Miniature valveless ultrasonic pumps and mixers

Rife, J. C.; Bell, M. I.; Horwitz, J. S.; Kabler, M. N.; Auyeung, R. C. Y.; Kim, W.J

doi:10.1016/s0924-4247(00)00433-7

Cited by 185 publications

(121 citation statements)

References 11 publications

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“…Ultrasonic pumps use acoustic radio-frequency transducers to move liquid in small channels or in reservoirs [115]. This system does not require controlled surface chemistry and special mobile phase composition to generate the flow that is otherwise necessary in EOFdriven systems.…”

Section: Flow Generation and Pumping Mechanismmentioning

confidence: 99%

New advances in microchip fabrication for electrochromatography

Szekeres

Guttman

2005

Electrophoresis

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There is a great demand in separation technologies for faster and more effective analysis processes. Miniaturization is a suitable technique for satisfying this demand as reduction in size gives increased separation speed with higher efficiency. CEC is an electric-field-mediated separation technique where the liquid flow is generated by the electric field itself. The main advantage of using electric field over pressure for flow generation is the flat flow profile of the EOF; thus, CEC is one of the best candidates to construct a novel and high-efficiency microanalytical device. The aim of the present paper is to review the basic fabrication and bonding principles, as well as connection and system integration options for microfluidics-based electrochromatography. The physical structure and fluidic channel formation are critically evaluated, including glass microstructuring and fusion bonding. Recent developments in nanoflow measurements and the application of various flow control units are also extensively discussed.

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Section: Flow Generation and Pumping Mechanismmentioning

confidence: 99%

New advances in microchip fabrication for electrochromatography

Szekeres

Guttman

2005

Electrophoresis

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“…A calculation has shown that the penetration depth for a 4 MHz acoustic wave traveling in glycerin is about 8 mm. 24,25 The high attenuation may also cause a decrease in the contribution of the waves generated from the outer electrodes to the interference, making the axial pressure distributions of the three FZPs become similar ͑Fig. 5͒.…”

Section: ͑4͒mentioning

confidence: 99%

Self-focused acoustic ejectors for viscous liquids

Hon

Kwok

Li³

et al. 2010

Review of Scientific Instruments

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Self-focused acoustic ejectors using the Fresnel zone plate ͑FZP͒ have been developed for ejecting viscous liquids, without nozzle, in the drop-on-demand mode. The FZP is composed of a lead zirconate titanate piezoelectric plate patterned with a series of annular electrodes, with the unelectroded region of the plate removed. Our results show that the acoustic waves are effectively self-focused by constructive interference in glycerin ͑with a viscosity of 1400 mPa s͒, giving small focal points with a high pressure. Due to the high attenuation, the wave pressure decreases significantly with the distance from the FZP. Nevertheless, the pressure at the focal points 2.5 and 6.5 mm from the FZP is high enough to eject glycerin droplets in the drop-on-demand mode. Driven by a simple wave train comprising a series of sinusoidal voltages with an amplitude of 35 V, a frequency of 4.28 MHz, and a duration of 2 ms, the ejector can eject fine glycerin droplets with a diameter of 0.4 mm at a repetition frequency of 120 Hz in a downward direction. Droplets of other viscous liquids, such as the prepolymer of an epoxy with a viscosity of 2000 mPa s, can also be ejected in the drop-on-demand mode under similar conditions.

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“…Therefore, mixing in microchannels is mainly driven by laminar flow advection and diffusion. The mixing effect can be further worsened if the mixing process only relies on pure diffusion (Rife et al, 2000). Most present-day micromixers exploit the active and passive design approaches.…”

Section: Introductionmentioning

confidence: 99%

CFD-Based Optimization of a Diamond-Obstacles Inserted Micromixer with Boundary Protrusions

Tseng

Yang

Lee

et al. 2011

Engineering Applications of Computational Fluid Mechanics

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Effective mixing is vitally important to many microfluidic devices with applications in the areas of biotechnical industries, analytic chemistry and medical industries. In practice, passive micromixers are dependent on the proper layout of channel geometric configurations with obstacles deposited in microchannels to break-up and recombine the flow and reduce the diffusion path to improve the mixing performance. This study aims to investigate the mixing behavior of two different fluids in a passive micromixer with protruded boundary structures. The predicted mixing indexes at different longitudinal locations and Reynolds numbers achieved a good approximation of the experimental data in the literature for numerical simulations. The simulation results also indicated that intense vortices and secondary flows in spanwise planes were induced near the boundary protrusion regions to augment mixing efficiency along the flow course. In order to attain the optimal micromixer design, numerical calculations were attempted for the first time to thoroughly examine the effects of shape, length, width and placement of boundary protrusion structures on the mixing efficiency of a diamond-obstacles inserted micromixer.

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Miniature valveless ultrasonic pumps and mixers

Cited by 185 publications

References 11 publications

New advances in microchip fabrication for electrochromatography

New advances in microchip fabrication for electrochromatography

Self-focused acoustic ejectors for viscous liquids

CFD-Based Optimization of a Diamond-Obstacles Inserted Micromixer with Boundary Protrusions

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