Water pollution by toxic heavy metals is one of the most serious environmental hazards to humansÃ¢â‚¬â„¢ health. As they are emitted into the water resources and adsorbed by soil, plants, fish and animals and eventually accumulate in human bodies causing a variety of serious diseases. Therefore, there is an urgent need to develop a continuous, rapid, automatic, and on-site heavy metals environmental monitoring system for the online detection of heavy metals pollution at various water resources and industrial waste networks. In this thesis the main objective is to develop a microfluidic platform for heavy metal analyte sensing in which a variety of sensing schemes can be applied. The proposed platform contains microfluidic microchannels for the handling and separation of heavy metal analytes to improve the selectivity, integrated with a sensing device for the optical detection and monitoring of various heavy metal analytes and concentrations. In this context, the design and micro-fabrication of polymer based microchannels were conducted as the microfluidic platform on which the integration of the various optical sensing materials can take place. Afterward a novel design of MEMS based Fourier transform spectrometer is proposed, in which a new scheme for input Gaussian beam splitting into symmetrically two semi Gaussian beam is introduced using V shape mirror. The design is fully integrated and can operate in the Infrared and visible region. The analysis shows that, a minimum resolution of 9nm at a wavelength of 1.45ÃŽÂ¼m and a mechanical displacement of 160ÃŽÂ¼m is achievable. Unlike the traditional Michelson interferometer which returns half of the optical power to the source, this design uses the full optical power to get the interference pattern using movable reflecting mirrors thus enhancing the signal to noise ratio, and allowing the use of differential moving scheme for the mirrors which increase the optical path difference by a factor of four. An analytical model that describes the beams propagation and interference is derived using Fourier optics techniques and verified using Finite Difference Time Domain (FDTD) method. Then, a mechanical model that describes the mirror displacement to produce optical pass difference is derived and verified using finite element method (FEM). Finally, the effect of different design parameters on the interference pattern, interferograme and resolution are also shown.
MS in Nanotechnology
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(2013).MEMS based heavy metal detector [Master's Thesis, the American University in Cairo]. AUC Knowledge Fountain.
Ramsis, Inas. MEMS based heavy metal detector. 2013. American University in Cairo, Master's Thesis. AUC Knowledge Fountain.
I would like to express my deep thankfulness to all the people who helped me in fulfilling this research and rendering it to such a level. First and foremost, I would like to thank my supervisor Prof. Sherif Sedky for his valuable contributions to this research, and for his support, guidance, and his endless knowledge and research skills that he taught me during this research that without it this work would have never been achieved. I also would like to acknowledge the support and guidance of Dr. Mohamed Serry and his valuable contribution and comments that guided me during the research, and also for his guidance for me during the fabrication phase which taught me how to use the clean room facilities at the American University in Cairo (AUC). I would like to acknowledge Dr. Mohamed Swillam for his valuable contribution and guidance in research and for his valuable comments that taught me a lot during the optical design and simulation and that without them this work would not have been achieved. I would like also to thank my colleagues, especially Eng. Kareem Khairallah for his help and contribution in the optical design. I would also like to acknowledge Eng. Mohamed Ibrahim for helping me during the use of microfabrication facilities, also I would like to thank Eng. Hani Tawfik for helping me in taking the SEM images. I would like to express my deep appreciation for The Youssef Jameel Science and Technology Research Center (YJ-STRC) that has provided me with fincial support and state-of-the-art equipment to conduct this work. At last but not least I would like to express my warm appreciation for my family because everything I have achieved is because of them, without their love, inspiration and guidance I would not be able to come to this point, thank you so much for being there for me.