Behavior Of Transducer Research Articles

Mechanic-electric-thermal coupling simulation method of Lamb wave under variable temperature

The propagation mechanism of Lamb waves exhibits more intricate in the variable operational environment of high-speed trains. Simulation methods are widely used to study Lamb wave propagation characteristics due to economic and time constraints. A mechanic-electric-thermal coupling simulation method to study the propagation mechanism of Lamb waves under variable temperatures is proposed in this paper. To accurately simulate the dynamic behavior of Piezoelectric Transducer (PZT) under variable temperature, a nonlinear numerical model of the dynamic parameters (piezoelectric coefficient, dielectric constant) of PZTs has been developed based on the experiment of the temperature influence on Lamb wave. The model emphasizes the nonlinear pattern of change in the key dynamic parameters of the PZT with temperature fluctuations. In addition, a thermal expansion stress model of the PZT-bonding layers-structure is established to reveal the mechanical-thermal coupling mechanism. Based on the COMSOL, a mechanical-electrical-thermal direct coupling simulation model of PZT-bonding layers- structure under variable temperature is established. The simulation results at −40 °C to 80 °C are obtained and compared to the experiment. The results show that the simulation signal is highly consistent with the experimental measurement signal, and the simulation method proposed in this paper has high accuracy.

Dynamic Characteristic Model of Giant Magnetostrictive Transducer with Double Terfenol-D Rods.

Giant magnetostrictive transducer can be widely used in active vibration control, micro-positioning mechanism, energy harvesting system, and ultrasonic machining. Hysteresis and coupling effects are present in transducer behavior. The accurate prediction of output characteristics is critical for a transducer. A dynamic characteristic model of a transducer is proposed, by providing a modeling methodology capable of characterizing the nonlinearities. To attain this objective, the output displacement, acceleration, and force are discussed, the effects of operating conditions on the performance of Terfenol-D are studied, and a magneto-mechanical model for the behavior of transducer is proposed. A prototype of the transducer is fabricated and tested to verify the proposed model. The output displacement, acceleration, and force have been theoretically and experimentally studied at different working conditions. The results show that, the displacement amplitude, acceleration amplitude, and force amplitude are about 49 μm, 1943 m/s2, and 20 N. The error between the model and experimental results are 3 μm, 57 m/s2, and 0.2 N. Calculation results and experimental results show a good agreement.

Layered piezoelectric structures with arbitrary acoustic termination impedances.

Multilayer piezoelectric transducers and resonators are widely used for generating propagating and standing acoustic waves as well as for sensor devices. More recently, layered piezoelectric structures based on thin film technology became increasingly important for electromechanical filters used in mobile phones. As a consequence, analytical mathematical modeling of such structures is of high interest. In this paper, a general rigorous transfer matrix description for one-dimensional (1D) layered structures consisting of piezoelectric, visco-elastic, and dielectric layers of arbitrary number is introduced to characterize the electrical and mechanical behavior of a general piezoelectric transducer or resonator with two electrodes and arbitrary acoustic termination impedances (Rig-1D-model). This model is the most general 1D analytical description of layered piezoelectric structures available and can be used for the characterization of various composite transducer and resonant sensor applications. Considered in detail are layered structures with the technically important cases of only one electromechanically coupled mode, and the structure at one or both outer surfaces is in contact with semi-infinite media. For such devices, it is shown how the frequency dependence of the total electrical admittance and spatial dependence of the displacements can be calculated.

Determination of the Temperature-Dependent Resonance Behavior of Ultrasonic Transducers Using the Finite-Element Method

PurposeLangevin transducers are ultrasonic transducers that convert electrical into mechanical energy through the piezoelectric effect. This class of transducers achieves the highest efficiency in their mechanical resonance. Studies have shown that the resonant frequency changes with temperature. The aim of this contribution is to reproduce this temperature-dependence resonance frequency as accurately as possible with FEM simulations.MethodsTherefore, the temperature-dependent resonance behavior of Langevin transducers is examined experimentally. A FEM model is created on the basis of temperature-dependent measured material coefficients. Using parameter correlations and optimization algorithms, the FEM model is fitted and validated by experimental results. Six variants of Langevin transducers are examined in the range from 30 °C to 80 °C with resonance frequencies between 34 and 38 kHz. They differ in three geometries and two materials.ResultsThe experimental results show that the resonance frequencies decrease with increasing temperatures by 5.0–19.4 Hz/°C, depending on the material and geometry. As decisive parameters for the model fitting of the FEM results, three function-dependent stiffness coefficients of the piezoelectric material PZT8 and the Young’s moduli of the metallic materials are determined by parameter correlation.ConclusionThrough the targeted fitting of these function-dependent parameters, the calculation of the resonance frequencies of Langevin transducers can be qualitatively and quantitatively improved, independent of shape and material.

