scholarly journals A Frequency-Dependent Model for the Shape of the Fourier Amplitude Spectrum of Acceleration at High Frequencies

2020 ◽  
Vol 110 (6) ◽  
pp. 2743-2754 ◽  
Author(s):  
Annabel Haendel ◽  
John G. Anderson ◽  
Marco Pilz ◽  
Fabrice Cotton
Keyword(s):  
Frequency Dependence ◽  
Amplitude Spectrum ◽  
Frequency Interval ◽  
Borehole Data ◽  
High Frequencies ◽  
Dependent Model ◽  
Fourier Amplitude Spectrum ◽  
Log Linear ◽  
Frequency Dependent Model ◽  
Quality Factor Q

ABSTRACT The high-frequency decay term of the acceleration spectrum κ is a commonly used parameter in engineering seismology. In recent years, the assumption of a linearly decaying spectrum in log–linear space has been recognized to not always be valid as the value of κ depends on the analyzed frequency band. We present an alternative model for the spectral falloff in which the frequency dependence is explicitly taken into account. This is motivated by observations that the quality factor Q has a power-law dependence on frequency at high frequencies. The new model describes the spectral decay with the help of two variables, opposite to the single parameter κ. The approach is applied to borehole data of the EUROSEISTEST site in Greece. The misfit between modeled and observed spectra is reduced with the new approach compared with the classical kappa model. The new estimates compare well with κ estimates if the same frequency interval is considered but additionally allows for the capture of the frequency dependence of the spectral shape.

scholarly journals Circuit-based grounding electrode considering frequency dependence for different input current

2020 ◽  
Vol 20 (2) ◽  
pp. 613
Author(s):  
Ruqayyah Othman ◽  
Zulkurnain Abdul-Malek
Keyword(s):  
Frequency Dependence ◽  
Input Current ◽  
Soil Parameters ◽  
Voltage Response ◽  
Current Response ◽  
Frequency Dependent ◽  
Dependent Model ◽  
Grounding Electrode ◽  
Frequency Dependent Model ◽  
Impulse Current

<p>This paper presents a simulation work of circuit-based grounding electrode considering frequency dependence of soil parameters for three input currents which are impulse, AC 50 Hz, and DC. The circuit parameters were determined by using Dwight and Sunde equations where a single horizontal grounding electrode was considered. Scott model was used for the frequency dependent model, to determine the frequency dependent soil resistivity and relative permittivity. It is found that the voltage response of the impulse current was highly affected (75.2%) by the frequency compared to the voltage response of AC 50 Hz and DC. The impulse current response also gave the lowest peak in the analysis by the influence of frequency which make it better compared to the two other inputs. Therefore, it can be concluded that the frequency dependent of soil parameters is crucial and need to be considered in the transient analysis for any kind of input current to obtain accurate results.</p>

Regional attenuation models in Central and Eastern North America using the NGA-East database

2021 ◽  
pp. 875529302110187
Author(s):  
Jeff Bayless
Keyword(s):  
North America ◽  
Frequency Dependence ◽  
Gulf Coast ◽  
Site Response ◽  
Epistemic Uncertainty ◽  
Amplitude Spectrum ◽  
Active Regions ◽  
Atlantic Coastal Plain ◽  
Eastern North America ◽  
Anelastic Attenuation

The anelastic attenuation term found in ground motion prediction equations (GMPEs) represents the distance dependence of the effect of intrinsic and scattering attenuation on the wavefield as it propagates through the crust and contains the frequency-dependent quality factor, [Formula: see text], which is an inverse measure of the effective anelastic attenuation. In this work, regional estimates of [Formula: see text] in Central and Eastern North America (CENA) are developed using the NGA-East regionalization. The technique employed uses smoothed Fourier amplitude spectrum (FAS) data from well-recorded events in CENA as collected and processed by NGA-East. Regional [Formula: see text] is estimated using an assumption of average geometrical spreading applicable to the distance ranges considered. Corrections for the radiation pattern effect and for site response based on [Formula: see text] result in a small but statistically significant improvement to the residual analysis. Apparent [Formula: see text] estimates from multiple events are combined within each region to develop the regional models. Models are provided for three NGA-East regions: the Gulf Coast, Central North America, and the Appalachian Province. Consideration of the model uncertainties suggests that the latter two regions could be combined. There were not sufficient data to adequately constrain the model in the Atlantic Coastal Plain region. Tectonically stable regions are usually described by higher [Formula: see text] and weaker frequency dependence ([Formula: see text]), while active regions are typically characterized by lower [Formula: see text] and stronger frequency dependence, and the results are consistent with these expectations. Significantly different regional [Formula: see text] is found for events with data recorded in multiple regions, which supports the NGA-East regionalization. An inspection of two well-recorded events with data both in the Mississippi embayment and in southern Texas indicates that the Gulf Coast regionalization by Cramer in 2017 may be an improvement to that of NGA-East for anelastic attenuation. The [Formula: see text] models developed serve as epistemic uncertainty alternatives in CENA based on a literature review and a comparison with previously published models.

scholarly journals EXTENSION OF THE FREQUENCY-RANGE OF INTERFEROMETERS FOR THE "MAGNETIC" COMPONENTS OF GRAVITATIONAL WAVES?

