scholarly journals Determination of spectral decay parameter and Quality factor in Kermanshah region, NW Iran

2021 ◽  
Vol 51 (2) ◽  
pp. 129-139
Author(s):  
Mehdi Nouri DELOUEI ◽  
Mohammad-Reza GHEITANCHI
Keyword(s):  
Quality Factor ◽  
Epicentral Distance ◽  
Spectral Amplitude ◽  
Quality Factors ◽  
High Frequencies ◽  
Nw Iran ◽  
Active Tectonic ◽  
Linear Fit ◽  
Quality Factor Q

Among important parameters in simulation of earthquake data in high frequencies are the high frequency spectral amplitude decay and the Quality factor. Amplitude spectral decay is determined by the Kappa parameter (K) and the Quality factor (Q) which is usually expressed by a power relation of frequency (f) as Q = Q0 f n, where Q0 is Q at 1 Hz. The 2017 Sarpol-e-Zahab earthquake with magnitude Mw = 7.3 in Kermanshah province near the Iran-Iraq border caused extensive destruction and heavy human loss. Thus, the study of different aspects of this event is of high importance. In this paper an attempt is made to partly explain the attenuation properties of this region in Zagros suture zone by determining the Kappa and the Quality factors in this region. In this study, accelerograph records of aftershocks of the above-mentioned earthquake have been analysed. The best linear fit for the Kappa, based on the distance (R) in km, is estimated as: K = 0.0005 R + 0.034 for the horizontal component, which exhibits increase with increasing epicentral distance. The correlation of the Quality factor was also found as Q = 88.6 f 0.8, which is in accordance with an active tectonic region.

scholarly journals Improved Determination of Q Quality Factor and Resonance Frequency in Sensors Based on the Magnetoelastic Resonance Through the Fitting to Analytical Expressions

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4708
Author(s):  
Beatriz Sisniega ◽  
Jon Gutiérrez ◽  
Virginia Muto ◽  
Alfredo García-Arribas
Keyword(s):  
Quality Factor ◽  
Resonance Curve ◽  
Peak Position ◽  
Precipitation Reaction ◽  
Magnetoelastic Sensors ◽  
Resonance Curves ◽  
Quality Factor Q ◽  
Magnetoelastic Resonance ◽  
Analytical Expressions

The resonance quality factor Q is a key parameter that describes the performance of magnetoelastic sensors. Its value can be easily quantified from the width and the peak position of the resonance curve but, when the resonance signals are small, for instance when a lot of damping is present (low quality factor), this and other simple methods to determine this parameter are highly inaccurate. In these cases, numerical fittings of the resonance curves allow to accurately obtain the value of the quality factor. We present a study of the use of different expressions to numerically fit the resonance curves of a magnetoelastic sensor that is designed to monitor the precipitation reaction of calcium oxalate. The study compares the performance of both fittings and the equivalence of the parameters obtained in each of them. Through these numerical fittings, the evolution of the different parameters that define the resonance curve of these sensors is studied, and their accuracy in determining the quality factor is compared.

Theoretical and practical aspects of absorption in the application of in‐seam seismic coal exploration

Geophysics ◽  
1982 ◽  
Vol 47 (12) ◽  
pp. 1645-1656 ◽  
Author(s):  
Th. Krey ◽  
H. Arnetzl ◽  
M. Knecht
Keyword(s):  
Quality Factor ◽  
Seismic Waves ◽  
Guided Waves ◽  
Country Rock ◽  
Low Frequency ◽  
Quality Factors ◽  
Ruhr Area ◽  
Phase Signal ◽  
Quality Factor Q

