scholarly journals Direct measurement of particle inertial migration in rectangular microchannels

Lab on a Chip ◽  
2016 ◽  
Vol 16 (15) ◽  
pp. 2840-2850 ◽  
Author(s):  
Kaitlyn Hood ◽  
Soroush Kahkeshani ◽  
Dino Di Carlo ◽  
Marcus Roper
Keyword(s):  
Direct Measurement ◽  
Asymptotic Theory ◽  
Rectangular Microchannels ◽  
Inertial Focusing ◽  
Inertial Migration

We experimentally measured the trajectories of particles undergoing microfluidic inertial focusing, and show that they can be predicted by an asymptotic theory with no unmeasured parameters.

scholarly journals Inertial focusing of finite-size particles in microchannels

2018 ◽  
Vol 840 ◽  
pp. 613-630 ◽  
Author(s):  
Evgeny S. Asmolov ◽  
Alexander L. Dubov ◽  
Tatiana V. Nizkaya ◽  
Jens Harting ◽  
Olga I. Vinogradova
Keyword(s):  
Lattice Boltzmann ◽  
Slip Velocity ◽  
Lift Force ◽  
Finite Size ◽  
Reynolds Numbers ◽  
Velocity Difference ◽  
Inertial Focusing ◽  
Inertial Migration ◽  
Lattice Boltzmann Simulations ◽  
Insight Into

At finite Reynolds numbers, $Re$, particles migrate across laminar flow streamlines to their equilibrium positions in microchannels. This migration is attributed to a lift force, and the balance between this lift and gravity determines the location of particles in channels. Here we demonstrate that velocity of finite-size particles located near a channel wall differs significantly from that of an undisturbed flow, and that their equilibrium position depends on this, referred to as slip velocity, difference. We then present theoretical arguments, which allow us to generalize expressions for a lift force, originally suggested for some limiting cases and $Re\ll 1$, to finite-size particles in a channel flow at $Re\leqslant 20$. Our theoretical model, validated by lattice Boltzmann simulations, provides considerable insight into inertial migration of finite-size particles in a microchannel and suggests some novel microfluidic approaches to separate them by size or density at a moderate $Re$.

Inertial focusing of spherical particles in rectangular microchannels over a wide range of Reynolds numbers

Lab on a Chip ◽  
2015 ◽  
Vol 15 (4) ◽  
pp. 1168-1177 ◽  
Author(s):  
Chao Liu ◽  
Guoqing Hu ◽  
Xingyu Jiang ◽  
Jiashu Sun
Keyword(s):  
Reynolds Numbers ◽  
Spherical Particles ◽  
Rectangular Microchannels ◽  
Inertial Focusing ◽  
Wide Range ◽  
Physical Insight ◽  
Insight Into

This work provides physical insight into the multiplex focusing of particles in rectangular microchannels with different geometries and Reynolds numbers.

scholarly journals Inertial Migration of Neutrally Buoyant Spherical Particles in Square Channels at Moderate and High Reynolds Numbers

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 198
Author(s):  
Yanfeng Gao ◽  
Pascale Magaud ◽  
Lucien Baldas ◽  
Yanping Wang
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Reynolds Numbers ◽  
Spherical Particles ◽  
Particle Volume ◽  
Inertial Focusing ◽  
Inertial Migration ◽  
High Reynolds Numbers ◽  
Micro Channels ◽  
High Reynolds

The inertial migration of particles in microchannel flows has been deeply investigated in the last two decades. In spite of numerous reports on the inertial focusing patterns in a square channel, the particle inertial focusing and longitudinal ordering processes remain unclear at high Reynolds numbers (>200) in square microchannels smaller than 100 µm in width. Thus, in this work, in situ visualization of particles flowing in square micro-channels at Reynolds numbers Re ranging from 5 to 280 has been conducted and their migration behaviors have been analyzed. The obtained results confirm that new equilibrium positions appear above a critical Re depending on the particle to channel size ratio and the particle volume fraction. It is also shown that, for a given channel length, an optimal Reynolds number can be identified, for which the ratio of particles located on equilibrium positions is maximal. Moreover, the longitudinal ordering process, i.e., the formation of trains of particles on equilibrium positions and the characterization of their length, has also been analyzed for the different flow conditions investigated in this study.

scholarly journals Research on the Inertial Migration Characteristics of Bi-Disperse Particles in Channel Flow

2021 ◽  
Vol 11 (19) ◽  
pp. 8800
Author(s):  
Dongmei Chen ◽  
Jianzhong Lin ◽  
Xiao Hu
Keyword(s):  
Engineering Practice ◽  
Inertial Focusing ◽  
Inertial Migration ◽  
Particle Spacing ◽  
Focusing Effect ◽  
Blocking Rate ◽  
Application Potential ◽  
Initial Spacing ◽  
Boltzmann Method ◽  
Final Spacing

The inertial focusing effect of particles in microchannels shows application potential in engineering practice. In order to study the mechanism of inertial migration of particles with different scales, the motion and distribution of two particles in Poiseuille flow are studied by the lattice Boltzmann method. The effects of particle size ratio, Reynolds number, and blocking rate on particle inertial migration are analyzed. The results show that, at a high blocking rate, after the same scale particles are released at the same height of the channel, the spacing between the two particles increases monotonically, and the change in the initial spacing has little effect on the final spacing of inertial migration. For two different size particles, when the smaller particle is downstream, the particle spacing will always increase and cannot remain stable. When the larger particle is downstream, the particle spacing increases firstly and then decreases, and finally tends to be stable.

Direct Measurement of the Listening of Hearing-Impaired Children

1970 ◽  
Vol 13 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Mary Mira
Keyword(s):  
Direct Measurement ◽  
Continuous Measurement ◽  
Hearing Impaired ◽  
Reinforcement System ◽  
School Aged Children ◽  
Conjugate Reinforcement ◽  
Impaired Children ◽  
Hearing Impaired Children

Listening, a significant dimension of the behavior of hearing-impaired children, may be measured directly by recording childrens' responses to obtain audio narrations programmed via a conjugate reinforcement system. Twelve hearing-impaired, school-aged children responded in varying ways to the opportunity to listen. Direct and continuous measurement of listening has relevance for evaluation of remediation methods and for discovery of variables potentially related to listening.

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