scholarly journals Doppler-Based Flow Rate Sensing in Microfluidic Channels

Sensors ◽  
2014 ◽  
Vol 14 (9) ◽  
pp. 16799-16807 ◽  
Author(s):  
Liron Stern ◽  
Avraham Bakal ◽  
Mor Tzur ◽  
Maya Veinguer ◽  
Noa Mazurski ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Channels

Fundamentals of elasto-inertial particle focusing in curved microfluidic channels

Lab on a Chip ◽  
2016 ◽  
Vol 16 (14) ◽  
pp. 2626-2635 ◽  
Author(s):  
Nan Xiang ◽  
Xinjie Zhang ◽  
Qing Dai ◽  
Jie Cheng ◽  
Ke Chen ◽  
...  
Keyword(s):  
Flow Rate ◽  
Process Model ◽  
Microfluidic Channels ◽  
Inertial Particle ◽  
Particle Focusing ◽  
Stage Process

We experimentally explore the elasto-inertial particle focusing in curved microfluidic channels and propose a six-stage process model illustrating the particle focusing with increasing flow rate.

scholarly journals Precision control of flow rate in microfluidic channels using photoresponsive soft polymer actuators

Lab on a Chip ◽  
2017 ◽  
Vol 17 (11) ◽  
pp. 2013-2021 ◽  
Author(s):  
Colm Delaney ◽  
Peter McCluskey ◽  
Simon Coleman ◽  
Jeffrey Whyte ◽  
Nigel Kent ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Channels ◽  
Precision Control ◽  
Polymer Actuators ◽  
Pid Algorithm ◽  
Control Of Flow ◽  
Soft Polymer

Precision control of flow using photoresponsive hydrogels within fluidic channels was demonstrated by applying a PID algorithm.

scholarly journals On-chip pressure measurements and channel deformation after oil absorption

2020 ◽  
Vol 2 (9) ◽  
Author(s):  
Liam Hunter ◽  
Julia Gala de Pablo ◽  
Ashley C. Stammers ◽  
Neil H. Thomson ◽  
Stephen D. Evans ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Flow Rate ◽  
Young's Modulus ◽  
Pressure Profile ◽  
Mineral Oil ◽  
Microfluidic Channels ◽  
Oil Absorption ◽  
Channel Deformation ◽  
Before And After ◽  
On Chip

Abstract Microfluidic channels moulded from the soft polymer poly(dimethylsiloxane) (PDMS) are widely used as a platform for mimicking biological environments, and can be used for the simulation of fluid filled structures such as blood and lung vessels. The control of pressure and flow rate within these structures is vital to mimic physiological conditions. The flexibility of PDMS leads to pressure-induced deformation under flow, leading to variable flow profiles along a device. Here, we investigate the change in Young’s modulus of microfluidic channels due to infiltration of mineral oil, a PDMS permeable fluid, and how this affects the resulting pressure profile using a novel pressure measurement method. We found a 53% decrease in Young’s modulus of PDMS due to mineral oil absorption over the course of 3 h accounted for lower internal pressure and larger channel deformation compared to fresh PDMS at a given flow rate. Confocal fluorescence microscopy used to image channel profiles before and after the introduction of mineral oil showed a change in pressure-induced deformation after infiltration of the oil. Atomic force microscopy (AFM) nanoindentation was used to measure Young’s modulus of PDMS before ($$2.80 \pm 0.03$$ 2.80 ± 0.03 MPa) and after ($$1.32 \pm 0.04$$ 1.32 ± 0.04 MPa) mineral oil absorption. Raman spectroscopy showed the infiltration of mineral oil into PDMS from channel walls and revealed the diffusion coefficient of mineral oil in PDMS.

