Simultaneous Measurement of Longitudinal and Transverse Waves Velocities Employing Spherically Focused Acoustic Transducer

2006 ◽  
Vol 321-323 ◽  
pp. 574-577
Author(s):  
Noh Yu Kim ◽  
Cheol Kyou Lee
Keyword(s):  
Transverse Wave ◽  
Simultaneous Measurement ◽  
Mode Conversion ◽  
Acoustic Microscopy ◽  
Transverse Waves ◽  
Wave Velocities ◽  
Acoustic Transducer ◽  
Transverse Acoustic ◽  
Novel Method ◽  
Relationship Of

Scanning acoustic microscopy (SAM) has been applied successfully to measure leaky surface wave(LSAW) velocity from V(z) curve for material characterization. Besides LSAW, SAM produces a variety of wave modes in the material propagating with different phase speeds and features, one of which is the mode-converted ultrasound. In this paper, a novel method for simultaneous measurement of longitudinal and transverse acoustic wave velocities using the mode-converted ultrasound is developed and studied at SAM. Each ultrasound arriving at the acoustic lens with different speed and phase (or time-of-flight (TOF)) is measured by the defocused transducer to calculate longitudinal and transverse wave velocities. Simple mathematical ray analysis for the mode conversion is conducted to determine the relationship of acoustic velocities with TOF of the waves in plate. Experimental results for metals and glass show that the longitudinal and transverse wave velocities measured by the proposed method are as accurate as maximum 3% in error.

Multiple-Transducer Scheme for Scanning Tomographic Acoustic Microscopy Using Transverse Waves

1997 ◽  
Vol 19 (4) ◽  
pp. 294-304
Author(s):  
Dae-Sik Ko
Keyword(s):  
Transverse Wave ◽  
Acoustic Waves ◽  
Mode Conversion ◽  
Tomographic Reconstruction ◽  
Wave Mode ◽  
Acoustic Microscopy ◽  
Good Resolution ◽  
Multiple Frequency ◽  
Transverse Waves ◽  
Resonance Frequencies

We propose a new type of multiple-transducer scheme with functions of multiple-angle and multiple-frequency tomography for scanning tomographic acoustic microscopy (STAM) using transverse waves. We review the data acquisition system and mode conversion of the acoustic waves for STAM and the multiple-angle and multiple-frequency tomography. Our multiple-transducer scheme has three insonification angles and three resonance frequencies in order to operate, in the transverse wave mode, multiple-angle and multiple frequency tomography for STAM. In order to evaluate the performance of our transducer scheme, we have simulated tomographic reconstruction with a back-and-forth propagation algorithm. Simulation results show that our multiple-transducer scheme is capable of obtaining good resolution with transverse wave mode and multiple-frequency tomography. We also show that our multiple-transducer scheme is an efficient rotation tool for a number of projections.

A novel method for the simultaneous measurement of temperature and strain using a three-wire connection

2001 ◽  
Vol 12 (4) ◽  
pp. 502-506 ◽  
Author(s):  
Paolo Cappa ◽  
Franco Marinozzi ◽  
Salvatore Andrea Sciuto
Keyword(s):  
Simultaneous Measurement ◽  
Novel Method

Identification of the Model of Nonlinear Elasticity in Dynamic Experiments

2021 ◽  
pp. 2150025
Author(s):  
Marina Sokolova ◽  
Yuri Astapov ◽  
Dmitrii Khristich
Keyword(s):  
Deformable Body ◽  
Polyamide 6 ◽  
Preliminary Deformation ◽  
Transverse Waves ◽  
Wave Velocities ◽  
Phase Velocities ◽  
Dynamic Methods ◽  
Dynamic Experiments ◽  
Effective Phase ◽  
Nonlinearly Elastic

Dynamic methods for identifying a model of a nonlinearly elastic deformable body are considered. By the effective phase velocities of longitudinal and transverse waves propagating along and across the axis of the compressed bar, it is possible to determine five elastic constants of the second and third orders included in the model relations. Calculation formulae are obtained and an example of determining the dependence of phase velocities on the preliminary deformation for polyamide 6 is given. The influence of preliminary deformations on polar diagrams of wave velocities is investigated.

scholarly journals A Novel Method for Intelligent Fault Diagnosis of Bearing Based on Capsule Neural Network

