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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Study of Disposable Silicon-based Chlorine and Ammonium Micro Ion Sensors

Chang, Wei-chun 04 September 2010 (has links)
Human blood reflects the health of internal organs and tissues, the constituent can be affected on account of abnormal health status. Moreover, the ion concentration of chloride and ammonium in human blood relates to the functionality of our kidney and liver, which is one of the most important health indicators. For real-time monitoring and detecting applications, this study uses micro-electromechanical systems (MEMS) surface micromachining process technology to develop an extended-gate field-effect transistors (EGFET), and by combining two different ion-selective membranes (ISM), a disposable silicon-based chloride and ammonium micro ion sensor was fabricated. The main process steps include four photolithography process and two thin film deposition. In order to probe into the influences on modulating three designing parameters: (i) channel width to length ratio; (ii) channel shape; (iii) mixing ratio of the sensing film additives, the size of the sensing area is fixed to 1¡Ñ1 mm2 while the device is fixed to 6 mm3. In this thesis, the optimization of the development chloride and ammonium micro ion sensors, according to the measuring results from the commercial semiconductor analyzer (Agilent B1500A), when measuring range of 10-1~10-5 mol/L, the sensitivity and linearity for the chlorine ion sensor is 47.5 mV/pCl and 99.13%, as for the ammonium ion sensor are 41.2 mV/pNH4 and 99.28%, the interfering ion selectivity coefficients (log KCl,OH, log KNH ,Na) are -4.71 and 0.53 respectively.
2

Desenvolvimento de membranas íon-seletivas com poliestireno sulfonado e polianilina dopada para a aplicação em eletrodiálise

Proença, Marcela Pinheiro January 2009 (has links)
Atualmente, a preocupação com a redução da poluição industrial tem motivado os pesquisadores na busca de novas tecnologias para o tratamento de resíduos industriais. Tecnologias limpas, como a eletrodiálise, são capazes de tratar alguns destes resíduos, como por exemplo o efluente da indústria de galvanoplastia, minimizando os impactos que ocorreriam caso eles fossem descartados diretamente no meio ambiente. O componente principal desta técnica é a membrana na qual ocorre a etapa de retirada dos íons da solução. Atualmente estas membranas são importadas e caras, o que justifica o desenvolvimento de membranas eficientes e acessíveis. Neste sentido, no presente trabalho membranas de poliestireno sulfonado/ poliestireno de alto impacto (SPS/HIPS), polianilina dopada com ácido canforsulfônico/ poliestireno sulfonado/ poliestireno de alto impacto (PAniCSA/SPS/HIPS), polianilina sulfonada/ poliestireno sulfonado/ poliestireno de alto impacto (SPAN/SPS/HIPS), e polianilina dopada com ácido p-tolueno sulfônico/ poliestireno sulfonado/ poliestireno de alto impacto (PAniTSA/SPS/HIPS) foram desenvolvidas usando o método de mistura química. As membranas foram caracterizadas utilizando as técnicas Análise termogravimétrica (TGA), Análise dinâmico Mecânica (DMA), e Microscopia Eletrônica de Varredura (MEV). Membranas foram submetidas a curvas corrente-potencial e ensaios de eletrodiálise em soluções de NaCl e KCl, a fim de determinar o transporte iônico através das mesmas. Os resultados foram comparados com uma membrana comercial Selemion CMT. A extração percentual média para íons de Na+ obtidos pelas membranas desenvolvidas foi superior a 20%. / Nowadays the concern with the reduction of industrial pollution has motivated researchers to found out new technologies for treatment of industrial waste. The clean technologies, as electrodialysis, are capable of treating some these residues, as for example the galvanoplasty’s waste, minimizing the impacts that would happen to them if they were discarded directly on the environment. The main component of this technique is the membrane on which occurs the ions removal stage of the solution. The membranes are imported and expensive what justifies the development of efficient and accessible membranes. In this sense, in the present work membranes of sulfonated polystyrene / high impact polystyrene (SPS/HIPS), polyaniline doped with camphorsulfonic acid / sulfonated polystyrene / high impact polystyrene (PAniCSA/SPS/HIPS), sulfonated polyaniline/ sulfonated polystyrene / high impact polystyrene (SPAN/SPS/HIPS), and polyaniline doped with p-toluenesulfonic acid / sulfonated polystyrene / high impact polystyrene (PAniTSA/SPS/HIPS) were developed using chemical mixture method. Membranes were characterized by Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA) and Scanning Electronic Microscopy (SEM). Membranes were submitted to current-voltage curves and electrodialysis experiments with NaCl and KCl solutions, in order to determine ionic transport through them. Results were compared with a commercial membrane, Selemion CMT. The average percent extraction for Na+ ions obtained by membranes developed were beyond 20%.
3

