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Journal articles on the topic 'Transducer'
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1
Yang, Qing Feng, Peng Wang, Yu Hong Wang, and Kai Zhang. "Simulation Analysis on Cymbal Transducer." Advanced Engineering Forum 2-3 (December 2011): 140–43. http://dx.doi.org/10.4028/www.scientific.net/aef.2-3.140.
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The resonance frequency of the cymbal transducer ranges from 2kHz to 40kHz and its effective electromechanical coupling factor is around 20%. Finite element analysis has been performed to ascertain how the transducer’s makeup affect the transducer’s performance parameters. Two-dimensional axisymmetric model of the cymbal transducer was founded by finite element software-ANSYS, the application of the element type was discussed and the FEM models were built up under the far field condition. Eight groups of cymbal transducers of resonance frequency around 3kHz with different structural dimensions were designed. It was better for choosing the cymbal transducer of the 8mm cavity coping diameter, 20.8mm cavity bottom diameter and 26.8mm piezoelectric ceramic wafer diameter than others for reducing distortion degree of the signal and improving communication turnover in the researched cymbal transducers. It was appropriate for choosing the cymbal transducer of the 8mm cavity coping diameter, 22.4mm cavity bottom diameter and 26.4mm piezoelectric ceramic wafer diameter in order to improve the free-field voltage sensitivity and transmission efficient.
2
Geng, Jie, Quan Lu Li, Jing Wu, Qing Qing Yang, and Hai Xia Chen. "The Performance and Material Selection of Medical Ultrasonic Transducer." Advanced Materials Research 340 (September 2011): 456–60. http://dx.doi.org/10.4028/www.scientific.net/amr.340.456.
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With the accelerating pace of mordern medicine, the various transducers that applicat in clinical diagnosis are also more and more, most medical ultrasonic transducer using acoustoelectric transducer to emiting and receiving of ultrasonic wave. However, the selection of transducer’s material is very important to the performance of medical ultrasonic transducer. This paper describes structures and properties of the medical ultrasonic transducer, and a variety of quantitative indicators that influence its performance. Aim to work out the most appropriate material for making the medical ultrasonic transducer.
3
Kong, Huan Ping, Zheng Zhang, and Li Fei Li. "Factors Influencing Acousto-Ultrasonic Approach to Impact Damage in Composite Materials." Advanced Materials Research 393-395 (November 2011): 97–101. http://dx.doi.org/10.4028/www.scientific.net/amr.393-395.97.
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This paper studied factors influencing AU detection results on different damage specimens, including simulation frequency, transducer modes and transducer location. Correlation between acousto-ultrasonic parameters (AUP1, AUP2) and impact damage severity in composite was investigated. The results showed that as damage severity increased, AUP1 and AUP2 of three different transducers decreased. Applying low frequency transducer, the variation of AUP1 may indicate a more rapid detection prospect. In addition, applying S1-transducer and WD-transducer, AUP2 was more effective for the early damage detection. Varying transducer’s location, S1-transducer applying 500khz simulation frequency presented a valuable results.
4
Klaus, Leonard, Barbora Arendacká, Michael Kobusch, and Thomas Bruns. "Dynamic torque calibration by means of model parameter identification." ACTA IMEKO 4, no. 2 (June 29, 2015): 39. http://dx.doi.org/10.21014/acta_imeko.v4i2.211.
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For the dynamic calibration of torque transducers, a model of the transducer and an extended model of the mounted transducer including the measuring device have been developed. The dynamic behaviour of a torque transducer under test is going to be described by its model parameters. This paper describes the models with these known and unknown parameters and how the calibration measurements are going to be carried out. The principle for the identification of the transducer's model parameters from measurement data is described using a least squares approach. The influence of a variation of the transducer's parameters on the frequency response of the expanded model is analysed.
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Hegazy, Riham, Gouda Mohammad, and Magdy Ibrahim Mohamed. "Extrapolation errors of force transducer curve fitting equations." Universitas Scientiarum 27, no. 3 (December 12, 2022): 315–31. http://dx.doi.org/10.11144/javeriana.sc273.eeof.
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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.
6
Nguyen, Thanh Phuoc, Jaeyeop Choi, Van Tu Nguyen, Sudip Mondal, Ngoc Thang Bui, Dinh Dat Vu, Sumin Park, and Junghwan Oh. "Design and Micro-Fabrication of Focused High-Frequency Needle Transducers for Medical Imaging." Sensors 22, no. 10 (May 15, 2022): 3763. http://dx.doi.org/10.3390/s22103763.
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In this study, we report an advanced fabrication technique to develop a miniature focused needle transducer. Two different types of high-frequency (100 MHz) transducers were fabricated using the lead magnesium niobate-lead titanate (PMN-0.3PT) and lithium niobate (LiNbO3) single crystals. In order to enhance the transducer’s performance, a unique mass–spring matching layer technique was adopted, in which gold and parylene play the roles of the mass layer and spring layer, respectively. The PMN-0.3PT transducer had a 103 MHz center frequency with a −6 dB bandwidth of 52%, and a signal-to-noise ratio (SNR) of 42 dB. The center frequency, −6 dB bandwidth, and SNR of the LiNbO3 transducer were 105 MHz, 66%, and 44 dB, respectively. In order to compare and evaluate the transducers’ performances, an ultrasonic biomicroscopy (UBM) imaging on the fish eye was performed. The results showed that the LiNbO3 transducer had a better contrast resolution compared to the PMN-0.3PT transducer. The fabricated transducer showed an excellent performance with high-resolution corneal epithelium imaging of the experimental fish eye. These interesting findings are useful for the future biomedical implementation of the fabricated transducers in the field of high-resolution ultrasound imaging and diagnosis purpose.
7
Wolterink, Tom A. W., Robin D. Buijs, Giampiero Gerini, A. Femius Koenderink, and Ewold Verhagen. "Localizing nanoscale objects using nanophotonic near-field transducers." Nanophotonics 10, no. 6 (March 12, 2021): 1723–32. http://dx.doi.org/10.1515/nanoph-2020-0669.
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Abstract We study how nanophotonic structures can be used for determining the position of a nearby nanoscale object with subwavelength accuracy. Through perturbing the near-field environment of a metasurface transducer consisting of nano-apertures in a metallic film, the location of the nanoscale object is transduced into the transducer’s far-field optical response. By monitoring the scattering pattern of the nanophotonic near-field transducer and comparing it to measured reference data, we demonstrate the two-dimensional localization of the object accurate to 24 nm across an area of 2 × 2 μm. We find that adding complexity to the nanophotonic transducer allows localization over a larger area while maintaining resolution, as it enables encoding more information on the position of the object in the transducer’s far-field response.
8
Liu, Houguang, Shirong Ge, Gang Cheng, Jianhua Yang, Zhushi Rao, and Xinsheng Huang. "Transducer Type and Design Influence on the Hearing Loss Compensation Behaviour of the Electromagnetic Middle Ear Implant in a Finite Element Analysis." Advances in Mechanical Engineering 6 (January 1, 2014): 867108. http://dx.doi.org/10.1155/2014/867108.
