Frequency-Dependent Spherical-Wave Reflection in Acoustic Media: Analysis and Inversion

2017 ◽  
Vol 174 (4) ◽  
pp. 1759-1778 ◽  
Author(s):  
Jingnan Li ◽  
Shangxu Wang ◽  
Jingbo Wang ◽  
Chunhui Dong ◽  
Sanyi Yuan
Keyword(s):  
Wave Reflection ◽  
Spherical Wave ◽  
Media Analysis ◽  
Frequency Dependent ◽  
Acoustic Media ◽  
And Inversion

Frequency-dependent spherical-wave reflection coefficient inversion in acoustic media: Theory to practice

Geophysics ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. R425-R435
Author(s):  
Binpeng Yan ◽  
Shangxu Wang ◽  
Yongzhen Ji ◽  
Xingguo Huang ◽  
Nuno V. da Silva
Keyword(s):  
Reflection Coefficient ◽  
Wave Reflection ◽  
Incident Angle ◽  
Spherical Wave ◽  
Frequency Dependent ◽  
Amplitude Variation With Offset ◽  
Reflection Data ◽  
Alternative Approach ◽  
Acoustic Media ◽  
The Time Domain

As an approximation of the spherical-wave reflection coefficient (SRC), the plane-wave reflection coefficient does not fully describe the reflection phenomenon of a seismic wave generated by a point source. The applications of SRC to improve analyses of seismic data have also been studied. However, most of the studies focus on the time-domain SRC and its benefit to using the long-offset information instead of the dependency of SRC on frequency. Consequently, we have investigated and accounted for the frequency-dependent spherical-wave reflection coefficient (FSRC) and analyzed the feasibility of this type of inversion. Our inversion strategy requires a single incident angle using reflection data for inverting the density and velocity ratios, which is distinctly different from conventional inversion methods using amplitude variation with offset. Hence, this investigation provides an alternative approach for estimating media properties in some contexts, especially when the range of aperture of the reflection angles is limited. We apply the FSRC theory to the inversion of noisy synthetic and field data using a heuristic algorithm. The multirealization results of the inversion strategy are consistent with the feasibility analysis and demonstrate the potential of the outlined method for practical application.

Influence of frequency-dependent spherical-wave effect on low-frequency seismic exploration: An example of AVA analysis

2017 ◽  
Author(s):  
Jingnan Li ◽  
Xinchao Yang ◽  
Shangxu Wang ◽  
Chunhui Dong ◽  
Shuangquan Chen
Keyword(s):  
Spherical Wave ◽  
Low Frequency ◽  
Seismic Exploration ◽  
Wave Effect ◽  
Frequency Dependent

Fast computation of seabed spherical-wave reflection coefficients in geoacoustic inversion

2015 ◽  
Vol 138 (4) ◽  
pp. 2106-2117 ◽  
Author(s):  
Jorge E. Quijano ◽  
Stan E. Dosso ◽  
Jan Dettmer ◽  
Charles W. Holland
Keyword(s):  
Wave Reflection ◽  
Spherical Wave ◽  
Reflection Coefficients ◽  
Fast Computation ◽  
Geoacoustic Inversion

Differential Effects of Isoflurane and Halothane on Aortic Input Impedance Quantified Using a Three-element Windkessel Model

1995 ◽  
Vol 83 (2) ◽  
pp. 361-373. ◽  
Author(s):  
Douglas A. Hettrick ◽  
Paul S. Pagel ◽  
David C. Warltier
Keyword(s):  
Blood Flow ◽  
Input Impedance ◽  
Wave Reflection ◽  
Conscious State ◽  
Left Ventricular ◽  
Arterial System ◽  
Windkessel Model ◽  
Frequency Dependent ◽  
Aortic Input Impedance ◽  
Arterial Wave Reflection

Background Systemic vascular resistance (the ratio of mean aortic pressure [AP] and mean aortic blood flow [AQ]) does not completely describe left ventricular (LV) afterload because of the phasic nature of pressure and blood flow. Aortic input impedance (Zin) is an established experimental description of LV afterload that incorporates the frequency-dependent characteristics and viscoelastic properties of the arterial system. Zin is most often interpreted through an analytical model known as the three-element Windkessel. This investigation examined the effects of isoflurane, halothane, and sodium nitroprusside (SNP) on Zin. Changes in Zin were quantified using three variables derived from the Windkessel: characteristic aortic impedance (Zc), total arterial compliance (C), and total arterial resistance (R). Methods Sixteen experiments were conducted in eight dogs chronically instrumented for measurement of AP, LV pressure, maximum rate of change in left ventricular pressure, subendocardial segment length, and AQ. AP and AQ waveforms were recorded in the conscious state and after 30 min equilibration at 1.25, 1.5, and 1.75 minimum alveolar concentration (MAC) isoflurane and halothane. Zin spectra were obtained by power spectral analysis of AP and AQ waveforms and corrected for the phase responses of the transducers. Zc and R were calculated as the mean of Zin between 2 and 15 Hz and the difference between Zin at zero frequency and Zc, respectively. C was determined using the formula C = (Ad.MAP).[MAQ.(Pes-Ped)]-1, where Ad = diastolic AP area; MAP and MAQ = mean AP and mean AQ, respectively; and Pes and Ped = end-systolic and end-diastolic AP, respectively. Parameters describing the net site and magnitude of arterial wave reflection were also calculated from Zin. Eight additional dogs were studied in the conscious state before and after 15 min equilibration at three equihypotensive infusions of SNP. Results Isoflurane decreased R (3,205 +/- 315 during control to 2,340 +/- 2.19 dyn.s.cm-5 during 1.75 MAC) and increased C(0.55 +/- 0.02 during control to 0.73 +/- 0.06 ml.mmHg-1 during 1.75 MAC) in a dose-related manner. Isoflurane also increased Zc at the highest dose. Halothane increased C and Zc but did not change R. Equihypotensive doses of SNP decreased R and produced marked increases in C without changing Zc. No changes in the net site or the magnitude of arterial wave reflection were observed with isoflurane and halothane, in contrast to the findings with SNP. Conclusions The major difference between the effects of isoflurane and halothane on LV afterload derived from the Windkessel model of Zin was related to R, a property of arteriolar resistance vessels, and not to Zc or C, the mechanical characteristics of the aorta. No changes in arterial wave reflection patterns determined from Zin spectra occurred with isoflurane and halothane. These results indicate that isoflurane and halothane have no effect on frequency-dependent arterial properties.

scholarly journals Reverberation time and audibility in phased geometrical acoustics using plane or spherical wave reflection coefficients

2019 ◽  
Vol 145 (3) ◽  
pp. 1888-1888
Author(s):  
Matthew Boucher ◽  
Monika Rychtarikova ◽  
Lukas Zelem ◽  
Bert Pluymers ◽  
Wim Desmet
Keyword(s):  
Wave Reflection ◽  
Spherical Wave ◽  
Reflection Coefficients ◽  
Reverberation Time ◽  
Geometrical Acoustics

scholarly journals New formulas for spherical wave reflection from an impedance surface

1992 ◽  
Vol 92 (4) ◽  
pp. 2432-2432
Author(s):  
Y. L. Li ◽  
Michael J. White ◽  
M. H. Hwang
Keyword(s):  
Wave Reflection ◽  
Spherical Wave ◽  
Impédance Surface ◽  
Impedance Surface
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