Effects of Electrode Materials and Compositions on the Resistance Behavior of Dielectric Elastomer Transducers

Dielectric elastomer (DE) transducers possess various advantages in comparison to alternative actuator technologies, such as, e.g., electromagnetic drive systems. DE can achieve large deformations, high driving frequencies, and are energy efficient. DEs consist of a dielectric membrane sandwiched between conductive electrodes. Electrodes are especially important for performance, as they must maintain high electrical conductivity while being subjected to large stretches. Low electrical resistances allow faster actuation frequencies. Additionally, a rate-independent, monotonic, and hysteresis-free resistance behavior over large elongations enables DEs to be used as resistive deformation sensors, in contrast to the conventional capacitive ones. This paper presents a systematic study on various electrode compositions consisting of different polydimethylsiloxane (PDMS) and nano-scaled carbon blacks (CB). The experiments show that the electrode resistance depends on the weight ratio of CB to PDMS, and the type of CB used. At low ratios, a high electrical resistance accompanied by a bimodal behavior in the resistance time evolution was observed, when stretching the electrodes cyclic in a triangular manner. This phenomenon decreases with increasing CB ratio. The type of PDMS also influences the resistance characteristics during elongation. Finally, a physical model of the observed phenomenon is presented.

Extrapolation errors of force transducer curve fitting equations

Calibration laboratories often face the challenge of the impossibility to perform full capacity range calibration of their force transducers, particularly below 10 % of the force transducer’s capacity. Sometimes these laboratories use curve fitting extrapolation to estimate and predict force transducer behavior within uncalibrated capacity ranges. This work deals with the study of extrapolation errors in force transducers to know and estimate prediction accuracies when using extrapolation for force transducer calibration in ranges below 10 % and between 50 % and 100 % of the transducer’s capacity. The results of this study showed that the magnitude of the extrapolation error is very close to the magnitude of the reproducibility error within calibrated capacity ranges in the laboratory.

Research and Experimental Verification of a Flextensional Disk Transducer Based on Relaxor Ferroelectric Single Crystals

In this article, the electroacoustic properties of the flextensional disk transducer based on relaxor ferroelectric single crystals are studied. First, the transducer structure, consisting of relaxor ferroelectric single crystals, metal plates, and air cavity, and an operating principle are introduced. Then, we investigate, by finite element modeling, the influence of different air cavity sizes on the transducer behavior. Furthermore, we optimize the size of the air cavity and analyze the performance of flextensional disk transducers based on relaxor ferroelectric single crystals and piezoelectric ceramics, such as the resonant frequency and transmitting voltage response (TVR). Finally, transducers of the same size are manufactured using the two kinds of materials, and the experimental measurements are carried out in an anechoic water tank. The measured maximum TVR of the single-crystal transducer is 141.04 dB at 22.2 kHz. Compared with the piezoelectric ceramic transducer, the maximum TVR of the single-crystal transducer is increased by 12.51 dB, and the corresponding resonant frequency is reduced by 4.8 kHz, which extends the working frequency.

Large-Signal Equivalent-Circuit Model of Asymmetric Electrostatic Transducers

This article presents a circuit model that is able to capture the full nonlinear behavior of an asymmetric electrostatic transducer whose dynamics are governed by a single degree of freedom. Effects such as stress-stiffening and pull-in are accounted for. The simulation of a displacement-dependent capacitor and a nonlinear spring is accomplished with arbitrary behavioral sources, which are a standard component of circuit simulators. As an application example, the parameters of the model were fitted to emulate the behavior of an electrostatic MEMS loudspeaker whose finite-element (FEM) simulations and acoustic characterisation where already reported in the literature. The obtained waveforms show good agreement with the amplitude and distortion that was reported both in the transient FEM simulations and in the experimental measurements. This model is also used to predict the performance of this device as a microphone, coupling it to a two-stage charge amplifier. Additional complex behaviors can be introduced to this network model if it is required.