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Several types of electromagnetic transducer for the middle ear implants (MEIs) have been developed as an alternative to conventional hearing aids for the rehabilitation of sensorineural hearing loss. Electromagnetic transducer type and design are thought to have a significant influence on their hearing compensation performance. To investigate these effects, a middle ear computational model was constructed based on a complete set of microcomputerized tomography section images of a human ear. Its validity was confirmed by comparing the model predicted motions with published experimental measurements. The result shows that the eardrum driving transducer (EDT) is superior to the floating mass transducer (FMT) in hearing compensation when the transducer mass is small but inferior to the FMT when the mass gets bigger. The incus body driving transducer (IBDT) is the most ineffective type of transducer for hearing compensation. Moreover, the masses of the EDT and the FMT decrease the transducer performance mainly at higher frequencies: the greater the transducer mass, the lower the displacement of the stapes excited by these transducers. On the other hand, the IBDT driving rod stiffness decreases transducer's performance severely at low frequencies and its adverse effect on transducer performance increases with the decrease of the stiffness of the IBDT driving rod.
9
Bogdan, Mihai. "About the Smart Weather Station." ACTA Universitatis Cibiniensis 68, no. 1 (December 1, 2016): 26–29. http://dx.doi.org/10.1515/aucts-2016-0006.
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Abstract Until recently, the Romanian weather stations utilized ordinary transducers that acquire useful information related to the desired physical inputs. These inputs will be converted into electrical signals easy to be processed by analog to digital converters. This paper proposed a new approach based on smart sensors system that change the interior behavior in order to optimize data acquirements from the environment. The smart sensor characteristics are stored into himself in a transducer electronic data sheet form (TEDS). The intelligent transducer generat together with the measured analogic signal also a digital interface. Through this interface the transducer’s catalog data can be read from the transducer.
10
Nguyen, Thanh Phuoc, Van Tu Nguyen, Sudip Mondal, Van Hiep Pham, Dinh Dat Vu, Byung-Gak Kim, and Junghwan Oh. "Improved Depth-of-Field Photoacoustic Microscopy with a Multifocal Point Transducer for Biomedical Imaging." Sensors 20, no. 7 (April 3, 2020): 2020. http://dx.doi.org/10.3390/s20072020.
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In this study, a photoacoustic microscopy (PAM) system based on a multifocal point (MFP) transducer was fabricated to produce a large depth-of-field tissue image. The customized MFP transducer has seven focal points, distributed along with the transducer’s axis, fabricated by separate spherically-focused surfaces. These surfaces generate distinct focal zones that are overlapped to extend the depth-of-field. This design allows extending the focal zone of 10 mm for the 11 MHz MFP transducer, which is a great improvement over the 0.48 mm focal zone of the 11 MHz single focal point (SFP) transducer. The PAM image penetration depths of a chicken-hemoglobin phantom using SFP and MFP transducers were measured as 5 mm and 8 mm, respectively. The significant increase in the PAM image-based penetration depth of the chicken-hemoglobin phantom was a result of using the customized MFP transducer.
11
Fa, Lin, Dongning Liu, Hong Gong, Wenhui Chen, Yandong Zhang, Yimei Wang, Rui Liang, et al. "A Frequency-Dependent Dynamic Electric–Mechanical Network for Thin-Wafer Piezoelectric Transducers Polarized in the Thickness Direction: Physical Model and Experimental Confirmation." Micromachines 14, no. 8 (August 20, 2023): 1641. http://dx.doi.org/10.3390/mi14081641.
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This paper is concerned with electric–acoustic/acoustic–electric conversions of thin-wafer piezoelectric transducers polarized in the thickness direction. By introducing two mechanical components with frequency-dependent values, i.e., radiation resistance and radiation mass, into the equivalent circuit of the thin-wafer piezoelectric transducer, we established a frequency-dependent dynamic mechanic-electric equivalent network with four terminals for an arbitrary given frequency, an enhancement from the conventional circuit networks. We derived the analytic expressions of its electric–acoustic and acoustic–electric conversion impulse responses using the four-terminal equivalent circuit to replace the traditional six-terminal equivalent circuit for a thin-wafer transducer with harmonic vibrational motion. For multifrequency electrical/acoustic signals acting on the transducer, we established parallel electric–acoustic/acoustic–electric conversion transmission networks. These two transmission network models have simple structures and clear physical and mathematical descriptions of thin-wafer transducers for electric–acoustic/acoustic–electric conversion when excited by a multifrequency electric/acoustic signal wavelet. The calculated results showed that the transducer’s center frequency shift relates to its mechanical load and vibration state. The method reported in this paper can be applied to conventional-sized and small-sized piezoelectric transducers with universal applicability.
12
Li, Shichang, Yu Lan, and Lianjin Hong. "A liquid column resonance transducer driven by Class IV flextensional transducer." Journal of the Acoustical Society of America 154, no. 1 (July 1, 2023): 401–10. http://dx.doi.org/10.1121/10.0020177.
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A liquid column resonance (LCR) transducer, also referred to as an organ pipe transducer, is a type of transducer that utilizes the liquid column resonance mode to produce acoustic energy underwater. Traditional transducers, such as piezoelectric rings or Janus transducers, are commonly used as the driving source in LCR transducers. A flextensional transducer (FT) is introduced into the LCR transducer as the driving source because of the relatively larger volume velocity at low frequencies. Moreover, the eigen-mode of the Class IV FT is easier to couple with the LCR mode to broaden the bandwidth of a LCR transducer. To overcome the problems associated with the low stiffness of elliptical metal pipes, an improved aluminum pipe, which has a cross-beam to increase the stiffness, was proposed and utilized in a LCR transducer driven by a Class IV FT. The fabricated LCR transducer prototype driven by the Class IV FT has two resonance peaks from 700–2000 Hz, and the transmitting voltage response values of these peaks are 132.1 and 137.8 dB (re 1 μPa/V @1 m). Comparing with an LCR transducer driven by a 33-mode ring, the results show that the LCR transducer driven by a Class IV FT provides good efficiency and broadband characteristics.
13
Mikitchuk, Alena P., and Konstantin V. Kozadaev. "Characteristics of fiber-optic photoacoustic transducers with monolayer of metal nanoparticles for systems of technical diagnostics." Journal of the Belarusian State University. Physics, no. 1 (January 31, 2020): 4–15. http://dx.doi.org/10.33581/2520-2243-2020-1-4-15.
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The work is devoted to the experimental study of the microstructural and morphological properties of nanostructures as part of a prototype of fiber-optic photoacoustic transducer. The transducer has been created to confirm the theoretical investigations previously obtained by the authors during the study the conditions of the most effective photoacoustic gene ration. To solve the main problem that arises when creating photoacoustic transducers, namely reducing the thickness of the absorbing layer, we used a nanostructure based on a monolayer of silver nanoparticles with size gamma-distribution, the average diameter of 35 nm with RMS-size of 12 nm. The method of simultaneous measuring both efficiency of photoacoustic conversion and frequency response of a photoacoustic transducer is proposed for the first time. The method allows experimental investigation of transduces output parameters versus the modulation mode of the optical signal. The proposed method is based on the usage of the main measurement channel for irradiating the photoacoustic transducer and a reference channel based on fiber optical coupler and photodiode. The experiment shows the reliable generation of ultrasound at frequencies of 10 –18 MHz with a prototype of photoacoustic transducer. During one hour irradiation, degradation of two-dimensional surface nanostructures has not been observed. This allows such type of photoacoustic transducer to be used as part of a new generation of technical diagnostics systems.
14
Sherar, M. D., and F. S. Foster. "The Design and Fabrication of High Frequency Poly(Vinylidene Fluoride) Transducers." Ultrasonic Imaging 11, no. 2 (April 1989): 75–94. http://dx.doi.org/10.1177/016173468901100201.
