Numerical Study on the Influence of Microchannel’s Geometry on Sub-Micron Particles Separation Using Acoustophoresis

2020 ◽  
Author(s):  
Tsz Wai Lai ◽  
Sau Chung Fu ◽  
Ka Chung Chan ◽  
Christopher Yu Hang Chao ◽  
Anthony Kwok Yung Law
Keyword(s):  
Acoustic Radiation ◽  
Numerical Study ◽  
Acoustic Streaming ◽  
Particle Separation ◽  
Radiation Force ◽  
Rectangular Microchannel ◽  
Cross Sectional ◽  
Fluid Medium ◽  
Particle Sorting ◽  
Micron Particle

Abstract Application of acoustophoresis to cell and particle separation in microchannel filled with fluid medium has been drawing increasing attention in many disciplines in the past decades due to its high precision and minimum damage to the matters of interest. Previous studies on particle separation often rely on the size-dependent feature of the acoustic radiation force (ARF), while the acoustic streaming effect (ASE) is a hurdle as the particle size goes down. Sub-micron particles circulate according to the streaming vortices and become inseparable from the particles settled on the pressure node. Instead of suppressing the ASE, this study intends to utilize the combined effect of ARF and ASE on sub-micron particle sorting by altering the microchannel’s cross-sectional shapes. The roles of ARF and ASE on particles with 0.2um and 2um in radius in various cross-sectional shapes are studied numerically. The studied geometries include 1. rectangular, 2. trapezoidal, and 3. triangular. The results show that changing the cross-sectional shapes affects the acoustic field’s magnitude and distribution, the streaming patterns, the magnitude of streaming velocity, and the movement of sub-micron particles. In non-rectangular microchannel, sub-micron particles circulate towards and settle at the center of the streaming vortices. This phenomenon shows the potential to manipulate the streaming-dominant particles, thereby enhancing the acoustophoretic particle sorting performance.

scholarly journals Acoustic radiation force impulse (ARFI) elastography compared with biopsy for evaluating hepatic fibrosis after liver transplantation: a cross-sectional diagnostic study

2016 ◽  
Vol 134 (6) ◽  
pp. 513-518 ◽  
Author(s):  
Joel Schmillevitch ◽  
◽  
Maria Cristina Chammas ◽  
Vincenzo Pugliese ◽  
Edson Abdala ◽  
...  
Keyword(s):  
Liver Transplantation ◽  
Hepatitis C ◽  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse ◽  
Diagnostic Study ◽  
Cross Sectional ◽  
Significant Difference ◽  
Arfi Elastography

ABSTRACT CONTEXT AND OBJECTIVE: Biopsies are used after liver transplantation to evaluate fibrosis. This study aimed to evaluate the elasticity of transplanted livers by means of a non-invasive examination, acoustic radiation force imaging (ARFI) elastography, correlating the results with the histological analysis. DESIGN AND SETTING: Cross-sectional study in a public university hospital. METHODS: All patients consecutively operated between 2002 and 2010 with an indication for biopsy were evaluated by means of elastography. The radiologist evaluating ARFI and the pathologist doing anatomopathological examinations were blinded to each other's evaluations. RESULTS: During the study period, 33 patients were included. The indication for transplantation was cirrhosis due to hepatitis C in 21 cases (63%). Liver biopsies showed absence of fibrosis (F0) in 10 patients, F1 in 11, F2 in 8 and F3 in 4. There were no cases of F4 (cirrhosis). The difference in ARFI values (degree of fibrosis) was 0.26 (95% confidence interval, CI: 0.07-0.52) between the groups F0-F1 and F2-F4 (P = 0.04). An area under the curve of 0.74 (CI: 0.55-0.94) and a cutoff of 1.29 m/s between the groups resulted in the best relationship between sensitivity and specificity. Sensitivity (0.66; CI: 0.50-0.83) was lower than specificity (0.85; CI: 0.72-0.97). There was no significant difference in ARFI between patients with hepatitis C and those with other diseases. CONCLUSIONS: The values obtained from elastography were not affected by inflammatory reaction or anatomical alterations. A cutoff point of 1.29 m/s separating patients with or without significant fibrosis was identified.

