Volume Oscillation of Microphase-Separated Gel

2012 ◽  
Vol 214 (3) ◽  
pp. 343-349 ◽  
Author(s):  
Shingo Maeda ◽  
Shuji Hashimoto
Keyword(s):  
Volume Oscillation

scholarly journals Lamb-type waves generated by a cylindrical bubble oscillating between two planar elastic walls

2016 ◽  
Vol 472 (2188) ◽  
pp. 20160031 ◽  
Author(s):  
A. A. Doinikov ◽  
F. Mekki-Berrada ◽  
P. Thibault ◽  
P. Marmottant
Keyword(s):  
Resonance Frequency ◽  
Surface Waves ◽  
Wave Speed ◽  
Microfluidic Channel ◽  
Scattered Wave ◽  
Channel Height ◽  
Volume Oscillation ◽  
Scholte Wave ◽  
Rigid Walls ◽  
Elastic Walls

The volume oscillation of a cylindrical bubble in a microfluidic channel with planar elastic walls is studied. Analytical solutions are found for the bulk scattered wave propagating in the fluid gap and the surface waves of Lamb-type propagating at the fluid–solid interfaces. This type of surface wave has not yet been described theoretically. A dispersion equation for the Lamb-type waves is derived, which allows one to evaluate the wave speed for different values of the channel height h . It is shown that for h <λ t , where λ t is the wavelength of the transverse wave in the walls, the speed of the Lamb-type waves decreases with decreasing h , while for h on the order of or greater than λ t , their speed tends to the Scholte wave speed. The solutions for the wave fields in the elastic walls and in the fluid are derived using the Hankel transforms. Numerical simulations are carried out to study the effect of the surface waves on the dynamics of a bubble confined between two elastic walls. It is shown that its resonance frequency can be up to 50% higher than the resonance frequency of a similar bubble confined between two rigid walls.

scholarly journals Volume oscillation and acoustical scattering of a gas bubble

2019 ◽  
Vol 283 ◽  
pp. 06002
Author(s):  
Yan Ma ◽  
Tao Ma ◽  
Feiyan Zhao
Keyword(s):  
Cross Section ◽  
Acoustic Field ◽  
Driving Pressure ◽  
Single Bubble ◽  
Gas Bubble ◽  
Scattering Cross ◽  
Resonance Response ◽  
Linear Resonance ◽  
Volume Oscillation ◽  
Big Bubble

The exact solution of a gas bubble’ volume was obtained based on volume oscillation of a gas bubble. The volume pulsation, acoustic impedance, scattering pressure of a gas bubble, acoustical power of scattering and acoustical scattering cross section of a single bubble are researched in a small amplitude acoustic field. The results show that a big bubble oscillates more violently than that of a small bubble in a weak acoustic field if the linear resonance does not happen. The occurrence of a linear resonance response of a single bubble leads to the volume oscillation and the scattering ability of a gas bubble become stronger. Additionally, the scattering cross section does not depend on the driving pressure. The amplitude of scattering pressure of a big bubble can reach the magnitude compared to the driving pressure when the resonance response occurs.

scholarly journals Phase Velocity of Facial Blood Volume Oscillation at a Frequency of 0.1 Hz

2021 ◽  
Vol 12 ◽  
Author(s):  
Kenichiro Yoshida ◽  
Izumi Nishidate
Keyword(s):  
Blood Flow ◽  
Phase Velocity ◽  
Blood Volume ◽  
Phase Distribution ◽  
Digital Camera ◽  
Imaging Method ◽  
Large Area ◽  
Oscillation Phase ◽  
Mayer Waves ◽  
Volume Oscillation