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Poly(vinylidene fluoride) (PVDF) transducers are well suited for use in high frequency pulse-echo ultrasound systems because of their high bandwidth. We analyze the design parameters of PVDF transducers operating in the 100 MHz range using the KLM transducer model. The effect of backing layers, electrode configuration, transducer surface area and tuning circuits on the insertion loss and pulse-echo response of the transducers are investigated. Using this design procedure, an experimental PVDF transducer is proposed for applications in the 100 MHz range. The transducer is built into a high frequency SMA electrical connector. Insertion loss and pulse-echo response measurements are compared with theoretical predictions.
15
Mieczkowski, Grzegorz, Andrzej Borawski, and Dariusz Szpica. "Static Electromechanical Characteristic of a Three-Layer Circular Piezoelectric Transducer." Sensors 20, no. 1 (December 31, 2019): 222. http://dx.doi.org/10.3390/s20010222.
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The paper presents research related to the functional features of a novel three-layer circular piezoelectric actuator/sensor. The outer layers of the transducer are made of non-piezoelectric material. The middle layer comprises two elements—a piezoelectric disk, and a ring made of non-piezoelectric material. The additional external passive layer has a very important function; it protects the transducer’s electrical components against damage caused by external factors. Also, if sparking on the transducer wires or electrodes occurs, this layer prevents fire. So far, there is no analytical model for such a transducer. Closed-form analytical equations are important tools for predicting and optimizing the operation of devices. Thus, using both the Plate Theory and constitutive equations of piezoelectric materials, an analytical formula describing transducer deflection as a function of electrical loads has been found (electromechanical characteristic of the transducer). In addition, it is worth noting that under certain assumptions, the developed analytical model can also be used for two-layer transducers. The tests carried out show satisfactory compliance of the results obtained through the developed solution with both literature data and numerical data. Moreover, based on the obtained analytical model, the effect of selected non-dimensional variables on the actuator performance has been examined. These parameters include dimensions and mechanical properties of both piezoelectric disk and passive plates and strongly influence the behavior of the transducer.
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Pan, Jingxi. "Performance Analysis and Prospect of Piezoelectric Ultrasonic Transducers Based on Vibration Modes." Academic Journal of Science and Technology 6, no. 1 (May 29, 2023): 40–44. http://dx.doi.org/10.54097/ajst.v6i1.8280.
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With the maturity of ultrasonic transducer technology, as a traditional ultrasonic transducer, piezoelectric ultrasonic transducer has leaped into the public view. This article briefly summarizes the development of ultrasonic transducers and the classification of piezoelectric ultrasonic transducers. In practical applications, different piezoelectric ultrasonic transducers are mostly selected based on the different sound source vibrations in the application scenarios. The principle analysis and structure introduction of longitudinal vibration type ultrasonic transducers, longitudinal bending vibration mode conversion type ultrasonic transducers, and torsional vibration piezoelectric ceramic ultrasonic transducers are conducted respectively, and the application fields are pointed out. Besides, heat dissipation is an important link that affects the energy transfer efficiency of piezoelectric ultrasonic transducers. For traditional air-cooled heat dissipation and phase change heat dissipation, the heat dissipation ability is investigated and analyzed separately, and the advantages and disadvantages of the two are compared. It is concluded that phase change heat dissipation can effectively solve the impact caused by excessive temperature difference inside the transducer, while traditional heat dissipation methods cannot solve this problem.
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Xia, Lili, Hongwei Wang, and Qiguo Huang. "Design and Fabrication of a Stacked Three-Phase Piezoelectric Composites Ring Array Underwater Ultrasound Transducer." Materials 14, no. 20 (October 11, 2021): 5971. http://dx.doi.org/10.3390/ma14205971.
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A stacked three-phase piezoelectric composites ring array underwater ultrasound transducer was developed in this paper. The circular structure of three-phase piezoelectric composite with a large open angle was improved based on the 1-3 piezoelectric composites. The structure size of the transducer’s sensitive component was designed by using ANSYS simulation software, and the single-ring samples of three-phase piezoelectric composites with different thicknesses were fabricated. Based on the bandwidth broadening theory of multimode coupled vibration, the piezoelectric composite ring-shaped sensitive component was fabricated by the piezoelectric composite curved-surface-forming process. According to the design structure of the transducer, the stacked three-phase piezoelectric composites ring array underwater ultrasound transducer was processed. The experimental results show that the maximum transmission voltage response is 154 dB, the open angle of the horizontal beam reaches 360°, and the bandwidth of −3 dB is 86 kHz. The developed transducers achieved a high frequency, broadband, and large open angle to radiate sound waves.
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Genin, Guy M., and Joseph Genin. "Sensor Placement for Angular Velocity Determination." Journal of Dynamic Systems, Measurement, and Control 128, no. 3 (August 23, 2005): 543–47. http://dx.doi.org/10.1115/1.2192823.
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Velocity transducer placement to uniquely determine the angular velocity of a rigid body is investigated. The angular velocity of a rigid body can be determined with no fewer than five properly placed velocity transducers, if no other types of sensors are present and no algebraic constraint equation involving the angular velocity vector can be written. Complete characterization of the velocity of a rigid body requires six transducers. Choice of transducer placement and orientation requires care, as suboptimal transducer placement can result in data from which the determination of a unique angular velocity vector is impossible. Conditions for successful transducer placement are established, and two examples of adequate transducer placement are presented: an Earth-penetrating projectile, and a bioengineering device for the measurement of head motion.
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Peng, Chang, Huaiyu Wu, Seungsoo Kim, Xuming Dai, and Xiaoning Jiang. "Recent Advances in Transducers for Intravascular Ultrasound (IVUS) Imaging." Sensors 21, no. 10 (May 19, 2021): 3540. http://dx.doi.org/10.3390/s21103540.
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As a well-known medical imaging methodology, intravascular ultrasound (IVUS) imaging plays a critical role in diagnosis, treatment guidance and post-treatment assessment of coronary artery diseases. By cannulating a miniature ultrasound transducer mounted catheter into an artery, the vessel lumen opening, vessel wall morphology and other associated blood and vessel properties can be precisely assessed in IVUS imaging. Ultrasound transducer, as the key component of an IVUS system, is critical in determining the IVUS imaging performance. In recent years, a wide range of achievements in ultrasound transducers have been reported for IVUS imaging applications. Herein, a comprehensive review is given on recent advances in ultrasound transducers for IVUS imaging. Firstly, a fundamental understanding of IVUS imaging principle, evaluation parameters and IVUS catheter are summarized. Secondly, three different types of ultrasound transducers (piezoelectric ultrasound transducer, piezoelectric micromachined ultrasound transducer and capacitive micromachined ultrasound transducer) for IVUS imaging are presented. Particularly, the recent advances in piezoelectric ultrasound transducer for IVUS imaging are extensively examined according to their different working mechanisms, configurations and materials adopted. Thirdly, IVUS-based multimodality intravascular imaging of atherosclerotic plaque is discussed. Finally, summary and perspectives on the future studies are highlighted for IVUS imaging applications.
20
Klaus, Leonard. "Model parameter identification from measurement data for dynamic torque calibration – Measurement results and validation." ACTA IMEKO 5, no. 3 (November 4, 2016): 55. http://dx.doi.org/10.21014/acta_imeko.v5i3.318.
