Time and frequency domain deconvolution for cross-sectional cultured cell observation using an acoustic impedance microscope

Ultrasonics ◽  
2022 ◽  
Vol 119 ◽  
pp. 106601
Author(s):  
Edo Bagus Prastika ◽  
Taichi Shintani ◽  
Tomohiro Kawashima ◽  
Yoshinobu Murakami ◽  
Naohiro Hozumi ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Acoustic Impedance ◽  
Cross Sectional ◽  
Cultured Cell

Acoustic impedance interpretation of cross-sectional human skin by using time and frequency domain deconvolution

2020 ◽  
Vol 59 (SK) ◽  
pp. SKKB06
Author(s):  
Edo Bagus Prastika ◽  
Atsushi Imori ◽  
Tomohiro Kawashima ◽  
Yoshinobu Murakami ◽  
Naohiro Hozumi ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Human Skin ◽  
Acoustic Impedance ◽  
Cross Sectional

Investigation of Effective Bending and Shear Stiffness of Thin-Walled Girders Related to Ship Hull Vibration Analysis

1989 ◽  
Vol 33 (04) ◽  
pp. 298-309
Author(s):  
Ivo Senjanovic ◽  
Ying Fan
Keyword(s):  
Finite Element ◽  
Frequency Domain ◽  
Vibration Analysis ◽  
Ship Hull ◽  
Moment Of Inertia ◽  
Cross Sectional ◽  
Simply Supported ◽  
Thin Walled ◽  
Beam Parameters ◽  
Shear Area

Application of beam theory in flexural vibration analysis of thin-walled girders is extended for the high-frequency domain by introducing the concept of effective values of beam parameters, that is, cross-sectional moment of inertia, shear area, mass, and mass moment of inertia. Formulation of these parameters is based on equivalence of deformation energy and inertia work, respectively, for a considered structure and its beam model, resulting in the same values of their natural frequencies. For illustration, the natural vertical vibration of a simply supported pontoon has been considered, where it was possible to obtain the analytical solution due to sinusoidal mode shapes. The effective values of cross-sectional moment of inertia and shear area show significant variation in frequency domain. Transfer of effective values of beam parameters, determined for simply supported structure, in the case of other boundary conditions is suggested, based on equal mode wavelengths, and checked for the free pontoon. The results show very low discrepancies compared with a three-dimensional finite-element model solution, so this procedure may be applied generally, as well as to the problem of ship hull vibration. In conclusion, the possibility of calculating the values of effective parameters for multicell ship cross sections, utilizing the theory of folded structure and the finite-element method, is pointed out.

scholarly journals Dynamic Response of an Inhomogeneous Viscoelastic Pile in a Multilayered Soil to Transient Axial Loading

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Zhiqing Zhang ◽  
Jian Zhou ◽  
Kuihua Wang ◽  
Qiang Li ◽  
Kaifu Liu
Keyword(s):  
Frequency Domain ◽  
Longitudinal Wave ◽  
Soil Layer ◽  
Axial Loading ◽  
Analytical Form ◽  
Sine Wave ◽  
Function Technique ◽  
Cross Sectional ◽  
Soil System ◽  
Single Defect

A quasi-analytical solution is developed in this paper to investigate the mechanism of one-dimensional longitudinal wave propagating in inhomogeneous viscoelastic pile embedded in layered soil and subjected to a transient axial loading. At first, the pile-soil system is subdivided into several layers along the depth direction in consideration of the variation of cross-sectional acoustic impedance of the pile or differences in soil properties. Then, the dynamic governing equation of arbitrary soil layer is established in cylindrical coordinates and arbitrary viscoelastic pile segment is modeled using a single Voigt model. By using the Laplace transform and boundary conditions of the pile-soil system, the vertical impedance at the top of arbitrary pile segment is defined in a closed form in the frequency domain. Then by utilizing the method of recursion typically used in the Transfer Function technique, the vertical impedance at the pile top can be derived in the frequency domain and the velocity response of an inhomogeneous viscoelastic pile subjected to a semi-sine wave exciting force is obtained in a semi-analytical form in the time domain. Selected numerical results are obtained to study the mechanism of longitudinal wave propagating in a pile with a single defect or double defects.

Design of acoustic foam wedge panels by finite element frequency domain acoustical analysis

2019 ◽  
Vol 55 (3) ◽  
pp. 283-295
Author(s):  
Huoy-Shyi Tsay ◽  
Fung-Huei Yeh
Keyword(s):  
Finite Element ◽  
Numerical Method ◽  
Frequency Domain ◽  
Acoustic Field ◽  
High Frequency ◽  
Sound Absorption ◽  
Wedge Angle ◽  
Cross Sectional ◽  
Calculation Time ◽  
Acoustical Analysis

Acoustic foam wedge panels provide good sound absorption qualities in the mid and high frequency ranges. In this study, a finite element frequency domain acoustical analysis is used for analysis. Such a numerical method is more efficient than the earlier studies by saving the calculation time on the elements of the incident acoustic field. During the design of a wedge panel, the cross-sectional width and the area of one section of the wedge panel are kept the same throughout the study. By varying the wedge angle, the maximum sound absorption capability of the wedge foam can be found. It is concluded that in the interested frequency regions, 100–4000 and 2000–4000 Hz, the wedge foam with wedge angle of 31° has the excellent sound absorption capability.

scholarly journals Heart Rate Variability Analysis in Episodic Migraine: A Cross-Sectional Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Lvming Zhang ◽  
Shi Qiu ◽  
Chunxia Zhao ◽  
Peifu Wang ◽  
Shengyuan Yu
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Frequency Domain ◽  
Time Domain ◽  
Domain Analysis ◽  
Episodic Migraine ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Autonomic Nervous

Objective: It has been reported that autonomic nervous dysfunction is more prevalent in migraineurs. Heart rate variability (HRV) is a commonly used method to evaluate the cardiac autonomic nervous function modulation. However, HRV changes in migraine are still contradictory. The main objective of this study was to explore the potential HRV change patterns in episodic migraine (EM) and whether there were differences in HRV between EM ictal period and the interictal period.Patients and Methods: We conducted a cross-sectional study including 18 patients with EM and 18 age- and sex-matched controls. The characteristics of demographics, some lifestyle factors, and psychological conditions were assessed at baseline. HRVs including time-domain analysis and frequency-domain analysis were performed in all participants. HRV analyses in migraine were recorded not only in the interictal period but also in the ictal period.Results: All the HRV parameters showed a decreased trend in migraine than controls. Time-domain parameters standard deviation of all NN intervals in 24 h (SDNN) and triangular index were significantly lower in the migraine ictal period than controls separately (SDNN, 56.94 ± 22.09 ± 7.76 vs. 135.78 ± 35.16, p < 0.001; triangular index, 12.61 ± 3.20 vs. 22.11 ± 6.90, p < 0.001). Frequency-domain parameter low-frequency power was also lower in the migraine ictal period than controls (351.28 ± 206.71 vs. 559.61 ± 281.24, p = 0.02). SDNN was much lower in the migraine ictal period than migraine interictal period (56.94 ± 22.09 vs. 115.94 ± 46.88, p < 0.001). HRV changes during migraine interictal period did not differ from the control group. The correlation analysis revealed a negative correlation between visual analog scale and HRV parameters in the migraine ictal period (p = 0.04).Conclusions: The present cross-sectional study indicates that HRV was significantly decreased in EM population especially during the migraine ictal period, which means unbalance of autonomic system in EM. Perhaps larger prospective cohort studies are wanted to validate these findings.

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