Optimization of the ultrasonic excitation stage

Svilainis, Linas; Dumbrava, V.; Motiejunas, G.

doi:10.1109/iti.2008.4588512

Cited by 12 publications

(19 citation statements)

References 5 publications

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“…Moreover, vibrometry results evaluated the energy propagation on the contact surface of the transducers at the selected frequencies. In the following, dispersion curve and wave mode analyses following the principles of UGW were performed to determine the best excitation wave mode and the geometrical arrangement of the [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] transducer array that most efficiently deliver distributed energy over the ship hull represented by the test plate. Finally, the plate was immersed in sea water in a port and the results were monitored photographically.…”

Section: 1overall Approachmentioning

confidence: 99%

“…The ability to generate a frequency sweep is a useful feature as it potentially prevents the formation of null points due to effects such as the interference of transmitted and reflected waves. The frequency sweep also reduces the possibility [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] of overloading the system due to the low impedance of the transducers at their resonance frequency. A frequency sweep may be implemented by varying the voltage across the frequency control resistor with time, using a frequency sweep circuit.…”

Section: Signal Generatormentioning

confidence: 99%

“…Piezoelectric transducers have been modelled using an equivalent circuit [20]. They have complex input impedance which affects their driving response, bandwidth, sensitivity and power output.…”

Section: Impedance Analysismentioning

confidence: 99%

“…Table 1 lists the transducers and their specifications in use for fouling removal. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Each piezoelectric transducer was connected to the impedance analyser which generated a frequency sweep between 1 kHz and 100 kHz at constant voltage amplitude while measuring the impedance, transmittance and phase of the circuit at each frequency to be used for the design of generator impedance matching circuit. The measured impedance is shown in Figs.…”

Section: Impedance Analysismentioning

confidence: 99%

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An Acoustic Antifouling Study in Sea Environment for Ship Hulls Using Ultrasonic Guided Waves

Habibi

Gan

Legg³

et al. 2020

Int. J. Eng. Tech. Mgmt. Res.

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Biofouling results in a range of adverse issues for ships and boats such as an increase in hydrodynamic drag force and fuel consumption and increased maintenance cost. To address this issue, toxic antifouling coatings have been developed. However, these toxic coatings can pose threats to marine life. This has led to research on less harmful techniques such as acoustic methods in the main implemented as laboratory trials. In fact, there have been relatively few sea trials and these are poorly documented. The current work has performed one of the few implemented field trials and the only one to be fully documented. In this sea trial, an optimised array of transducers generating ultrasound guided waves was attached to a hull representative plate in a port environment. The results of this work are evidenced by the significant reduction in-situ of a wide range of biofouling materials and organisms. The documented photographical evidence makes up for its scarcity in the published records of antifouling advances using acoustic techniques.

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Section: 1overall Approachmentioning

confidence: 99%

Section: Signal Generatormentioning

confidence: 99%

Section: Impedance Analysismentioning

confidence: 99%

Section: Impedance Analysismentioning

confidence: 99%

See 2 more Smart Citations

An Acoustic Antifouling Study in Sea Environment for Ship Hulls Using Ultrasonic Guided Waves

Habibi

Gan

Legg³

et al. 2020

Int. J. Eng. Tech. Mgmt. Res.

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“…But usually speed is required so several truncated interpolation techniques exist. All techniques locate the peak position using discrete signal and then use interpolation to estimate the subsample delay [3,10]. Convenient peak position estimation can be done using parabolic interpolation [1].…”

Section: Peak Position Interpolationmentioning

confidence: 99%

The influence of digital domain on time of flight estimation performance

Svilainis

Dumbrava²,

Kitov³

et al. 2012

AIP Conference Proceedings

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A field-programmable-gate-array based time digitizer for the time-of-flight mass spectrometry Rev. Sci. Instrum. 85, 045115 (2014); 10.1063/1.4870922 Digital implementation of linear gammatone filters: Comparison of design methods ARLO 4, 59 (2003);Abstract. Analysis of the time of flight estimation performance when signal digitization is used is presented. The crosscorrelation function peak position was used as time-of-flight estimator. In order to cope with the discrete nature of the cross-correlation the time of flight subsample estimates used interpolation techniques: parabolic peak, derivative's zero crossing, zero crossing of imaginary of Hilbert transform, double zero crossing and frequency domain phase. Noise density component of the Cramer-Rao lower error bound was modified to include the jittering and quantization noise. Basing the real amplifier noise density theoretical analysis concluded that taking the 180 nV/Hz as lowest noise density at ADC input, 10 bit is needed for 100 MHz sampling. Numerical experiments have been conducted using Matlab to investigate the standard deviation of ToF in presence of additive white Gaussian noise and signal's digitization. It has been concluded that systematic errors are related to subsample interpolation and are in cubic relation to sampling frequency and in inverse quadratic relation to carrier. Random errors are in opposite relation: little influence by sampling frequency and direct proportion to carrier frequency. Investigation on the digital filtering influence revealed that digital filtering does not improve the time-of-flight estimation accuracy.

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