An algorithmic approach to electroacoustical analogies

The low-frequency behavior of acoustical transducers can be simulated with the so-called electroacoustical analogies (or lumped parameters). The main idea is that visual inspection of the transducer allows the derivation of an electroacoustic circuit that can be analyzed. The technique is computationally efficient and provides significant physical insight into the transducer. Electroacoustical analogies are taught today in many courses around the world. However, it is difficult to find reading material with an algorithmic approach to derive the electroacoustic circuit from the visual inspection of the transducer. This paper presents algorithms to derive the mechanical and acoustical circuits of transducer systems and how to couple the electrical, mechanical, and acoustical circuits for electrodynamic and capacitive transducers. A number of examples of the derivation are presented in detail. These techniques were conceived from an extensive search of the classical literature in acoustics and adapted to the teaching needs of undergraduate and graduate students of the Acoustical Engineering at the Federal University of Santa Maria in Brazil.

Transduction Efficiency of a Magnetostrictive Sensor for the Generation of Guided Waves in Pipes Using Rapidly Quenched Amorphous Ribbons

The investigation addresses the magnetostrictive sensor (MsS) signal received from pipes of different materials using an amorphous alloy as a sensor element. This sensing system also acts as a transducer to generate ultrasonic waves which appear as echoes from pipe end and defect. The static magnetic field revealed different MsS signals from magnetically different pipes, viz., aluminum (nonmagnetic), galvanized iron (nonmagnetic coating), and mild steel (magnetic) pipes. Applied static field enhanced MsS signals in all the pipes. The extent of this enhancement is influenced by transduction efficiency of the MsS transducer. This efficiency varied with the magnetic nature of the pipe. Simulation through COMSOL Multiphysics elucidated the magnetic flux intensity patterns in these pipes and the consequent behavior of MsS transducer in inspection of pipes of different materials. The study indicated the role of static magnetic field in an MsS transducer for structural health monitoring (SHM) of pipes used prevalently in domestic and industrial sites.

Theoretical and Empirical Verification of Electrical Impedance Matching Method for High-Power Transducers

In our prior study, a systematic approach was used to devise Langevin transducers for high-power applications where the energy efficiency was not considered in the design criteria. In this paper, the impedance matching methods are thus proposed to evaluate what matching topology is appropriate for their use. Both the series inductor scheme and low pass filter composed of a series inductor and shunt capacitor are examined as matching circuits. According to MATLAB simulation, the resonance frequency is seen at 36.79 kHz due to a series L circuit, and its associated impedance is reduced by 70.45% from that of its non-matching condition. The measured resonance frequency is 36.77 kHz and the corresponding impedance is decreased by 59.52%. Furthermore, the acoustic pressure is measured to determine the effect of the matching circuit on the transducer’s actual behavior. The transducer with a series L circuit shows more efficient matching results, 2.28 kPa of positive acoustic pressure is emitted without matching and 3.35 kPa is emitted with a series L element, respectively. As a result, this study demonstrates how to evaluate the influence of matching circuits by using our customized approach rather than commercial SPICE programs, as well as how to experimentally verify the acoustic behavior of high-power Langevin transducers.

Experimental Verification of System Model Behavior of Piezoelectric Ceramic Transducers

Experimental Verification of System Model Behavior of Piezoelectric Ceramic Transducers

The role of understudied post-translational modifications for the behavior and function of Signal Transducer and Activator of Transcription 3.

