Une plate-forme sans fil pour electrochimique spectroscopie d'impédance

Avec l’émergence soutenue de capteurs et de dispositifs électrochimiques innovants, la spectroscopie d'impédance électrochimique est devenue l'un des outils les plus importants pour la caractérisation et la modélisation de la matière ionique et de l'interfaçage des capteurs. La capacité de détecter automatiquement, à l’aide de dispositifs électrochimiques peu couteux, les caractéristiques physiques et chimiques de la matière ionique ouvre une gamme d’application très variée pour la compréhension et l’optimisation des procédés ou interviennent les processus électrochimiques. Cette thèse décrit le développement d’une plate-forme microélectronique miniaturisée, connectée, multiplexée, et à faible coût pour la spectroscopie d'impédance diélectrique (SID) conçue pour les mesures électrochimiques in-situ et adaptée aux architectures de réseau sans fil. La plate-forme développée durant ce travail de maitrise a été testée et validée au sein d’une maille ZigBee et a été en mesure d'interfacer jusqu'à trois capteurs SID en même temps et de relayer l'information à travers le net Zigbee pour l'analyse de données et le stockage. Le système a été construit à partir de composants microélectroniques disponibles commercialement et bénéficie des avantages d'une calibration système on-the-fly qui effectue la calibration du capteur de manière aisée. Dans ce mémoire de maitrise, nous rapportons la modélisation et la caractérisation de senseurs électrochimiques de nitrate; notamment nous décrivons la conception microélectronique, la réponse d'impédance de Nyquist, la sensibilité et la précision de la mesure électrochimique, et les résultats de tests de la plate-forme pour les applications de spectroscopie d'impédance relatives à la détection du nitrate, de la détection de la qualité de l'eau, et des senseurs tactiles.The emergence of the various applications of electrochemical sensors and devices, electrochemical impedance spectroscopy became one of the most important tools for characterizing and modeling of the material and interfacing the sensors. The ability to sense in an automatic manner enables a wide variety of processes to be better understood and optimized cost-effectively. This thesis describes the development of a low-cost, miniaturized, multiplexed, and connected platform for dielectric impedance spectroscopy (DIS) designed for in-situ measurements and adapted to wireless network architectures. The platform has been tested and used as a DIS sensor node on a ZigBee mesh and was able to interface up to three DIS sensors at the same time and relay the information through the Zigbee net for data analysis and storage. The system was built from commercial microelectronics components and benefits from an on-the-fly calibration system that makes sensor calibration easy. The thesis reports characterizing and modeling of two electro-chemical devices (i.e. nitrate sensor and optically-transparent electrically-conductive glasses) and also describes the microelectronics design, the Nyquist impedance response, the measurement sensitivity and accuracy, and the testing of the platform for in-situ dielectric impedance spectroscopy applications pertaining to fertilizer sensing, water quality sensing, and touch sensing

Mars aqueous chemistry experiment

The Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. Progress for the first year MACE PIDDP is reported in two major areas of effort: (1) fluids handling concepts, definition, and breadboard fabrication and (2) aqueous chemistry ion sensing technology and test facility integration. A fluids handling breadboard was designed, fabricated, and tested at Mars ambient pressure. The breadboard allows fluid manipulation scenarios to be tested under the reduced pressure conditions expected in the Martian atmosphere in order to validate valve operations, orchestrate analysis sequences, investigate sealing integrity, and to demonstrate efficacy of the fluid handling concept. Additional fluid manipulation concepts have also been developed based on updated MESUR spacecraft definition. The Mars Aqueous Chemistry Experiment Ion Selective Electrode (ISE) facility was designed as a test bed to develop a multifunction interface for measurements of chemical ion concentrations in aqueous solution. The interface allows acquisition of real time data concerning the kinetics and heats of salt dissolution, and transient response to calibration and solubility events. An array of ion selective electrodes has been interfaced and preliminary calibration studies performed

Distributed environmental monitoring

With increasingly ubiquitous use of web-based technologies in society today, autonomous sensor networks represent the future in large-scale information acquisition for applications ranging from environmental monitoring to in vivo sensing. This chapter presents a range of on-going projects with an emphasis on environmental sensing; relevant literature pertaining to sensor networks is reviewed, validated sensing applications are described and the contribution of high-resolution temporal data to better decision-making is discussed

Application of electro-active biofilms

The concept of an electro-active biofilm (EAB) has recently emerged from a few studies that discovered that certain bacteria which form biofilms on conductive materials can achieve a direct electrochemical connection with the electrode surface using it as electron exchanger, without the aid of mediators. This electro-catalytic property of biofilms has been clearly related to the presence of some specific strains that are able to exchange electrons with solid substrata (eg Geobacter sulfurreducens and Rhodoferax ferrireducens). EABs can be obtained principally from natural sites such as soils or seawater and freshwater sediments or from samples collected from a wide range of different microbially rich environments (sewage sludge, activated sludge, or industrial and domestic effluents). The capability of some microorganisms to connect their metabolisms directly in an external electrical power supply is very exciting and extensive research is in progress on exploring the possibilities of EABs applications. Indeed, the best known application is probably the microbial fuel cell technology that is capable of turning biomass into electrical energy. Nevertheless, EABs coated onto electrodes have recently become popular in other fields like bioremediation, biosynthesis processes, biosensor design, and biohydrogen production

Electrochemical Sensors and On-chip Optical Sensors

abstract: The microelectronics technology has seen a tremendous growth over the past sixty years. The advancements in microelectronics, which shows the capability of yielding highly reliable and reproducible structures, have made the mass production of integrated electronic components feasible. Miniaturized, low-cost, and accurate sensors became available due to the rise of the microelectronics industry. A variety of sensors are being used extensively in many portable applications. These sensors are promising not only in research area but also in daily routine applications. However, many sensing systems are relatively bulky, complicated, and expensive and main advantages of new sensors do not play an important role in practical applications. Many challenges arise due to intricacies for sensor packaging, especially operation in a solution environment. Additional problems emerge when interfacing sensors with external off-chip components. A large amount of research in the field of sensors has been focused on how to improve the system integration. This work presents new methods for the design, fabrication, and integration of sensor systems. This thesis addresses these challenges, for example, interfacing microelectronic system to a liquid environment and developing a new technique for impedimetric measurement. This work also shows a new design for on-chip optical sensor without any other extra components or post-processing.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

POTENTIOMETRIC SENSOR FOR HYDROGENE ION BASED ON NEUTRAL CARRIER IN A POLY (VINYL CHLORIDE) MEMBRANE WITH POLYANILINE SOLID CONTACT

Joint Research on Environmental Science and Technology for the Eart