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<p><span lang="EN-US">The dynamic calibration of torque transducers requires the </span><span lang="EN-GB">modelling</span><span lang="EN-US"> of the measuring device and of the transducer under test. The transducer's dynamic properties are described by means of model parameters, which are going to be identified from measurement data. To be able to do so, two transfer functions are calculated. In this paper, the transfer functions and the procedure for the model parameter identification are presented. Results of a parameter identification of a torque transducer are also given, and the validity of the identified parameters is </span><span lang="EN-GB">analysed</span><span lang="EN-US"> by comparing the results with independent measurements. The successful parameter identification is a prerequisite for a model-based dynamic calibration of torque transducers.</span></p>
21
Hale, J. E., and C. L. Vaughan. "Some Problems in Using a Polyvinylidene Fluoride Transducer for the Intra-Articular Determination of Joint Contact Stress." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 207, no. 2 (June 1993): 127–31. http://dx.doi.org/10.1243/pime_proc_1993_207_281_02.
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A piezoelectric transducer and associated instrumentation were developed and evaluated as a means of experimentally determining joint contact stress. Each transducer, fabricated from a polyvinylidene fluoride film, comprised four discrete sensing elements. Following dynamic calibration of all sensing elements, in vitro evaluations were performed with transducers positioned in canine tibio-femoral joints. Quantitative measurements of contact stress as a function of time were obtained using these transducers, the magnitudes of which ranged between 0.01 and 7.99 MPa. Limitations associated with the transducer material and its use in this specific application included calibration variability and temporal phase shift of the transducer output signal relative to the applied load.
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Pyun, Joo Young, Young Hun Kim, and Kwan Kyu Park. "Design of Piezoelectric Acoustic Transducers for Underwater Applications." Sensors 23, no. 4 (February 6, 2023): 1821. http://dx.doi.org/10.3390/s23041821.
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Interest in underwater transducers has persisted since the mid-1900s. Underwater transducers are designed in various shapes using various materials depending on the purpose of use, such as to achieve high power, improve broadband, and enhance beam steering. Therefore, in this study, an analysis is conducted according to the structural shape of the transducer, exterior material, and active material. By classifying transducers by structure, the transducer design trends and possible design issues can be identified. Researchers have constantly attempted new methods to improve the performance of transducers. In addition, a methodology to overcome this problem is presented. Finally, this review covers old and new research, and will serve as a reference for designers of underwater transducer.
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Kong, YouDi, JianRui Zhao, HaiTao Wang, XinPeng Wang, GuangJie Wang, YuHua Wu, and WeiXing Zhang. "Development and Engineering Application of the Measurement System Based on the Miniaturized Ultrasonic Transducer." Journal of Physics: Conference Series 2366, no. 1 (November 1, 2022): 012005. http://dx.doi.org/10.1088/1742-6596/2366/1/012005.
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Abstract The iron terminals are mostly used in the small ultrasonic transducers which are connected to the circuit board by the direct or indirect welding method. Although the method is considered to be firm and reliable, the ultrasonic transducer or the whole system is easy to be damaged when the ultrasonic transducer is replaced or maintained. Moreover, the terminals of the ultrasonic transducer are easy to be oxidized. The miniaturized ultrasonic transducer with the electroplated copper terminals is innovatively designed to enhance the oxidation resistance of its terminals. Then the ultrasonic transducers are installed on the circuit board by the copper claw spring instead of welding. In addition, the waterproof miniaturized ultrasonic transducer is replaced by the fully covered waterproof sound permeable membrane and the non waterproof miniaturized ultrasonic transducer. The experimental results demonstrate that the quality of the signal transmission of the ultrasonic transducer is not affected, and the convenience of replacement and maintenance of the ultrasonic transducer is improved. With this design process, the overall waterproof performance of the system is also significantly enhanced while the system cost is reduced, market future is wide prospect.
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Zhu, Ke, Jinpeng Ma, Yang Liu, Bingzhong Shen, Da Huo, Yixiao Yang, Xudong Qi, Enwei Sun, and Rui Zhang. "Increasing Performances of 1–3 Piezocomposite Ultrasonic Transducer by Alternating Current Poling Method." Micromachines 13, no. 10 (October 11, 2022): 1715. http://dx.doi.org/10.3390/mi13101715.
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Ultrasonic transducers are the basic core component of diagnostic imaging devices, wherein the piezoelectric materials are the active element of transducers. Recent studies showed that the alternating current poling (ACP) method could develop the properties of piezocomposites, which had great potential to improve transducer performance. Herein, transducers (fc = 3 MHz) made of DCP and ACP 1–3 piezocomposites (prepared by PZT-5H ceramics and PMN-PT single crystals) were fabricated. The effect of the ACP method on the bandwidth and insertion loss (sensitivity) was explored. The results indicate that the ACP method can significantly enhance the bandwidth and slightly increase the insertion loss of transducers. Particularly, a superhigh bandwidth of 142.8% was achieved in the transducer of ACP 1–3 PMN-PT single crystal combined with suitable matching and backing layers. This bandwidth is higher than that of all reported transducers with similar center frequency. Moreover, the optimization mechanism of transducer performance by the ACP method was discussed. The obtained results suggested that the ACP is an effective and convenient technology to improve transducer performances, especially for the bandwidth.
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Paeng, Dong Guk, Hyung Ham Kim, Sang Goo Lee, Sung Min Rhim, and Min Joo Choi. "Fabrication of a 40 MHz Single Element Ultrasonic Transducer Using a PMN-PT Single Crystal." Key Engineering Materials 321-323 (October 2006): 978–83. http://dx.doi.org/10.4028/www.scientific.net/kem.321-323.978.
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PMN-PT, a piezoelectric single crystal, has been known to be a better material for transducer arrays due to its high electromechanical coupling coefficient (k33) and high dielectric and piezoelectric constants. It may also be good even for high frequency single element transducers using relatively high kt and low attenuation and velocity dispersion. However, it’s challenging to fabricate high frequency transducers using PMN-PT since it is easily breakable and requires small area and thickness of the transducer. A KLM model was used to simulate a 40 MHz single element transducer including 2 matching layers and a conductive backing. The simulation showed that the PMN-PT transducer turned out to be better in sensitivity and bandwidth than a 40 MHz LiNbO3 transducer. A 40 MHz PMN-29%PT transducer was fabricated and the pulse echo signals were obtained and analyzed. Its sensitivity was found to be –48 dB and –6dB bandwidth was about 48 %.
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Yu, Jinpeng, Yan Zhou, Ni Mo, Zhe Sun, and Lei Zhao. "Theoretical and Experimental Analysis on the Influence of Rotor Non-Mechanical Errors of the Inductive Transducer in Active Magnetic Bearings." Sensors 18, no. 12 (December 11, 2018): 4376. http://dx.doi.org/10.3390/s18124376.
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Inductive transducers are widely applied to active magnetic bearings (AMBs). However, when the rotor rotates at a high speed, the rotor defects will affect the measuring signal (the magnetic field generated by transducer coils) and then reduce the transducer measuring accuracy. The rotor in AMBs is assembled with laminations, which will result in rotor non-mechanical errors. In this paper, rotor non-mechanical errors, including the anisotropic internal permeability and anisotropic surface conductivity, and their influence on double-pole variable-gap inductive transducers are explored in depth. The anisotropic internal permeability will affect the transducer measuring accuracy and bring about 1.3 ± 0.1 % measurement error. The anisotropic surface conductivity leads to different eddy currents around the rotor, influences the equivalent reluctance of the magnetic circuit, and then affectsthe transducer measuring accuracy. The experiments prove that rotor non-mechanical errors have a significant influence on transducer measurement accuracy, and the reduction of the transducer excitation frequency can reduce the measurement error and improve the AMB control performance.
