. To measure the cavitation threshold, we developed an analogue and robust piezoelectric detection method. The evaluation of this method on the reference test orifice plate and on a chosen control valve shows that it eliminates the sound noise of an industrial environment, largely removes the subjectivity of the operator and enables a more detailed observation of the cavitation phenomenon.

Magnetic-repulsion-coupled piezoelectric-film-based stretchable and flexible acoustic emission sensor

This paper presents a stretchable and flexible acoustic emission (AE) sensor composed of patterned upper, lower piezoelectric film foils, magnets and stereolithographic structures. The proposed device possesses the following novelties. The piezoelectric sensing structures with magnetic repulsion is effective for AE signal coupling. The lower piezoelectric serpentine-shaped AE detection structure with stretchable and flexible characteristics allows sensing various curved surfaces. Additionally, the contact force between the sensing target and AE sensor can be evaluated by monitoring the structural characteristic change of the upper piezoelectric structure of the AE sensor. The magnetic-repulsion-enhanced AE sensor exhibits a better bandwidth compared to that with only a lower AE sensing structure. Also, the fabricated sensor subjected to a sensing target force ranging from 4.98 to 14.85 mN resulting in a frequency change of the piezoelectric sensing beam of the upper foil from 20.073 to 20.135 kHz is verified. The developed AE sensor can open a new field for various applications. For instance, AE waves can be monitored without contacting the target (e.g. interfacing with air). The detection mechanism of AE waves by an action at a distance is successfully demonstrated.

Metabolic breath signature of 13C-enriched wheat bran consumption related to gut fermentation in humans: a Fiber-TAG study

AbstractIntroductionDietary fibers (DF) have been classified mainly according to their physico-chemical and fermentability properties but it remains unclear whether such classification is relevant when addressing their health effects. Indeed, the nature of physiological effects induced by DF, particularly through their interaction with gut microbiota, remains poorly known due to their diversity, to gut microbiota inter-subjects variability and to the lack of validated non-invasive biomarkers to characterize DF-gut microbiota interaction. The aim of this pilot study was 1) to follow the metabolic fate of 13C-labeled DF through the assessment of 13C-labelled gut-derived metabolites in excreted breath and 2) to evaluate novel non-invasive breath-derived biomarkers of DF-gut microbiota interactions.Materials and methodsSix healthy women (29.7 ± 1.7 years old, BMI: 23.2 ± 0.9kg/m2, fiber intake: 23 ± 1g/d) consumed in research settings a controlled breakfast containing eight 13C-labelled wheat bran biscuits (50 g of labelled wheat bran, 3.0At%13C). 13C-labelled wheat bran was obtained from wheat cultivated under 13CO2 enriched atmosphere. Samples of expired gases were collected during 24 h after ingestion in order to measure H2 and CH4 by gas chromatography (GC) with piezoelectric detection and 13CO2 and 13CH4 by gas chromatography coupled with an isotope ratio mass spectrometer (GC-IRMS). Apart test breakfast, subjects only consumed standardized meals without fibers.ResultsThe analysis of H2 and CH4 24h-kinetic measurements distinguished 2 groups in terms of fermentation related gas excretion: the high-CH4 producers with high baseline CH4 concentrations (42.1 ± 13.7ppm) and low baseline H2 concentrations (7.3 ± 5.8ppm) and the low-CH4 producers with low baseline CH4 concentrations (6.5 ± 3.6ppm) and high baseline H2 concentrations (20.8 ± 16.0ppm). Following the 13C-wheat bran biscuits’ ingestion, postprandial H2 and CH4 concentrations increased more significantly in the high-CH4 producer subjects. 13C enrichment was detectable in expired gases in all subjects. 13CO2 kinetics were similar for all subjects and correspond to the oxidation of the digestible part of the bran. The appearance of 13CH4 was significantly enhanced and prolonged after 180 min in high-CH4 producers compared to low-CH4 producers, suggesting distinct fiber fermentation profile.DiscussionThis pilot study allowed to consider novel procedures for development of non-invasive breath biomarkers of fiber-gut microbiota interactions. Assessment of expired gas excretion following 13C-labelled fiber ingestion allowed deciphering distinct fermentation profiles: high-CH4 producers vs low-CH4 producers and accordingly provide a related non-invasive breath metabolic signature of the fiber fermentation for each profile. Further gut microbiota and 13C-metabolites analysis will permit to relate the gut bacteria composition with breath gas excretion kinetics according to fiber fermentation profile.