Facial blood flow, which typically exhibits distinctive oscillation at a frequency of around 0.1 Hz, has been extensively studied. Although this oscillation may include important information about blood flow regulation, its origin remains unknown. The spatial phase distribution of the oscillation is thus desirable. Therefore, we visualized facial blood volume oscillation at a frequency of around 0.1 Hz using a digital camera imaging method with an improved approximation equation, which enabled precise analysis over a large area. We observed a slow spatial movement of the 0.1-Hz oscillation. The oscillation phase was not synchronized, but instead moved slowly. The phase velocity varies with person, measurement location, and time. An average phase velocity of 3.8 mm/s was obtained for several subjects. The results are consistent with previous studies; however, the conventional explanation that the blood flow at a certain point oscillates independently of adjacent areas should be corrected. If the primary origin of the movement is myogenic activity, the movement may ascend along a blood vessel toward the upstream. Otherwise, the oscillation and its propagation can be considered to be related to Mayer waves. By determining the mechanism, some questions regarding Mayer waves can be answered. The direction of the wave (upstream or downstream) provides important information.

520 Measurement of Dynamic Viscoelastic Properties from Volume Oscillation of Gas Bubbles

2001 ◽  
Vol 2001.7 (0) ◽  
pp. 199-200
Author(s):  
Takuya KAMEMIZU ◽  
Fumito KAJITANI ◽  
Mie ICHIHARA ◽  
Masaharu KAMEDA
Keyword(s):  
Viscoelastic Properties ◽  
Gas Bubbles ◽  
Volume Oscillation

scholarly journals Shape Oscillation of Bubble(s) in Acoustic Field

2010 ◽  
Author(s):  
Ichiro Ueno ◽  
Keishi Matsumoto ◽  
Atsumi Machida ◽  
Tsuyoshi Hanyu
Keyword(s):  
Acoustic Wave ◽  
Fundamental Frequency ◽  
High Speed ◽  
Pressure Field ◽  
Capillary Tube ◽  
Gradual Transition ◽  
Distinct Mode ◽  
Shape Oscillation ◽  
Volume Oscillation ◽  
Axisymmetric Shape

We focus on dynamics of multiple air bubbles exposed to acoustic pressure field while ascending in water. The bubbles are injected into the pool filled with water from a vertical capillary tube, and then the acoustic wave of designated frequency is applied toward the bubbles. The frequency of the acoustic wave is varied from 0.5 to 20 kHz. Volume and shape oscillations of the bubbles are captured by a high-speed camera at frame rates up to 40000 fps with a back-lighting system. Through this system, we succeed in capturing the dynamics of the axisymmetric shape oscillation with a distinct mode number; the bubble exhibits the volume oscillation first with a fundamental frequency f0, and then the gradual transition to the shape oscillation with a fundamental frequency fnm takes place. We evaluate the correlation through the careful observations between the f0 and fnm as f0 ∼ 2.1fnm, which brings almost perfectly confirmation of the prediction through the preceding theoretical works. We also indicate the criterion of the excitation of the shape oscillation by varying the frequencies of the adding pressure field.

A Modeling Framework Capable of Characterizing the Dynamics of POGO Oscillations in Space Rocket Turbopumps

2018 ◽  
Author(s):  
A. Pasini ◽  
M. Amoroso
Keyword(s):  
Rocket Engine ◽  
Feeding System ◽  
Experimental Characterization ◽  
Modeling Framework ◽  
Pressure Oscillations ◽  
Space Rocket ◽  
Volume Oscillation ◽  
Liquid Rocket ◽  
The Time Domain

A modeling framework defined in the time-domain has been developed to characterize the steady state and dynamic behavior of each component of a typical feeding system for liquid rocket engine. A typical water loop for experimental characterization of liquid rocket turbopumps has been modeled according to the modeling framework in order to understand which is the best way to perform forced experiments for the characterization of the transfer matrix of cavitating turbopumps necessary for understanding the POGO instability phenomena that affect rocket launchers. The best results in terms of capability of generating mass flow rate and pressure oscillations at the inlet of the inducer have been obtained by means of a device that produces a volume oscillation located downstream of the pump.

