scholarly journals Fabrication of a Pneumatic Microparticle Concentrator

Micromachines ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 40
Author(s):  
Jun Ho Jang ◽  
Ok Chan Jeong
Keyword(s):  
Three Dimensional ◽  
Fem Simulation ◽  
Particle Diameter ◽  
Microfluidic Channel ◽  
Solid Particles ◽  
Working Fluid ◽  
Operating Pressure ◽  
Fluidic Channel ◽  
Outlet Port ◽  
Pneumatic Valves

We developed a microfluidic platform employing (normally open) pneumatic valves for particle concentration. The device features a three-dimensional network with a curved fluidic channel and three pneumatic valves (a sieve valve (Vs) that concentrates particles and two ON/OFF rubber-seal pneumatic valves that block the working fluid). Double-sided replication employing polydimethylsiloxane (PDMS) was used to fabricate the network, channel, and chamber. Particles were blocked by deformation of the Vs diaphragm, and then accumulated in the curved microfluidic channel. The working fluid was discharged via operation of the two ON/OFF valves. After concentration, particles were released to an outlet port. The Vs pressure required to block solid particles varying in diameter was determined based on the height of the curved microchannel and a finite element method (FEM) simulation of Vs diaphragm displacement. Our method was verified according to the temporal response of the fluid flow rate controlled by the pneumatic valves. Furthermore, all particles with various diameters were successfully blocked, accumulated, and released. The operating pressure, time required for concentration, and concentration ratio were dependent on the particle diameter. The estimated concentration percentage of 24.9 µm diameter polystyrene particles was about 3.82% for 20 min of operation.

Vortex Simulation for Behavior of Solid Particles Falling in Air

2011 ◽  
Author(s):  
Hisanori Yagami ◽  
Tomomi Uchiyama
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Air Flow ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Vortex Method ◽  
Solid Particles ◽  
Particle Volume ◽  
Two Phase ◽  
Spherical Region

The behavior of small solid particles falling in an unbounded air is simulated. The particles, initially arranged within a spherical region in a quiescent air, are made to fall, and their fall induces the air flow around them, resulting in the gas-particle two-phase flow. The particle diameter and density are 1 mm and 7.7 kg/m3 respectively. A three-dimensional vortex method proposed by one of the authors is applied. The simulation demonstrates that the particles are accelerated by the induced downward air flow just after the commencement of their fall. It also highlights that the particles are whirled up by a vortex ring produced around the downward air flow after the acceleration. The effect of the particle volume fraction at the commencement of the fall is also explored.

scholarly journals Selective Retrieval of Individual Cells from Microfluidic Arrays Combining Dielectrophoretic Force and Directed Hydrodynamic Flow

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 322
Author(s):  
Pierre-Emmanuel Thiriet ◽  
Joern Pezoldt ◽  
Gabriele Gambardella ◽  
Kevin Keim ◽  
Bart Deplancke ◽  
...  
Keyword(s):  
Single Cell ◽  
Single Cells ◽  
Three Dimensional ◽  
Microfluidic Channel ◽  
Microfluidic System ◽  
Transcriptional Analysis ◽  
Molecular Profile ◽  
Cell Phenotype ◽  
Pneumatic Valves ◽  
On Chip

Hydrodynamic-based microfluidic platforms enable single-cell arraying and analysis over time. Despite the advantages of established microfluidic systems, long-term analysis and proliferation of cells selected in such devices require off-chip recovery of cells as well as an investigation of on-chip analysis on cell phenotype, requirements still largely unmet. Here, we introduce a device for single-cell isolation, selective retrieval and off-chip recovery. To this end, singularly addressable three-dimensional electrodes are embedded within a microfluidic channel, allowing the selective release of single cells from their trapping site through application of a negative dielectrophoretic (DEP) force. Selective capture and release are carried out in standard culture medium and cells can be subsequently mitigated towards a recovery well using micro-engineered hybrid SU-8/PDMS pneumatic valves. Importantly, transcriptional analysis of recovered cells revealed only marginal alteration of their molecular profile upon DEP application, underscored by minor transcriptional changes induced upon injection into the microfluidic device. Therefore, the established microfluidic system combining targeted DEP manipulation with downstream hydrodynamic coordination of single cells provides a powerful means to handle and manipulate individual cells within one device.

