scholarly journals Microfluidic Network Simulations Enable On-Demand Prediction of Control Parameters for Operating Lab-On-A-Chip-Devices

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1320
Author(s):  
Julia Sophie Böke ◽  
Daniel Kraus ◽  
Thomas Henkel
Keyword(s):  
Fluid Management ◽  
Lab On A Chip ◽  
Microfluidic System ◽  
Flow Rates ◽  
Demand Prediction ◽  
Fast Running ◽  
Microfluidic Network ◽  
Fluid Properties ◽  
Network Simulations ◽  
User Friendly

Reliable operation of lab-on-a-chip systems depends on user-friendly, precise, and predictable fluid management tailored to particular sub-tasks of the microfluidic process protocol and their required sample fluids. Pressure-driven flow control, where the sample fluids are delivered to the chip from pressurized feed vessels, simplifies the fluid management even for multiple fluids. The achieved flow rates depend on the pressure settings, fluid properties, and pressure-throughput characteristics of the complete microfluidic system composed of the chip and the interconnecting tubing. The prediction of the required pressure settings for achieving given flow rates simplifies the control tasks and enables opportunities for automation. In our work, we utilize a fast-running, Kirchhoff-based microfluidic network simulation that solves the complete microfluidic system for in-line prediction of the required pressure settings within less than 200 ms. The appropriateness of and benefits from this approach are demonstrated as exemplary for creating multi-component laminar co-flow and the creation of droplets with variable composition. Image-based methods were combined with chemometric approaches for the readout and correlation of the created multi-component flow patterns with the predictions obtained from the solver.

Development of Planar Microfluidic Systems Using Conventional and Low Temperature Assembling Schemes for Components

1999 ◽  
Author(s):  
Nihat Okulan ◽  
Shekhar Bhansali ◽  
Arum Han ◽  
Saman Dharmatilleke ◽  
Jin-Woo Choi ◽  
...  
Keyword(s):  
Low Temperature ◽  
Electrochemical Detection ◽  
Biochemical Analysis ◽  
Magnetic Particle ◽  
Lab On A Chip ◽  
Microfluidic System ◽  
Microfluidic Systems ◽  
Detection Techniques

Abstract This center is currently working on the development of a remotely accessible generic microfluidic system (“lab on a chip”) for biological and biochemical analysis, based on electrochemical detection techniques. Modular microfluidic components, including micro reservoirs, microvalves, micropumps, filterless magnetic particle separators, biosensors and flowsensors, were fabricated and tested, and integrated on a system motherboard. Other air-to-liquid measurand concentrators and integrated sieve/filters are being explored in related efforts. The fabrication of these microfluidic components and the utilization of wax for low temperature assembly and even bonding is discussed.

The Effects of Variable Properties on MHD Flow in Finite Ducts

1970 ◽  
Vol 37 (4) ◽  
pp. 954-958 ◽  
Author(s):  
W. J. Thomson ◽  
G. R. Bopp
Keyword(s):  
Numerical Solutions ◽  
Mhd Flow ◽  
Duct Flow ◽  
Variable Properties ◽  
Temperature Dependent ◽  
Constant Property ◽  
Flow Rates ◽  
Friction Factors ◽  
Fluid Properties ◽  
Fluid Parameters

Numerical solutions are obtained of the coupled partial differential equations which describe variable property MHD flow in finite rectangular ducts. The fluid properties are allowed to vary to the extent that electrical conductivity and viscosity are assumed to be temperature-dependent. It is shown that it is not possible to account for fluid property variations in terms of “weighted” fluid parameters such as average Hartmann numbers. Analysis leads to the conclusion that it is the nature of the current distributions in the duct which is important in predicting the behavior of nonisothermal MHD duct flow. It is possible that this conclusion may aid in the evaluation and correlation of experimental data. It is also shown that consideration of variable fluid properties results in friction factors and flow rates which differ from constant property solutions by as much as a factor of two and by 50 percent, even for small variations.

