Quantification of lung surface wave speed in a water-filled lung: An ex vivo swine lung study

2019 ◽  
Vol 146 (4) ◽  
pp. 3070-3070
Author(s):  
Xiaoming Zhang ◽  
Boran Zhou ◽  
Alex X. Zhang
Keyword(s):  
Surface Wave ◽  
Wave Speed ◽  
Ex Vivo

scholarly journals A Pilot Study of Wet Lung Using Lung Ultrasound Surface Wave Elastography in an Ex Vivo Swine Lung Model

2019 ◽  
Vol 9 (18) ◽  
pp. 3923 ◽  
Author(s):  
Xiaoming Zhang ◽  
Boran Zhou ◽  
Alex X. Zhang
Keyword(s):  
Surface Wave ◽  
Pilot Study ◽  
Wave Speed ◽  
Lung Ultrasound ◽  
Ex Vivo ◽  
Lung Model ◽  
Water Volume ◽  
Lung Water ◽  
Wave Speeds ◽  
Lung Sample

Extravascular lung water (EVLW) is a basic symptom of congestive heart failure and other conditions. Computed tomography (CT) is standard method used to assess EVLW, but it requires ionizing radiation and radiology facilities. Lung ultrasound reverberation artifacts called B-lines have been used to assess EVLW. However, analysis of B-line artifacts depends on expert interpretation and is subjective. Lung ultrasound surface wave elastography (LUSWE) was developed to measure lung surface wave speed. This pilot study aimed at measureing lung surface wave speed due to lung water in an ex vivo swine lung model. The surface wave speeds of a fresh ex vivo swine lung were measured at 100 Hz, 200 Hz, 300 Hz, and 400 Hz. An amount of water was then filled into the lung through its trachea. Ultrasound imaging was used to guide the water filling until significant changes were visible on the imaging. The lung surface wave speeds were measured again. It was found that the lung surface wave speed increases with frequency and decreases with water volume. These findings are confirmed by experimental results on an additional ex vivo swine lung sample.

The Piezoelectric and Piezomagnetic Effects on the Surface Wave Speed

2012 ◽  
Vol 268-270 ◽  
pp. 1619-1622 ◽  
Author(s):  
Li Li ◽  
Yi Wen Wei ◽  
P.J. Wei
Keyword(s):  
Surface Wave ◽  
Half Space ◽  
Wave Speed ◽  
Open Circuit ◽  
Numerical Examples ◽  
Piezomagnetic Effects

the piezoelectric and piezomagnetic effects and the influence of short and open circuit on the surface wave speed are investigated in this paper. First, the elastic, piezoelectric and piezomagnetic coefficients in the considered ordinate system are obtained by Bonde transformation from that in the crystal axes ordinate system. Then, the equation which surface wave speed satisfies is derived from the free traction condition on the surface of piezoelectric and piezomagnetic half space with consideration of short and open circuit case. Some numerical examples are given and the piezoelectric and piezomagnetic effects and the influence of short and open circuit on the surface wave speed are shown graphically.

Steady State Motion and Surface Waves

1996 ◽  
Author(s):  
T. T. C. Ting
Keyword(s):  
Steady State ◽  
Surface Wave ◽  
Surface Waves ◽  
Existence And Uniqueness ◽  
Wave Speed ◽  
Wave Theory ◽  
Two Dimensional ◽  
Elastic Materials ◽  
Steady State Motion ◽  
Anisotropic Elastic

The Stroh formalism for two-dimensional elastostatics can be extended to elastodynamics when the problem is a steady state motion. Most of the identities in Chapters 6 and 7 remain applicable. The Barnett-Lothe tensors S, H, L now depend on the speed υ of the steady state motion. However S(υ), H(υ), L(υ) are no longer tensors because they do not obey the laws of tensor transformation when υ≠0. Depending on the problems the speed υ may not be prescribed arbitrarily. This is particularly the case for surface waves in a half-space where υ is the surface wave speed. The problem of the existence and uniqueness of a surface wave speed in anisotropic materials is the crux of surface wave theory. It is a subject that has been extensively studied since the pioneer work of Stroh (1962). Excellent expositions on surface waves for anisotropic elastic materials have been given by Farnell (1970), Chadwick and Smith (1977), Barnett and Lothe (1985), and more recently, by Chadwick (1989d).

