A new torque transfer standard using metallic TBTF resonant sensor was developed to overcome the overload capability problem which occurs with conventional metallic resistance strain gauges. Previous research work, however, has shown that the first prototype of the metallic TBTF resonant sensor was not suitable for use in a torque transfer standard due to its size and subsequent sensitivity to parasitic lateral forces. To maximize the benefits from this sensor, particularly overload capability and long-term stability, in the high accuracy torque measurement application area, there is a need to develop significantly smaller devices. The aim of this thesis is to research through FEA modelling and experimental characterisation the key performance parameters required to produce a miniaturised metallic TBTF resonant sensor that provides better performance when applied in a torque measurement system. For high accuracy any torque transducer using these sensors ought to have low sensitivity to parasitic influences such as bending moments and lateral forces, which can only be achieved with reduced size. The problems with the existing design, key design issues, possible configuration and packaging solutions of the metallic TBTF resonant sensor that could be used for achieving a higher accuracy torque transfer standard are considered. Two designs of miniaturised metallic TBTF resonant sensors, SL20 and SL12, are considered and experimentally investigated. The lateral forces are reduced by 52% for SL20 design and by 80% for SL12 design when compared to the original SL40 design. A torque transducer using the SL20 design was calibrated falling into the Torque Transfer Standard class of accuracy 1 category, uncertainty 0.8%. A torque transducer using the SL12 design was made and calibration showed a class of accuracy 0.5 category, uncertainty 0.2%. The results from this research indicate that the SL12 design is suitable for use in a torque transfer standard. The SL12 design is optimal and the smallest size possible based on the overload capability design criteria requiring the tine cross sectional area to remain constant.

La détection de gaz, qui utilise aujourd'hui principalement des capteurs optiques, des capteurs électrochimiques à base de plomb et des capteurs catalytiques est un marché très porteur (estimé à 3 milliards d'euros) et doté d'une forte croissance (10% par an). La nécessité de développer de nouveaux systèmes d'instrumentation dédiés à la surveillance de la qualité de l'air intérieur et à la détection de substances dangereuses implique l'étude et le développement de nouveaux capteurs élaborés à partir de produits compatibles avec les enjeux environnementaux (RoHs, REACH), et économiques (matériaux à faible coût, techniques de réalisation fiables, durée de vie élevée). Le projet ANR OSPÉGAZ (Oxydes sans plomb pour la détection de gaz) vise à développer des systèmes d'instrumentations intégrés innovants dédiés à la caractérisation des différentes expositions environnementales en lien notamment avec les actions recommandées dans le cadre du PNSE2 pour les impacts sanitaires avérés. Le travail de thèse présenté dans ce manuscrit fait partie du projet OSPÉGAZ. L'objectif du travail a été, d'une part, de mettre au point un nouveau procédé d'élaboration d'encre au sein du laboratoire UDSMM pour l'élaboration et la caractérisation de films épais poreux, et d'autre part, de réaliser des capteurs de gaz à base de ces films. Nous avons choisi d'utiliser le matériau BaTiO₃, bien connu de la littérature, comme matériau de départ afin de mettre au point le procédé d'élaboration de couches épaisses. Par la suite, nous avons choisi le BaSrTiFeO₃ comme matériau sensible au gaz, et nous avons étudié deux compositions correspondant à deux taux de fer : Ba₀.₈₅Sr₀.₁₅Ti₀.₉Fe₀.₁O₃ (BSTF 10%) et Ba₀.₈₅Sr₀.₁₅Ti₀.₉₈Fe₀.₀₂O₃ (BSTF 2%). Ces matériaux ont été caractérisés dans une large gamme de fréquence (100 Hz à 1 MHz) et de température (25°C à 500°C). Les propriétés diélectriques en fonction de la fréquence et de la température ont été étudiées sur deux structures différentes d'électrodes : capacité parallèle (MIM) et capacité interdigitée (CID). Enfin, des démonstrateurs de capteurs de gas basés sur le principe des capteurs semi-conducteurs, ont été réalisés à partir de films épais poreux (BT, BST, BSFT 10% et 2%). Ces démonstrateurs ont été testés dans les locaux de la société SIMTRONICS sous différents gaz comme le monoxyde de carbone CO (200ppm), le sulfure d'hydrogène H₂S (50ppm) et le dioxyde de soufre SO₂ (20ppm) à 400°C et 450°C. Sous H₂S (50ppm), ils ont montré une plus grande sensibilité relative du BSTF (10%) (55.4%) par rapport au BSTF (2%) (48%) à 450°C. La bonne sensibilité relative et la réponse dynamique très intéressante montrent que le matériau BSTF dispose d'un potentiel très intéressant pour la détection de gaz. L'optimisation de la géométrie des capteurs, du taux de fer et de la température de fonctionnement devrait nous permettre d'améliorer les performances de nos démonstrateurs. / Today gas detection, which now mainly uses optical sensors, electrochemical sensors based on lead, and catalytic sensors, is a very promising market (estimated at 3 billion euros) with a strong growth (10% per year). The need for new instrumentation systems dedicated to the monitoring of the air quality and to the detection of hazardous substances, requires the study and development of new sensors compatible with the European environmental standards : Restriction of the use of Hazardous Substances (RoHS) ; Registration, Evaluation and Authorization of Chemicals (REACh). The OSPÉGAZ project aims to develop innovative integrated instrumentations systems for the characterization of different environmental exposures linked to the actions recommended by the PNSE2 for proven health impacts. Our research project aims to develop innovating and cost-effective gas sensors containing lead-free oxides and dedicated to the detection of flammable gases and protection against toxic risks. The works of the thesis presented in this manuscript is a part of this project. The objectives were, firstly, to develop a new process for ink preparation in UDSMM laboratory, for the elaboration, electrical and physicochemical characterizations, of thick porous film, and secondly to make gas sensors based on these films. We chose to use the BaTiO3 (well-known material in literature) material as a first material in order to develop the process of thick film elaboration. After that, we chose the BaSrTiFeO₃ as gas-sensitive material, and we studied two compositions of Ba₁₋ ₓ Sr ₓ Ti₁₋yFeyO₃ with two different concentrations or iron : Ba₀.₈₅Sr₀.₁₅Ti₀.₉Fe₀.₁O₃ (BSTF 10%) and Ba₀.₈₅Sr₀.₁₅Ti₀.₉₈Fe₀.₀₂O₃ (BSTF 2%). Electrical characterizations were made in a wide range of frequency (100 HZ to 1 MHz) and temperature (25° C to 500° C). The dielectric properties as a function of temperature and frequency were studied using two different structures of capacitance : metal-insulator-metal (MIM) and interdigital electrodes (CID). Finally we have developed semi-conductor gas sensors based on BT, BST and BSTF (10% ; 2%) thick films. All our sensors were tested under different gases such as carbon monoxide CO (200ppm), hydrogen sulphide H₂S (50ppm) and sulfur dioxide SO₂ (20ppm), at various temperature, in the laboratory of SIMTRONICS SAS. We have measured the greatest relative sensitivity under H₂S (50ppm) gas ; 55.4% and 48% respectively for BSTF (10%) and BSTF (2%), at 450°C. Good relative sensitivity and very interesting dynamic responsesof BSTF show that the material has a great potential for the detection of gas. The optimization of the sensor geometry, iron rate and operating temperature should allow us to improve the performance of our demonstrators.