Untethered MicroRobot Motion Mechanism with Increased Longitudinal Force

2021 ◽  
pp. 1-12
Author(s):  
Ali Anil Demircali ◽  
Rahmetullah Varol ◽  
Kadir Erkan ◽  
Huseyin Uvet
Keyword(s):  
Flow Rate ◽  
Permanent Magnets ◽  
Pyrolytic Graphite ◽  
Longitudinal Force ◽  
High Flow ◽  
Experimental Results ◽  
Microfluidic Channels ◽  
Simulation Studies ◽  
Field Lines

Abstract The importance of an untethered microrobotic platform that can operate on high flow rate microfluidic channels for in-vitro applications is increasing rapidly. This paper presents a method to manipulate a microrobot in a fluidic chip when high flow rates (4 mL/min, 82.304 mm/s) are applied. This method is based on a novel permanent magnet-based diamagnetic levitation configuration. This configuration includes a thin layer of pyrolytic graphite, which is placed just below the microrobot. In this way, microrobot stability and manipulation capability are increased. Also, we aim to increase the longitudinal forces imposed on the microrobot to withstand the drag force proportional to the flow rate. Hence, magnetic field lines are generated more linearly around the microrobot by a different combination of permanent magnets. The proposed magnetic configuration, named “Kerkan configuration,” significantly improves the microrobot's longitudinal forces. In this configuration, two different ring-shaped ferromagnetic magnets are used. One of the magnets has a smaller diameter than the other magnet. A combination of one smaller and one bigger magnet is placed above and below the microrobot. In order to validate the advantages of this configuration, analytical and simulation studies are conducted. Their results are then compared with experimental results. Experimental results are on par with analytical and simulation studies. Kerkan configuration has a lower displacement than the next best configuration at the highest flow rate we applied (relatively 3301 µm, %21.8).

scholarly journals Laser Processing of Quartz for Microfluidic Device Fabrication

2012 ◽  
Vol 445 ◽  
pp. 436-441 ◽  
Author(s):  
A. Ben Azouz ◽  
M. Vázquez ◽  
Brett Paull ◽  
Dermot Brabazon
Keyword(s):  
Flow Rate ◽  
Flat Glass ◽  
Chemical Separation ◽  
Device Fabrication ◽  
Microfluidic Channels ◽  
Pressure Sensitive Adhesive ◽  
Average Width ◽  
Detection Systems ◽  
Wide Range ◽  
Quartz Substrates

This paper presents a fast fabrication process of microfluidic channels with quartz substrates. Microchannels were ablated on the surface of quartz samples with a CO2laser. Double sided Pressure Sensitive Adhesive (PSA) was applied to bond the samples with scribed microchannels to flat glass sheets. Dimensions of the fabricated channels were characterised with optical microscopy and laser profilometry. The recorded data was modelled with a BoxBehnken experiment design using Response Surface Methodology. Characterisation included also the measurement of optical transmission through the processed glass and measurement of flow rate through the fabricated channels. With an average width of 165 µm and depth of 280µm, fabricated channels had appropriate dimensions for a range of microfluidic applications. A significant width of the laser processed channels provided 100% transmission for a wide range of the optical spectrum. These fabricated channels were also shown to not significantly retard the fluid flow rate thus making these channels applicable for integration into numerous detection systems for chemical separation applications.

Numerical Simulation and Optimization of Electric Field-Based Sorting in Particle Laden Flows in Microchannels

2018 ◽  
Author(s):  
Ashkan Davanlou ◽  
Venkateswara Reddy
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Electric Potential ◽  
Separation Efficiency ◽  
Solid Particles ◽  
Microfluidic Channels ◽  
Simulation And Optimization ◽  
Particle Sorting ◽  
Proposed Model

Advances in nanotechnology allows for electrodeposition and fabrication of micro/nano electrodes between substrates of microfluidic channels which later can be used as electrodes to apply DC or AC voltage. Microchannels taking advantage of this technology have shown promising results in flow cytometry [1,2], and cell sorting applications [3–6]. In this paper, first we study the influence of electric potential on particle sorting in a microchannel. For this purpose, a two dimensional computational fluid dynamics (CFD) model is created, meshed and solved in STAR-CCM+ which is a commercial simulation tool. Two type of spherical solid particles with different diameter are introduced through an injector from particulate flow inlet. These solid particles are treated as Lagrangian phase. The simulations are conducted in transient mode and the particle injection is occurred once the flow regime became steady state. The proposed model is based on finite volume approach and confirms the effectiveness of dielectrophoresis on particle sorting. In the second part of this work, we focus on optimizing the separation efficiency of microchannel by implementing Siemens exclusive automated design exploration technology named SHERPA. Through this hybrid and adaptive strategy we investigate 4 key parameters including electric potential, flow velocity at two inlets, and particle mass flow rate. The objective is to minimize the electric potential while maximize the efficiency of device, measured by amount of particles separated at the outlet. In total 40 designs are evaluated. The results show that by adjusting the flow rate ratio between inlets, and applying a low voltage such as 5 V, you can increase the mass flow rate of segregated particles by approximately 100 times. The proposed model not only can help shortening the time to market for new dielectrophoresis based channels, but also be used to optimize the overall device performance to achieve the best separation efficiency at optimal condition.

