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Full-Text Articles in Engineering

Development Of A Polysilicon Check Microvalve, William C. Hart Jan 2005

Development Of A Polysilicon Check Microvalve, William C. Hart

Journal of the Microelectronic Engineering Conference

Check valves are used frequently within the field of microfluidic MEMS, particularly in micropump applications. Check valves serve to limit the flow of a fluid to one direction through a channel. This project was an attempt to manufacture an efficient check microvalve using polysilicon as the valve cover material. Previous work on a microvalve at RIT has been unsuccessful, as the final KOH etch has attacked the polysilicon, thus removing the valves from the openings in the silicon. It was determined that pinholes in the LPCVD nitride were allowing KOH to penetrate the etch mask and attack the substrate surface …


Simulations And Experimental Analysis Of High-Aspect-Ratio Diffusive Micro-Mixers, Amit Maha Jan 2005

Simulations And Experimental Analysis Of High-Aspect-Ratio Diffusive Micro-Mixers, Amit Maha

LSU Master's Theses

Passive (diffusional) mixing has been used in designing high-aspect-ratio micro-mixers for the purpose of performing the Liagase Detection Reaction (LDR). A simple model was used to design such mixers optimized for pressure drop or time required to deliver a prescribed volume of mixture. The types of mixers considered are simple, cheap, and durable and can perform over a broad range of volumetric flow rates at reasonably modest pressure drops. The fluids typically have a very low diffusion coefficient of=1.2x10^10m^2/s, and thus diffusional mixing can only be effective in high-aspect-ratio micro-channels. A realizable aspect ratio of 6 has been considered initially …


A New Microsensor System For Plant Root Zone Monitoring, Chang-Soo Kim, Sandeep Sathyan, D. M. Porterfield Jan 2005

A New Microsensor System For Plant Root Zone Monitoring, Chang-Soo Kim, Sandeep Sathyan, D. M. Porterfield

Electrical and Computer Engineering Faculty Research & Creative Works

The objective of this work is to develop a new microsensor system that can monitor dissolved oxygen and hydration environment at the plant root zone. A miniaturized plant growth system is prepared including the root zone layer, either a porous ceramic tube or porous ceramic wafer on which the plant is grown, and an underlying fluidic channel to deliver nutrients and water to the root zone. We demonstrate the feasibility of using a flexible microsensor array for dissolved oxygen detection, and a four-electrode impedance microelectrode for wetness detection on the surface of a porous tube nutrient delivery system. The unique …