The Signal Transducer and Activator of Transcription (STAT) family of transcription factors is involved in inflammation, immunity, development, cancer, and response to injury, among other biological phenomena. Canonical STAT signaling is often represented as a 3-step pathway involving the sequential activation of a membrane receptor, an intermediate kinase, and a STAT transcription factor. The rate-limiting phosphorylation at a highly conserved C-terminal tyrosine residue determines the nuclear translocation and transcriptional activity of STATs. This apparent simplicity is actually misleading and can hardly explain the pleiotropic nature of STATs, the existence of various noncanonical STAT pathways, or the key role of the N-terminal domain in STAT functions. More than 80 post-translational modifications (PTMs) have been identified for STAT3, but their functions remain barely understood. Here, we provide a brief but comprehensive overview of these underexplored PTMs and their role on STAT3 canonical and noncanonical functions. A less tyrosine-centric point of view may be required to advance our understanding of STAT signaling.

Thermal noise in electro-optic devices at cryogenic temperatures

The quantum bits (qubits) on which superconducting quantum computers are based have energy scales corresponding to photons with GHz frequencies. The energy of photons in the gigahertz domain is too low to allow transmission through the noisy room-temperature environment, where the signal would be lost in thermal noise. Optical photons, on the other hand, have much higher energies, and signals can be detected using highly efficient single-photon detectors. Transduction from microwave to optical frequencies is therefore a potential enabling technology for quantum devices. However, in such a device the optical pump can be a source of thermal noise and thus degrade the fidelity; the similarity of input microwave state to the output optical state. In order to investigate the magnitude of this effect we model the sub-Kelvin thermal behavior of an electro-optic transducer based on a lithium niobate whispering gallery mode resonator. We find that there is an optimum power level for a continuous pump, whilst pulsed operation of the pump increases the fidelity of the conversion.

New study on force transducer’s temperature behaviour

This paper describes a new study about the temperature behaviour of force transducers. A special force transducer with a PT100 for temperature measuring was developed by GTM. The curve of heating was created, and test data indicates the time for attaining the stable temperature. Meanwhile the different sensitivity of the transducer under different temperatures was obtained, thus the temperature effect on characteristic value per 10 K (so-called TKc) was calculated. At the end, the correction of force transducer at different temperatures was made by the TKc factor of temperature.

On the Model Checking Problem for Some Extension of CTL*

Sequential reactive systems include programs and devices that work with two streams of data and convert input streams of data into output streams. Such information processing systems include controllers, device drivers, computer interpreters. The result of the operation of such computing systems are infinite sequences of pairs of events of the request-response type, and, therefore, finite transducers are most often used as formal models for them. The behavior of transducers is represented by binary relations on infinite sequences, and so, traditional applied temporal logics (like HML, LTL, CTL, mu-calculus) are poorly suited as specification languages, since omega-languages, not binary relations on omega-words are used for interpretation of their formulae. To provide temporal logics with the ability to define properties of transformations that characterize the behavior ofreactive systems, we introduced new extensions ofthese logics, which have two distinctive features: 1) temporal operators are parameterized, and languages in the input alphabet oftransducers are used as parameters; 2) languages in the output alphabet oftransducers are used as basic predicates. Previously, we studied the expressive power ofnew extensions Reg-LTL and Reg-CTL ofthe well-known temporal logics oflinear and branching time LTL and CTL, in which it was allowed to use only regular languages for parameterization of temporal operators and basic predicates. We discovered that such a parameterization increases the expressive capabilities oftemporal logic, but preserves the decidability of the model checking problem. For the logics mentioned above, we have developed algorithms for the verification of finite transducers. At the next stage of our research on the new extensions of temporal logic designed for the specification and verification of sequential reactive systems, we studied the verification problem for these systems using the temporal logic Reg-CTL*, which is an extension ofthe Generalized Computational Tree Logics CTL*. In this paper we present an algorithm for checking the satisfiability of Reg-CTL* formulae on models of finite state transducers and show that this problem belongs to the complexity class ExpSpace.

Peroxides and Bisphenols Detection in Extra Virgin Olive Oil (EVOO) by Plasmonic Nanodomes Transducers

Large-area nanostructured transducer for absorption opto-plasmonic measurements in the ultraviolet visible UV-VIS spectral range have been realized by colloidal lithography. The design and simulation performed guarantee the optical behaviour of the nanostructured transducers. Morphological characterization by AFM microscopy evidences the nanodome structure of the object realized in array configuration. A microfluidic device was optimized to perform measurements in real time. Qualitative evaluation of the peroxides’ and bisphenols’ concentration in extra virgin olive oil (EVOO) have been obtained by following the variation in the plasmonic resonance monitoring of a suitable array nanodome structure deposited onto a glass substrate. Comparison of the obtained results with laboratory-standard methodologies gives us guaranteed support of the potential of the realized technology.

