Construction Of Transducer Research Articles

Operational stability study of lactate biosensors: modeling, parameter identification, and stability analysis.

This paper investigates the operational stability of lactate biosensors, crucial devices in various biomedical and biotechnological applications. We detail the construction of an amperometric transducer tailored for lactate measurement and outline the experimental setup used for empirical validation. The modeling framework incorporates Brown and Michaelis-Menten kinetics, integrating both distributed and discrete delays to capture the intricate dynamics of lactate sensing. To ascertain model parameters, we propose a nonlinear optimization method, leveraging initial approximations from the Brown model's delay values for the subsequent model with discrete delays. Stability analysis forms a cornerstone of our investigation, centering on linearization around equilibrium states and scrutinizing the real parts of quasi-polynomials. Notably, our findings reveal that the discrete delay model manifests marginal stability, occupying a delicate balance between asymptotic stability and instability. We introduce criteria for verifying marginal stability based on characteristic quasi-polynomial roots, offering practical insights into system behavior. Qalitative examination of the model elucidates the influence of delay on dynamic behavior. We observe a transition from stable focus to limit cycle and period-doubling phenomena with increasing delay values, as evidenced by phase plots and bifurcation diagrams employing Poincaré sections. Additionally, we identify limitations in model applicability, notably the loss of solution positivity with growing delays, underscoring the necessity for cautious interpretation when employing delayed exponential function formulations. This comprehensive study provides valuable insights into the design and operational characteristics of lactate biosensors, offering a robust framework for understanding and optimizing their performance in diverse settings.

Highly Electroconductive Metal-Polymer Hybrid Foams Based on Silver Nanowires: Manufacturing and Characterization.

Due to their electroconductive properties, flexible open-cell polyurethane foam/silver nanowire (PUF/AgNW) structures can provide an alternative for the construction of cheap pressure transducers with limited lifetimes or used as filter media for air conditioning units, presenting bactericidal and antifungal properties. In this paper, highly electroconductive metal-polymer hybrid foams (MPHFs) based on AgNWs were manufactured and characterized. The electrical resistance of MPHFs with various degrees of AgNW coating was measured during repeated compression. For low degrees of AgNW coating, the decrease in electrical resistance during compression occurs in steps and is not reproducible with repeated compression cycles due to the reduced number of electroconductive zones involved in obtaining electrical conductivity. For high AgNW coating degrees, the decrease in resistance is quasi-linear and reproducible after the first compression cycle. However, after compression, cracks appear in the foam cell structure, which increases the electrical resistance and decreases the mechanical strength. It can be considered that PUFs coated with AgNWs have a compression memory effect and can be used as cheap solutions in industrial processes in which high precision is not required, such as exceeding a maximum admissible load or as ohmic seals for product security.

Design, construction and performance analysis of dynamic torque transducer

Most of the dynamic torque measurement devices present are not easy to afford and accurate for higher shaft speed, at the same time, especially in the case of Micro-hydropower stations where dynamic torque fluctuates and requires constant monitoring. To fulfill the lack of standard devices, this project concentrated on fabricating non-contact torque transducer devices using easily accessible materials. The project primarily focuses on developing electronics and mechanical systems required to measure dynamic torque. The hollow Aluminum shaft is taken as a torque transducer specimen with a coupling facility. A strain gauge is attached with the specimen shaft in the Wheatstone bridge arrangement such that the strain gauge produces an electrical signal while the shaft experiences strain. Arduino NANO as an I/O device, HX711 ADC module as a signal amplifier, HC05 as a Bluetooth module for wirelessly measured data communication. For calibration, torque is applied to the specimen by coupling it with motor-generator dynamic torque measurement apparatus (DL 10055ETM) which is manufactured by DE LORENZO. Linear regression is used to predict the value of applied torque. The experimental data obtained using the proposed torque transducer prototype has made it clear that it is possible to measure and analyze real-time digital data of dynamic torque produced on specimen shaft rotating at high speed, wirelessly, using locally available resources.

Finite element-based diffraction correction for piezoelectric transducers accounting for diffraction at transmission, propagation, and reception.