Desenvolvimento de membranas íon-seletivas com poliestireno sulfonado e polianilina dopada para a aplicação em eletrodiálise

Proença, Marcela Pinheiro January 2009 (has links)
Atualmente, a preocupação com a redução da poluição industrial tem motivado os pesquisadores na busca de novas tecnologias para o tratamento de resíduos industriais. Tecnologias limpas, como a eletrodiálise, são capazes de tratar alguns destes resíduos, como por exemplo o efluente da indústria de galvanoplastia, minimizando os impactos que ocorreriam caso eles fossem descartados diretamente no meio ambiente. O componente principal desta técnica é a membrana na qual ocorre a etapa de retirada dos íons da solução. Atualmente estas membranas são importadas e caras, o que justifica o desenvolvimento de membranas eficientes e acessíveis. Neste sentido, no presente trabalho membranas de poliestireno sulfonado/ poliestireno de alto impacto (SPS/HIPS), polianilina dopada com ácido canforsulfônico/ poliestireno sulfonado/ poliestireno de alto impacto (PAniCSA/SPS/HIPS), polianilina sulfonada/ poliestireno sulfonado/ poliestireno de alto impacto (SPAN/SPS/HIPS), e polianilina dopada com ácido p-tolueno sulfônico/ poliestireno sulfonado/ poliestireno de alto impacto (PAniTSA/SPS/HIPS) foram desenvolvidas usando o método de mistura química. As membranas foram caracterizadas utilizando as técnicas Análise termogravimétrica (TGA), Análise dinâmico Mecânica (DMA), e Microscopia Eletrônica de Varredura (MEV). Membranas foram submetidas a curvas corrente-potencial e ensaios de eletrodiálise em soluções de NaCl e KCl, a fim de determinar o transporte iônico através das mesmas. Os resultados foram comparados com uma membrana comercial Selemion CMT. A extração percentual média para íons de Na+ obtidos pelas membranas desenvolvidas foi superior a 20%. / Nowadays the concern with the reduction of industrial pollution has motivated researchers to found out new technologies for treatment of industrial waste. The clean technologies, as electrodialysis, are capable of treating some these residues, as for example the galvanoplasty’s waste, minimizing the impacts that would happen to them if they were discarded directly on the environment. The main component of this technique is the membrane on which occurs the ions removal stage of the solution. The membranes are imported and expensive what justifies the development of efficient and accessible membranes. In this sense, in the present work membranes of sulfonated polystyrene / high impact polystyrene (SPS/HIPS), polyaniline doped with camphorsulfonic acid / sulfonated polystyrene / high impact polystyrene (PAniCSA/SPS/HIPS), sulfonated polyaniline/ sulfonated polystyrene / high impact polystyrene (SPAN/SPS/HIPS), and polyaniline doped with p-toluenesulfonic acid / sulfonated polystyrene / high impact polystyrene (PAniTSA/SPS/HIPS) were developed using chemical mixture method. Membranes were characterized by Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA) and Scanning Electronic Microscopy (SEM). Membranes were submitted to current-voltage curves and electrodialysis experiments with NaCl and KCl solutions, in order to determine ionic transport through them. Results were compared with a commercial membrane, Selemion CMT. The average percent extraction for Na+ ions obtained by membranes developed were beyond 20%.
4

Desenvolvimento de membranas íon-seletivas com poliestireno sulfonado e polianilina dopada para a aplicação em eletrodiálise

