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.

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.

scholarly journals Programmable hydraulic resistor for microfluidic chips using electrogate arrays

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marie L. Salva ◽  
Yuksel Temiz ◽  
Marco Rocca ◽  
Yulieth C. Arango ◽  
Christof M. Niemeyer ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Chip ◽  
Rate Control ◽  
Flow Resistance ◽  
Smartphone Application ◽  
Microfluidic Chips ◽  
Specific Flow ◽  
Flow Rates ◽  
Peripheral Device ◽  
Flow Rate Control

AbstractFlow rates play an important role in microfluidic devices because they affect the transport of chemicals and determine where and when (bio)chemical reactions occur in these devices. Flow rates can conveniently be determined using external peripherals in active microfluidics. However, setting specific flow rates in passive microfluidics is a significant challenge because they are encoded on a design and fabrication level, leaving little freedom to users for adjusting flow rates for specific applications. Here, we present a programmable hydraulic resistor where an array of “electrogates” routes an incoming liquid through a set of resistors to modulate flow rates in microfluidic chips post-fabrication. This approach combines a battery-powered peripheral device with passive capillary-driven microfluidic chips for advanced flow rate control and measurement. We specifically show a programmable hydraulic resistor composed of 7 parallel resistors and 14 electrogates. A peripheral and smartphone application allow a user to activate selected electrogates and resistors, providing 127 (27-1) flow resistance combinations with values spanning on a 500 fold range. The electrogates feature a capillary pinning site (i.e. trench across the flow path) to stop a solution and an electrode, which can be activated in a few ms using a 3 V bias to resume flow based on electrowetting. The hydraulic resistor and microfluidic chip shown here enable flow rates from ~0.09 nL.s−1 up to ~5.66 nL.s−1 with the resistor occupying a footprint of only 15.8 mm2 on a 1 × 2 cm2 microfluidic chip fabricated in silicon. We illustrate how a programmable hydraulic resistor can be used to set flow rate conditions for laminar co-flow of 2 liquids and the enzymatic conversion of a substrate by stationary enzymes (alkaline phosphatase) downstream of the programmable hydraulic resistor.

scholarly journals Effect of Subglottic Stenosis on Vocal Fold Vibration and Voice Production Using Fluid–Structure–Acoustics Interaction Simulation

2021 ◽  
Vol 11 (3) ◽  
pp. 1221
Author(s):  
Dariush Bodaghi ◽  
Qian Xue ◽  
Xudong Zheng ◽  
Scott Thomson
Keyword(s):  
Flow Rate ◽  
Vocal Fold ◽  
Flow Resistance ◽  
Signal To Noise Ratio ◽  
Area Ratio ◽  
Subglottic Stenosis ◽  
Fluid Structure ◽  
Voice Production ◽  
Vocal Fold Vibration ◽  
Glottal Flow

An in-house 3D fluid–structure–acoustic interaction numerical solver was employed to investigate the effect of subglottic stenosis (SGS) on dynamics of glottal flow, vocal fold vibration and acoustics during voice production. The investigation focused on two SGS properties, including severity defined as the percentage of area reduction and location. The results show that SGS affects voice production only when its severity is beyond a threshold, which is at 75% for the glottal flow rate and acoustics, and at 90% for the vocal fold vibrations. Beyond the threshold, the flow rate, vocal fold vibration amplitude and vocal efficiency decrease rapidly with SGS severity, while the skewness quotient, vibration frequency, signal-to-noise ratio and vocal intensity decrease slightly, and the open quotient increases slightly. Changing the location of SGS shows no effect on the dynamics. Further analysis reveals that the effect of SGS on the dynamics is primarily due to its effect on the flow resistance in the entire airway, which is found to be related to the area ratio of glottis to SGS. Below the SGS severity of 75%, which corresponds to an area ratio of glottis to SGS of 0.1, changing the SGS severity only causes very small changes in the area ratio; therefore, its effect on the flow resistance and dynamics is very small. Beyond the SGS severity of 75%, increasing the SGS severity, leads to rapid increases of the area ratio, resulting in rapid changes in the flow resistance and dynamics.

Continuous separation of particles using a microfluidic device equipped with flow rate control valves

2006 ◽  
Vol 1127 (1-2) ◽  
pp. 214-220 ◽  
Author(s):  
Yuushi Sai ◽  
Masumi Yamada ◽  
Masahiro Yasuda ◽  
Minoru Seki
Keyword(s):  
Microfluidic Device ◽  
Flow Rate ◽  
Rate Control ◽  
Continuous Separation ◽  
Control Valves ◽  
Flow Rate Control

Variable Powder Flow Rate Control in Laser Metal Deposition Processes

2008 ◽  
Author(s):  
Lie Tang ◽  
Jianzhong Ruan ◽  
Robert G. Landers ◽  
Frank Liou
Keyword(s):  
Transport System ◽  
Flow Rate ◽  
Rate Control ◽  
Metal Deposition ◽  
Powder Flow ◽  
Laser Metal Deposition ◽  
Motion System ◽  
Powder Flow Rate ◽  
Deposition Processes ◽  
Flow Rate Control