Performance and Robustness Improvements in Ultrasonic Transportation Against Large-Scale Streaming

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Kun Jia ◽  
Ke-ji Yang ◽  
Bing-Feng Ju
Keyword(s):  
Elastic Constant ◽  
Lead Zirconate Titanate ◽  
Large Scale ◽  
Acoustic Radiation ◽  
Plane Waves ◽  
Acoustic Streaming ◽  
Sound Field ◽  
Radiation Force ◽  
Lead Zirconate ◽  
Potential Well

Acoustic streaming generated from the traveling-wave component of a synthesized sound field often has considerable influence on ultrasonic manipulations, in which the behavior of microparticles may be disturbed. In this work, the large-scale streaming pattern in a chamber with three incident plane waves is simulated, illustrating a directional traveling stream pattern and several vortical structures. Based on the numerical results, the trapping capability of an acoustic potential well is quantitatively characterized according to several evaluation criteria: the boundary and elastic constant of the acoustic potential well, the acoustic radiation force offset ratio, and the elastic constant offset ratio. By optimizing these parameters, the constraint of the acoustic potential well can be strengthened to promote the performance and robustness of the ultrasonic transportation. An ultrasonic manipulation device employing three 1.67-MHz lead zirconate titanate (PZT) transducers with rectangular radiation surface is prototyped and performance tested. The experimental results show that the average fluctuations of a microparticle during transportation have been suppressed into a region less than 0.01 times the wavelength. Particle displacement from equilibrium is no longer observed.

ULTRASONIC CONCENTRATION AND TRAPPING OF MICROSIZED PARTICLES IN A FLUID SUSPENSION

2012 ◽  
Vol 19 ◽  
pp. 196-205
Author(s):  
THEIN MIN HTIKE ◽  
KIAN-MENG LIM
Keyword(s):  
Acoustic Radiation ◽  
Radiation Force ◽  
Acoustic Energy ◽  
Ultrasonic Power ◽  
Fluidic Channel ◽  
Fluid Medium ◽  
Nodal Lines ◽  
Ultrasonic Standing Wave ◽  
Contrast Factor ◽  
Micro Organisms

We present a millimeter scale fluidic channel for concentrating and filtering microsized particles suspended in the fluid medium. The device takes on an h-shape with a narrow inlet and a wide outlet. By setting up an ultrasonic standing wave across the channel width, microparticles with positive acoustic contrast factor are constrained to move along pressure nodal lines within the fluid. The acoustic radiation force acts on the particles in the transverse direction, keeping the particles to the lower part of the outlet. As a result, a suspension with higher particle concentration is formed at the lower part of the outlet, while clean fluid can be extracted at the upper part of the outlet. A series of experimental results were obtained to study the performance of this concentration process for various volume flowrates and ultrasonic power used. For high ultrasonic power, the microparticles were found to be trapped in the fluid channel. A numerical model was also developed to study the strength of the acoustic energy density in the channel and its influence on the performance of the concentrator. This ultrasonic concentrator has potential in biomedical and environmental applications where cells and micro-organisms need to be filtered out from a fluid suspension.

scholarly journals Measurement of the acoustic streaming pattern in a standing surface acoustic wave field

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Sebastian Sachs ◽  
Christian Cierpka ◽  
Jörg König
Keyword(s):  
Wave Field ◽  
Acoustic Waves ◽  
Acoustic Radiation ◽  
Electrical Power ◽  
Surface Acoustic Waves ◽  
Acoustic Streaming ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Radiation Force ◽  
Flow Measurements