Cette étude a été motivée par les nombreux avantages du procédé de micromoulage, qui couple la croissance électrolytique et la localisation du film avec un moule en résine épaisse. Ce procédé permet en effet la réalisation de micro-objets, dont les dimensions sont uniquement dépendantes de la résolution des techniques de lithographie employées pour définir les moules en résine. Le micromoulage permet donc de réaliser des microstructures métalliques et est compatible avec la technologie MEMS. Nous avons mis en évidence l’influence de différents paramètres expérimentaux dans le cadre de l’étude de la croissance électrolytique du samarium-cobalt en solution aqueuse dans une cellule de Hull. Cette étude nous a permis de déterminer plusieurs points de fonctionnement conduisant à des teneurs en samarium et des épaisseurs élevées : jusqu'à 50 % de samarium et plusieurs microns d’épaisseur. En outre, un certain nombre d’hypothèse ont été émises, qui lient le procédé d’élaboration et le mécanisme de croissance. Nous avons aussi réussi a montré qu’il est possible de réaliser des micromotifs de plusieurs microns d’épaisseur contenant un rapport Sm/(Sm+Co) relativement élevé (10 %) et une faible contamination en oxygène (8 %). / This study was motivated by the advantags of micromolding process, which couples the electrolytic growth and location of the film with a thick resin mold. This method makes it possible the achievement of micro-objects, the dimensions of which are only dependent on the resolution of the lithographic techniques used to define the resin molds. The micromolding can therefore produce metal microstructures and is compatible with MEMS technology. We have highlighted the influence of various experimental parameters in the context of the study of the electrolytic growth of samarium-cobalt in aqueous solution in a Hull cell. this study allowed us to identified several operating points resulting in samarium contents and high thicknesses up to 50% of samarium and several microns thick. In addition, a number of hypotheses have been put forward, which link the process of development and growth mechanism. We also successfully showed that it is possible to create micropatterns of several microns thick report containing Sm / (Sm + Co) relatively high (10%) and low oxygen contamination (8%).