During the last two decades, the detection of coal seam discontinuities by seismic waves guided by the seam has become a special branch of exploration seismics in Europe. Waves consisting purely of SH motion (so‐called waves of Love type) are of special interest, and the rather high frequencies of the Airy phase, in thin seams, are most important because they present very high reflectivity at seam interruptions. Absorption increases with frequency in most layers, and therefore attenuates the high Airy‐phase frequencies more severely than the earlier low‐frequency part of the guided waves. Another fact additionally impairs the Airy‐phase signal: the quality factor Q is much lower in coal than in the schists and sandstones of the Carboniferous country rock. Unfortunately, most of the energy of the Airy phase is transferred by the coal, whereas the lower frequencies have their main energy conveyed by the country rock above and below the seam. In order to allow a better understanding of the influence of absorption on Love‐type seam waves, several simplified computations were carried out for the fundamental mode of a seam typical for the northwest‐German Ruhr area. The assumptions are as follows: The quality factors [Formula: see text] for coal and [Formula: see text] for the country rock do not depend upon frequency; higher powers of [Formula: see text] and [Formula: see text] can be neglected; and the distance from the source is large enough to allow the two‐dimensional plane‐wave case to be considered. The mathematics resulting from these assumptions and adequate data processing of transmission records provides the possibility to determine the quality factor [Formula: see text] of coal in‐situ, although the thickness of the seam may be much smaller than the wavelengths involved. [Formula: see text] may become of interest for practical mining problems.

NÉEL LINES STRUCTURES IN UNIAXIAL FERROMAGNETS WITH QUALITY FACTOR Q > 1

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-1947-C8-1948
Author(s):  
J. Miltat ◽  
P. Trouilloud
Keyword(s):  
Quality Factor ◽  
Quality Factor Q

scholarly journals 422 Million intrinsic quality factor planar integrated all-waveguide resonator with sub-MHz linewidth

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Matthew W. Puckett ◽  
Kaikai Liu ◽  
Nitesh Chauhan ◽  
Qiancheng Zhao ◽  
Naijun Jin ◽  
...  
Keyword(s):  
Quality Factor ◽  
High Capacity ◽  
Precision Spectroscopy ◽  
Narrow Linewidth ◽  
Waveguide Resonator ◽  
Environmental Disturbances ◽  
Fiber Communications ◽  
Intrinsic Quality ◽  
Quality Factor Q ◽  
Quantum Photonics

AbstractHigh quality-factor (Q) optical resonators are a key component for ultra-narrow linewidth lasers, frequency stabilization, precision spectroscopy and quantum applications. Integration in a photonic waveguide platform is key to reducing cost, size, power and sensitivity to environmental disturbances. However, to date, the Q of all-waveguide resonators has been relegated to below 260 Million. Here, we report a Si3N4 resonator with 422 Million intrinsic and 3.4 Billion absorption-limited Qs. The resonator has 453 kHz intrinsic, 906 kHz loaded, and 57 kHz absorption-limited linewidths and the corresponding 0.060 dB m−1 loss is the lowest reported to date for waveguides with deposited oxide upper cladding. These results are achieved through a careful reduction of scattering and absorption losses that we simulate, quantify and correlate to measurements. This advancement in waveguide resonator technology paves the way to all-waveguide Billion Q cavities for applications including nonlinear optics, atomic clocks, quantum photonics and high-capacity fiber communications.

Reynolds-averaged Navier–Stokes simulation of hydrofoil effects on hydrodynamic coefficients of a catamaran in forced oscillation

2016 ◽  
Vol 231 (2) ◽  
pp. 364-383
Author(s):  
Amin Najafi ◽  
Mohammad Saeed Seif
Keyword(s):  
High Speed ◽  
Experimental Approach ◽  
Navier Stokes ◽  
Hydrodynamic Coefficients ◽  
Laboratory Equipment ◽  
Factors Affecting ◽  
High Frequencies ◽  
Frequency Independent ◽  
Reynolds Averaged Navier Stokes

Determination of high-speed crafts’ hydrodynamic coefficients will help to analyze the dynamics of these kinds of vessels and the factors affecting their dynamic stabilities. Also, it can be useful and effective in controlling the vessel instabilities. The main purpose of this study is to determine the coefficients of longitudinal motions of a planing catamaran with and without a hydrofoil using Reynolds-averaged Navier–Stokes method to evaluate the foil effects on them. Determination of hydrodynamic coefficients by experimental approach is costly and requires meticulous laboratory equipment; therefore, utilizing the numerical methods and developing a virtual laboratory seem highly efficient. In this study, the numerical results for hydrodynamic coefficients of a high-speed craft are verified against Troesch’s experimental results. In the following, after determination of hydrodynamic coefficients of a planing catamaran with and without foil, the foil effects on its hydrodynamic coefficients are evaluated. The results indicate that most of the coefficients are frequency-independent especially at high frequencies.

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