Existing diffraction correction models for ultrasonic transmit-receive measurement systems rely on simplifying assumptions with respect to the boundary conditions at the transmitter or receiver. Common simplifications include approximating the sound field radiated by a piezoelectric transducer using a baffled piston model and assuming that the receiver's electrical response is proportional to the spatially averaged free-field pressure over its front surface. In many applications, such simplifications may be adequate, but their validity and accuracy need to be evaluated and quantified. Here, a diffraction correction model utilizing the full set of electrical and mechanical boundary conditions at the transmitter and receiver is presented, avoiding these simplifications. The model is based on finite element modeling of coaxially aligned piezoelectric transducers in a fluid medium. Comparison is made with existing models for an example case of cylindrical piezoelectric ceramic disk transducers operating in air at 50-300 kHz and 0.03-2 m apart, relevant for, e.g., sound velocity and absorption measurements in fluids and ultrasonic gas flow metering. In the near-field, errors introduced by the simplifications are up to 3 dB and 47° for the first radial resonance. Generally, such errors are application-specific and depend on distance, frequency, transducer construction, vibration pattern, and medium properties.

CLASSIFICATION OF VECTOR CONVERTERS

In the work, the classification of vector converters of mechanical quantity is performed. The classification is made depending on the types of sensitive elements, schemes of construction of transducers and the number of measuring projections, transducers

Lead‐free versus PZT: Acoustic characterization of ultrasonic immersion transducers fabricated with lead‐free NBT‐BT piezoceramic

AbstractAn evaluation of the performance of a recently developed formulation of (lead‐free) Sodium‐Bismuth titanate – Barium Titanate (NBT‐BT) piezoceramic is presented through the construction and testing of several immersion transducers based around a new material formulation “Pz12” from CTS Ferroperm (Kvistgaard, Denmark). Results are intended to yield insight into the applicability of this lead‐free material for use within industrial, NDT, medical or underwater sectors through the reporting of experimentally realised performance characteristics. Results of several performance tests are reported including: pulse‐echo amplitude, electrical insertion loss, transducer efficiency, power output and transmitting voltage response (TVR). Benchmarking is provided against comparable lead zirconate‐titanate (PZT) based transducers using an industry standard Navy Type 1 (Pz26, CTS Ferroperm). Performance of the Pz12 transducers was found to exceed expectations, although was lower than that of the comparable Pz26 transducers. Pulse‐echo amplitudes indicated a −4.3 dB relative amplitude between lead and lead‐free variants with electrical insertion loss and transmitting voltage response both showing an average −3.1 dB between the Pz12 and Pz26. Electroacoustic conversion efficiencies of up to 52% are reported for the Pz12 transducers compared with a 62% maximum efficiency for the Pz26 variant. Temperature stability is also investigated in the 10–70 ˚C range.

Design and Development of a Tri-Axial Turning Dynamometer Utilizing Cross-Beam Type Force Transducer for Fine-Turning Cutting Force Measurement.

The main focus of this work was the design and development of a cross-beam force transducer for use in the construction of a tri-axial dynamometer. This dynamometer would be able to measure the cutting force along all three axes simultaneously during turning operations. The force transducer was built on the concept of the Maltese cross-beam, but it had been modified and improved so that it had a higher sensitivity and reduced the amount of interference error or cross-talk error that it produced. An investigation into the distribution of strain, as well as the determination of sensor locations within the transducer construction was carried out by means of finite element analysis. In order to develop a prototype of a turning dynamometer, a number of piezoresistive strain gauges were utilized in the transducer. In order to determine sensitivity, linearity, hysteresis, and repeatability, calibration tests were performed in three directions that were perpendicular to one another. To investigate the dynamic properties and capabilities of the dynamometer for use in turning applications, both modal analysis and actual turning tests were performed. The results of the experiments demonstrated that the newly developed turning dynamometer is a realistic approach for measuring cutting force in machining without reliability and accuracy.

Transducer Design for Clamp-on Guided Wave Flow Measurement in Thin-Walled Pipes

Clamp-on ultrasonic transit time difference flow meters provide opportunities for metering where it is impractical or undesirable to cut into an existing pipeline to install an alternative flow meter. Up until now, it has been difficult to perform this type of measurement on thin-walled metal pipes, due to the difficulty of interpreting the guided wave modes in the combined pipe wall and internal fluid system, but a new method has been reported recently that utilises these guided wave modes for flow measurement. Through computational modelling, and construction and testing of different transducers, the design considerations for clamp-on transducers are highlighted and their impact on guided wave flow rate measurement is evaluated. The design features considered include a curved contact face to provide focusing of the ultrasound within the pipe and a scattering surface to reduce internal reflections. It is found that additional unwanted ultrasonic modes can be minimised by ultrasonic transducer wedge design features such as profiling the curvature of the transducer to conform to the pipe wall or creating a scattering edge to minimise internal wedge reflections. It is also observed that minimising these unwanted modes does not offer any advantage for the transit time difference measurement used in calculating flow.

A high frequency, power, and efficiency diaphragm acoustic-to-electric transducer for thermoacoustic engines and refrigerators.

