scholarly journals Fundamentals of Inertial Focusing in High Aspect Ratio Curved Microfluidics

2020 ◽  
Author(s):  
Javier Cruz ◽  
Klas Hjort
Keyword(s):  
Aspect Ratio ◽  
Natural Water ◽  
High Aspect Ratio ◽  
Lift Force ◽  
Complex Fluids ◽  
Scaling Law ◽  
Valuable Insight ◽  
High Quality ◽  
Inertial Focusing ◽  
Insight Into

Abstract Microfluidics exploiting the phenomenon of inertial focusing have attracted much attention in the last decade, as they provide the means to facilitate the detection and analysis of rare particles of interest in complex fluids such as blood and natural water. Although many interesting applications have been demonstrated, the systems remain difficult to engineer. A recently presented line of the technology, inertial focusing in High Aspect Ration Curved (HARC) microfluidics, has the potential to change this and make the benefits of inertial focusing more accessible to the community. In this paper, with experimental evidence and fluid simulations, we provide the two necessary equations to design the systems and successfully focus the desired targets in a single, stable, and high-quality position. Last, the experiments revealed an interesting scaling law of the lift force, which we believe provides a valuable insight into the phenomenon of inertial microfluidics.

scholarly journals The upper limit and lift force within inertial focusing in high aspect ratio curved microfluidics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Javier Cruz ◽  
Klas Hjort
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Lift Force ◽  
Complex Fluids ◽  
Scaling Law ◽  
Valuable Insight ◽  
High Quality ◽  
Inertial Focusing ◽  
Upper Limit ◽  
Insight Into

AbstractMicrofluidics exploiting the phenomenon of inertial focusing have attracted much attention in the last decade as they provide the means to facilitate the detection and analysis of rare particles of interest in complex fluids such as blood and natural water. Although many interesting applications have been demonstrated, the systems remain difficult to engineer. A recently presented line of the technology, inertial focusing in High Aspect Ratio Curved microfluidics, has the potential to change this and make the benefits of inertial focusing more accessible to the community. In this paper, with experimental evidence and fluid simulations, we provide the two necessary equations to design the systems and successfully focus the targets in a single, stable, and high-quality position. The experiments also revealed an interesting scaling law of the lift force, which we believe provides a valuable insight into the phenomenon of inertial focusing.

scholarly journals High-resolution particle separation by inertial focusing in high aspect ratio curved microfluidics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Javier Cruz ◽  
Klas Hjort
Keyword(s):  
High Resolution ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Biological Fluids ◽  
Essential Feature ◽  
Particle Separation ◽  
Size Difference ◽  
Inertial Focusing ◽  
Complex Samples ◽  
Wide Range

AbstractThe ability to focus, separate and concentrate specific targets in a fluid is essential for the analysis of complex samples such as biological fluids, where a myriad of different particles may be present. Inertial focusing is a very promising technology for such tasks, and specially a recently presented variant, inertial focusing in High Aspect Ratio Curved systems (HARC systems), where the systems are easily engineered and focus the targets together in a stable position over a wide range of particle sizes and flow rates. However, although convenient for laser interrogation and concentration, by focusing all particles together, HARC systems lose an essential feature of inertial focusing: the possibility of particle separation by size. Within this work, we report that HARC systems not only do have the capacity to separate particles but can do so with extremely high resolution, which we demonstrate for particles with a size difference down to 80 nm. In addition to the concept for particle separation, a model considering the main flow, the secondary flow and a simplified expression for the lift force in HARC microchannels was developed and proven accurate for the prediction of the performance of the systems. The concept was also demonstrated experimentally with three different sub-micron particles (0.79, 0.92 and 1.0 µm in diameter) in silicon-glass microchannels, where the resolution in the separation could be modulated by the radius of the channel. With the capacity to focus sub-micron particles and to separate them with high resolution, we believe that inertial focusing in HARC systems is a technology with the potential to facilitate the analysis of complex fluid samples containing bioparticles like bacteria, viruses or eukaryotic organelles.

High aspect ratio, high-quality microholes in PMMA: a comparison between femtosecond laser drilling in air and in vacuum

2014 ◽  
Vol 119 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Bo Xia ◽  
Lan Jiang ◽  
Xiaowei Li ◽  
Xueliang Yan ◽  
Weiwei Zhao ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Femtosecond Laser ◽  
High Aspect Ratio ◽  
Laser Drilling ◽  
High Quality

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 $Re$.

