Multi-Step Dynamic Control for Enhanced Electrokinetic Transport Characteristics in Microchip Capillary Electrophoresis

2008 ◽  
Author(s):  
Zhanjie Shao ◽  
Carolyn L. Ren ◽  
Gerry E. Schneider
Keyword(s):  
Dynamic Control ◽  
Electrokinetic Transport ◽  
Electrokinetic Flow ◽  
Separation Processes ◽  
Typical Sample ◽  
Electrophoretic Mobilities ◽  
Multi Stage ◽  
Contour Plots ◽  
One Step ◽  
On Chip

A numerical model has been developed and is used to study the loading and dispensing processes in on-chip cross-linked microchannels. The electrokinetic transport characteristics and the roles of species’ electrophoretic mobilities and diffusion coefficients on the electrokinetic flow are revealed. A study is also performed on an implementation of multi-stage injection. The study of conventional one-step injection and separation is performed and helps construct a distinct understanding of the processes. Species movement and sample plug development with diffusion are examined; results include concentration profiles and contour plots over a range of injection and separation time. Real-time monitoring of different species’ movements is performed for injection guidance. Some limitations of the separation process are presented with potential solutions, such as the removable tail effect and exceptional quick diffusion. Using innovative dynamic control, efforts are made to control the flow and species transport for improved sample plugs, which is key to achieving excellent electrophoretic separation. Through a series of multi-step injection schemes, four typical sample plugs are produced with specific attributes such as reduced dispersion leakage, desirable sample plug size, enhanced shape, etc. Comparisons of conventional and the proposed methods are performed. Typical resulting sample plugs are evaluated using the two developed parameters of resolution and detectability for numerically simulated separation processes. Depending on requirements, one can generate some specific sample plugs through this multi-step dynamic injection method. The resulting understanding will assist in the design of microfluidic devices for separation by providing insight into the process influences and controls and by identifying areas for further research.

Theoretical Investigation of On-Chip Multi-Species Transport in Micro-Channels for Analysis Applications

2007 ◽  
Author(s):  
Zhanjie Shao ◽  
Gerry E. Schneider ◽  
Carolyn L. Ren
Keyword(s):  
Effective Control ◽  
Separation Processes ◽  
Chip Design ◽  
Fundamental Parameters ◽  
Electrophoretic Mobilities ◽  
Micro Channels ◽  
Contour Plots ◽  
Parametric Studies ◽  
Unique Manner ◽  
On Chip

A complete mathematical model is developed for application to simulate the unsteady two-step on-chip sample injection and separation processes in microfluidic devices. The origin and applicability of the slip-wall velocity boundary condition is discussed. Due to electrophoresis effect, migration influence of every species is considered in the model and then solved for separation analysis. The model is non-dimensionalized in a unique manner to reveal effects of some key fundamental parameters: the Reynolds-Schmidt number, electrophoretic mobility of sample species, applied potentials, etc. In particular, the influence of ReSci is examined over the commonly encountered range and the effect of electrophoretic mobilities on separation is investigated for three different types of samples. Results include center-line concentration profiles as well as concentration contour plots over a range of nondimensional time (less than 400). Resolution is defined and employed to evaluate the separation results. The magnitude of calculated separation resolution (around 2.0) is comparable to experimental results. Through parametric studies, the characteristics of both injection and separation are revealed numerically and well understood for future effective control and innovative chip design.

scholarly journals Low-Process–Voltage–Temperature-Sensitivity Multi-Stage Timing Monitor for System-on-Chip Applications

Electronics ◽  
2021 ◽  
Vol 10 (13) ◽  
pp. 1587
Author(s):  
Duo Sheng ◽  
Hsueh-Ru Lin ◽  
Li Tai
Keyword(s):  
High Performance ◽  
Power Reduction ◽  
System On Chip ◽  
Timing Information ◽  
Multi Stage ◽  
Dynamic Voltage ◽  
And Performance ◽  
On Chip ◽  
Maximum Measurement ◽  
Maximum Measurement Error