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Nakamura, Kae, Yuna Koike, Yusuke Sato, and Takahiko Yanagitani. "Giga-hertz ultrasonic reflectometry for fingerprint imaging using epitaxial PbTiO3 transducers." Applied Physics Letters 121, no. 17 (October 24, 2022): 172903. http://dx.doi.org/10.1063/5.0106931.
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A fingerprint reader based on epitaxial PbTiO3 (PTO) transducer array operating thickness extensional mode in GHz range was fabricated. The device consisted of nine square transducers with 0.1 mm per side arranged 1.3 mm apart in a 3 × 3 array. Minimum conversion loss of the fabricated transducer was 2.5 dB at 0.8 GHz, and electromechanical coupling coefficient kt2 was estimated to be 28.9%. In contrast to MHz range ultrasonic fingerprint readers such as those based on piezoelectric micromachined ultrasonic transducers using a piezoelectric transducer and ScAlN, a GHz range transducer enables imaging in higher spatial resolution. Furthermore, PTO transducers have a high dielectric constant and electromechanical coupling coefficient kt2. A high dielectric constant realizes 50 Ω impedance matching with small electrode area. The small acoustic source is expected to improve the spatial resolution of a fingerprint reader. We achieved the fingerprint imaging by evaluating the acoustic reflectance of the medium/transducer interface. Furthermore, piezostage that allows mechanical movement in the 100 nm order was introduced to image a 12 × 12 μm2 area with total of 3600 data points.
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Mannila, Vilma, and Outi Sipilä. "Phantom-based quality assurance measurements in B-mode ultrasound." Acta Radiologica Short Reports 2, no. 8 (December 1, 2013): 204798161351196. http://dx.doi.org/10.1177/2047981613511967.
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Background Recommended phantom-based quality assurance measurements in B-mode ultrasound (US) may be tedious. For the purpose of cost-effective US quality assurance it is important to evaluate measurements that effectively reflect the quality of US scanner. Purpose To find out which recommended phantom-based quality assurance measurements are effective in detecting dead or weak transducer elements or channels in US scanners when visual image analysis and manual measurements are used. Material and Methods Altogether 66 transducers from 33 US scanners were measured using a general purpose phantom and a transducer tester. The measurements were divided into two groups. Group I consisted of phantom-based uniformity measurement, imaging the air with a clean transducer (air image) and measuring the transducer with the transducer tester, and group II of phantom-based measurements of depth of penetration, beam profile, near field, axial and lateral resolution, and vertical and horizontal distance accuracy. The group II measurements were compared to group I measurements. Results With group I measurements, the results with 20% of the transducers were found defective. With 35% of the transducers the results were considered defective in group II measurements. Concurrent flaws in both groups were found with 11% of the transducers. Conclusion Phantom-based measurements of depth of penetration, beam profile, near field, axial and lateral resolution, and vertical and horizontal distance accuracy did not consistently detect dead or weak transducer elements or channels in US scanners.
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Wang, Zi Ping, and Ying Luo. "Focusing Actuating Performance of OPFC Phased Array Transducer Based on DPSM." Key Engineering Materials 609-610 (April 2014): 1299–304. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.1299.
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As a new functional composite material, Orthotropic Piezoelectric Fiber Composite (OPFC) may be developed conveniently actuators and sensors. By constructing multi-element linear array, the phased array transducers can generate special directional strong actuator power and high sensitivity. The advantage of the transducers is that no mechanical movement is needed to scan an object. Focusing beam is obtained simply only by adjusting a parabolic time delay. The DPSM (distributed point source method) is used to model the ultrasonic field by OPFC linear array transducer. Using this approach, beam directivity and pressure distributions are studied to predict the behavior of focusing as compared to current formulation of traditional transducer. The interaction effect of two OPFC phased array transducers is also modeled in the same medium. Which shows the pressure beam produced by the OPFC array transducer is narrower or more collimated than that produced by the conventional transducer at different angles.
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Shim, Hayeong, and Yongrae Roh. "Design and Fabrication of a Wideband Cymbal Transducer for Underwater Sensor Networks." Sensors 19, no. 21 (October 27, 2019): 4659. http://dx.doi.org/10.3390/s19214659.
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Cymbal transducers are characterized by a high mechanical quality factor and low power efficiency. The research conducted so far on cymbal transducers has focused on improving the power efficiency and structural stability, but modern underwater sensor network systems need transducers to have a wide frequency bandwidth as well. In this study, a wideband cymbal transducer was designed to fill that need. First, the effect of various structural parameters on the performance of the cymbal transducer was analyzed with emphasis on the bandwidth using the finite element method. Based on the analysis results, the structure of the cymbal transducer was optimized to have the widest possible bandwidth while maintaining its transmitting voltage response (TVR) level over a typical power requirement as well. The validity of the design was verified by fabricating a prototype of the optimized cymbal transducer and comparing its measured performance with the design.
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Gou, Yang, and Xin Fu. "Vibration and horizontal directivity analysis of transmitting transducer for acoustic logging while drilling." Journal of Geophysics and Engineering 18, no. 3 (June 2021): 379–91. http://dx.doi.org/10.1093/jge/gxab021.
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Abstract Radially polarized open-cylindrical piezoelectric transducers are widely used in the field of acoustic logging while drilling (LWD). Unlike the wireline logging transducer, the structure of the acoustic LWD transducer is an open structure; in this case, its radial vibration is accompanied by apparent circumferential vibration. In this paper, based on the two-dimensional wave equations and electrostatic charge equation, according to the free boundary conditions of the transducer, the resonance frequency equation of radial-circumferential coupled vibration for the acoustic LWD transducer is obtained. The vibration modal and resonance frequency for transducers of several typical sizes are simulated using COMSOL software. The results show that when the geometrical size of the transducer satisfies certain conditions, the theoretical calculation and the numerical analysis are in good agreement and the relative error is controlled below 3%. Meanwhile, the horizontal directivity of the LWD transducer after actual installation is discussed, and it is found that adding appropriate coupling materials can improve the monopole sound field radiation. So, it is expected that this work can serve as a reference for the acoustic LWD transducer design and install.
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Ge, Chang. "Numerical Simulation of Vibration Deflection Effects on the Energy Efficiency of Ultrasonic Transducer for Sonochemistry." Mathematical Problems in Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/591352.
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The energy efficiency of ultrasound transducers for sonochemistry applications was studied from the point of view of vibration deflection effects of different transducer structures, including the configurations of rectangular plate, cylindrical shell, triangular strip array, rectangular strip array, and pentagonal strip array. It was found that the deflections are not uniform over the transducer surface with the maximum deflection locating at the geometry center of transducers. The simulated maximum deflection of rectangular plate results in the value of2.5×10-16, which is larger than the maximum deflection of cylindrical shell with the value of2×10-16. This finding suggests that the envelope deflection volume of two transducers has significant difference, which has been neglected in the design and selection of ultrasound transducer. For this reason, a quantitative index involving the envelope deflection volume was proposed to compare the efficiency of ultrasound transducers. Based on the simulation results, the triangular strip array transducer structure with higher ultrasound generation efficiency was proposed, which was also theoretically validated by the MATLAB simulation.
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Park, Sunghun, Sungwoo Kang, and Jin Ho Chang. "Optically Transparent Focused Transducers for Combined Photoacoustic and Ultrasound Microscopy." Journal of Medical and Biological Engineering 40, no. 5 (May 26, 2020): 707–18. http://dx.doi.org/10.1007/s40846-020-00536-5.
