Full text
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| Author(s): |
Murilo Zubioli Mielli
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Escola Politécnica (EP/BC) |
| Defense date: | 2012-07-27 |
| Examining board members: |
Marcelo Nelson Paez Carreño;
Renato Machado Cotta;
Gustavo Pamplona Rehder
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| Advisor: | Marcelo Nelson Paez Carreño |
| Abstract | |
This project presents the development of a thermal flow sensor integrated into a microchannel. The whole design cycle is discussed: concept, modeling and simulation, fabrication and characterization. The sensor consists of a nickel filament fabricated on a glass substrate which is bonded to a polydimethylsiloxane (PDMS) block containing the microchannels. The flow inside the microchannel is indirectly measured through the heat exchange between the filament and the fluid. Finite methods analysis revealed that the sensor has three operating ranges and in two of them (flows below 20 ìL/min or higher than 130 ìL/min) the electric response of the sensor varies linearly with respect to the flow. Several flow sensors were fabricated according to the fabrication method presented in this project and some of them were characterized electrically. The response of the voltage on the filament as a function of the flow inside the microchannel was obtained. The experimental results demonstrated that the flow sensors could measure flow rates as small as tens of microliters per minute even when working on the less sensitive operating range. Alternative fabrication methods were proposed in order to improve the sensor sensitivity, leaving the filaments self-sustained inside the microchannels. A lumped element model was introduced in order to simulate the behavior of the optimized flow sensors. Some preliminary results of these simulations and of the fabrication processes were presented. (AU) | |
| FAPESP's process: | 10/04139-5 - Microfluidic systems for biotechnology and sensors |
| Grantee: | Murilo Zubioli Mielli |
| Support Opportunities: | Scholarships in Brazil - Master |