Preparation of Monodisperse PEG Microspheres by a T-Junction Microfluidic Chip

2012 ◽  
Vol 465 ◽  
pp. 178-181 ◽  
Author(s):  
Yu Min Ren ◽  
Bing Yu ◽  
Hai Lin Cong ◽  
Yu Rong Ma ◽  
Zhen Zhen Ma ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Flow Rate ◽  
Microfluidic Chip ◽  
Uv Exposure ◽  
Microfluidic Channels ◽  
Microfluidic Chips ◽  
Silicon Oil ◽  
Sample Flow Rate ◽  
Rate Ratios

Monodisperse polyethylene glycol (PEG) microspheres were prepared using microfluidic chips coupled with photopolymerization technique. Based on sheath effect in T-junction microfluidic channels, dispersions of uniform PEG prepolymer droplets in silicon oil are formed. The diameters of the formed PEG prepolymer droplets in the dispersions were controlled very well by altering the relative sheath/sample flow rate ratios. After photopolymerization under UV exposure, the uniform PEG prepolymer droplets isolated by silicon oil underwent photocrosslinking and became monodisperse PEG microspheres.

Particle Separation in Microfluidic Channels Using Flow Rate Control

2004 ◽  
Author(s):  
Sung Yang ◽  
Jeffrey D. Zahn
Keyword(s):  
Flow Rate ◽  
Flow Resistance ◽  
Melanoma Cells ◽  
Microfluidic Channels ◽  
Cell Recovery ◽  
Fluorescent Particles ◽  
Green Fluorescent ◽  
Rate Ratios ◽  
Pdms Replica ◽  
Flow Rate Control

Microfluidic devices for particle recovery are successfully developed by controlling flow rate ratios of two daughter channels. Devices are prepared by using conventional Polydimethylsiloxane (PDMS) replica molding technique. The flow rate ratios of two daughter channels are controlled by changing the flow resistance through changing the geometry of the downstream channels. The particle recovery studies are conducted using 16 μm-diameter green fluorescent particles and using 8–10 μm-diameter human C8161 melanoma cells. For the fluorescent particles, the particle recovery efficiencies are 87.2%, 95.7%, 100%, and 100% for 2.5:1, 4:1, 6:1, and 8:1 flow rate ratios, respectively. Also, for the human C8161 melanoma cells, the cell recovery efficiencies are 88.7%, 98.9%, 100%, and 100% for 2.5:1, 4:1, 6:1, and 8:1 flow rate ratios, respectively.

Masked and Unmasked Machining of Glass by Micro Abrasive Jet

2009 ◽  
Vol 69-70 ◽  
pp. 182-186 ◽  
Author(s):  
Y.F. Qiu ◽  
Cheng Yong Wang ◽  
J. Wang ◽  
Yue Xian Song
Keyword(s):  
Mass Flow Rate ◽  
Flow Rate ◽  
Glass Substrate ◽  
Erosion Rate ◽  
Scanning Speed ◽  
Microfluidic Channels ◽  
Machining Parameters ◽  
Micro Structure ◽  
Optimum Parameters ◽  
Abrasive Jet Machining

The micro abrasive jet machining is used to make the microfluidic channels on the glass substrate. Based on the tests with or without masks, the structure profile and erosion rate with different basic machining parameters, such as nozzle standoff distance, scanning speed, abrasive mass flow rate etc. are investigated. The optimum parameters for micro-structure machining of glass is discussed. The effect of the secondary rebounding particles in mask underetching was analyzed using oblique machining. And the flux effect was also studied comparing with the unmasked machining.

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