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Abstract Purpose Photoacoustic (PA) microscopy has emerged as a useful tool in biomedical imaging applications such as visualization of microvasculature and hemoglobin oxygen saturation, single-cell, and label-free imaging of organs including cancer. Since the ultrasound transducers used for PA signal detection are not optically transparent, the integration of optical and acoustic modules for coaxial alignment of laser and acoustic beam fields in PA microscopy is complex and costly. Methods Here, we report a recently developed optically transparent focused transducer for combined PA and ultrasound (US) microscopy. All the acoustic layers including the acoustic lens are optically transparent, enabling simple integration of optical and acoustic modules for both imaging modalities. Results The mean light transmittance of the transducer’s backing layer and acoustic lens and of the transducer itself were measured at 92%, 83%, and 66%, respectively. Results from in vitro and in vivo experiments demonstrated the transducer to be suitable for both US and PA imaging. Conclusions The results of this study represent a step toward efficient construction of probes for combined PA and US microscopy.
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Duquennoy, Marc, Nikolay Smagin, Tahar Kadi, Mohammadi Ouaftouh, and Frédéric Jenot. "Development of a Broadband (100–240 MHz) Surface Acoustic Wave Emitter Devoted to the Non-Destructive Characterization of Sub-Micrometric Thin Films." Sensors 22, no. 19 (October 1, 2022): 7464. http://dx.doi.org/10.3390/s22197464.
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In the ultrasonic non-destructive evaluation of thin films, it is essential to have ultrasonic transducers that are able to generate surface acoustic waves (SAW) of suitably high frequencies in a wide frequency range of between ten and several hundred megahertz. If the characterization is carried out with the transducer in contact with the sample, it is also necessary that the transducers provide a high level of mechanical displacement (>100 s pm). This level allows the wave to cross the transducer–sample interface and propagate over the distance of a few millimeters on the sample and be properly detected. In this paper, an emitter transducer formed of interdigitated chirp electrodes deposited on 128° Y-cut LiNbO3 is proposed. It is shown that this solution efficiently enables the generation of SAW (displacement level up to 1 nm) in a frequency range of between 100 and 240 MHz. The electrical characterization and a displacement field analysis of SAW by laser Doppler vibrometry are presented. The transducer’s significant unidirectionality is demonstrated. Finally, the characterization of two titanium thin films deposited on silicon is presented as an example. A meaningful SAW velocity dispersion (~10 m/s) is obtained, which allows for the precise estimation (5% of relative error) of the submicrometer thickness of the layers (20 and 50 nm).
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Zhao, Guozhu, Kaibo Shi, and Shouming Zhong. "Research on Array Structures of Acoustic Directional Transducer." Mathematical Problems in Engineering 2021 (January 2, 2021): 1–5. http://dx.doi.org/10.1155/2021/6670277.
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This paper focuses on the directivity design of array structures of acoustic directional transducers. Based on Huygens principles, the directivity formula of transducer arrays under random distribution in xyz space is derived when the circular piston transducers are used as the array element, which is used to analyze the directivity and acoustic pressure of conical transducer arrangements. In addition, a practical approach to analyze the directivity and acoustic pressure of transducer arrays under random arrangements is proposed. Findings. The conical transducer arrays show side lobes at higher frequency. Below the frequency of 2 kHz, array directivity shows rapid changes. Above the frequency of 2 kHz, array directivity varies slowly with frequency. Besides, the beam width is Θ − 3 dB ≤ 29.85 ° .
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Wang, Jianjun, Donghuan Liu, Weijie Li, Peijun Wei, and Lihua Tang. "Effects of electrodes and electrical connections of piezoelectric layers on dynamic characteristics of radially polarized multilayer piezoelectric cylindrical transducers." Journal of Intelligent Material Systems and Structures 30, no. 1 (October 8, 2018): 63–81. http://dx.doi.org/10.1177/1045389x18803454.
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Piezoelectric cylindrical transducer is a type of excellent smart devices that can generate radial sound radiation due to its unique structural characteristics and has been widely used for ultrasonic and underwater sound applications. In the design of a piezoelectric cylindrical transducer, especially with the multilayer structure, the electrodes and electrical connections of piezoelectric layers are two key factors affecting the device performance but have not been well evaluated, which result in the inaccurate prediction of dynamic characteristics. This work establishes the exact theoretical models for radially polarized multilayer piezoelectric cylindrical transducers by taking into account the electrodes and electrical connections of piezoelectric layers. Based on the plane stress assumption, the dynamic solutions of the models are derived. Analytical expressions of electric impedances are also derived to obtain the resonance frequencies. In addition, the analytical solutions are validated using the special example in the earlier work and comparing them with the finite element analysis results. Subsequently, the effects of the electrodes and electrical connections of piezoelectric layers on the dynamic characteristics of the transducer are analyzed and discussed. The results show that the electrode thickness, the electrode type, and the parallel and series connections significantly affect the transducer’s performance, thus providing useful guidelines in the design of piezoelectric cylindrical transducers. This work contributes to an overall analysis on the dynamic characteristics of the radially polarized multilayer piezoelectric cylindrical transducers, which is very helpful to improve the performance of two-dimensional emitter and receiver in underwater sound and ultrasonic applications.
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Siegl, Alexander, Stefan Leithner, Bernhard Schweighofer, and Hannes Wegleiter. "Excitation of Mechanical Resonances in the Stationary Ring of a Mechanical Seal by a Continuously Operated Electromagnetic Acoustic Transducer." Sensors 23, no. 2 (January 16, 2023): 1015. http://dx.doi.org/10.3390/s23021015.
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Acoustic/ultrasonic testing is now a common method in the field of nondestructive testing for detecting material defects or monitoring ongoing mechanical changes in a structure during operation. In many applications, piezoelectric transducers are used to generate mechanical waves inside the specimen. Their actual operating frequency is highly dependent on the dimensions of the transducer. Larger dimensions of the piezoelectric transducer allow for a lower operating frequency. However, these dimensions limit the use of piezoelectric transducers in certain applications where the size of the transducer is restricted due to limited installation space and when low-frequency excitation is required. One application that places these requirements on the transducer is the monitoring of mechanical seals. Here, the transducer must be mounted on the stationary ring of the seal. In this paper, a continuously operated electromagnetic acoustic transducer (EMAT) is presented as an alternative to piezoelectric transducers as a transmitter. The advantage of a EMAT is that it meets the requirements of limited sensor size (sensor area < 10 × 6 mm) and can excite mechanical waves with frequencies below 10 kHz. A structural analysis of the stationary ring shows that the first two mechanical resonances occur around 4 and 5.5 kHz. An experimental study meterologically demonstrates the ability of the EMAT to excite these first two mechanical resonances of the ring. A comparative simulation agrees well with the measurement.
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Hu, Jiuling, Lianjin Hong, Lili Yin, Yu Lan, Hao Sun, and Rongzhen Guo. "Research and Fabrication of Broadband Ring Flextensional Underwater Transducer." Sensors 21, no. 4 (February 23, 2021): 1548. http://dx.doi.org/10.3390/s21041548.