Proença, Marcela Pinheiro January 2009 (has links)
Atualmente, a preocupação com a redução da poluição industrial tem motivado os pesquisadores na busca de novas tecnologias para o tratamento de resíduos industriais. Tecnologias limpas, como a eletrodiálise, são capazes de tratar alguns destes resíduos, como por exemplo o efluente da indústria de galvanoplastia, minimizando os impactos que ocorreriam caso eles fossem descartados diretamente no meio ambiente. O componente principal desta técnica é a membrana na qual ocorre a etapa de retirada dos íons da solução. Atualmente estas membranas são importadas e caras, o que justifica o desenvolvimento de membranas eficientes e acessíveis. Neste sentido, no presente trabalho membranas de poliestireno sulfonado/ poliestireno de alto impacto (SPS/HIPS), polianilina dopada com ácido canforsulfônico/ poliestireno sulfonado/ poliestireno de alto impacto (PAniCSA/SPS/HIPS), polianilina sulfonada/ poliestireno sulfonado/ poliestireno de alto impacto (SPAN/SPS/HIPS), e polianilina dopada com ácido p-tolueno sulfônico/ poliestireno sulfonado/ poliestireno de alto impacto (PAniTSA/SPS/HIPS) foram desenvolvidas usando o método de mistura química. As membranas foram caracterizadas utilizando as técnicas Análise termogravimétrica (TGA), Análise dinâmico Mecânica (DMA), e Microscopia Eletrônica de Varredura (MEV). Membranas foram submetidas a curvas corrente-potencial e ensaios de eletrodiálise em soluções de NaCl e KCl, a fim de determinar o transporte iônico através das mesmas. Os resultados foram comparados com uma membrana comercial Selemion CMT. A extração percentual média para íons de Na+ obtidos pelas membranas desenvolvidas foi superior a 20%. / Nowadays the concern with the reduction of industrial pollution has motivated researchers to found out new technologies for treatment of industrial waste. The clean technologies, as electrodialysis, are capable of treating some these residues, as for example the galvanoplasty’s waste, minimizing the impacts that would happen to them if they were discarded directly on the environment. The main component of this technique is the membrane on which occurs the ions removal stage of the solution. The membranes are imported and expensive what justifies the development of efficient and accessible membranes. In this sense, in the present work membranes of sulfonated polystyrene / high impact polystyrene (SPS/HIPS), polyaniline doped with camphorsulfonic acid / sulfonated polystyrene / high impact polystyrene (PAniCSA/SPS/HIPS), sulfonated polyaniline/ sulfonated polystyrene / high impact polystyrene (SPAN/SPS/HIPS), and polyaniline doped with p-toluenesulfonic acid / sulfonated polystyrene / high impact polystyrene (PAniTSA/SPS/HIPS) were developed using chemical mixture method. Membranes were characterized by Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA) and Scanning Electronic Microscopy (SEM). Membranes were submitted to current-voltage curves and electrodialysis experiments with NaCl and KCl solutions, in order to determine ionic transport through them. Results were compared with a commercial membrane, Selemion CMT. The average percent extraction for Na+ ions obtained by membranes developed were beyond 20%.
5

DESIGN AND FABRICATION OF FLEXIBLE SENSORS FOR SINGLE-USE APPLICATIONS

Aiganym Yermembetova (13954878) 13 October 2022 (has links)
<p>The development of reliable, robust and low-cost sensor devices is growing in importance and an ongoing challenge. From environmental monitoring and household safety to food and biopharmaceutical industries, the necessity for specific analyte detection is crucial. Over the years researchers have come up with myriad materials that can be used for efficient sensing devices. The materials employed are governed by application and performance criteria as well as the sensing mechanism, which might be based on physical or chemical principles. In this thesis, two different types of electrochemical sensor technologies were examined with special attention paid to the application of the devices, the materials used, and their feasibility for scalable manufacturing.</p> <p>In the first study, binary mixtures of conducting and semiconducting nanomaterials were explored as promising candidates for the manufacturing of low-cost ethylene sensor on flexible substrates. Ethylene (C2H4) is a small plant hormone which has been shown to affect the growth and senescence of flowers, leaves and fruits. Currently available devices have demonstrated high ethylene sensitivities with great potential for technology size reduction; however, some are not practical for use outside of the laboratory, lack portability, or require more research to demonstrate their reproducibility and stability in different environments, as well as selectivity to C2H4 in large-scale applications. Conductometric gas sensors based on a combination of carbon nanotubes (CNTs) and exfoliated molybdenum disulfide (MoS2) coated with molecular receptors is demonstrated for the selective detection of ethylene, including details on materials preparation, manufacturing, and characterization. Mixtures of CNTs and exfoliated MoS2 were deposited onto screen-printed interdigitated electrodes on plastic substrates, with optimization for scalable and continuous manufacturing by roll-to-roll methods. C2H4 detection levels of 0.1 ppm were readily achieved with responses on the second timescale.</p> <p>The second sensor technology shows how thin-film potentiometric electrodes based on ion-selective membranes can be designed to tolerate sterilizing radiation while providing excellent performance and signal stability. This sensor's development was motivated by the expanding need for single-use bioreactor systems in the biopharmaceutical industry, which require strict control over cell culture conditions for several weeks or more. Until recently, critical analysis has been conducted mostly by offline or “at-line” sampling of aliquots withdrawn from the sterile bioreactor. The latter is inefficient and can increase the risk of contamination. Inspired by the challenges related to cost, integration and performance following irradiation a potentiometric pH electrode was developed, intended for single-use applications. It was shown to be radiation-tolerant while providing reliable data comparable to a commercial pH meter over a period of three months. The electrodes exhibited quasi-linear signal drifts of +0.28 mV/day or 0.005 pH units/day. Thin-film γ-irradiated electrodes could provide accurate pH readings in sterilized culture media using a single-point calibration, within 0.07 pH units of a commercial meter with glass electrode and daily calibration. Furthermore, to advance the development of market-ready sensors past the conceptual stage, a few automated processes for scalable membrane deposition were investigated.</p>

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