A high frequency, power, and efficiency diaphragm transducer is described for use with thermoacoustic engines and refrigerators. It uses a tube acting in compression and extension as the primary spring so that the mechanical resonant frequency is around 500 Hz. A high-frequency transducer results in more compact and higher power density thermoacoustic engines, refrigerators, and heat pumps. The tube spring furthermore constitutes a part of the pressure vessel so that the alternator is outside the pressure vessel, thereby simplifying transducer construction and reducing mass. The hermetically sealed transducer operates entirely without wear or lubricants, leading to a long maintenance-free lifetime. We present in situ efficiency measurement results at the full power operating frequency and temperature of the transducer. Despite the high operating frequency, the transducer efficiency is better than that of other transducers previously used in thermoacoustic systems. Accelerated fatigue test results on tube spring coupons justify the long-life claims. The exceptional stiffness of the primary spring in this transducer leads to the unusual need to consider stretch in additional transducer structural components. We present a multi-mass, lumped-element, coupled oscillator model of the transducer and discuss thermoacoustic system design using this model.

Effects of ultrasound technology advances on measurement of carotid intima-media thickness: A review.

In this review, we describe how technological advances in ultrasound imaging related to transducer construction and image processing fundamentally alter generation of ultrasound images to produce better quality images with higher resolution. However, carotid intima-media thickness (IMT) measurements made from images acquired on modern ultrasound systems are not comparable to historical population nomograms that were used to determine wall thickness thresholds that inform atherosclerotic cardiovascular disease risk. Because it is nearly impossible to replicate instrumentation settings that were used to create the reference carotid IMT nomograms and to place an individual's carotid IMT value in or above a clinically relevant percentile, carotid IMT measurements have a very limited role in clinical medicine, but remain a useful research tool when instrumentation, presets, image acquisition, and measurements can be standardized. In addition to new validation studies, it would be useful for the ultrasound imaging community to reach a consensus regarding technical aspects of ultrasound imaging acquisition, processing, and display for blood vessels so standard presets and imaging approaches could reliably yield the same measurements.

Photonic Voltage Transducer with Lightning Impulse Protection for Distributed Monitoring of MV Networks

The design, construction and characterization of a photonic voltage transducer with a lightning impulse protection for distributed measurements on medium voltage (MV) networks (11 kV) was presented in this paper. The sensor prototype, comprising a combination of a piezoelectric transducer and a fibre Bragg grating (FBG) as a core optical sensing element, and a dedicated lightning protection device comprising a set of reactive components, was evaluated through laboratory testing and its performance was assessed based on the accuracy requirements specified by the relevant industry standards. It was demonstrated that the sensor has the potential to meet the accuracy requirements for the 3P protection and 0.2 metering classes specified by the IEC 60044-7. The device successfully underwent lightning impulse withstand tests, satisfying the safety requirements applicable to 11 kV networks as specified by the standard. The usage of an FBG as a photonic sensing component enables the multiplexing of multiple such sensors to provide the distributed measurement of voltage along a power network.

Optical Fiber Transducer for Monitoring Single-Phase and Two-Phase Flows in Pipes

Fluid flow monitoring is essential in many industrial processes. However, some flow measurement methods may not be feasible in a few applications such as the ones in potentially explosive atmospheres or under presence of intense electromagnetic fields. In this study, we present the construction and evaluation of an optical fiber transducer, which is suitable for flow monitoring in industrial environments pipes. Besides single-phase flow, which has been already monitored by similar techniques in the past, we also present in this paper the measurement of two-phase gas-liquid flows. Working principle is based on the measurement of the force induced by the streaming fluid into a cantilever whose deformation is indirectly and optically monitored by means of fiber Bragg gratings. Static and dynamic tests were performed for transducer calibration and validation. In static calibration, sensor sensitivity to force corresponded to 2.34 nm/N. The transducer was successfully applied to measure single-phase flow rate in the range of 0 $\text{m}^{{3}}$ /h to 6.68 $\text{m}^{{3}}$ /h, presenting maximal uncertainty of 0.3 $\text{m}^{{3}}$ /h. Finally, the transducer was applied in two-phase gas-liquid flow, being able to correctly identify gaseous and liquid phases since the cantilever is exposed to different forces during the passage of the gas and liquid. In this way, the developed transducer may be well applied to two-phase flow monitoring.