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At present, high-speed underwater acoustic communication requires underwater transducers with the characteristics of low frequency and broadband. The low-frequency transducers also are expected to be low-frequency directional for realization of point-to-point communication. In order to achieve the above targets, this paper proposes a new type of flextensional transducer which is constructed of double mosaic piezoelectric ceramic rings and spherical cap metal shells. The transducer realizes broadband transmission by means of the coupling between radial vibration of the piezoelectric rings and high-order flexural vibration of the spherical cap metal shells. The low-frequency directional transmission of the transducer is realized by using excitation signals with different amplitude and phase on two mosaic piezoelectric rings. The relationship between transmitting voltage response (TVR), resonance frequency and structural parameters of the transducer is analyzed by finite element software COMSOL. The broadband performance of the transducer is also optimized. On this basis, the low-frequency directivity of the transducer is further analyzed and the ratio of the excitation signals of the two piezoelectric rings is obtained. Finally, a prototype of the broadband ring flextensional underwater transducer is fabricated according to the results of simulation. The electroacoustic performance of the transducer is tested in an anechoic water tank. Experimental results show that the maximum TVR of the transducer is 147.2 dB and the operation bandwidth is 1.5–4 kHz, which means that the transducer has good low-frequency, broadband transmission capability. Meanwhile, cardioid directivity is obtained at 1.4 kHz and low-frequency directivity is realized.
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Saillant, Marlier, Navacchia, and Baqué. "Ultrasonic Transducer for Non-Destructive Testing of Structures Immersed in Liquid Sodium at 200 °C." Sensors 19, no. 19 (September 25, 2019): 4156. http://dx.doi.org/10.3390/s19194156.
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TUCSS transducer (French acronym standing for Transducteur Ultrasonore pour CND Sous Sodium) is designed for performing NDT (Non-Destructive Testing) under liquid sodium. Under sodium, the tests results obtained show that these transducers have sufficiently good acoustic properties to perform basic NDT of a structure immersed under liquid sodium at about 200 °C using conventional immersion ultrasonic technics. Artificial defects were made next to an X-shaped weld and could clearly be detected.
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Talbot, George H., Maureen Skros, and Mary Provencher. "70% Alcohol Disinfection of Transducer Heads: Experimental Trials." Infection Control 6, no. 6 (June 1985): 237–39. http://dx.doi.org/10.1017/s0195941700061609.
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AbstractWe investigated the feasibility of transducer head disinfection with 70% alcohol wipes. In the initial trial, nine gas-sterilized transducers were inoculated with an estimated 5 × 106 organisms of a clinical isolate of Enterobacter cloacae, mimicking a contaminated fluid couple. A sterile disposable transducer dome was attached to each transducer. The units were allowed to sit for 24 hours at room temperature; the domes were then removed. Three transducer heads were cultured prior to disinfection to ensure that viable organisms remained. Each transducer head was wiped clean with a single alcohol wipe, allowed to dry, and then cultured. All nine cultures showed growth of E. cloacae. A second series of trials with 54 transducers employed an identical protocol, except that each transducer head received not one, but two, applications of alcohol. In addition to E. cloacae (26 runs), Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans were employed in nine, nine and ten runs, respectively. Cultures of 53 of 54 transducer heads showed no growth; the single positive culture was attributed to an error in technique. These preliminary results suggest that the double-alcohol-wipe technique may be an easy, cost-effective, alternative or supplemental method of transducer head disinfection. However, we do not advocate routine implementation of this technique in patient care settings until clinical trials confirm its safety and efficacy.
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Wang, Wenjie, Weihao Shi, Peter Thomas, and Mingsui Yang. "Design and Analysis of Two Piezoelectric Cymbal Transducers with Metal Ring and Add Mass." Sensors 19, no. 1 (January 2, 2019): 137. http://dx.doi.org/10.3390/s19010137.
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Based on traditional sandwich structure, two piezoelectric transducers were designed to meet the strict underwater application backgrounds such as high pressure, corrosion resistance, and high strength. Both transducers integrated most of previous researches while one transducer has a multilayer cavity structure which is different from the other structure and previous transducer structures. After a detailed simulation analysis of every structural parameter, key parameters were pointed out to have an obvious influence on its performance. Then, two models were constructed and compared with chosen sets of geometry parameters and manufacturing process, which can also provide a reference for low-frequency transducer design. The simulation results and experimental results of our transducers show a good consistency which indicates the cavity structure can reduce the resonance frequency.
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MOHRI, MEHRYAR. "ON THE DISAMBIGUATION OF FINITE AUTOMATA AND FUNCTIONAL TRANSDUCERS." International Journal of Foundations of Computer Science 24, no. 06 (September 2013): 847–62. http://dx.doi.org/10.1142/s0129054113400224.
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This paper introduces a new disambiguation algorithm for finite automata and functional finite-state transducers. It gives a full description of this algorithm, including a detailed pseudocode and analysis, and several illustrating examples. The algorithm is often more efficient and the result dramatically smaller than the one obtained using determinization for finite automata or the construction of Schützenberger. The unambiguous automaton or transducer created by our algorithm are never larger than those generated by the construction of Schützenberger. In fact, in a variety of cases, the size of the unambiguous transducer returned by our algorithm is only linear in that of the input transducer while the transducer created by the construction of Schützenberger is exponentially larger. Our algorithm can be used effectively in many applications to make automata and transducers more efficient to use.
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Busch-Vishniac, Ilene J. "Spatially Distributed Transducers: Part II—Augmented Transmission Line Models." Journal of Dynamic Systems, Measurement, and Control 112, no. 3 (September 1, 1990): 381–90. http://dx.doi.org/10.1115/1.2896155.
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Transducer models are typically comprised of a finite number of discrete lumped elements connected using circuit conventions. Such models are inappropriate for transducers which explicitly depend upon the continuous nature of one or more system element. These transducers must be modeled as spatially distributed devices. In this article we present a class of models which is useful for spatially distributed transducers in which the response at one location is coupled to that at other locations. The models use a transmission line to describe the mechanical coupling between locations on the transducer, but have been augmented to include interaction with the environment and sources everywhere along the line. If only one element is used at every location to represent the interaction of the transducer and the environment, and only one type of source is present, then there are only four general models which need to be considered. These models are analyzed for the general case of spatially varying sources and physical parameters. It is shown that it is possible to prescribe up to four response characteristics of the transducer if the physical parameters are permitted to vary with space. Examples of spatially distributed transducers are presented and applications discussed.
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Ahern, Brian J., Jonathan D. Monti, Jason F. Naylor, Aaron J. Cronin, and Michael D. Perreault. "U.S. Army Combat Medic eFAST Performance with a Novel Versus Conventional Transducers: A Randomized, Crossover Trial." Military Medicine 185, Supplement_1 (January 2020): 19–24. http://dx.doi.org/10.1093/milmed/usz277.
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ABSTRACT Background Point-of-injury extended focused assessment with sonography in trauma (eFAST) may identify life-threatening torso hemorrhage and expedite casualty evacuation. The purpose of this study was to compare combat medic eFAST performance between the novel and conventional ultrasound (US) transducers. Methods We conducted a randomized crossover trial. Medic participants, previously naïve to US, were randomized to the type of transducer first utilized. The primary outcome was eFAST completion time in seconds. Secondary outcomes included diagnostic accuracy, technical adequacy, and transducer ease-of-use rating. Results Forty medics performed 160 eFASTs. We found a statistically significant difference in eFAST completion times in favor of conventional transducers (304 vs. 358 s; P = 0.03). There was no statistically significant difference between the conventional and novel transducers in terms of diagnostic accuracy (97.7% vs. 96.0%; P = 0.25) and technical adequacy (65% vs. 72.5%; P = 0.11). Median transducer ease-of-use rating (Likert 1–5 scale) was statistically significant in favor of the conventional transducers (5 vs. 4; P = < 0.001). Conclusions Extended focused assessment with sonography in trauma exam times was faster with the conventional transducers. Combat medics performed diagnostically accurate eFASTs with both transducer types in a simulated aid station setting after a brief training intervention. Conventional transducers were rated higher for ease-of-use.