High performance and complex system-on-chip (SoC) design require a throughput and stable timing monitor to reduce the impacts of uncertain timing and implement the dynamic voltage and frequency scaling (DVFS) scheme for overall power reduction. This paper presents a multi-stage timing monitor, combining three timing-monitoring stages to achieve a high timing-monitoring resolution and a wide timing-monitoring range simultaneously. Additionally, because the proposed timing monitor has high immunity to the process–voltage–temperature (PVT) variation, it provides a more stable time-monitoring results. The time-monitoring resolution and range of the proposed timing monitor are 47 ps and 2.2 µs, respectively, and the maximum measurement error is 0.06%. Therefore, the proposed multi-stage timing monitor provides not only the timing information of the specified signals to maintain the functionality and performance of the SoC, but also makes the operation of the DVFS scheme more efficient and accurate in SoC design.

scholarly journals Membrane Distillation for the Production of Pharmaceutical-Grade Water—Investigation into the Application of AGMD and VMD

2021 ◽  
Vol 18 (11) ◽  
pp. 6058
Author(s):  
Cornelius Nellessen ◽  
Thomas Klein ◽  
Hans-Jürgen Rapp ◽  
Frank Rögener
Keyword(s):  
Energy Demand ◽  
Tap Water ◽  
Membrane Distillation ◽  
Pharmaceutical Products ◽  
Optimum Process ◽  
The European Union ◽  
Pharmaceutical Ingredients ◽  
Multi Stage ◽  
One Step ◽  
Selection Of

The production of pharmaceutical ingredients, intermediates and final products strongly depends on the utilization of water. Water is also required for the purification and preparation of reagents. Each specific application determines the respective water quality. In the European Union, the European Pharmacopeia (Ph. Eur.) contains the official standards that assure quality control of pharmaceutical products during their life cycle. According to this, the production of water for pharmaceutical use is mainly based on multi-stage distillation and membrane processes, especially, reverse osmosis. Membrane distillation (MD) could be an alternative process to these classical methods. It offers advantages in terms of energy demand and a compact apparatus design. In the following study, the preparation of pharmaceutical-grade water from tap water in a one-step process using MD is presented. Special emphasis is placed on the performance of two different module designs and on the selection of optimum process parameters.

scholarly journals Electro-Optofluidicis: Achieving Dynamic Control On-Chip

2013 ◽  
Vol 104 (2) ◽  
pp. 503a
Author(s):  
Mohammad Soltani ◽  
James Inman ◽  
Michal Lipson ◽  
Michelle D. Wang
Keyword(s):  
Dynamic Control ◽  
On Chip

scholarly journals Analysis of the criteria of efficiency of work of separators for the field of hydrocarbon raw

2019 ◽  
pp. 114-119
Author(s):  
Valeriy V. Piven ◽  
Vladislav S. Shchelkonogov
Keyword(s):  
Technological Process ◽  
Raw Materials ◽  
Comprehensive Assessment ◽  
Technological Scheme ◽  
Qualitative Composition ◽  
Separation Processes ◽  
Process Flow ◽  
Multi Stage ◽  
Flow Diagrams

Assessment of the quality of separation of hydrocarbon raw during its field preparation is necessary to determine the efficiency of the entire technological process of preparation. The absence of complex criteria for assessing the quality of separation for multi-stage processes does not allow one to obtain unambiguous solutions in justifying the process flow diagrams and equipment for separation. We have analyzed the typical technological scheme of separation of hydrocarbon raw materials and existing criteria for separation processes. It is proposed to use the criterion for a comprehensive assessment of the separation processes of hydrocarbon raw materials, allowing calculating the efficiency of the process, taking into account the possible production of intermediate fractions and their qualitative composition

Effects of Non-Linearity of the Momentum Conservation Equation During Electrokinetic Transport in Nano and Microchannels

2010 ◽  
Author(s):  
Subir Bhattacharjee ◽  
Noor Al Quddus
Keyword(s):  
Porous Media ◽  
Electric Fields ◽  
Stokes Equations ◽  
Momentum Conservation ◽  
Conservation Equation ◽  
Small Scale ◽  
Electrokinetic Transport ◽  
Electrokinetic Flow ◽  
Non Linear ◽  
Momentum Conservation Equation

Electrokinetic transport phenomena, such as electroosmosis, streaming potential, electrophoresis, and sedimentation potential, are central to many micro- and nano-channel flows. During continuum modeling of such phenomena, incorporation of the electrical body force term can make the fluid momentum conservation equation highly non-linear. This non-linearity is often ignored in small-scale electrokinetic flow modeling because of our implicit reliance on the linearity of the Stokes equations for low Reynolds number flows. In this paper, ramifications of this non-linear Stokes equation in electrokinetic flows will be described with examples of our recent studies on pressure driven flows through porous media for electrokinetic power generation, electroosmotic flow of charged entities in nanochannels, and flow of DNA through self-assembled porous media under pulsed electric fields.