USING AN EXTENSIONS OF CTL* FOR SPECIFICATION AND VERIFICATION OF SEQUENTIAL REACTIVE SYSTEMS

Sequential reactive systems such as controllers, device drivers, computer interpreters operate with two data streams and transform input streams of data (control signals, instructions) into output streams of control signals (instructions, data). Finite state transducers are widely used as an adequate formal model for information processing systems of this kind. Since runs of transducers develop over time, temporal logics, obviously, could be used as both simple and expressive formalism for specifying the behavior of sequential reactive systems. However, the conventional applied temporal logics (LTL, CTL) do not suit this purpose well, since their formulae are interpreted over omega-languages, whereas the behavior of transducers are represented by binary relations on infinite sequences, i.e. omega-transductions. To provide temporal logic with the ability to take into account this general feature of the behavior of reactive systems, we introduced new extensions of this logic. Two distinguished features characterize these extension: 1) temporal operators are parameterized by sets of streams (languages) admissible for input, and 2) sets (languages) of expected output streams are used as basic predicates. In the previous series of works we studied the expressive power and the model checking problem for Reg-LTL and Reg-CTL which are such extensions of LTL and CTL where the languages mentioned above are regular ones. We discovered that such an extension of temporal logics increases their expressive capability though retains the decidability of the model checking problem. Our next step in the systematic study of expressive and algorithmic properties of new extensions temporal logics is the analysis of the model checking problem for finite state transducers against Reg-CTL* formulae. In this paper we develop a model checking algorithm for Reg-CTL* and show that this problem is in ExpSpace.

Calculation of seismic qualities of the damper and vibration transducer with the possibility of their use in aircraft

The aim of the work. The article aims to determine the most effective seismic protection devices, as well as their degree of reliability in different conditions. The method of comparative calculation for determining the quality of seismic protection devices is given. An example of calculation for the damper and vibration transducer is carried out. Calculations show that the use of seismic protection devices reduces the coefficient of K 3 more than twice. Seismic protection is an urgent problem not only in construction, but also in all branches of the technosphere. The option of using seismic protection devices in aircraft is also considered. Methods. A comparative calculation of the behavior of dampers and vibration transducer taking into account the friction coefficients f tr, the sum of vertical loads ∑ Qkd , the total shear seismic force ∑ Sdc is considered. The diagram of the location of seismic protection devices (damper and vibration transducer) under the building is presented, as well as the options for installation in aircraft are given. Comparative calculations are carried out with the presence of seismic protection installations and without them. Results. The total result is given taking into account the change in the value of horizontal seismic loads Sik , which has changed in the range of 2.26-2.46 times. This circumstance allows to conclude that the proposed damping device reduces the seismic load, which falls on the protected structure, by 1-2 points, with almost the same efficiency as the vibration transducers (difference of 0.3 times).

Nanomaterials towards Biosensing of Alzheimer's Disease Biomarkers.

Alzheimer’s disease (AD) is an incurable and highly debilitating condition characterized by the progressive degeneration and/or death of nerve cells, which leads to manifestation of disabilities in cognitive functioning. In recent years, the development of biosensors for determination of AD’s main biomarkers has made remarkable progress, particularly based on the tremendous advances in nanoscience and nanotechnology. The unique and outstanding properties of nanomaterials (such as graphene, carbon nanotubes, gold, silver and magnetic nanoparticles, polymers and quantum dots) have been contributing to enhance the electrochemical and optical behavior of transducers while offering a suitable matrix for the immobilization of biological recognition elements. Therefore, optical and electrochemical immuno- and DNA-biosensors with higher sensitivity, selectivity and longer stability have been reported. Nevertheless, strategies based on the detection of multiple analytes still need to be improved, as they will play a crucial role in minimizing misdiagnosis. This review aims to provide insights into the conjugation of nanomaterials with different transducers highlighting their crucial role in the construction of biosensors for detection of AD main biomarkers.