Concurrent Detection of Linear and Angular Motion using a Single-Mass 6-axis Piezoelectric IMU

This paper exhibits operating system and performances of a novel single-mass 6-axis Inertial Measurement Unit (IMU) using piezoelectric detection. The electronic processing circuitry for the concurrent detection of linear and angular motion is proposed. The IMU structure is based on the use of 2 rings, connected with eight electrodes, implemented on the top of a piezoelectric membrane used for both sense and drive modes. The four inner electrodes are used for components detection due to the direct piezoelectric effect, while the outer electrodes are used to generate the drive mode due to the reverse piezoelectric effect. Through finite element analysis, we show that linear accelerations generate an offset voltage on the sensing electrodes, while angular rates lead to a change in the amplitude of the initial AC signal caused by the drive mode. The present work represents an innovative design able to separate 6 motion data from signals using only 4 electrodes. The specific electronic circuitry for acceleration and angular rate data dissociation shows a very efficient method for signal separation since no leakage readout occurs in all six axes. Besides, other particular interest is that under no circumstances, angular outputs disturb or affect acceleration ones and vice versa. The evaluated sensitivities are 364 mV/g and 65.5 mV/g for in-plane and out-of-plane linear accelerations, respectively. Similarly, angular rates sensitivities are 2.59 mV/rad/s and 522 mV/rad/s.

Analysis of Viscoelastic Parameters of Fluids by Low-Frequency Piezoelastography.

Theoretical and experimental analysis of viscoelastic properties of fluids at low oscillating shear stresses was performed. Mathematic approach for calculating the complex coefficient of viscosity on the basis of experimental data on the amplitude-phase characteristics measured by the method of low-frequency piezoelastography was developed. The dependencies of the amplitude and phase shift of the signal recorded by a piezoelectric detector of a ARP-01M Mednord piezoelectric thromboelastograph on the frequency of forced oscillations of a resonator needle in air, water, and glycerin at fixed temperature of 37°C were studied. It was found that with increasing fluid viscosity, the resonance frequency of oscillations decreases in comparison with the frequency of oscillations in air.

Amino acids nanocrystals for piezoelectric detection of ultra-low mechanical pressure.

Developing biocompatible nano-materials with the ability to detect ultra-low mechanical pressure is promising for biomedical sensors. This paper reports the detection of pressure as low as 1Pa in the environmental pressure of 1atm (10-3% pressure change) by nanocrystals of amino acids glycine and alanine through the piezoelectric effect. Piezoelectricity enables detection of pressure by a change of dielectric polarization when the material is subjected to external pressure. This work exploits the non-centro-symmetric structure of some amino acids and their weak hydrogen bonds to develop sensitive mechanical pressure sensors. The β-glycine and l-alanine nanocrystals were grown from aqueous solution inside porous alumina substrate. The nanocrystals exhibit pronounced preferred crystallographic orientation. The sensitive piezoelectric response to ultra-low mechanical pressure is discussed based on atomic and crystal symmetry considerations.