The application of standing surface acoustic waves (sSAW) has enabled the development of many flexible and easily scalable concepts for the fractionation of particle solutions in the field of microfluidic lab-ona-chip devices. In this context, the acoustic radiation force (ARF) is often employed for the targeted manipulation of particle trajectories, whereas acoustically induced flows complicate efficient fractionation in many systems [Sehgal and Kirby (2017)]. Therefore, a characterization of the superimposed fluid motion is essential for the design of such devices. The present work focuses on a structural analysis of the acousticallyexcited flow, both in the center and in the outer regions of the standing wave field. For this, experimental flow measurements were conducted using astigmatism particle tracking velocimetry (APTV) [Cierpka et al. (2010)]. Through multiple approaches, we address the specific challenges for reliable velocity measurements in sSAW due to limited optical access, the influence of the ARF on particle motion, and regions of particle depletion caused by multiple pressure nodes along the channel width and height. Variations in frequency, channel geometry, and electrical power allow for conclusions to be drawn on the formation of a complex, three-dimensional vortex structure at the beginning and end of the sSAW.

scholarly journals Diversity of 2D Acoustofluidic Fields in an Ultrasonic Cavity Generated by Multiple Vibration Sources

Micromachines ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 803 ◽  
Author(s):  
Qiang Tang ◽  
Song Zhou ◽  
Liang Huang ◽  
Zhong Chen
Keyword(s):  
Particle Trajectory ◽  
Acoustic Radiation ◽  
Preliminary Investigation ◽  
Acoustic Streaming ◽  
Radiation Force ◽  
Structure Design ◽  
Microfluidic Mixing ◽  
Promising Tool ◽  
Induced Drag ◽  
Novel Method

Two-dimensional acoustofluidic fields in an ultrasonic chamber actuated by segmented ring-shaped vibration sources with different excitation phases are simulated by COMSOL Multiphysics. Diverse acoustic streaming patterns, including aggregation and rotational modes, can be feasibly generated by the excitation of several sessile ultrasonic sources which only vibrate along radial direction. Numerical simulation of particle trajectory driven by acoustic radiation force and streaming-induced drag force also demonstrates that micro-scale particles suspended in the acoustofluidic chamber can be trapped in the velocity potential well of fluid flow or can rotate around the cavity center with the circumferential acoustic streaming field. Preliminary investigation of simple Russian doll- or Matryoshka-type configurations (double-layer vibration sources) provide a novel method of multifarious structure design in future researches on the combination of phononic crystals and acoustic streaming fields. The implementation of multiple segmented ring-shaped vibration sources offers flexibility for the control of acoustic streaming fields in microfluidic devices for various applications. We believe that this kind of acoustofluidic design is expected to be a promising tool for the investigation of rapid microfluidic mixing on a chip and contactless rotational manipulation of biosamples, such as cells or nematodes.

The use of acoustic streaming in sub-micron particle sorting

2021 ◽  
pp. 1-15
Author(s):  
Tsz Wai Lai ◽  
Sau Chung Fu ◽  
Ka Chung Chan ◽  
Christopher Y. H. Chao
Keyword(s):  
Acoustic Streaming ◽  
Particle Sorting ◽  
Micron Particle

Acoustofluidic Simulations: Ultrasound Handling of Liquids and Particles in Microfluidic Systems

2008 ◽  
Author(s):  
Peder Skafte-Pedersen ◽  
Henrik Bruus
Keyword(s):  
Acoustic Radiation ◽  
Acoustic Streaming ◽  
Radiation Force ◽  
Second Order ◽  
Order Effects ◽  
Perturbation Approach ◽  
First Order ◽  
At Resonance ◽  
Liquid Flows ◽  
Second Order Equations

Within the field of lab-on-a-chip systems large efforts are devoted to the development of onchip tools for particle handling and mixing in viscosity-dominated liquid flows on the sub-mm scale. One technology involves ultrasound with frequencies in the MHz range, which leads to wavelengths of the order of 0.1–1 mm suitable for mm-sized microchambers. Due to the nonlinearity of the governing acoustofluidic equations, second-order effects will induce steady forces on fluids and suspended particles through the effects known as acoustic streaming and acoustic radiation force. We extend the basic perturbation approach for treating these effects in systems at resonance in various geometries. The first-order eigenmodes are used as source terms for the time-averaged viscous second-order equations. The theory is applied to explain experimental results on aqueous microbead solutions in silicon-glass microchips.