This paper proposes a novel method, called Variable Powder Flow Rate Control (VPFRC), for the regulation of powder flow rate in laser metal deposition processes. The idea of VPFRC is to adjust the powder flow rate to maintain a uniform powder deposition per unit length even when disturbances occur (e.g., the motion system accelerates and decelerates). Dynamic models of the powder delivery system motor and the powder transport system (i.e., five–meter pipe, powder dispenser, and cladding head) are constructed. A general tracking controller is then designed to track variable powder flow rate references. Since the powder flow rate at the nozzle exit cannot be directly measured, it is estimated using the powder transport system model. The input to this model is the DC motor rotation speed, which is estimated on–line using a Kalman filter. Experiments are conducted to examine the performance of the proposed control methodology. The experimental results demonstrate that the VPFRC method is successful in maintaining a uniform track morphology, even when the motion system accelerates and decelerates.

Feasibility Study on the Use of a Voice Coil Motor Direct Drive Flow Rate Control Valve

2009 ◽  
Author(s):  
Shuai Wu ◽  
Richard Burton ◽  
Zongxia Jiao ◽  
Juntao Yu ◽  
Rongjie Kang
Keyword(s):  
Neural Network ◽  
Flow Control ◽  
Flow Rate ◽  
Rate Control ◽  
Network Flow ◽  
Voice Coil Motor ◽  
Direct Drive ◽  
Hydraulic Test ◽  
Servo Valve ◽  
Flow Rate Control

This paper considers the feasibility of a new type of voice coil motor direct drive flow control servo valve. The proposed servo valve controls the flow rate using only a direct measurement of the spool position. A neural network is used to estimate the flow rate based on the spool position, velocity and coil current. The estimated flow rate is fed back to a closed loop controller. The feasibility of the concept is established using simulation techniques only at this point. All results are validated by computer co-simulation using AMESim and Simulink. A simulated model of a VCM-DDV (Voice Coil Motor-Direct Drive Valve) and hydraulic test circuit are built in an AMESim environment. A virtual digital controller is developed in a Simulink environment in which the feedback signals are received from the AMESim model; the controller outputs are sent to the VCM-DDV model in AMESim (by interfacing between these two simulation packages). A LQR (Linear Quadratic Regulator) state feedback and nonlinear compensator controller for spool position tracking is considered as this is the first step for flow control. A flow rate control loop is subsequently included via a neural network flow rate estimator. Simulation results show that this method could control the flow rate to an acceptable degree of precision, but only at low frequencies. This kind of valve can find usage in open loop hydraulic velocity control in many industrial applications.

Magnetofluidic control of the breakup of ferrofluid droplets in a microfluidic Y-junction

RSC Advances ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 778-785 ◽  
Author(s):  
Huajun Li ◽  
Yining Wu ◽  
Xiaoda Wang ◽  
Chunying Zhu ◽  
Taotao Fu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Rate Ratios

Breakup of the ferrofluid droplets at the Y-junction divergence under various flow rate ratios.

EXPERIMENTAL INVESTIGATION OF ENHANCEMENT IN EFFICIENCY OF CENTRIFUGAL PUMP BY REDUCTION IN CAVITATION OF PUMP

2021 ◽  
Vol 5 (10) ◽  
Author(s):  
Gaffar G. Momin
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Rate Control ◽  
Flowing Liquid ◽  
Discharge Flow ◽  
Pump Performance ◽  
Cavitation Phenomenon ◽  
Discharge Flow Rate ◽  
Flow Rate Control

Cavitation phenomenon is basically a process formation of bubbles of a flowing liquid in a region where the pressure of the liquid falls below its vapour pressure and it is the most challenging fluid flow abnormalities leading to detrimental effects on both the centrifugal pump discharge characteristics as well as physical characteristics. In this low pressure zones are the first victims of cavitation. Due to cavitation pitting of impeller occurs and wear of internal walls of pumps occurs due to which there is creation of vibrations and noize are there. Due to this there is bad performance of centrifugal pump is there. Firstly, description of the centrifugal pump with its various parts are described after that pump characteristics and its important parameters are presented and discussed. Passive discharge (flow rate) control methods are utilized for improvement of flow rate and mechanical and volumetric and overall efficiency of the pump. Mechanical engineers is considering an important phenomenon which is known as Cavitation due to which there is decrease in centrifugal pump performance. There is also effect on head of the pump which is getting reduced due to cavitation phenomenon. In present experimental investigation the cavitation phenomenon is studied by starting and running the pump at various discharges and cavitating conditions of the centrifugal pump. Passive discharge (flow rate) control is realized using three different impeller blade leading edge angles namely 9.5 degrees, 16.5 degrees .and 22.5 degrees for reduction in the cavitation and increase the of the centrifugal pump performance at different applications namely, domestic, industrial applications of the centrifugal pump.

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