2007 ◽  
Vol 22 (13) ◽  
pp. 2361-2381 ◽  
Author(s):  
CHRISTIAN CORDA
Keyword(s):  
Data Analysis ◽  
Frequency Dependence ◽  
Gravitational Waves ◽  
Response Functions ◽  
Frequency Range ◽  
Total Response ◽  
High Frequencies ◽  
Magnetic Components ◽  
Linear Dimensions ◽  
Dominant Part

Recently, with an enlightening treatment, Baskaran and Grishchuk have shown the presence and importance of the so-called "magnetic" components of gravitational waves (GW's), which have to be taken into account in the context of the total response functions of interferometers for GW's propagating from arbitrary directions. In this paper the analysis of the response functions for the magnetic components is generalized in its full frequency dependence, while in the work of Baskaran and Grishchuk the response functions were computed only in the approximation of wavelength much larger than the linear dimensions of the interferometer. It is also shown that the response functions to the magnetic components grow at high frequencies, differently from the values of the response functions to the well-known ordinary components that decrease at high frequencies. Thus the magnetic components could in principle become the dominant part of the signal at high frequencies. This is important for a potential detection of the signal at high frequencies and confirms that the magnetic contributions must be taken into account in the data analysis. More, the fact that the response functions of the magnetic components grow at high frequencies shows that, in principle, the frequency-range of Earth-based interferometers could extend to frequencies over 10000 Hz.

EFFECTS OF ELECTRODE RESISTANCE ON THE DIELECTRIC BEHAVIORS OF Au/BaxSr1−xTiO3/La1.1Sr0.9NiO4 CAPACITORS

2016 ◽  
Vol 23 (04) ◽  
pp. 1650028
Author(s):  
JIE QIU ◽  
GUOZHEN LIU ◽  
JÉRÔME WOLFMAN
Keyword(s):  
Frequency Dependence ◽  
High Frequency ◽  
Electronic Devices ◽  
Equivalent Circuit Model ◽  
Simulation Studies ◽  
Oxide Electrode ◽  
Theoretical Simulation ◽  
High Frequencies ◽  
Electrode Resistance ◽  
Apparent Deviation

BaxSr[Formula: see text]TiO3 ([Formula: see text]) (BST) thin films were prepared on La[Formula: see text]Sr[Formula: see text]NiO4 (LSNO)/SrTiO3 (STO) structure by combinatorial pulsed laser deposition (comb-PLD). The capacitances of the Au/BST/LSNO capacitors exhibited strong frequency dependence especially when the applied frequency was higher than 10[Formula: see text]kHz. On the basis of an equivalent circuit model, we presented a theoretical simulation of the relationships between capacitance and frequency for the capacitors with different electrode serial resistances. Based on the fitting results, the observed strong frequency dependence of the measured capacitance at high frequency in our study could be ascribed to the large serial resistance of 750 [Formula: see text] for oxide electrode LSNO. Further simulation studies found that large serial resistance (1000 [Formula: see text]) could result in an apparent deviation from the intrinsic dielectric properties especially at high frequencies ([Formula: see text]100[Formula: see text]kHz) for capacitors with capacitances above 1[Formula: see text]nF. Our results provide useful information for the design of all-oxide electronic devices.

Nonlinear Frequency-Dependent Model for Microinductors With Magnetic Core

2013 ◽  
Vol 34 (2) ◽  
pp. 304-306 ◽  
Author(s):  
Steven Gaskill ◽  
Andrei Papou ◽  
Anuraag Mohan ◽  
William French ◽  
Andreas Weisshaar
Keyword(s):  
Magnetic Core ◽  
Nonlinear Frequency ◽  
Frequency Dependent ◽  
Dependent Model ◽  
Frequency Dependent Model

scholarly journals Time- and frequency-dependent model of time-resolved coherent anti-Stokes Raman scattering (CARS) with a picosecond-duration probe pulse

2014 ◽  
Vol 140 (2) ◽  
pp. 024316 ◽  
Author(s):  
Hans U. Stauffer ◽  
Joseph D. Miller ◽  
Mikhail N. Slipchenko ◽  
Terrence R. Meyer ◽  
Benjamin D. Prince ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Probe Pulse ◽  
Frequency Dependent ◽  
Time Resolved ◽  
Dependent Model ◽  
Frequency Dependent Model ◽  
Anti Stokes
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