Providing of Rod Piezoceramic Electroacoustic Transducers Thermal Mode Operation

The basis of the electro-acoustic transducer is piezoceramics - a quite fragile material. A rod type transducer was chosen for analysis due to the lack of research on this type of transducer and its widespread use. The most dangerous operational load is thermal. The mechanism of the transducer heating and the negative effects that the transducer heating causes are analyzed. Ways of heat prevention are analyzed. To exclude negative effects, it is necessary to deal with undesirable heating at the stage of construction. To check the construction of the transducer for thermal loads, it is proposed to compare two methods for estimate the temperature field of the transducer. Two methods of thermal field analysis for the construction of piezoceramic electro-acoustic transducers are considered - analytical calculation and modeling in computer-aided design system. For a proper comparison of the two methods, it is necessary to take the same model of the electro-acoustic transducer for calculation and simulation. In both cases, the transducer is simplified to structurally important elements - the active element, the radiating and the back mass. The active element is CTBS-3 piezoceramic, a radiating mass is made of Amg-6 aluminum and a back mass is made of St-20 steel. The analytical method for finding the thermal field is based on the solution of the Fourier differential heat equation. A simplified model of an acoustic transducer is presented in the form of three layers, and a thermal conductivity equation is applied to each. Unknown quantities are found by substituting the heat equation into the boundary conditions. Three pairs of boundary conditions are used: the equality of temperature at the points of contact of the layers, the equality of heat flow at the border between the body and the medium, and the equality of heat flow at the boundaries of the layers. Computer simulation performed using the finite element method in the SolidWorks computer-aided design system. The advantage of the modeling method instead by the calculations is demonstrated. In addition to easy use, rapid change of parameters and the ability to solve more complex problems, modeling can show the heating of the transducer at different points in time. The heat-up process can be informative when it is impossible to change the design to improve the thermal regime and therefore heating is inevitable. In this case, it is necessary to analyze the time during which the transducer heat-up to the permissible temperature for pulse mode implementation. The obtained results can be used in the design of core piezoceramic electroacoustic transducers.

Theoretical model construction and structure optimization of electromagnetic flow transducer based on neural network

Theoretical model construction and structure optimization of electromagnetic flow transducer based on neural network

RADIOMEASURING GAS CONCENTRATION TRANSDUCER BASED ON TRANSISTOR STRUCTURE WITH NDR FOR THE DIAGNOSIS OF STRAINS OF THE BACTERIUM HELICOBACTER PYLORI

The article discusses a radiomeasuring gas concentration transducer for the diagnosis of strains of the bacterium Helicobacter pylori. One of the promising directions in the construction of gas concentration transducers for respiratory diagnostics is the use of gas concentration frequency transducers based on the reactive properties of transistor structures with negative differential resistance (NDR). This type of transducers allows you to solve the problem of using analog-to-digital converters, because it implements the method of converting "informative signal - frequency", which is one of the best for further processing on a computer. Theoretical and practical studies have shown that using the reactive properties of semiconductor devices and transistor structures in which there is a negative differential resistance, it is possible to significantly increase the sensitivity and accuracy of measuring gas concentration, in particular NH3. The authors proposed and studied a gas concentration measuring transducer, which is built on the basis of a transistor structure with negative differential resistance and a gas-sensitive element to NH3. With a change in gas concentration, the conductivity of the sensitive element changes, which adsorbs NH3 molecules, which in turn changes the active and reactive components of the impedance of the transistors structure. The reactive component of the impedance of the transistors structure is capacitive in nature. This capacitance is part of the total capacitance that occurs at the electrodes of the drain of a double-gate MOS transistor and collector of a bipolar transistor, which together with the inductance L form a resonant oscillatory circuit. A dynamic mathematical model of the frequency transducer of gas concentration by the method of variable states is developed. The dynamic model of the self-generating secondary transducer of gas concentration allows you to determine the value of the frequency of the output signal depending on the change in gas concentration at any time. Analytical expressions of the transformation function and sensitivity equations are obtained. The sensitivity of the developed device for the diagnosis of strains of the bacterium Helicobacter pylori ranges from 2.1 kHz/ppm to 3.4 kHz/ppm.