Enhanced piezoelectricity and excellent thermal stabilities in Nb–Mg co-doped CaBi4Ti4O15 Aurivillius high Curie temperature ceramics

Nb–Mg co-doped CaBi4Ti4O15 ceramics were synthesized for potential high temperature piezoelectric applications via the solid-state reaction technique. The influences of Nb–Mg doping level on structure, piezoelectricity and other electrical properties were systematically researched. The XRD, EDS and Raman scattering results confirmed that the doped Nb–Mg ions had successfully diffused into the crystal lattice of CaBi4Ti4O15 ceramic. Co-doping of Nb–Mg enhanced the piezoelectric coefficient d33 effectively without causing significant deterioration on Curie temperature TC. The CaBi4Ti3.9(Nb2/3Mg1/3)0.1O15 ceramic possessed the optimized electric properties with a high d33 value of 24 pC/N accompanied by a high TC value of 787 °C. In addition, this ceramic also exhibited a good thermal stability with d33 keeping 91% of its original value after annealing at 600 °C. All these results suggested that Nb–Mg co-doped CaBi4Ti4O15 ceramic could be a potential candidate for high temperature piezoelectric sensor or detector applications.

Improvement of the Vibratory Diagnostic Method by Evolution of the Piezoelectric Sensor Performances

Vibration analysis is an important means in the industrial field to monitor electromechanical systems; their evolution can provide the correct information on vibration. For this purpose; it is necessary to focus the study on improving the piezoelectric sensor performance to progress the vibration analysis method. In industry, the piezoelectric accelerometer is the instrument often used to monitor rotating machines and detect their defects in an early stage. In this paper, piezoelectric detection is studied to understand the operating principle of the piezoelectric accelerometer and translate it into a mathematical model. Validation of the model developed of measurement accuracy and measurement error as a function of relative vibration movement by simulation and experimental tests is performed. Using this validated model, the improvement of the characteristics and performance of this sensor can be achieved as well as a new conception of the latter can be proposed. This new design of piezoelectric sensor aims to obtain more accurate results and to provide correct information’s on the vibratory level. A comparative study is made to show the importance of our results compared to literature, these results have showed that a suitable and appropriate choice of damping ratio develops the accelerometer parameters and enhances the vibratory analysis technique.

Applicability investigation of piezoelectric sensor-based damage detection technique for membrane

Applicability investigation of piezoelectric sensor-based damage detection technique for membrane

Piezoelectric effect-based detector for spectroscopic application

A standoff laser spectroscopy sensor based on a broadband tunable external cavity quantum cascade laser (ECQCL) and a piezoelectric effect-based detector was developed for simultaneous detection of multiple chemicals. Instead of using a standard infrared detector, a custom quartz crystal tuning fork (QCTF) with a high resonant frequency (∼75 kHz) was adopted as a light detector for laser signal collection. To explore the capabilities of this technique, the impact of the position of incident light beam excitation with respect to the QCTF on the signal amplitude, resonant frequency and Q-factor was observed in detail. In addition, the influence of incident light intensity and pressure on the intrinsic property of the QCTF was also systematically investigated. Finally, the ECQCL sensor was successfully demonstrated for the standoff detection of plumes for three volatile organic compounds (VOCs) (i.e., alcohol, acetone and ether) at a distance of 40 m, which proves the applicability of the technique for the detection of leak plumes in security fields.

Progression of the vibratory analysis technique by improving the piezoelectric sensor measurement accuracy

AbstractThe piezoelectric sensor is the best choice for large industrial installations for instantaneous monitoring and premature fault diagnosis of electromechanical systems. In this work, we made a study on the piezoelectric detection and the piezoelectric sensor then a model of the physical behavior of this sensor extracted. The developed model of measurement accuracy as a function of the relative vibration movement is validated by experimental tests and simulation. The good choice of the damping rate allowed to improve the parameters of the sensor on the one hand and to advance the technique of vibratory analysis on the other hand.

Looking at sound: optoacoustics with all-optical ultrasound detection

Originally developed for diagnostic ultrasound imaging, piezoelectric transducers are the most widespread technology employed in optoacoustic (photoacoustic) signal detection. However, the detection requirements of optoacoustic sensing and imaging differ from those of conventional ultrasonography and lead to specifications not sufficiently addressed by piezoelectric detectors. Consequently, interest has shifted to utilizing entirely optical methods for measuring optoacoustic waves. All-optical sound detectors yield a higher signal-to-noise ratio per unit area than piezoelectric detectors and feature wide detection bandwidths that may be more appropriate for optoacoustic applications, enabling several biomedical or industrial applications. Additionally, optical sensing of sound is less sensitive to electromagnetic noise, making it appropriate for a greater spectrum of environments. In this review, we categorize different methods of optical ultrasound detection and discuss key technology trends geared towards the development of all-optical optoacoustic systems. We also review application areas that are enabled by all-optical sound detectors, including interventional imaging, non-contact measurements, magnetoacoustics, and non-destructive testing.

