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Ultrasonics

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https://www.readbyqxmd.com/read/27930917/love-mode-surface-acoustic-wave-devices-based-on-multilayers-of-teo2-zno-112%C3%A2-0-si-100-with-high-sensitivity-and-temperature-stability
#1
Jing-Ting Luo, Ao-Jie Quan, Guang-Xing Liang, Zhuang-Hao Zheng, Sami Ramadan, Chen Fu, Hong-Lang Li, Yong-Qing Fu
A multilayer structure of TeO2/interdigital transducers (IDTs)/ZnO(112¯0)/Si(100) was proposed and investigated to achieve both high sensitivity and temperature-stability for bio-sensing applications. Dispersions of phase velocities, electromechanical coupling coefficients K(2), temperature coefficient of delay (TCD) and sensitivity in the multilayer structures were simulated as functions of normalized thicknesses of ZnO (hZnO/λ) and TeO2 (hTeO2/λ) films. The fundamental mode of Love mode (LM) - surface acoustic wave (SAW) shows a larger value of K(2) and higher sensitivity compared with those of the first mode...
November 25, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27915136/dynamics-of-two-interacting-bubbles-in-a-nonspherical-ultrasound-field
#2
Jinfu Liang, Xun Wang, Jing Yang, Lunxun Gong
In this paper, we present and analyze a model of the oscillations of a pair of gas bubbles driven by nonspherical ultrasound. We derived our model based on the perturbation and potential flow theories and use it to study three cases of oscillation of two bubbles under driving ultrasound with different initial phases, different separation distances between the bubbles and different sound pressure amplitudes. For the driving ultrasound with different initial phases, we obtain the in-phase and anti-phase radial pulsations of the bubbles in incompressible liquid...
November 22, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27898301/an-energy-harvesting-type-ultrasonic-motor
#3
Guangqing Wang, Wentan Xu, Shuaishuai Gao, Binqiang Yang, Guoli Lu
An energy harvesting type ultrasonic motor is presented in this work. The novel motor not only can drive and/or position the motion mechanism, but also can harvest and convert the vibration-induced energy of the stator into electric energy to power small electronic devices. In the new motor, the stator is a sandwich structure of two PZT rings and an elastic metal body. The PZT ring bonded on the bottom surface is used to excite the stator metal body to generate a traveling wave with converse piezoelectric effect, and the other PZT ring bonded on top surface is used to harvest and convert the vibration-induced energy of the stator into electric energy with direct piezoelectric effect...
November 16, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27898300/a-new-topological-structure-for-the-langevin-type-ultrasonic-transducer
#4
Xiaolong Lu, Junhui Hu, Hanmin Peng, Yuan Wang
In this paper, a new topological structure for the Langevin-type ultrasonic transducer is proposed and investigated. The two cylindrical terminal blocks are conically shaped with four supporting plates each, and two cooling fins are disposed at the bottom of terminal blocks, adjacent to the piezoelectric rings. Experimental results show that it has larger vibration velocity, lower temperature rise and higher electroacoustic energy efficiency than the conventional Langevin transducer. The reasons for the phenomena can be well explained by the change of mass, heat dissipation surface and force factor of the transducer...
November 16, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27898302/a-novel-sandwich-type-traveling-wave-piezoelectric-tracked-mobile-system
#5
Liang Wang, Chengyou Shu, Quan Zhang, Jiamei Jin
In this paper, a novel sandwich-type traveling wave piezoelectric tracked mobile system was proposed, designed, fabricated and experimentally investigated. The proposed system exhibits the advantages of simple structure, high mechanical integration, lack of electromagnetic interference, and lack of lubrication requirement, and hence shows potential application to robotic rovers for planetary exploration. The tracked mobile system is comprised of a sandwich actuating mechanism and a metal track. The actuating mechanism includes a sandwich piezoelectric transducer and two annular parts symmetrically placed at either end of the transducer, while the metal track is tensioned along the outer surfaces of the annular parts...
November 15, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27907827/similarity-assessment-of-acoustic-emission-signals-and-its-application-in-source-localization
#6
Shiwan Chen, Chunhe Yang, Guibin Wang, Wei Liu
In conventional AE source localization acoustic emission (AE) signals are applied directly to localize the source without any waveform identification or quality evaluation, which always leads to large errors in source localization. To improve the reliability and accuracy of acoustic emission source localization, an identification procedure is developed to assess the similarity of AE signals to select signals with high quality to localize the AE source. Magnitude square coherence (MSC), wavelet coherence and dynamic timing warping (DTW) are successively applied for similarity assessment...
November 14, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27898303/effect-of-acoustic-softening-on-the-thermal-mechanical-process-of-ultrasonic-welding
#7
Kunkun Chen, Yansong Zhang, Hongze Wang
Application of ultrasonic energy can reduce the static stress necessary for plastic deformation of metallic materials to reduce forming load and energy, namely acoustic softening effect (ASE). Ultrasonic welding (USW) is a rapid joining process utilizing ultrasonic energy to form a solid state joint between two or more pieces of metals. Quantitative characterization of ASE and its influence on specimen deformation and heat generation is essential to clarify the thermal-mechanical process of ultrasonic welding...