ACOUSTIC RADIATION FORCE AND TORQUE ON A SOLID ELLIPTIC CYLINDER

2007 ◽  
Vol 15 (03) ◽  
pp. 377-399 ◽  
Author(s):  
SEYYED M. HASHEMINEJAD ◽  
R. SANAEI
Keyword(s):  
Boundary Conditions ◽  
Acoustic Radiation ◽  
Classical Method ◽  
Elliptic Cylinder ◽  
Radiation Force ◽  
Acoustic Radiation Force ◽  
Mathieu Functions ◽  
Steel Cylinder ◽  
Cross Sectional ◽  
Wide Range

Exact expressions for the acoustic radiation torque and force components experienced by elastic cylinders of elliptic cross-section immersed in ideal fluids and placed in a progressive or standing wave field is developed. The classical method of eigen-function expansion and the pertinent boundary conditions are employed to develop analytical expressions in the form of infinite series involving Mathieu and modified Mathieu functions. The complications arising due to the nonorthogonality of angular Mathieu functions corresponding with distinct wave numbers as well as problems associated with the appearance of additional angular dependent terms in the boundary conditions are all avoided in an elegant manner by expansion of the angular Mathieu functions in terms of transcendental functions and subsequent integration, leading to a linear set of independent equations in terms of the unknown scattering coefficients. Numerical calculations of the radiation force and torque function amplitudes are performed in a wide range of frequencies and cross-sectional eccentricities for a stainless steel cylinder submerged in water. Particular attention is paid to assessment of the effects of cross-sectional ellipticity as well as incident field asymmetry on the acoustic radiation force/torque acting on the elliptical cylinder. Limiting case involving an elastic circular or elliptic cylinder in an ideal fluid is considered and fair agreements with well-known solutions are established.

scholarly journals Renal Acoustic Radiation Force Impulse Elastography in Hypertensive Nephroangiosclerosis Patients

2021 ◽  
Vol 11 (22) ◽  
pp. 10612
Author(s):  
Alexandru Caraba ◽  
Andreea Munteanu ◽  
Stela Iurciuc ◽  
Mircea Iurciuc
Keyword(s):  
Acoustic Radiation ◽  
Resistive Index ◽  
Radiation Force ◽  
Cross Sectional Study ◽  
Acoustic Radiation Force ◽  
Acoustic Radiation Force Impulse ◽  
Cross Sectional ◽  
Albumin Creatinine Ratio ◽  
Diagnosis Method ◽  
New Diagnosis

Objective: Hypertensive nephroangiosclerosis (HN) represents the second most common cause of chronic kidney disease. Kidney damage secondary to high blood pressure favors the appearance of serum and urinary changes, but also imaging, highlighted by ultrasonography (B-mode, Doppler, Acoustic Radiation Force Impulse Elastography). Acoustic Radiation Force Impulse Elastography (ARFI) represents a new imagistic method which characterizes renal stiffness in the form of shear wave velocity (SWV). Aim: This study aims to investigate renal stiffness in HN patients, and to assess the correlations between it and urinary albumin/creatinine ratio (UACR), estimated glomerular filtration rate (eGFR), and intrarenal resistive index (RRI). Material and Methods: This cross-sectional study was performed on a group of 80 HN patients and 50 healthy, sex and age-matched, as controls. UACR (urinary immunoturbidimetry), eGFR (Jaffe method), RRI, and renal SWV (Siemens Acuson 2000) were determined in all patients and controls. Data were expressed as mean ± standard deviation. Statistical analysis was done by means Pearson’s test and t-Student test, p values of less than 0.05 were considered statistically significant. Results: UACR, eGFR, RRI and SWV showed statistically significant differences between the HN patients and controls (p < 0.0001). In the hypertensive patients group, statistically significant correlations were observed between the SWV and UACR (r = −0.7633, p < 0.00001), eGFR (r = 0.7822, p = 0.00001), and RRI (r = −0.7978, p = 0.00001). Conclusions: Kidney sonoelastography characterizes imagistically the existence of intrarenal lesions associated with essential hypertension, offering a new diagnosis method for these patients.

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