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The study presents a novel microfluidic mixing scheme in which the fluid streams are mixed via the applications of harmonic and chaotic electric potentials to four electrodes mounted on the upper and lower surfaces of the mixing chamber. Numerical simulations are performed to analyze the effects of the resulting harmonic oscillating and chaotic oscillating electrokinetic perturbation forces. The harmonic...
Diffusion is often the rate-limiting step in microfluidic-based biochemical analysis systems. In this paper, an alternative current electrothermal mixer for molecular diagnostic is presented. The mixer consists of a concentric electrode design integrated in a microfluidic cartridge. We investigated the electrothermal flow by visualizing the trajectories of seeded particles. The velocity shows a fourth...
We present the numerical method for explaining cooling enhancement in a microchannel heat sink which utilizes carbon nanotubes-in-fluid suspensions as coolant. We also show that by increasing CNT nanolayer thickness, the microchannel heat sink temperature gradient is decreased. The temperature contours of the microchannel heat sink with CNTs (with ~25 nm diameter) dispersed in water is investigated...
This paper investigates the EKI phenomenon in a double T-shaped microchannel, in which two aqueous electrolyte solutions with a 3.5:1 conductivity ratio are driven electrokinetically into the mixing channel via the application of a DC electrical field. A stratified flow condition is formed when the intensity of the applied DC electrical field is below a certain threshold value. However, as the intensity...
The friction and wear problems have remarkably affected the reliability of Micro-Electro-Mechanical System (MEMS) devices. We present, for the first time, a novel integrated micro-scale closed synthetic-jet-like flow field, which provides a velocity-orientation-constant flow in an enclosure, being available as gas lubrication of the motion parts of MEMS devices to solve the friction problem. Based...
In this work, we present a novel technique to compensate the plug dispersion for the moving field capillary electrophoresis (CE) in the presence of flow loss via the side channels. A forward electroosmotic pump (EOP) is employed to compensate the back flow in the electroosmotic (EOF) segment between the active electrodes. By the analog electrical models to the fluid systems, the optimal pump structure...
Fluid dynamics and mixing transport of the rhombic micromixer with truncate angles have been investigated by 3D numerical simulations and experiments. Simulation result shows this rhombic microchannel with truncate angles has high mixing efficiency, compared to cross-shape microchannel. Over 90% mixing enhanced by vortices had been achieved at Re > 100. Different to photolithography process, CO...
This study reports on the development of a novel perfusion microfluidic cell culture device integrated drug delivering, fluid controlling and cell culturing functions on a two- layer PDMS chip. The device consists of an array of 6 X 6 cell culture chambers, a drug gradient generator and two control valves. Cells are physically trapped and cultured in the center of the chamber by a C-shaped dam when...
This paper investigates new pumping phenomena induced by surface waves in a microchannel. Acoustic streaming is known as fluid motion due to high intensity sound. This phenomenon usually occurs near an oscillating surface of a body in a sound field. In this study, a new acoustic pumping mechanism, different from surface acoustic streaming phenomenon, is found. According to current parameters, the...
A new microfluidic reaction chip capable of mixing, transporting and reacting is developed for synthesis of gold nanoparticles with tunable sizes. It allows for a rapid and a cost-effective approach to accelerate the synthesis of gold nanoparticles. The microfluidic reaction chip was made of CNC machining and PDMS casting process to integrate a vortex-type micro-mixer and a micro-pump on a single...
A new-style functional nanomaterial-magnetic fluid and its preparing technology was studied. The preparing method of the kerosene based nano-magnetic fluid was presented and the characteristic of the magnetic fluid was studied. The principle and inductance calculation of the pressure difference sensor with magnetic fluid was presented based on the fluidity and paramagnetism of magnetic fluid. The...
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