Sensitivity of Slug Flow Mechanistic Models on Slug Length

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Cem Sarica ◽  
Hong-Quan Zhang ◽  
Robert J. Wilkens
Keyword(s):  
Slug Flow ◽  
Gas Flow ◽  
Model Development ◽  
Unified Model ◽  
Mechanistic Models ◽  
Flow Rates ◽  
Fluid Properties ◽  
The Common ◽  
Pipe Geometry ◽  
Probabilistic Nature

Slug flow is one of the common flow patterns in gas and oil production and transportation. One of the closure relationships required by the multiphase flow mechanistic models is slug length correlation. There are several closure relationships proposed in the literature as function of pipe geometry, pipe diameter, and inclination angle, and to a lesser extent to the flow rates and fluid properties. In this paper, we show that most of the frequently used mechanistic models are insensitive to slug length information. The only exception to this is identified as the Zhang et al. (2003, “Unified Model for Gas-Liquid Pipe Flow via Slug Dynamics—Part 1: Model Development,” ASME J. Energy Resour. Technol., 125, pp. 266–272). The unified model shows sensitivity at high gas flow rates, while displaying a negligible sensitivity at low gas flow rates. In conclusion, the slug length closure relationship is not crucial for pressure loss and holdup calculations. It can be speculated that the success of the unit cell slug flow modeling approach could be attributed to insensitivity of the models to slug length considering the highly probabilistic nature of the slug length.

scholarly journals Elasto-Magnetic Pumps Integrated within Microfluidic Devices

2021 ◽  
Vol 4 (1) ◽  
pp. 48
Author(s):  
Jacob L. Binsley ◽  
Elizabeth L. Martin ◽  
Thomas O. Myers ◽  
Stefano Pagliara ◽  
Feodor Y. Ogrin
Keyword(s):  
Magnetic System ◽  
Point Of Care ◽  
Microfluidic Channel ◽  
Lab On A Chip ◽  
Microfluidic Devices ◽  
Point Of Care Testing ◽  
Ongoing Research ◽  
Flow Rates ◽  
Pumping System ◽  
Oscillating Magnetic Field

Many lab-on-a-chip devices require a connection to an external pumping system in order to perform their function. While this is not problematic in typical laboratory environments, it is not always practical when applied to point-of-care testing, which is best utilized outside of the laboratory. Therefore, there has been a large amount of ongoing research into producing integrated microfluidic components capable of generating effective fluid flow from on-board the device. This research aims to introduce a system that can produce practical flow rates, and be easily fabricated and actuated using readily available techniques and materials. We show how an asymmetric elasto-magnetic system, inspired by Purcell’s three-link swimmer, can provide this solution through the generation of non-reciprocal motion in an enclosed environment. The device is fabricated monolithically within a microfluidic channel at the time of manufacture, and is actuated using a weak, oscillating magnetic field. The flow rate can be altered dynamically, and the direction of the resultant flow can be controlled by adjusting the frequency of the driving field. The device has been proven, experimentally and numerically, to operate effectively when applied to fluids with a range of viscosities. Such a device may be able to replace external pumping systems in portable applications.

Temperatures in a Gas Turbine Vaporizer at Near Idle Engine Conditions

1993 ◽  
Author(s):  
Theodore Vaskopulos ◽  
Constantine E. Polymeropoulos ◽  
Valentinas Sernas
Keyword(s):  
Gas Turbine ◽  
Liquid Flow ◽  
Diesel Fuel ◽  
Additional Data ◽  
Engine Operation ◽  
Flow Rates ◽  
Local Overheating ◽  
Experimental Correlation ◽  
Fluid Properties ◽  
The Mean

The work is a laboratory investigation of the effect of different liquids and liquid flow rates on the metal temperature of a gas turbine T vaporizer. Most of the experimentation was carried out using JP5. A limited number of runs using Diesel Fuel Marine and calibration runs using water provided additional data for different fluids. Conditions that approach local liquid depletion inside the vaporizer were identified by monitoring local overheating of the vaporizer metal. Because of apparatus limitations, testing was carried out only at vaporizer pressure and liquid flow rates approaching idle engine operation. An experimental correlation was developed allowing estimation of the mean vaporizer temperature as a function of input conditions and fluid properties.