November 10, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27914306/a-contactless-ultrasonic-surface-wave-approach-to-characterize-distributed-cracking-damage-in-concrete
#8
Suyun Ham, Homin Song, Michael L Oelze, John S Popovics
We describe an approach that utilizes ultrasonic surface wave backscatter measurements to characterize the volume content of relatively small distributed defects (microcrack networks) in concrete. A simplified weak scattering model is used to demonstrate that the scattered wave field projected in the direction of the surface wave propagation is relatively insensitive to scatterers that are smaller than the propagating wavelength, while the scattered field projected in the opposite direction is more sensitive to sub-wavelength scatterers...
November 9, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27690237/acoustical-spinner-tweezers-with-nonparaxial-hermite-gaussian-acoustical-sheets-and-particle-dynamics
#9
F G Mitri
Hermite-Gaussian (HGl) acoustical-sheets are introduced and their beamforming properties are examined. A general nonparaxial mathematical solution for the incident beam of any order l is derived based on the angular spectrum decomposition in plane waves. The beam-shape coefficients characterizing the incident beam in cylindrical coordinates are expressed in an integral form and computed using the standard numerical integration procedure based on the trapezoidal rule. The analysis is further extended to calculate the longitudinal and transverse acoustic radiation force functions as well as the axial radiation torque function for a viscous fluid cylindrical cross-section submerged in a non-viscous fluid and located arbitrarily in space in the field of the HGl beams in the Rayleigh and resonance (Mie) regimes...
September 20, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27723531/directivity-analysis-of-meander-line-coil-emats-with-a-wholly-analytical-method
#10
Yuedong Xie, Zenghua Liu, Liyuan Yin, Jiande Wu, Peng Deng, Wuliang Yin
This paper presents the simulation and experimental study of the radiation pattern of a meander-line-coil EMAT. A wholly analytical method, which involves the coupling of two models: an analytical EM model and an analytical UT model, has been developed to build EMAT models and analyse the Rayleigh waves' beam directivity. For a specific sensor configuration, Lorentz forces are calculated using the EM analytical method, which is adapted from the classic Deeds and Dodd solution. The calculated Lorentz force density are imported to an analytical ultrasonic model as driven point sources, which produce the Rayleigh waves within a layered medium...
September 17, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27693600/nonlinear-coda-wave-interferometry-for-the-global-evaluation-of-damage-levels-in-complex-solids
#11
Yuxiang Zhang, Vincent Tournat, Odile Abraham, Olivier Durand, Stéphane Letourneur, Alain Le Duff, Bertrand Lascoup
A nonlinear acoustic method to assess the damage level of a complex medium is discussed herein. Thanks to the highly nonlinear elastic signatures of cracks or, more generally, internal solid contacts, this method is able to distinguish between contributions from linear wave scattering by a heterogeneity and contributions from nonlinear scattering by a crack or unbounded interface. The coda wave interferometry (CWI) technique is applied to reverberated and scattered waves in glass plate samples featuring various levels of damage...
September 17, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27665297/guided-wave-scattering-by-geometrical-change-or-damage-application-to-characterization-of-fatigue-crack-and-machined-notch
#12
Nicolas Quaegebeur, Nidhal Bouslama, Maxime Bilodeau, Robin Guitel, Patrice Masson, Ahmed Maslouhi, Philippe Micheau
Validation of guided-wave based systems for Non-Destructive Evaluation (NDE) and Structural Health Monitoring (SHM) under realistic conditions or environment requires complex setups. For this purpose, numerical or theoretical approaches are useful to save time and cost associated with experiential tests. However, the interaction with realistic geometrical (rivets, thickness changes, stiffeners, extrusions) or damage features (fatigue cracks, fillet cracks, delaminations, disbonds) must be accurately captured in order to be representative...
September 14, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27668998/evaluation-and-comparison-of-current-biopsy-needle-localization-and-tracking-methods-using-3d-ultrasound
#13
Yue Zhao, Yi Shen, Adeline Bernard, Christian Cachard, Hervé Liebgott
This article compares four different biopsy needle localization algorithms in both 3D and 4D situations to evaluate their accuracy and execution time. The localization algorithms were: Principle component analysis (PCA), random Hough transform (RHT), parallel integral projection (PIP) and ROI-RK (ROI based RANSAC and Kalman filter). To enhance the contrast of the biopsy needle and background tissue, a line filtering pre-processing step was implemented. To make the PCA, RHT and PIP algorithms comparable with the ROI-RK method, a region of interest (ROI) strategy was added...
