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Ultrasonic Investigation of Snow and Ice Parameters

100%
Gudra T., Najwer L.
Acta Physica Polonica A
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2011
|
vol. 120
|
issue 4
625-629
EN
In the paper some ultrasonic methods of measurement of sound velocity and attenuation in snow and ice media are presented. The measurement setup consists of ultrasonic airborne transducers working at the frequency of f = 40 kHz. A non-contact method of reflection coefficient on air-snow border was applied during measurement of different types of snow in the density range of 120-700 kg/m^3. Examples of obtained signals are also presented. It was proved that there is a linear dependence between reflection coefficient and snow density. The state of snow or ice layer is not precisely correlated with their acoustical parameters: ultrasound wave velocity and attenuation of ultrasonic wave during the measurement of the layer depth using the non-contact method. Reflection coefficient of snow can be used for estimation of snow density.
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The Possibility of a Simultaneous Transmission οf Ultrasound and Laser Radiation via Flexible Optical Silica Glass Fibre

81%
Muc S., Gudra T., Beres-Pawlik E.
Acta Physica Polonica A
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2009
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vol. 116
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issue 3
359-362
EN
Glass optical fibres are a promising medium for simultaneous laser-ultrasonic applications. The proposed application system is based on simultaneous transmission of laser radiation and ultrasounds in a flexible silica glass fibre. The optical fibre's core was made of SiO_2 (97%) and GeO_2 (3%) and the cladding was 100% SiO_2. The material the optical fibre is made of enables simultaneous transmission of laser radiation and ultrasonic wave. Experiments were performed using a Mach-Zehnder optical waveguide interferometer with single-mode optical fibre coupler. This paper presents measurement results for delivering ultrasonic waves to the optical fibre using longitudinal vibrations generated by a sandwich ultrasonic transducer with a velocity transformer. The study presents the relations concerning simultaneous operation of both types of waves and the possibilities of transmission of low frequency, high power ultrasonic wave in optical fibres using a sandwich type transducer.
3
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Non-Contact Interaction of Ultrasonic Wave on Laser Beam

81%
Muc S., Gudra T., Bereś-Pawlik E.
Acta Physica Polonica A
|
2011
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vol. 120
|
issue 4
702-704
EN
The article presents the results of Matlab simulations and experimental studies of non-contact influence of ultrasonic wave on laser beam. A role of the air-gap and the influence of the air-gap on laser-ultrasonic transmission in optical fiber were examined. Two optical fibers were used with air-gap between them. One fiber was attached to a laser diode and positioned to pass through a hole in a sandwich type transducer and in a velocity transformer. In the velocity transformer (at its end), after leaving small air-gap, to the end of the transformer, the other optical fiber is attached. The second fiber can interact with a given biological structure.
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