An Automated System for Controlling the Laminar Flow Interface in a Microfluidic System

2004 ◽  
Author(s):  
Brandon Kuczenski ◽  
Philip R. LeDuc ◽  
William C. Messner
Keyword(s):  
Laminar Flow ◽  
Feedback System ◽  
Microfluidic System ◽  
Automated System ◽  
Time Varying ◽  
Relative Flow Rate ◽  
Microfluidic Network ◽  
Piezoresistive Pressure Sensor ◽  
Pressure Feedback ◽  
And Performance

The interface between adjacent laminar flow streams in the output channel of a Y-shaped confluent microfluidic network is useful for investigating the response of individual living cells to steep chemical gradients. This paper reports the design and performance of an automated pressure-feedback system for accurately and rapidly changing the position of that interface. The device will be employed to investigate the dynamic response of cells to time-varying chemical stimulation. The system works by controlling the pressure difference between the two adjoining inputs of the microfluidic network, altering the relative flow rate of the laminar streams in the output microchannel. Continuity of incompressible fluids dictates that the plane of the interface between the two streams will move from side to side as the flow rates change. The sample-data control system samples a temperature-compensated monolithic piezoresistive pressure sensor at 1 kilohertz, allowing the control of high-bandwidth microfluidic systems. This automated system enables long-duration, high-precision experiments that involve time-varying parameters to be performed simply, rapidly, and inexpensively.

Vacuum pouch microfluidic system and its application for thin-film micromixers

Lab on a Chip ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 2834-2843 ◽  
Author(s):  
Cheng-Je Lee ◽  
Yu-Hsiang Hsu
Keyword(s):  
Thin Film ◽  
Lab On A Chip ◽  
Microfluidic System ◽  
System A ◽  
New Type ◽  
On Chip

Vacuum pouch microfluidic system: a new type of lab-on-a-chip device that uses an on-chip vacuum pouch to drive a thin-film micromixer with a wide operation range.

Electrochemical Affinity Assays/Sensors: Brief History and Current Status

2021 ◽  
Vol 14 (1) ◽  
pp. 109-131
Author(s):  
Kenneth R. Wehmeyer ◽  
Ryan J. White ◽  
Peter T. Kissinger ◽  
William R. Heineman
Keyword(s):  
Quantum Dots ◽  
Early Development ◽  
Electrochemical Detection ◽  
Wearable Sensors ◽  
Lab On A Chip ◽  
Ease Of Use ◽  
Current Status ◽  
The Past ◽  
User Friendly

The advent of electrochemical affinity assays and sensors evolved from pioneering efforts in the 1970s to broaden the field of analytes accessible to the selective and sensitive performance of electrochemical detection. The foundation of electrochemical affinity assays/sensors is the specific capture of an analyte by an affinity element and the subsequent transduction of this event into a measurable signal. This review briefly covers the early development of affinity assays and then focuses on advances in the past decade. During this time, progress on electroactive labels, including the use of nanoparticles, quantum dots, organic and organometallic redox compounds, and enzymes with amplification schemes, has led to significant improvements in sensitivity. The emergence of nanomaterials along with microfabrication and microfluidics technology enabled research pathways that couple the ease of use of electrochemical detection for the development of devices that are more user friendly, disposable, and employable, such as lab-on-a-chip, paper, and wearable sensors.

scholarly journals Blood Plasma Self-Separation Technologies during the Self-Driven Flow in Microfluidic Platforms

2021 ◽  
Vol 8 (7) ◽  
pp. 94
Author(s):  
Yudong Wang ◽  
Bharath Babu Nunna ◽  
Niladri Talukder ◽  
Ernst Emmanuel Etienne ◽  
Eon Soo Lee
Keyword(s):  
Blood Plasma ◽  
Capillary Flow ◽  
Lab On A Chip ◽  
The Self ◽  
Microfluidic Platforms ◽  
Biomedical Analysis ◽  
Plasma Separation ◽  
User Friendly ◽  
Separation Devices ◽  
Blood Plasma Separation

Blood plasma is the most commonly used biofluid in disease diagnostic and biomedical analysis due to it contains various biomarkers. The majority of the blood plasma separation is still handled with centrifugation, which is off-chip and time-consuming. Therefore, in the Lab-on-a-chip (LOC) field, an effective microfluidic blood plasma separation platform attracts researchers’ attention globally. Blood plasma self-separation technologies are usually divided into two categories: active self-separation and passive self-separation. Passive self-separation technologies, in contrast with active self-separation, only rely on microchannel geometry, microfluidic phenomena and hydrodynamic forces. Passive self-separation devices are driven by the capillary flow, which is generated due to the characteristics of the surface of the channel and its interaction with the fluid. Comparing to the active plasma separation techniques, passive plasma separation methods are more considered in the microfluidic platform, owing to their ease of fabrication, portable, user-friendly features. We propose an extensive review of mechanisms of passive self-separation technologies and enumerate some experimental details and devices to exploit these effects. The performances, limitations and challenges of these technologies and devices are also compared and discussed.

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