Capillary Flow in Microchannel With Pillars

2008 ◽  
Author(s):  
Auro Ashish Saha ◽  
Mark Tweedie ◽  
Susanta Roy ◽  
Sushanta K. Mitra ◽  
Jim McLaughlin
Keyword(s):  
Free Surface ◽  
Capillary Flow ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Microfluidic Channel ◽  
Free Surface Flow ◽  
Surface Flow ◽  
Fluidic Channel ◽  
Cyanoacrylate Adhesive ◽  
Microfluidic Analysis

Numerical simulation and experimental results of free surface flow in microfluidic channel containing 10 × 15 array of 350 micron circular cross-section pillars is presented here. Passive capillary driven transport of de-ionized (DI) water and isopropyl alcohol is considered in the study. The channel is fabricated from glass microscope slides patterned with SU8 photoresist using an SF 100 maskless lithography system. Subsequently, microscope slide have been adhered with cyanoacrylate adhesive for sealing the device. The pillars are 120 micron deep, with adjacent pillars being separated by 300 micron. The three-dimensional free surface phenomena is simulated by volume of fluid (VOF) technique and microfluidic imaging is used to experimentally visualize the interface movement. This helps in understanding how free surface is modified by the presence of pillars for performing microfluidic analysis. The effectiveness of using pillars in the fluidic channel to enhance capillary flow and create a more uniform wavefront is demonstrated.

scholarly journals Integration of Ultra-Low Volume Pneumatic Microfluidics with a Three-Dimensional Electrode Network for On-Chip Biochemical Sensing

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 762
Author(s):  
Saurabh Tomar ◽  
Charlotte Lasne ◽  
Sylvain Barraud ◽  
Thomas Ernst ◽  
Carlotta Guiducci
Keyword(s):  
Field Effect Transistors ◽  
Scale Up ◽  
Three Dimensional ◽  
Microfluidic Channel ◽  
Reference Electrode ◽  
Open Circuit ◽  
Cmos Scaling ◽  
Pneumatic Valves ◽  
On Chip ◽  
The Stability

This paper reports a novel miniaturized pseudo reference electrode (RE) design for biasing Ion Sensitive Field Effect Transistors (ISFETs). It eliminates the need for post-CMOS processing and can scale up in numbers with the CMOS scaling. The presented design employs silane-mediated transfer of patterned gold electrode lines onto PDMS microfluidics such that the gold conformally coats the inside of microfluidic channel. Access to this electrode network is made possible by using “through-PDMS-vias” (TPV), which consist of high metal-coated SU-8 pillars manufactured by a novel process that employs a patterned positive resist layer as SU-8 adhesion depressor. When integrated with pneumatic valves, TPV and pseudo-RE network were able to bias 1.5 nanoliters (nL) of isolated electrolyte volumes. We present a detailed characterization of our pseudo-RE design demonstrating ISFET operation and its DC characterization. The stability of pseudo-RE is investigated by measuring open circuit potential (OCP) against a commercial Ag/AgCl reference electrode.

THREE DIMENSIONAL FEM SIMULATION OF TITANIUM HOLLOW MONOLITHIC STRUCTURE PROCESS BASED ON VISCO--PLASTIC CONSTITUTIVE

2010 ◽  
Vol 46 (4) ◽  
pp. 396-403
Author(s):  
Bing ZHAO ◽  
Zhiqiang LI ◽  
Xiuquan HAN ◽  
Jinhua LIAO ◽  
Hongliang HOU ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Fem Simulation ◽  
Monolithic Structure

Theoretical Analysis and FEM Simulation of Piezoelectric Vibrator Used in Ultrasonic EDM System

2013 ◽  
Vol 694-697 ◽  
pp. 3020-3024
Author(s):  
Hong Bing Wang ◽  
Zhi Rong Li ◽  
Chun Hua Sun
Keyword(s):  
Theoretical Analysis ◽  
Natural Frequencies ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Model Analysis ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Piezoelectric Vibrator ◽  
Working Frequency

