The Optimum Design of Traveling-Wave Electroosmotic Micropumps

2009 ◽  
Author(s):  
Shou-Ping Hsu ◽  
Hong-Jun Ye ◽  
Win-Jet Luo ◽  
Jauh-Shyong Chen
Keyword(s):  
Electric Field ◽  
Optimum Design ◽  
Double Layer ◽  
Traveling Wave ◽  
Microelectrode Arrays ◽  
Operating Frequency ◽  
Optimum Operating ◽  
Gap Size ◽  
Wave Potential

This study investigates the performace of electroosmotic micropumps with arrays of microelectrodes for pumping electrolyte in a microchannel. Traveling-wave potentials are applied to the microelectrode arrays. Ions accumulate in the double layer in response to the applied signal. The electric field acts on the charge pulling the fluid in the direction of the traveling wave. In this study, the effects of the widths and heights of the electrodes, the gap size between the electrodes and the frequency of the applied traveling-wave potential on the pumping velocity of the micropump are investigated in order to obtain the optimum design of the micropump. The optimum operating frequency of the traveling-wave potential is about 1 kHz for the micropumps with different electrode widths and gap sizes. The pumping velocities increase with the decrease of the electrode widths and gap sizes for the micropumps. For the micropumps with different electrode widths and gap sizes, it is found the optimum electrode heights are about 5.5 μm when the gap sizes are less than the electrode widths, and the optimum electrode heights are about 10.4 μm when the gap sizes are greater than the electrode widths.

Modeling the Electrical Double Layer to Understand the Reaction Environment in a CO2 Electrocatalytic System

2019 ◽  
Author(s):  
Divya Bohra ◽  
Jehanzeb Chaudhry ◽  
Thomas Burdyny ◽  
Evgeny Pidko ◽  
wilson smith
Keyword(s):  
Electric Field ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Surface Reaction ◽  
Catalyst Surface ◽  
Local Reaction ◽  
Reaction Diffusion ◽  
Alkali Metal Cations ◽  
Applied Potential ◽  
Critical Aspect

<p>The environment of a CO<sub>2</sub> electroreduction (CO<sub>2</sub>ER) catalyst is intimately coupled with the surface reaction energetics and is therefore a critical aspect of the overall system performance. The immediate reaction environment of the electrocatalyst constitutes the electrical double layer (EDL) which extends a few nanometers into the electrolyte and screens the surface charge density. In this study, we resolve the species concentrations and potential profiles in the EDL of a CO<sub>2</sub>ER system by self-consistently solving the migration, diffusion and reaction phenomena using the generalized modified Poisson-Nernst-Planck (GMPNP) equations which include the effect of volume exclusion due to the solvated size of solution species. We demonstrate that the concentration of solvated cations builds at the outer Helmholtz plane (OHP) with increasing applied potential until the steric limit is reached. The formation of the EDL is expected to have important consequences for the transport of the CO<sub>2</sub> molecule to the catalyst surface. The electric field in the EDL diminishes the pH in the first 5 nm from the OHP, with an accumulation of protons and a concomitant depletion of hydroxide ions. This is a considerable departure from the results obtained using reaction-diffusion models where migration is ignored. Finally, we use the GMPNP model to compare the nature of the EDL for different alkali metal cations to show the effect of solvated size and polarization of water on the resultant electric field. Our results establish the significance of the EDL and electrostatic forces in defining the local reaction environment of CO<sub>2</sub> electrocatalysts.</p>

Dynamic Behavior of Space Charge in Double-layer Insulation Structure under High External Electric Field

2021 ◽  
Author(s):  
Ling Zhang ◽  
Yuxuan Xu ◽  
Quzong Gesang ◽  
Zhichao Qiao ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
External Electric Field ◽  
Dynamic Behavior ◽  
Double Layer

Optimum design method for double-layer thick-walled concrete cylinder with different modulus

2010 ◽  
Vol 44 (5) ◽  
pp. 923-928 ◽  
Author(s):  
Ai-Zhong Lu ◽  
Gui-Sheng Xu ◽  
Lu-Qing Zhang
Keyword(s):  
Optimum Design ◽  
Double Layer ◽  
Design Method ◽  
Concrete Cylinder

A Double-Layer Shaped-Beam Traveling-Wave Slot Array Based on SIW

2016 ◽  
Vol 64 (11) ◽  
pp. 4639-4647 ◽  
Author(s):  
Lei Qiu ◽  
Ke Xiao ◽  
Shun Lian Chai ◽  
Hui Ying Qi ◽  
Jun Jie Mao
Keyword(s):  
Double Layer ◽  
Traveling Wave ◽  
Shaped Beam

Controlled Separation and Trapping of Particles Using Two-frequency DEP

2005 ◽  
Author(s):  
Sophie Loire ◽  
Yanting Zhang ◽  
Frederic Bottausci ◽  
Noel C. MacDonald ◽  
Igor Mezic
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Traveling Wave ◽  
Electrode Array ◽  
Theoretical Work ◽  
Single Frequency ◽  
Ac Electroosmosis ◽  
Biomedical Analysis ◽  
Precise Control ◽  
Flow Effects

We present numerical simulations and experiments on dielectrophoretic (DEP) separation and trapping performed in a titanium-based microchannel linear electrode array. The use of electric fields and in particular dielectrophoresis (DEP) have a great potential to help miniaturize and increase the speed of biomedical analysis. Precise control and manipulation of micro/nano/bio particles inside those miniaturized devices depend greatly on our understanding of the phenomena induced by AC electric fields inside microchannels and how we take advantage of them. The studied DEP devices are composed of two parts: the inter-digitated titanium electrodes and the channel. The electrode substrate is constituted of two layers to form 4-phase traveling wave. Each electrode is 20 μm wide and separated from the other by a gap of 20 μm. The channel is 200 μm wide, 50 μm deep and 6 mm long. The device is designed to generate inhomogeneities in electric-field magnitude. This allows positive and negative DEP (p-DEP and n-DEP). Moreover, it can also produce inhomogeneities in electric-field phase, hence authorizing traveling wave DEP (twDEP). It is also capable of inducing two-frequency DEP, in contrast with most of the previous, single-frequency, designs. The advantages of two-frequency DEP were shown by theoretical work (Chang et al. 2003) and permit precise and optimal control of particles movements. We show that fluid flow effects are substantial and can affect the particle motion in a positive (enhanced trapping) and negative (trapping when separation is desired) way. We discuss the effects of AC-electroosmosis, electrothermal and dielectrophoresis combined. We discuss the advantages of two-frequency dielectrophoretic handling of bioparticles. We investigate the limits of particle size that can be accurately controlled.

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