Devices for Diagnostics and Lithium Collection on the T-11M and T-10 Tokamaks. First Results

The use of lithium as a material of the tokamak in-vessel plasma-facing components made it necessary to develop appropriate diagnostic instruments. For the T-10 and T-11M tokamaks, devices have been developed that allow one to investigate the processes of lithium transport in the tokamak scrape-off layer, the dynamics of lithium deposition at different temperatures of the collecting surface in real time by using a piezoelectric quartz detector, adsorption and desorption of the plasma-forming gas by lithium, and the influence of the electric field on the process of lithium collection. The plasma parameters are monitored using Langmuir probes. The developed devices can be used to extract lithium deposited on the tokamak vessel wall without breaking vacuum conditions. For these purposes, a gateway and a vacuum input without bellows have been designed on the basis of an innovative liquid-metal coupling.

A high-sensitive current-mode pressure/force detector based on piezoelectric polymer PVDF

This paper introduces new electronic sensor circuits based on the usage of a piezoelectric Polyvinylidene fluoride-PVDF pressure detector coupled with a current-mode instrumentation amplifier, Schmitt comparator, and only grounded resistors. Pressure/force is measured in terms of the charge generated by the PVDF element as a result of the direct piezoelectric effect. The experimental test results demonstrated that the dynamic pressure response, the sensitivity and linearity of the designed sensor were higher than the sensitivity and linearity of a traditional piezoelectric sensor. The sensitivity of the PVDF sensor was 0.08 mV/Pa. The detector is calibrated over a frequency range of 1 Hz–1 kHz. The proposed signal conditioning electronics offer a potential for future miniaturization in order to be integrated with different commercial devices, for detecting certain tiny activities including finger movements, robotics and smart electronic devices.

Moisture-triggered actuator and detector with high-performance: interface engineering of graphene oxide/ethyl cellulose

Actuators that can directly convert other forms of environmental energy into mechanical work offer great application prospects in intriguing energy applications and smart devices. But to-date, low cohesion strength of the interface and humidity responsive actuators primarily limit their applications. Herein, by experimentally optimizing interface of bimorph structure, we build graphene oxide/ethyl cellulose bidirectional bending actuators --- a case of bimorphs with fast and reversible shape changes in response to environmental humidity gradients. Meanwhile, we employ the actuator as the engine to drive piezoelectric detector. In this case, graphene oxide and ethyl cellulose are combined with chemical bonds, successfully building a bimorph with binary synergy strengthening and toughening. The excellent hygroscopicity of graphene oxide accompanied with huge volume expansion triggers giant moisture responsiveness greater than 90 degrees. Moreover, the open circuit voltage of piezoelectric detector holds a peak value around 0.1 V and exhibits excellent reversibility. We anticipate that humidity-responsive actuator and detector hold promise for the application and expansion of smart devices in varieties of multifunctional nanosystems.

On the Piezoelectric Detection of Guided Ultrasonic Waves.