The dynamic performance of the piezoelectric vibrator used in ultrasonic EDM machine in natural frequencies has a great effect on machining precision. Firstly, Through theoretical analysis the dynamic characteristics of the piezoelectric vibrator is obtained. Then the three-dimensional model of the piezoelectric vibrator is constructed by using PRO/E software, and model analysis is carried by using FEM software. Through theoretical analysis and FEM simulation, the appropriate working frequency and mode of the piezoelectric vibrator was found, and the piezoelectric vibrator was fabricated. Experimented results show that the model analysis of frequency is accord with that of FEM.

scholarly journals Tephra4D: A Python-Based Model for High-Resolution Tephra Transport and Deposition Simulations—Applications at Sakurajima Volcano, Japan

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 331
Author(s):  
Kosei Takishita ◽  
Alexandros P. Poulidis ◽  
Masato Iguchi
Keyword(s):  
Scale Effects ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Terminal Velocity ◽  
Diameter Distribution ◽  
Velocity Variation ◽  
Small Scale ◽  
Modified Model ◽  
Sakurajima Volcano ◽  
Ash Transport

Vulcanian eruptions (short-lived explosions consisting of a rising thermal) occur daily in volcanoes around the world. Such small-scale eruptions represent a challenge in numerical modeling due to local-scale effects, such as the volcano’s topography impact on atmospheric circulation and near-vent plume dynamics, that need to be accounted for. In an effort to improve the applicability of Tephra2, a commonly-used advection-diffusion model, in the case of vulcanian eruptions, a number of key modifications were carried out: (i) the ability to solve the equations over bending plume, (ii) temporally-evolving three-dimensional meteorological fields, (iii) the replacement of the particle diameter distribution with observed particle terminal velocity distribution which provides a simple way to account for the settling velocity variation due to particle shape and density. We verified the advantage of our modified model (Tephra4D) in the tephra dispersion from vulcanian eruptions by comparing the calculations and disdrometer observations of tephra sedimentation from four eruptions at Sakurajima volcano, Japan. The simulations of the eruptions show that Tephra4D is useful for eruptions in which small-scale movement contributes significantly to ash transport mainly due to the consideration for orographic winds in advection.

scholarly journals Fast three-dimensional heat transfer model for computing internal temperatures in the bearing housing of automotive turbochargers

2018 ◽  
Vol 21 (8) ◽  
pp. 1286-1297 ◽  
Author(s):  
Antonio Gil ◽  
Andrés Omar Tiseira ◽  
Luis Miguel García-Cuevas ◽  
Tatiana Rodríguez Usaquén ◽  
Guillaume Mijotte
Keyword(s):  
Heat Transfer ◽  
Coke Formation ◽  
Three Dimensional ◽  
Heat Transfer Model ◽  
Operating Conditions ◽  
Thermal Design ◽  
Working Fluid ◽  
Transfer Model ◽  
Lumped Model ◽  
Bearing System

Each of the elements that make up the turbocharger has been gradually improved. In order to ensure that the system does not experience any mechanical failures or loss of efficiency, it is important to study which engine-operating conditions could produce the highest failing rate. Common failing conditions in turbochargers are mostly achieved due to oil contamination and high temperatures in the bearing system. Thermal management becomes increasingly important for the required engine performance. Therefore, it has become necessary to have accurate temperature and heat transfer models. Most thermal design and analysis codes need data for validation; often the data available fall outside the range of conditions the engine experiences in reality leading to the need to interpolate and extrapolate disproportionately. This article presents a fast three-dimensional heat transfer model for computing internal temperatures in the central housing for non-water cooled turbochargers and its direct validation with experimental data at different engine-operating conditions of speed and load. The presented model allows a detailed study of the temperature rise of the central housing, lubrication channels, and maximum level of temperature at different points of the bearing system of an automotive turbocharger. It will let to evaluate thermal damage done to the system itself and influences on the working fluid temperatures, which leads to oil coke formation that can affect the performance of the engine. Thermal heat transfer properties obtained from this model can be used to feed and improve a radial lumped model of heat transfer that predicts only local internal temperatures. Model validation is illustrated, and finally, the main results are discussed.

Sign in / Sign up

Export Citation Format

Share Document