Effect of methacholine on low-frequency mechanics of canine airways and lung tissue

1993 ◽  
Vol 75 (1) ◽  
pp. 55-62 ◽  
Author(s):  
J. Sato ◽  
B. Suki ◽  
B. L. Davey ◽  
J. H. Bates
Keyword(s):  
Continuous Distribution ◽  
Low Frequency ◽  
Constant Term ◽  
Ventilation Distribution ◽  
Regional Ventilation ◽  
Ventilation Inhomogeneity ◽  
Tracheal Pressure ◽  
Before And After ◽  
Volume Oscillation ◽  
Uneven Ventilation

We measured tracheal flow, tracheal pressure, and alveolar capsule pressure in four anesthetized paralyzed tracheostomized open-chest dogs. Lung impedance between 0.12 and 4.88 Hz was measured with a forced volume oscillation technique before and after the intravenous administration of methacholine (MCh). Before MCh administration, lung impedance was well described by a model featuring a single airway leading to an alveolar region surrounded by tissue with a continuous distribution of viscoelastic time constants as used by Hantos et al. (J. Appl. Physiol. 68: 849–860, 1990). After MCh, however, this model gave a poor fit to the impedances. The impedances were well accounted for, however, when the model was enhanced to include an extra time constant term, which we suspect is required to account for the uneven ventilation distribution produced by MCh. Airway impedance before MCh administration was well described by a simple resistance-inertance model, but a model incorporating serial inhomogeneity of ventilation was again required after MCh. Our results support those of previous studies indicating that the impedance of the normal dog lung is well described by a homogeneously ventilated viscoelastic tissue model. In contrast, our results after MCh administration show strong evidence of marked regional ventilation inhomogeneity in addition to the rheological properties of the tissues.

Volume Oscillation in Macroporous Gel

2012 ◽  
Vol 41 (11) ◽  
pp. 1526-1528 ◽  
Author(s):  
Shingo Maeda ◽  
Wahei Oda
Keyword(s):  
Volume Oscillation

Investigation of Optimized Homogenization by Ball Mills for Quantitative Chemical Analysis in Sandy Soils

2011 ◽  
Vol 50 (1-2) ◽  
pp. 57-63
Author(s):  
V. Rudovica ◽  
J. Tjutrins ◽  
A. Viksna ◽  
G. Zarina
Keyword(s):  
Chemical Analysis ◽  
Sandy Soils ◽  
Sample Volume ◽  
Quantitative Chemical Analysis ◽  
Ball Mills ◽  
Soil Fraction ◽  
Volume Oscillation ◽  
Precision And Accuracy ◽  
Grinding Time ◽  
Quantitative Chemical

Investigation of Optimized Homogenization by Ball Mills for Quantitative Chemical Analysis in Sandy SoilsThe efficiency of homogenization was studied by examining particle size distribution and element quantification in the sandy soils using the ball mills. The following parameters were optimized - sample volume, oscillation frequency and grinding time. The homogenized soil fraction with ~ 85% of particles with sizes below 40 μm was established to give high precision and accuracy of quantitative analysis of the results.

Estimation of Ventilation Impact on Fluid–Structure Interaction for Partially Cavitating Hydrofoils

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Compressible Flows ◽  
Fluid Structure Interaction ◽  
Cavity Volume ◽  
Bending Vibration ◽  
Fluid Structure ◽  
One Dimensional ◽  
Structure Interaction ◽  
Partial Cavitation ◽  
Volume Oscillation ◽  
Naca 0015

Abstract Fluid–structure interaction is analyzed for natural and ventilated partial cavitation of conventional hydrofoils. Quasi-linear two-dimensional (2D) analysis of ideal fluid incompressible flow outside the cavity is coupled with one-dimensional analysis of compressible flows within the cavity and with analysis of hydrofoil bending vibration under impact of periodical oscillations of hydrodynamic forces. The old experimental data for hydrofoils Clark Y-11.7% and NACA 0015 are used for validation of this coupling. Estimations based on obtained computational results show that the force oscillations can be significantly mitigated by ventilation, whereas the ventilation effect on the cavity volume oscillation is less significant. The presented estimations also show that ventilation can suppress generation of shock waves in the cavity tail and affect their propagation.

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