Direct inversion of 3-D shear wave speed azimuthal and radial anisotropy from surface-wave traveltime data: methodology and applications

2020 ◽  
Author(s):  
Yao Huajian ◽  
Liu Chuanming ◽  
Hu Shaoqian
Keyword(s):  
Surface Wave ◽  
Shear Wave ◽  
Wave Speed ◽  
Joint Inversion ◽  
Azimuthal Anisotropy ◽  
Crust And Upper Mantle ◽  
Shear Wave Speed ◽  
Dispersion Data ◽  
Radial Anisotropy ◽  
Deformation Patterns

<p>Seismic anisotropy plays a key role in understanding deformation patterns of Earth’s material.  Surface wave dispersion data have been widely used to invert for azimuthal and radial anisotropy of shear wave speeds in the crust and upper mantle typically based on a 1-D pointwise inversion scheme. Here we present new methods of inverting for 3-D shear wave speed azimuthal and radial anisotropy directly from surface-wave traveltime data with the consideration of period-dependent surface wave raytracing. For the inversion of 3-D azimuthal anisotropy, our new method includes two steps: (1) inversion for the 3-D isotropic Vsv model directly from Rayleigh wave traveltime data (DSurfTomo; Fang et al., 2015, GJI); (2) joint inversion for both 3-D Vsv azimuthal anisotropy and additional 3-D isotropic Vsv perturbation. The joint inversion can significantly mitigatethe trade-off between the strong heterogeneity and azimuthal anisotropy. We apply the new method (DAzimSurfTomo) (Liu et al., 2019, JGR)to a regional array in Yunnan, southwestern China using the Rayleigh-wave phase velocity dispersion data in the period band of 5-40 s extracted from ambient noise interferometry. The obtained 3-D model of shear wave speed and azimuthal anisotropy indicates differentdeformation styles between the crust and upper mantle insouthern Yunnan. For the inversion of 3-D radial anisotropy, we presented a new inversion matrix that directly inverts Rayleigh and Love wave traveltime data jointly for 3-D Vsv and radial anisotropy parameters (Vsh/Vsv) simultaneously without intermediate steps (Hu et al., submitted to JGR).  The new approach allows for adding the smoothing or model regularization terms directly on the radial anisotropy parameters, which helps to obtain more reliable radial anisotropy structures compared to the previous division approach (Vsh/Vsv) from separate inversion of Vsv and Vsh structures. We apply this new approach (DRadiSurfTomo) to the region around the eastern Himalayan syntaxis using ambient noise dispersion data (5-40s). The obtained 3-D Vs and radial anisotropy models reveals complex distribution of crustal low velocity zones and spatial variation of deformation patterns around the eastern syntaxis region.</p>

scholarly journals An ex vivo technique for quantifying mouse lung injury using ultrasound surface wave elastography

2020 ◽  
Vol 98 ◽  
pp. 109468 ◽  
Author(s):  
Boran Zhou ◽  
Kyle J. Schaefbauer ◽  
Ashley M. Egan ◽  
Eva M. Carmona Porquera ◽  
Andrew H. Limper ◽  
...  
Keyword(s):  
Surface Wave ◽  
Lung Injury ◽  
Ex Vivo ◽  
Mouse Lung

Shear Wave Speeds Track Axial Stress in Porcine Collateral Ligaments

2019 ◽  
Author(s):  
Jonathon Blank ◽  
Darryl Thelen ◽  
Joshua Roth
Keyword(s):  
Shear Wave ◽  
Wave Speed ◽  
Ex Vivo ◽  
Axial Stress ◽  
Axial Loading ◽  
Orthopedic Procedures ◽  
Stress Distributions ◽  
Collateral Ligaments ◽  
Wave Speeds ◽  
Shear Wave Speed