The global elements of vital signs' assessment: a guide for clinical practice

2021 ◽  
Vol 30 (16) ◽  
pp. 956-962
Author(s):  
Malcolm Elliott
Keyword(s):  
Clinical Practice ◽  
Outcomes Research ◽  
Quality Care ◽  
Vital Signs ◽  
Clinical Judgement ◽  
Evidence Based ◽  
Valuable Insight ◽  
High Quality ◽  
Culture Tradition ◽  
Insight Into

The assessment of vital signs is critical for safe, high-quality care. Vital signs' data provide valuable insight into the patient's condition, including how they are responding to medical treatment and, importantly, whether the patient is deteriorating. Although abnormal vital signs have been associated with poor clinical outcomes, research has consistently found that vital signs' assessment is often neglected in clinical practice. Factors contributing to this include nurses' knowledge, clinical judgement, culture, tradition and workloads. To emphasise the importance of vital signs' assessment, global elements of vital signs' assessment are proposed. The elements reflect key principles underpinning vital signs' assessment and are informed by evidence-based literature.

scholarly journals Designing Model Systems for Enhanced Adhesion

MRS Bulletin ◽  
2007 ◽  
Vol 32 (6) ◽  
pp. 496-503 ◽  
Author(s):  
Edwin P. Chan ◽  
Christian Greiner ◽  
Eduard Arzt ◽  
Alfred J. Crosby
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Model Systems ◽  
Adhesion Forces ◽  
Synthetic Analogues ◽  
Jumping Spiders ◽  
Topographic Features ◽  
Considerable Research ◽  
Insight Into ◽  
Primary Strategy

AbstractNature provides inspiration for enhanced control of adhesion through numerous examples ranging from geckos to jumping spiders. The primary strategy in these examples is the incorporation of patterns, specifically high-aspect-ratio topographic features, to ingeniously maximize adhesion forces while maintaining ease of release. Recently, considerable research efforts have been devoted toward the understanding, development, and optimization of synthetic analogues to these examples in nature. In this article, we provide insight into the mechanisms that lead to enhanced control of interfacial properties through patterning, the strategies that can be used for fabricating synthetic patterns, and an overview of experimental results that have been used to gain understanding and guidance in this emerging field.

Growth of High-Quality, Thickness-Reduced Zeolite Membranes towards N2 /CH4 Separation Using High-Aspect-Ratio Seeds

2015 ◽  
Vol 54 (37) ◽  
pp. 10843-10847 ◽  
Author(s):  
Yi Huang ◽  
Lei Wang ◽  
Zhuonan Song ◽  
Shiguang Li ◽  
Miao Yu
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Quality ◽  
Zeolite Membranes

Experimental Investigation of the Evaporation and Stability of a Meniscus in a Flat Microchannel

2011 ◽  
Vol 312-315 ◽  
pp. 1178-1183
Author(s):  
Souad Harmand ◽  
Khellil Sefiane ◽  
Rachid Bennacer ◽  
Nicolas Lancial
Keyword(s):  
Experimental Investigation ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Speed ◽  
Evaporation Rate ◽  
Liquid Meniscus ◽  
Line Region ◽  
Three Phase ◽  
Increasing Temperature ◽  
Insight Into

We present the results of an experimental investigation of the evaporation of a liquid meniscus in a high aspect ratio micro-channel. The study investigates evaporation rates of a stationary liquid meniscus in a high aspect ratio microchannel, the wall of which is electrically heated using transparent resistive coating. Four different liquids are used as working fluids. We report on the dependence of the measured overall evaporation rate on the applied power. The results indicate, and consistently, that the evaporation rate increases with the applied power then peaks before declining. In order to gain insight into these results, we used thermographic infra red imaging to map the temperature field on the external wall of the microchannel. The measurements show that there is a good correlation between the maximum in the evaporative rate and the onset of instabilities of the interface. These instabilities, to our mind, are induced by an increasing temperature gradient along the microchannel wall around the three phase contact line region. These instabilities are revealed by a high speed camera used to record the behaviour of the interface during evaporation.

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