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Wang, Ziping, and Ying Luo. "Focusing Modeling of OPFC Linear Array Transducer by Using Distributed Point Source Method." Abstract and Applied Analysis 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/840748.
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The improvement of ultrasonic phased array detection technology is a major concern of engineering community. Orthotropic piezoelectric fiber composite (OPFC) can be constructed to multielement linear array which may be applied conveniently to actuators and sensors. The phased array transducers can generate special directional strong actuator power and high sensitivity for its orthotropic performance. Focusing beam of the linear phased array transducer is obtained simply only by adjusting a parabolic time delay. In this work, the distributed point source method (DPSM) is used to model the ultrasonic field. DPSM is a newly developed mesh-free numerical technique that has been developed for solving a variety of engineering problems. This work gives the basic theory of this method and solves the problems from the application of new OPFC phased array transducer. Compared with traditional transducer, the interaction effect of two OPFC linear phased array transducers is also modeled in the same medium, which shows that the pressure beam produced by the new transducer is narrower or more collimated than that produced by the conventional transducer at different angles. DPSM can be used to analyze and optimally design the OPFC linear phased array transducer.
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Nosian, Jozef, Ľubomír Hujo, Marcin Zastempowski, and Romana Janoušková. "Design of Laboratory Test Equipment for Testing the Hydrostatic Transducers." Acta Technologica Agriculturae 24, no. 1 (January 29, 2021): 35–40. http://dx.doi.org/10.2478/ata-2021-0006.
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Abstract The article presented describes a new design of measuring chains in laboratory test equipment, which are used for testing the hydrostatic transducers and hydraulic fluids. Laboratory test equipment allows simultaneous observation of parameters of hydrostatic transducers and hydraulic fluids by simulating the operating conditions under laboratory conditions, what can significantly reduce the testing time and economic costs. The new design functionality was verified via measurement of the basic parameters of hydrostatic transducers and changing the load of hydraulic fluids. Based on the results measured, the flow efficiency of tested hydrostatic transducer UD-25R was calculated and compared with the transducer parameters specified by the manufacturer using different types of operating hydraulic fluids. Verification measurements of the unloaded hydrostatic transducer were performed at various rotation speeds: Q 250 = 5.694 dm3·rpm at speed of n 1 = 250 rpm; Q 500 = 12.286 dm3·rpm at speed of n 2 = 500 rpm; Q 750 = 18.747 dm3·rpm at speed of n 3 = 750 rpm. Based on the hydrostatic transducer flow rate, the UD-25R transducer flow efficiency was determined: at n 1 = 250 rpm, the flow efficiency was η250 = 0.8946; at n 2 = 500 rpm, the efficiency was η500 = 0.9651; at n 3 = 750 rpm, the flow efficiency was η750 = 0.9812.
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Brown, David A., and Eric K. Aikins. "Measurement of electroacoustic transducer sensitivity in extreme hydrostatic pressure environments." Journal of the Acoustical Society of America 153, no. 3_supplement (March 1, 2023): A320. http://dx.doi.org/10.1121/10.0018994.
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The measurement and acoustic calibration of electroacoustic transducers for underwater sound under extreme pressures (to 10,000 psi / 7km depth) and variety range of temperatures is a great challenge. Specialized facilities consisting of large pressure vessels with pressure and temperature control do exist at Navy faciliites (www.navsea.navy.mil + USRD) but operate to moderate pressures, have limited availability, are expensive and limited access. An alternative or supplement is to measure the change in the electro-mechanical impedance of the of a transducer and use equivalent electrical cirucuit analysis to determine the resulting change in all electrical, electromechanical, and mechanical properties. Having the pressure and temperature depedence of all the consitutent parameters allows an accurate pediction of the transduer performance sensitivity and frequency response (such as TVR Transmit Pressure per Volt, and receive voltage per pressure sensitivity. We measured transducer performance of several devices in the laboratory pressure vessels up to 10 000psi and report on findings.
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Pyo, Seonghun, and Yongrae Roh. "Equivalent circuit for analyzing the transmitting characteristics of multimode Tonpilz transducer." Journal of the Acoustical Society of America 151, no. 6 (June 2022): 3594–602. http://dx.doi.org/10.1121/10.0011515.
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Multimode Tonpilz transducers operate at longitudinal and flexural vibration modes simultaneously. Consequently, they have wider bandwidths than conventional single-mode transducers. Generally, the performance of Tonpilz transducers is analyzed using the finite element method (FEM), whereas the equivalent circuit method (ECM) has proven to be a fast and efficient alternative to the FEM. However, the ECM for analyzing the acoustic characteristics of multimode Tonpilz transducers has not yet been developed. To address this issue, an equivalent circuit for the multimode Tonpilz transducer is developed herein. The proposed ECM encompasses the flexural characteristics of the Tonpilz head mass, which is impossible with conventional equivalent circuits. Furthermore, a prototype of the multimode Tonpilz transducer was fabricated to verify the validity of the developed ECM. Additionally, the accuracy and compliance of the ECM were confirmed by comparing the measured performance of the transducer with that from the equivalent circuit analysis.
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Yuan, Y. W., and K. K. Shung. "The Effect of Focusing on Ultrasonic Backscatter Measurements." Ultrasonic Imaging 8, no. 2 (April 1986): 121–30. http://dx.doi.org/10.1177/016173468600800204.
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In this paper, the effect of transducer focusing on the integrity of ultrasonic backscattering measurements is examined. The rationale for this study stems from our observation that the calculated values of backscattering coefficients from data obtained with nonfocused transducers are always substantially lower than those obtained with focused transducers when the standard substitution method is used for backscattering measurements. It is postulated that this discrepancy is caused by the extremely complicated beam behavior of a focused transducer. This hypothesis is verified experimentally. It is therefore concluded that focused transducer could yield misleading results when a standard substitution method is used for absolute backscattering measurements.
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Mosland, Eivind N., Jan Kocbach, and Per Lunde. "Errors using the spatially averaged free-field pressure approximation for description of the receiving properties of piezoelectric transducers." Journal of the Acoustical Society of America 152, no. 4 (October 2022): A227. http://dx.doi.org/10.1121/10.0016092.
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In modelling of ultrasonic measurement systems and calculation of diffraction corrections for such systems, it is often assumed that the spatially averaged free-field pressure over the front surface of a piezoelectric transducer, ⟨ p⟩, can be used to calculate its voltage output. It is of interest to investigate whether errors due to this ⟨ p⟩-approximation are acceptable for piezoelectric transducers applied in high-precision ultrasonic measurements in fluids. 3D-axisymmetric finite element (FE) modelling is used to investigate such errors in a transmit-receive measurement setup employing two identical transducers. The approximate output voltage is found by Vout = ⟨ p⟩ MV and compared to the output voltage from FE modelling of the transmitter-medium-receiver system, Vout,ref , using the appropriate boundary conditions at the two transducers. MV is the open-circuit free-field receiving voltage sensitivity of the receiver for normally incident plane wavefronts, calculated assuming spherical reciprocity. Two examples of piezoelectric transducer pairs are studied, operated in the frequency range of their lower radial modes. It is shown that the ⟨ p⟩-approximation may introduce notable deviations between V out and Vout,ref , of up to approximately 40° for the phase angle and 2 dB for the magnitude. The deviations depend on the fluid medium, separation distance, frequency, and the transducer’s construction and vibrational characteristics.