Ligament tension is an important factor that can affect the success of total knee arthroplasty (TKA) procedures. However, surgeons currently lack objective approaches for assessing tension in a particular ligament intraoperatively. The purpose of this study was to investigate the use of noninvasive shear wave tensiometry to characterize stress in medial and lateral collateral ligaments (MCLs and LCLs) ex vivo. Nine porcine MCL and LCL specimens were subjected to cyclic axial loading while wave speeds were measured using laser vibrometry. We found that squared shear wave speed increased linearly with stress in both the MCL (r2avg = 0.94) and LCL (r2avg = 0.98). Wave speeds were slightly lower in the MCL than the LCL when subjected to comparable axial stress (p < 0.001). Ligament-specific wave speeds may arise from differences in geometry and stress distributions between ligaments. These observations suggest it may be feasible to use noninvasive shear wave speed measures as a proxy of ligament loading during orthopedic procedures such as TKA.

scholarly journals Accurate Sparse Recovery of Rayleigh Wave Characteristics Using Fast Analysis of Wave Speed (FAWS) Algorithm for Soft Soil Layers

2018 ◽  
Vol 8 (7) ◽  
pp. 1204
Author(s):  
Zhuoshi Chen ◽  
Baofeng Jiang ◽  
Jingjing Song ◽  
Wentao Wang
Keyword(s):  
Surface Wave ◽  
Phase Velocity ◽  
Dispersion Curve ◽  
Wave Speed ◽  
Soft Soil ◽  
Wave Dispersion ◽  
Surface Wave Dispersion ◽  
Fast Analysis ◽  
Soil Layers ◽  
Norm Minimization

This paper presents a novel fast analysis of wave speed (FAWS) algorithm from the waveforms recorded by a random-spaced geophone array based on a compressive sensing (CS) platform. Rayleigh-type seismic surface wave testing is excited by a hammer source and conducted to develop the phase velocity characteristics of the subsoil layers in Shenyang Metro line 9. Data are filtered by a bandpass filter bank to pursue the dispersive profiles of phase velocity at various frequencies. The Rayleigh-type surface-wave dispersion curve for the soil layers at each frequency is conducted by the ℓ1-norm minimization algorithm of CS theory. The traditional frequency-wavenumber transform technique and in-site downhole observation are employed as the comparison of the proposed technique. The experimental results indicate the proposed FAWS algorithm has a good agreement with both the results of conventional even-spaced geophone array and the in-site measurements, which provides an effective and efficient way for accurate non-destructive evaluation of the surface wave dispersion curve of the soil.

Propagation of Rayleigh waves in an incompressible rotating orthotropic elastic solid half-space with impedance boundary conditions

2017 ◽  
Vol 26 (3-4) ◽  
pp. 73-78 ◽  
Author(s):  
Baljeet Singh ◽  
Baljinder Kaur
Keyword(s):  
Surface Wave ◽  
Boundary Conditions ◽  
Half Space ◽  
Wave Speed ◽  
Secular Equation ◽  
Tangential Displacement ◽  
Rayleigh Surface Wave ◽  
Impedance Boundary ◽  
Impedance Boundary Conditions ◽  
Dimensional Wave

AbstractIn this paper, the governing equations of an incompressible rotating orthotropic elastic medium are formulated and are solved to obtain Rayleigh surface wave solutions in a particular half-space. The surface of half-space is subjected to impedance boundary conditions, in which normal and tangential stresses are proportional to frequency times normal and tangential displacement components, respectively. A secular equation for Rayleigh surface wave is obtained. With the help of MATLAB, the secular equation is solved numerically to obtain non-dimensional wave speed. The dependence of non-dimensional wave speed on non-dimensional material constant, rotation parameter and impedance parameters is shown graphically.

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