Analysis of a semiconductor vibration and frequency sensor construction specifity

The model of direct transducering tensoresistive method of semiconductor filamentous monocrystal mechanical oscillations into an electrical signal and the principle of deformation into frequency transducer (sensor) construction are considered in this paper. The connections of output tensor signal parameters with resonator own geometric dimensions, mechanical stress and elasticity of the crystals, amplitude and their mechanical oscillations frequency are established. The value of tensor signal, which arises due to bending and tension of monocrystals under cyclic loads, is estimated, the specificity of their properties and structure is revealed

Investigation of property losses in single crystal transduction devices

With the advent of relaxor single crystal materials, such as lead indium niobate-lead magnesium niobate-lead titanate (PIN-PMN-PT) and lead magnesium niobate-lead titanate (PMN-PT), it was discovered that the highly oriented crystal structure of the materials leads to large values of dielectric and piezoelectric properties favorable to acoustic applications. When utilized in transduction devices, single crystal materials have demonstrated better acoustic performances compared to traditional designs. However, during construction of single crystal transducers, a capacitance loss is measured after mechanically bonding the crystal to a stiff backing material. The lower capacitance suggests a decrease in the effective permittivity, decreasing favorable piezoelectric constants for acoustic performance. In this study, the loss in effective permittivity was modeled using a commercial finite element analysis software. We present simulations used to demonstrate the loss in effective permittivity and compare with experimental measurements. Additionally, finite element simulations of several design considerations that can be utilized by transducer designers to minimize the loss in the effective permittivity are presented.

Rapid prototyping for therapeutic ultrasound transducers

Introduction: Piezoelectric materials are readily available from many suppliers at low cost. Finished ultrasound transducers, however, are significantly more expensive particularly for custom designs. Acoustics research often requires many iterations before a successful experiment design is achieved. This talk will present examples and what we’ve learned from ten years experience at the University of Michigan constructing transducers with rapid prototyping. Methods: Selective Laser Sintering, Stereolithography, and Fused Deposition Modeling techniques were all tested for transducer construction. Acoustic properties (sound speed, absorption, and impedance) were measured for various materials in each category. Ageing and degradation due to water ingress were assessed as well. Results: Housings for electrical/water isolation were successfully constructed using each technology. Professional quality machines yielded sufficient precision to create focused array structures up to 5 MHz. A majority of stereolithography materials showed very poor water compatibility degrading with exposure over time. Most materials have too low acoustic impedance for good matching layers. Particle filled stereolithography resins have increased density and sound speed that raise the impedance to more suitable values. Acoustic lenses were successfully constructed from stereolithography materials allowing focused transducers to be constructed from low cost flat piezoelectric materials.

A 35 MHz/105 MHz Dual-Element Focused Transducer for Intravascular Ultrasound Tissue Imaging Using the Third Harmonic.

The superharmonic imaging of tissue has the potential for high spatial and contrast resolutions, compared to the fundamental and second harmonic imaging. For this technique, the spectral bandwidth of an ultrasound transducer is divided for transmission of ultrasound and reception of its superharmonics (i.e., higher than the second harmonic). Due to the spectral division for the transmission and reception, transmitted ultrasound energy is not sufficient to induce superharmonics in media without using contrast agents, and it is difficult that a transducer has a −6 dB fractional bandwidth of higher than 100%. For the superharmonic imaging of tissue, thus, multi-frequency array transducers are the best choice if available; transmit and receive elements are separate and have different center frequencies. However, the construction of a multi-frequency transducer for intravascular ultrasound (IVUS) imaging is particularly demanding because of its small size of less than 1 mm. Here, we report a recently developed dual-element focused IVUS transducer for the third harmonic imaging of tissue, which consists of a 35-MHz element for ultrasound transmission and a 105-MHz element for third harmonic reception. For high quality third harmonic imaging, both elements were fabricated to have the same focus at 2.5 mm. The results of tissue mimicking phantom tests demonstrated that the third harmonic images produced by the developed transducer had higher spatial resolution and deeper imaging depth than the fundamental images.

Determination of the sonic properties of a Nigerian quartz for ultrasonic transducer.

There is abundant quartz deposit in Nigeria which has been used for export and building purposes. However, its electrical and piezoelectric properties have not been studied. Thus, whether it can be used as raw material for the indigenous electric industries is unknown to date. This study aims to characterize the piezoelectric properties of smoky quartz for ultrasonic transducer and determine its sonic properties. In the research approach, the raw quartz was cut into six crystals of rectangular shape using a universal cutter. The crystals were purified with a 100 ml hydrofluoric and hydrochloric acid solution under a temperature of 250°C in a furnace. The sizes, weights, and capacitance of crystals were determined using the standard measuring instruments. The resonance method was used for the determination of the frequency of minimum and maximum impedance of the crystals. The piezoelectric constants of the crystals were derived using the standard formula for determination of piezoelectric constants. The results show that the sonic properties represented by the piezoelectric charge constant (d31) and the piezoelectric voltage constant (g31) values are 2.52(±1.075)×10-8c/m2 and 1030.6114±250.89v/m2 respectively. The present study has characterized Nigerian quartz for its piezoelectric properties and found that it was suitable for use in the construction of ultrasonic transducers.