September 13, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27657480/sonodynamic-action-of-hypocrellin-b-triggers-cell-apoptoisis-of-breast-cancer-cells-involving-caspase-pathway
#14
Yali Jia, Xiaobing Wang, Quanhong Liu, Albert Wingnang Leung, Pan Wang, Chuanshan Xu
OBJECTIVES: The aim of the present study is to investigate the effects of sonodynamic action of hypocrellin B on human breast cancer cells and further explore its underlying mechanisms. METHODS: The cell viability of breast cancer MDA-MB-231 cells was examined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Alterations on cell apoptosis, intracellular reactive oxygen species generation (ROS), mitochondrial membrane potential, and DNA fragmentation was analyzed by flow cytometer...
September 13, 2016: Ultrasonics
https://www.readbyqxmd.com/read/27863341/physical-constraints-on-the-non-dimensional-absorption-coefficients-of-compressional-and-shear-waves-for-viscoelastic-cylinders
#15
F G Mitri, Z E A Fellah
BACKGROUND: Normalized absorption coefficients for the longitudinal and shear waves in viscoelastic (polymer-type) materials, extracted from non-fictional experimental data showed anomalous effects, such as the generation of a negative radiation force (NRF) in plane progressive waves, negative energy absorption and extinction efficiencies and a scattering enhancement, not in agreement with energy conservation. OBJECTIVE: The objective of this work is directed towards analyzing those anomalies from the standpoint of energy conservation...
February 2017: Ultrasonics
https://www.readbyqxmd.com/read/27863340/solder-joint-failure-localization-of-welded-joint-based-on-acoustic-emission-beamforming
#16
Xiandong Liu, Denghong Xiao, Yingchun Shan, Qiang Pan, Tian He, Yong Gao
A localization approach of welded joint damage is proposed based on acoustic emission (AE) beamforming. In this method, a uniform line array is introduced to detect the AE signal of welded joints in specified area. In order to investigate the influence of fillet and crimping commonly existing in a welded plate structure during the AE wave propagation process, the finite element method (FEM) is applied to simulate the behavior of AE wave in the specimen. The simulation localization results indicate that the proposed localization approach can effectively localize AE sources although there exist the fillet and crimping, and it is also validated by the pencil-lead-broken test on rectangular steel tube with welded joints...
February 2017: Ultrasonics
https://www.readbyqxmd.com/read/27838601/ultrasonic-bent-waveguides-approach-for-distributed-temperature-measurement
#17
Suresh Periyannan, Prabhu Rajagopal, Krishnan Balasubramaniam
This paper describes novel techniques for simultaneous measurement of temperatures at multiple locations using two configurations (a) a single transducer attached to multiple waveguides of different lengths (each with a single bend) and (b) single waveguide with multiple bends connected to single transducer. These techniques improve upon the earlier reported studies using straight waveguides, where the non-consideration of the effect of temperature gradients was found to be a major limitation. The range of temperature measurement is from room temperature to maximum utility temperature of the waveguide material...
February 2017: Ultrasonics
https://www.readbyqxmd.com/read/27835809/study-on-tangentially-polarized-composite-cylindrical-piezoelectric-transducer-with-high-electro-mechanical-coupling-coefficient
#18
Longyang Jia, Guangbing Zhang, Xiaofeng Zhang, Yu Yao, Shuyu Lin
In this work, we proposed an effective way to fabricate a tangentially polarized composite cylindrical transducer with high electro-mechanical coupling coefficient (EMCC) by radially connecting an inner tangential polarized piezoelectric tube with an outer metal ring. The resonance frequency and EMCC of the proposed transducer are calculated according to frequency equations, which are obtained from the equivalent circuit of the transducer, and the results indicate that EMCC of the tangentially polarized cylindrical transducer is much higher than that of the cylindrical transducer polarized in radial direction...
February 2017: Ultrasonics
https://www.readbyqxmd.com/read/27835808/evaluation-of-a-small-flat-rectangular-therapeutic-ultrasonic-transducer-intended-for-intravascular-use
#19
N Papadopoulos, G Menikou, M Yiannakou, C Yiallouras, K Ioannides, C Damianou
BACKGROUND: The aim of the proposed study was to evaluate the performance of a flat rectangular (2×10mm(2)) transducer operating at 4MHz. The intended application of this transducer is intravascular treatment of thrombosis and atherosclerosis. METHODS: The transducer's thermal capabilities were tested in two different gel phantoms. MR thermometry was used to demonstrate the thermal capabilities of this type of transducer. RESULTS: Temperature measurements demonstrated that this simple and small transducer adequately produced high temperatures, which can be utilized for therapeutic purposes...
February 2017: Ultrasonics
https://www.readbyqxmd.com/read/27816873/long-range-measurement-system-using-ultrasonic-range-sensor-with-high-power-transmitter-array-in-air
#20
Sahdev Kumar, Hideo Furuhashi
A long-range measurement system comprising an ultrasonic range sensor with a high-power ultrasonic transmitter array in air was investigated. The system is simple in construction and can be used under adverse conditions such as fog, rain, darkness, and smoke. However, due to ultrasonic waves are well absorbed by air molecules, the measurable range is limited to a few meters. Therefore, we developed a high-power ultrasonic transmitter array consisting of 144 transmitting elements. All elements are arranged in the form of a 12×12 array pattern...
February 2017: Ultrasonics
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