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Zhijian Wang ◽  
Likang Zheng ◽  
Wenhua Du ◽  
Wenan Cai ◽  
Jie Zhou ◽  
...  
Keyword(s):  
Neural Network ◽  
Fault Diagnosis ◽  
Weight Coefficient ◽  
Convergence Condition ◽  
Intelligent Fault Diagnosis ◽  
Wind Turbine Gearbox ◽  
Time Frequency ◽  
Proposed Model ◽  
Novel Method ◽  
Relationship Of

In the era of big data, data-driven methods mainly based on deep learning have been widely used in the field of intelligent fault diagnosis. Traditional neural networks tend to be more subjective when classifying fault time-frequency graphs, such as pooling layer, and ignore the location relationship of features. The newly proposed neural network named capsules network takes into account the size and location of the image. Inspired by this, capsules network combined with the Xception module (XCN) is applied in intelligent fault diagnosis, so as to improve the classification accuracy of intelligent fault diagnosis. Firstly, the fault time-frequency graphs are obtained by wavelet time-frequency analysis. Then the time-frequency graphs data which are adjusted the pixel size are input into XCN for training. In order to accelerate the learning rate, the parameters which have bigger change are punished by cost function in the process of training. After the operation of dynamic routing, the length of the capsule is used to classify the types of faults and get the classification of loss. Then the longest capsule is used to reconstruct fault time-frequency graphs which are used to measure the reconstruction of loss. In order to determine the convergence condition, the three losses are combined through the weight coefficient. Finally, the proposed model and the traditional methods are, respectively, trained and tested under laboratory conditions and actual wind turbine gearbox conditions to verify the classification ability and reliable ability.

scholarly journals A three-dimensional structural dissection of Drosophila polytene chromosomes.

1995 ◽  
Vol 131 (2) ◽  
pp. 279-295 ◽  
Author(s):  
Y Urata ◽  
S J Parmelee ◽  
D A Agard ◽  
J W Sedat
Keyword(s):  
Rna Polymerase Ii ◽  
Polytene Chromosome ◽  
Polytene Chromosomes ◽  
Three Dimensional ◽  
Spatial Relationship ◽  
Band Shape ◽  
Structural Details ◽  
Novel Method ◽  
Relationship Of

We have analyzed the three-dimensional structural details of Drosophila melanogaster polytene chromosome bands and interbands using three-dimensional light microscopy and a novel method of sample preparation that does not involve flattening or stretching the chromosomes. Bands have been visualized in unfixed chromosomes stained with the DNA specific dye 4,6-Diamidino-2-phenylindole (DAPI). Interbands have been visualized using fixed chromosomes that have been immunostained with an antibody to RNA polymerase II. Additionally, these structures have been analyzed using in situ hybridization with probes from specific genetic loci (Notch and white). Bands are seen to be composed of approximately 36 substructural features that measure 0.2-0.4 micron in diameter. We suggest that these substructural features are in fact longitudinal fibers made up of bundles of chromatids. Band shape can be a reproducible characteristic of a particular band and is dependent on the spatial relationship of these bundles, varying from bands with a uniform distribution of bundles to bands with a peripheral concentration of chromatin. Interbands are composed of bundles of chromatids of a similar size and number as those seen in the bands. The distribution of bundles is similar between a band and the neighboring interband, implying that there is a long range organization to the DNA that includes both the coding and the noncoding portions of genes. Finally, we note that the polytene chromosome has a circular shape when viewed in cross section, whether there are one or two homologs present.

Effect of Regular Transverse Wave on Ship Turning Maneuverability

2013 ◽  
Vol 312 ◽  
pp. 148-152 ◽  
Author(s):  
Lin Jia Yang ◽  
Yi Han Tao
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Transverse Wave ◽  
Simulation Method ◽  
Model Group ◽  
Regular Waves ◽  
Transverse Waves ◽  
Computer Simulation Method ◽  
Rudder Angle

Obtaining the effect of regular transverse wave is very significant for it is dangerous for ships to turn in transvers waves. To study ships motion law in regular transverse waves, computer simulation method was used. The simulation were based on ship mathematical model,called MMG(Maneuvering Model Group), and a waveforce mathematical model. In the simulation, the ship sailed in regular waves and calm sea with 0°and 20°rudder angle and the tracks were recorded. Hence, a ship trail was made to verify the truthfulness of simulation result. After analysing the simulation result, there is a diccussion to design a rudder controller, which can reduce the effect of waves. In conclusion, the effect of regular transverse wave on ship turning maneuverablity is obtained and it is feasible to design a rudder controller to reduce the effect.

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