Sensitivities of the Rayleigh and Love Phase Velocities and Attenuation Coefficients

2018 ◽  
Vol 144 (11) ◽  
pp. 04018086
Author(s):  
R. Verachtert ◽  
G. Lombaert ◽  
G. Degrande
Keyword(s):  
Attenuation Coefficients ◽  
Phase Velocities

scholarly journals HALL CONDUCTIVITY ESTIMATES FROM MAGNETOTELLURIC SOUNDING DATA

2020 ◽  
Vol 11 (4) ◽  
pp. 817-828
Author(s):  
V. Plotkin ◽  
V. V. Potapov
Keyword(s):  
Hall Effect ◽  
Normal Wave ◽  
Magnetotelluric Sounding ◽  
Hall Conductivity ◽  
Petroleum Reservoir ◽  
Attenuation Coefficients ◽  
Reservoir Rocks ◽  
Phase Velocities ◽  
Left Circular Polarization ◽  
Semiconductor Properties

Many minerals have semiconductor properties. It is known that petroleum reservoir rocks permeated with hydrocarbon fluids can sometimes behave as semiconductors. In the Earth’s magnetic field, the electrical conductivity of such materials becomes anisotropic, and the Hall effect is quite possible in rocks in natural conditions and detectable by magnetotelluric sounding. In the anisotropic medium, the field is subject to normal mode splitting, and its components show different attenuation coefficients and phase velocities. The modes differ due to polarization and rotation of the field vectors (clockwise in one mode, and counterclockwise in another). With account of the Hall effect, responses of the medium can be different when the medium is excited by a single normal wave. To detect the Hall effect in MTS surveys, we use the polarization analysis method and select the spectra of modes with right and left circular polarization. Special experiments were carried out to detect the contribution of the Hall effect during the MTS surveys. This article presents the first estimates of the Hall conductivity for the studied rocks.

Effect of Temperature and Frequency on the Acoustic Properties of Konjac Glucomannan-Agar Gels as Tissue Mimicking Materials

2020 ◽  
Vol 307 ◽  
pp. 351-356
Author(s):  
Anis Nazihah Mat Daud ◽  
Md Supar Rohani ◽  
Rosly Jaafar
Keyword(s):  
Soft Tissue ◽  
Konjac Glucomannan ◽  
Acoustic Properties ◽  
Effect Of Temperature ◽  
Attenuation Coefficients ◽  
Phase Velocities ◽  
Agar Gels ◽  
Immersion Technique ◽  
Pulse Echo

In this study, we determine the effect of temperature and frequency on the acoustic properties of konjac glucomannan (KGM)-agar gels to confirm their compatibilities as tissue mimicking materials (TMMs). The acoustic properties of four samples; A (KGM-0.10 g agar), B (KGM-0.20 g agar), C (KGM-0.30 g agar) and D (KGM-0.40 g agar) were measured using pulse echo immersion technique. Findings indicated that the longitudinal velocities of all samples were increased while their attenuation coefficients were decreased as the temperature increased from 27.0 to 37.0°C. It also showed that the phase velocities of all samples were independent to frequency but their attenuation coefficients were increased as the frequency increased from 4.0 to 6.0 MHz. KGM-agar gels are compatible as soft TMMs since their acoustic properties are comparable with the acoustic properties of soft tissue.

Plane Waves in Micropolar thermoelastic Materials with Voids

2016 ◽  
Vol 4 (2) ◽  
pp. 141-151 ◽  
Author(s):  
S.S. Singh ◽  
◽  
R. Lianngenga
Keyword(s):  
Linear Theory ◽  
Shear Waves ◽  
Plane Waves ◽  
Attenuation Coefficients ◽  
Phase Velocities ◽  
Dilatational Wave ◽  
Materials With Voids

The problem of plane waves in micropolar thermoelastic materials with voids has been investigated. Using the linear theory of micropolar thermoelastic materials with voids developed by Passarella [27], we come to know that there exist six waves, which are three coupled dilatational waves, two coupled shear waves and micropolar dilatational wave, in the materials. The phase velocities and their attenuation coefficients of the three coupled and micropolar dilatational and two coupled shear waves are obtained numerically and analytically.

A comparison study for mass attenuation coefficients of some amino acids using MCNP code

Kerntechnik ◽  
2017 ◽  
Vol 82 (3) ◽  
pp. 339-343 ◽  
Author(s):  
S. M. Vahabi ◽  
M. Bahreinipour ◽  
M. Shamsaie-Zafarghandi
Keyword(s):  
Amino Acids ◽  
Comparison Study ◽  
Mcnp Code ◽  
Attenuation Coefficients ◽  
Mass Attenuation Coefficients ◽  
Mass Attenuation

scholarly journals The Role of La2O3 in Enhancement the Radiation Shielding Efficiency of the Tellurite Glasses: Monte-Carlo Simulation and Theoretical Study

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3913
Author(s):  
Aljawhara H. Almuqrin ◽  
Mohamed Hanfi ◽  
K. G. Mahmoud ◽  
M. I. Sayyed ◽  
Hanan Al-Ghamdi ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Theoretical Study ◽  
Radiation Shielding ◽  
Photon Flux ◽  
Transmission Factor ◽  
Tellurite Glasses ◽  
Attenuation Coefficients ◽  
Binary Glass ◽  
Buildup Factors

The radiation shielding competence was examined for a binary glass system xLa2O3 + (1 − x) TeO2 where x = 5, 7, 10, 15, and 20 mol% using MCNP-5 code. The linear attenuation coefficients (LACs) of the glasses were evaluated, and it was found that LT20 glass has the greatest LAC, while LT5 had the least LAC. The transmission factor (TF) of the glasses was evaluated against thicknesses at various selected energies and was observed to greatly decrease with increasing thickness; for example, at 1.332 MeV, the TF of the LT5 glass decreased from 0.76 to 0.25 as the thickness increased from 1 to 5 cm. The equivalent atomic number (Zeq) of the glasses gradually increased with increasing photon energy above 0.1 MeV, with the maximum values observed at around 1 MeV. The buildup factors were determined to evaluate the accumulation of photon flux, and it was found that the maximum values for both can be seen at around 0.8 MeV. This research concluded that LT20 has the greatest potential in radiation shielding applications out of the investigated glasses due to the glass having the most desirable parameters.

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