Femtosecond laser-processed staining microchip for one-step preparation of fluorescent DNA sample without loss of DNAs

2019 ◽  
Author(s):  
Yeongseok Jang ◽  
Hojun Shin ◽  
Jinmu Jung ◽  
Jonghyun Oh
Keyword(s):  
Femtosecond Laser ◽  
Performance Test ◽  
Staining Method ◽  
Laser System ◽  
Molecular Transport ◽  
Main Channel ◽  
Step Procedure ◽  
One Step ◽  
On Chip ◽  
The One

In this study, we propose a microchip that is sequentially capable of fluorescently staining and washing DNAs. The main advantage of this microchip is that it allows for one-step preparation of small amounts of solution without degrading microscopic bio-objects such as the DNAs, cells, and biomolecules to be stained. The microchip consists of two inlets, the main channel, staining zone, washing zone, and one outlet, and was processed using a femtosecond laser system. High molecular transport of rhodamine B to deionized water was observed in the performance test of the microchip. Results revealed that the one-step procedure of on-chip DNA staining and washing was excellent compared to the conventional staining method. The one-step preparation of stained and washed DNAs through the microchip will be useful for preparing small volumes of experimental samples.

Capture of Magnetic Microspheres in Electrokinetic Flow for Application in Lab-on-Chip Devices

2012 ◽  
Author(s):  
Debarun Das ◽  
Marwan Al-Rjoub ◽  
Jagjit S. Yadav ◽  
Rupak K. Banerjee
Keyword(s):  
Magnetic Field ◽  
Electric Fields ◽  
Magnetic Beads ◽  
Magnetic Microspheres ◽  
Electrokinetic Flow ◽  
Lab On Chip ◽  
Micro Total Analysis Systems ◽  
Total Analysis ◽  
On Chip ◽  
The Magnetic Field

Isolation of bio-molecules, cells and pathogens for immunoassays is a critical component in micro total analysis systems (μTAS). Magnetophoretic technique is often used for separation of such target species, where magnetic beads tagged with specific antibodies against cell surface epitopes, are captured in the microfluidic device. In this study, a numerical model is developed for capture of beads under an external magnetic field in electrokinetically driven flow. The results indicate an increase in the number of beads captured when the magnetic field is higher and the flow is driven by lower electric fields.

Multistage Centrifugal Compressor Surge Analysis: Part I — Experimental Investigation

1998 ◽  
Author(s):  
G. L. Arnulfi ◽  
P. Giannattasio ◽  
C. Giusto ◽  
A. F. Massardo ◽  
D. Micheli ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Reference Data ◽  
Dynamic Control ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Multi Stage ◽  
Compressor Surge ◽  
Multistage Centrifugal Compressor ◽  
Insight Into

This paper reports an experimental investigation on centrifugal compressor surge. The compression system consists of a four-stage blower with vaned diffusers and a large plenum discharging into the atmosphere through a throttle valve. Measurements of unsteady pressure and flow rate in the plant, and of instantaneous velocity in the diffusers of the first and fourth compressor stage are performed during deep surge, at several valve settings and three different rotation speeds. Additional tests have been carried out on a different system configuration, i.e., without plenum, in order to obtain the steady-state compressor characteristics and to collect reference data on stall in surge-free conditions. In this configuration, a fully developed rotating stall was detected in the compressor diffusers, while during surge it affects only a limited part of the surge cycle. The goal of the present experimental work was to get a deeper insight into unstable operating conditions of multi-stage centrifugal compressors and to validate a theoretical model of the system instability to be used for the design of dynamic control systems.

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