On the Issue of Typical Grain Size Assessment by the Methods of Broadband Laser Opto-Acoustics

2017 ◽  
Vol 755 ◽  
pp. 212-218 ◽  
Author(s):  
Alexander N. Kravcov ◽  
Adam Konvalinka ◽  
Vladimir A. Vinnikov ◽  
Elmira A. Ertuganova ◽  
Ivan A. Shibaev ◽  
...  
Keyword(s):  
Amplitude Spectrum ◽  
Acoustic Signals ◽  
Original Signal ◽  
Time Profiles ◽  
Grain Sizes ◽  
Acoustic Spectroscopy ◽  
Broadband Laser ◽  
Laser Sources ◽  
Express Methods ◽  
Theoretical Assessment

It is shown that one of the express-methods for studying the internal structure and phase composition of geomaterial samples is broadband acoustic spectroscopy with laser sources of ultrasound. Theoretical assessment of time profiles and spectrums of opto-acoustic signals are presented. Numerical modelling of the spectrums and time profiles of ultrasound signals generated in opto-acoustic generators made of a different material is performed. The influence of diffraction and damping in rocks on the above characteristics is studied. The amplitude spectrum and time profiles of ultrasonic pulses transmitted through samples of marble of various thicknesses in which the most part of the characteristic grain sizes lies in the range of 500 μm - 1 mm are constructed. It has been established that, according to the amplitude spectrum of the original signal and the transmitted through the sample signal, it is possible to restore the characteristic dimensions of the grains.

Generation and detection of broadband laser generated ultrasound from low-power laser sources

2001 ◽  
Author(s):  
Kathryn Atherton ◽  
Brian Culshaw ◽  
Fengzhong Dong ◽  
Pan Jun ◽  
S. Gareth Pierce ◽  
...  
Keyword(s):  
Low Power ◽  
Power Laser ◽  
Broadband Laser ◽  
Laser Sources

High-resolution sum-frequency spectra using broadband laser sources

1996 ◽  
Vol 368 (1-3) ◽  
pp. 96-101 ◽  
Author(s):  
E.W.M. van der Ham ◽  
Q.H.F. Vrehen ◽  
E.R. Eliel
Keyword(s):  
High Resolution ◽  
Frequency Spectra ◽  
Sum Frequency ◽  
Broadband Laser ◽  
Laser Sources

Acquiring The Pulsation Characteristics Of An Unsteady Vortex Flow With The Aid Of Pressure Probes

2016 ◽  
Vol 11 (3) ◽  
pp. 27-33
Author(s):  
Andrey Mitryakov ◽  
Ivan Litvinov ◽  
Sergey Shtork
Keyword(s):  
Transfer Function ◽  
Flow Structure ◽  
Experimental Technique ◽  
Vortex Flow ◽  
Signal Reconstruction ◽  
Original Signal ◽  
Pressure Pulsations ◽  
Local Measurements ◽  
Theoretical Assessment

The special probes utilization together with measuring microphones allows to hold local measurements of pressure pulsations and to deform a flow structure marginally. Knowledge about a transfer function of the probe is required for the original signal reconstruction. This article presents the experimental technique of the probe transfer function obtainment. The theoretical assessment of the transfer function was carried out, using the model presented in the literature. Also the original signal reconstruction of pressure pulsations was carried out at the exit of the vortex tangential chamber.

scholarly journals Synchronization of Acoustic Signals for Steganographic Transmission

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3379
Author(s):  
Jarosław Wojtuń ◽  
Zbigniew Piotrowski
Keyword(s):  
Acoustic Signal ◽  
Speech Signal ◽  
Data Stream ◽  
Acoustic Signals ◽  
Signal Quality ◽  
Radio Link ◽  
Original Signal ◽  
Additional Information

Steganography is a technique that makes it possible to hide additional information (payload) in the original signal (cover work). This paper focuses on hiding information in a speech signal. One of the major problems with steganographic systems is ensuring synchronization. The paper presents four new and effective mechanisms that allow achievement of synchronization on the receiving side. Three of the developed methods of synchronization operate directly on the acoustic signal, while the fourth method works in the higher layer, analyzing the structure of the decoded steganographic data stream. The results of the research concerning both the evaluation of signal quality and the effectiveness of synchronization are presented. The signal quality was assessed based on both objective and subjective methods. The conducted research confirmed the effectiveness of the developed methods of synchronization during the transmission of steganographic data in the VHF radio link and in the VoIP channel.

Reflection electron microscopy of as-grown diamond surfaces

1993 ◽  
Vol 51 ◽  
pp. 1006-1007
Author(s):  
Z.L. Wang ◽  
J. Bentley ◽  
R.E. Clausing ◽  
L. Heatherly ◽  
L.L. Horton
Keyword(s):  
Electron Microscopy ◽  
Synthetic Diamond ◽  
High Energy ◽  
Dark Field ◽  
Reverse Direction ◽  
Diamond Surfaces ◽  
Grain Sizes ◽  
Synthetic Diamonds ◽  
De Beers ◽  
Reflection Electron Microscopy

It has been found that the abrasion of diamond-on-diamond depends on the crystal orientation. For a {100} face, the friction coefficient for sliding along <011> is much higher than that along <001>. For a {111} face, the abrasion along <11> is different from that in the reverse direction <>. To interpret these effects, a microcleavage mechanism was proposed in which the {100} and {111} surfaces were assumed to be composed of square-based pyramids and trigonal protrusions, respectively. Reflection electron microscopy (REM) has been applied to image the microstructures of these diamond surfaces.{111} surfaces of synthetic diamond:The synthetic diamonds used in this study were obtained from the De Beers Company. They are in the as-grown condition with grain sizes of 0.5-1 mm without chemical treatment or mechanical polishing. By selecting a strong reflected beam in the reflection high-energy electron diffraction (RHEED) pattern, the dark-field REM image of the surface is formed (Fig. 1).

A theoretical assessment of dismissal rates and unit performance, with empirical evidence.

2020 ◽  
Vol 105 (5) ◽  
pp. 527-537
Author(s):  
Mark A. Maltarich ◽  
Greg Reilly ◽  
Chris DeRose
Keyword(s):  
Empirical Evidence ◽  
Unit Performance ◽  
Theoretical Assessment
Sign in / Sign up

Export Citation Format

Share Document