In order to quantify the wave motion of guided ultrasonic waves, the characteristics of piezoelectric detectors, or ultrasonic transducers and acoustic emission sensors, have been evaluated systematically. Such guided waves are widely used in structural health monitoring and nondestructive evaluation, but methods of calibrating piezoelectric detectors have been inadequate. This study relied on laser interferometry for the base displacement measurement of bar waves, from which eight different guided wave test set-ups are developed with known wave motion using piezoelectric transmitters. Both plates and bars of 12.7 and 6.4 mm thickness were used as wave propagation media. The upper frequency limit was 2 MHz. Output of guided wave detectors were obtained on the test set-ups and their receiving sensitivities were characterized and averaged. While each sensitivity spectrum was noisy for a detector, the averaged spectrum showed a good convergence to a unique receiving sensitivity. Twelve detectors were evaluated and their sensitivity spectra determined in absolute units. Generally, these showed rapidly dropping sensitivity with increasing frequency due to waveform cancellation on their sensing areas. This effect contributed to vastly different sensitivities to guided wave and to normally incident wave for each one of the 12 detectors tested. Various other effects are discussed and recommendations on methods of implementing the approach developed are provided.

Relative measurement of the acoustic nonlinearity parameter using laser detection of an ultrasonic wave

The relative acoustic nonlinearity parameter β' is defined by the amplitudes of the fundamental and second-order harmonic components in the detected ultrasonic wave signal, in which a piezoelectric transducer is conventionally used for detection. Although it is not identical to the absolute parameter β defined by the displacement amplitudes, β' has been widely used for the relative comparison between the same materials since its ratio is identical to that of the absolute parameter when the detected signal amplitude is proportional to the displacement amplitude. However, β cannot be replaced by β' for the comparison between different materials due to the difference of respective acoustic impedance. This study aims to show that a laser detection method using a photorefractive interferometer can be used for the relative comparison of acoustic nonlinearity between different materials because its output is independent of the acoustic impedance. To demonstrate, two similar materials, Al6061-T6 and Al2024-T4, and one different material, copper, were tested. Experimental results showed that the ratio β 2024 / β 6061 , measured via the proposed method and the conventional piezoelectric detection method, were in good agreement with the references. However, in the case of β Cu / β 6061 , only the proposed method showed good agreement with the references.

Analysis of the transfer function for layered piezoelectric ultrasonic sensors

We model theoretically the voltage response to an acoustic pulse of a multilayer system forming a low noise capacitive sensor including a Polyvinylidene Fluoride piezoelectric film. First we model a generic piezoelectric detector consisting of a piezoelectric film between two metallic electrodes that are the responsible to convert the acoustic signal into a voltage signal. Then we calculate the pressure-to-voltage transfer function for a N-layer piezo-electric capacitor detector, allowing to study the effects of the electrode and protective layers thickness in typical layered piezoelectric sensors. The derived transfer function, when multiplied by the Fourier transform of the incident acoustic pulse, gives the voltage electric response in the frequency domain. An important concern regarding the transfer function is that it may have zeros at specific frequencies, and thus inverting the voltage Fourier transform of the pulse to recover the pressure signal in the time domain is not always, in principle, possible. Our formulas can be used to predict the existence and locations of such zeroes. We illustrate the use of the transfer function by predicting the electric signal generated at a multilayer piezoelectric sensor to an ultrasonic pulse generated photoacoustically by a laser pulse at a three media system with impedance mismatch. This theoretical calculations are compared with our own experimental measurements.

Optical Detection of Impact Contact Times with a Beam Deflection Probe

We present an optical detection technique, called the beam deflection probe, to accurately measure contact times of normal-incidence impacts of steel and sapphire spheres with a transparent glass block. It exploits the deformation of the area that is in a mechanical touch during the rebound. The deformation of the surface acts as a dynamic contact mirror. When illuminated by a laser beam, total internal reflection takes place at the contact mirror, the beam is deflected from it, and its angular deflection history is monitored by a quadrant photodiode. A simple threshold-level data processing of the photodiode signals is used to determine the impact duration. It is shown that the shape of the signal is highly dependent on the location of the impact relative to the center of the laser-beam illuminated area while the determination of the contact time does not depend on the impact position. Using an automated ball release mechanism, the contact time of low-velocity impacts was measured for various ball diameters and approach velocities conforming to the Hertz contact theory. The proposed optical detection of contact times supplements the existing measurement techniques and represents the only alternative to the piezoelectric detection when contact times are to be measured on the microsecond scale.