The research on electrochemical sensor applications in combination with application-defined electronic circuits is a very fast developing field of modern sensorics. Device designing of unique integrated systems with specific properties and parameters is now becoming the everyday practice for producers of devices based on the latest technology progress in microelectronics. In the process of realization of a new device type, the main objective consists in increasing the possibility of detecting very low concentrations of heavy metals in the given chemical solution, extending the signal-to-noise ratio, and measuring the potential of a sensor. The general aim of this Master’s thesis is to design the topology of a sensor based on the thick film technology, to materialize the sensor, and to make experimental measurement using the sensor prototype. The practical reason for basing the measurement on the application of this thick film sensor is to find out whether the operational integration of the sensor and the circuit has been achieved according to the original hypothesis. Importantly, it is also necessary to determine whether the reproducibility of measured results has been reached. The innovative aspect of the created device consists in the improvement of output characteristics given by the integration of ASIC (IMAM CHIP). The integration of ASIC on the surface of the sensor eliminates the huge parasitic influence that affects the accuracy of measurement.

In recent years (Of late year)microelectronic technology significantly affected in the field of sensor technology, especially in the field of electrochemical sensors. This thesis deals with design and construction of thick-film voltammetric sensors array. The reason for proposal of voltammetric sensors array is to increase of speed, increase the accuracy and extension possibilities measurement compared with common systems.By reason of increase of sensitivity of these sensors it is efficient use the potentiostat chip for measurement output signal. Created sensors must fulfill the specified parameters and also requirements of thick-film technology. Next step is design the basic blocks of electronic circuit used to evaluate the measured values.

Tato diplomová práce se zabývá technologií tlustých vrstev a jejím možným použitím pro nekonvenční aplikace. První část práce je rešeršní a zaměřuje se především na aplikace tlustovrstvé technologie v různých oblastech použití. V teoretické části práce je dále popsána technologie LTCC, včetně technologických postupů výroby. V praktické části jsou řešeny dvě aplikace v tlustovrstvé technologii. Jedná se návrh a výrobu vysokofrekvenčního filtru a optického senzoru tlaku technologií LTCC. V závěru práce jsou provedena měření a jsou zhodnoceny dosažené výsledky.

No description available.

Over the past decade vehicle judder caused by Disc Thickness Variation (DTV) has become of major concern to automobile manufacturers worldwide. Judder is usually perceived by the driver as minor to severe vibrations transferred through the chassis during braking [1-9]. In this research, DTV is investigated via the use of a Smart Brake Pad (SBP). The SBP is a tool that will enable engineers to better understand the processes which occur in the harsh and confined environment that exists between the brake pad and disc whilst braking. It is also a tool that will enable engineers to better understand the causes of DTV and stick-slip the initiators of low and high frequency vibration in motor vehicle brakes. Furthermore, the technology can equally be used to solve many other still remaining mysteries in automotive, aerospace, rail or anywhere where two surfaces may come in contact. The SBP consists of sensors embedded into an automotive brake pad enabling it to measure pressure between the brake pad and disc whilst braking. The two sensor technologies investigated were Thick Film (TF) and Fibre Optic (FO) technologies. Each type was tested individually using a Material Testing System (MTS) at room and elevated temperatures. The chosen SBP was then successfully tested in simulated driving conditions. A preliminary mathematical model was developed and tested for the TF sensor and a novel Finite Element Analysis (FEA) model for the FO sensor. A new method called the Total Expected Error (TEE) method was also developed to simplify the sensor specification process to ensure consistent comparisons are made between sensors. Most importantly, our achievement will lead to improved comfort levels for the motorist.

Cette thèse de doctorat porte sur l'étude et la réalisation d'une plateforme de pesage dynamique pour véhicule roulant basée sur un concept d'intégration de la charge. Ce concept est mis en œuvre en vue de pouvoir minimiser la taille et l'encombrement de ce type de dispositif tout en effectuant des pesées présentant des caractéristiques métrologiques acceptables. Nous démontrons tout d'abord au travers de la réalisation d'un prototype et de plusieurs campagnes d'essais, la faisabilité de la méthode utilisée. Nous évaluons dans un deuxième temps les performances présentées par le prototype lors du pesage de véhicules légers roulant jusqu'à des vitesses de 35km/h. Une étude est ensuite menée sur les jauges de déformation piézorésistives et les jauges piézoélectriques réalisées en couches épaisses grâce à des techniques de sérigraphie. Nous caractérisons ces transducteurs avec pour objectif leur utilisation dans des dispositifs de pesage en remplacement des jauges de déformation classiques à filaments métalliques. / This PhD thesis is devoted to the study and implementation of a weigh-in-motion platform for vehicle based on a concept of integration of load. This concept is used to minimize the size of this kind of device while performing weighings with acceptable results. First, we show thanks to a protoype and several test campagns, the feasability of the method used. In a second time, we evaluate the performances of the prototype in terms of precision and repeatability with the dynamic weighing of vehicles at speeds up to 35km/h. A study is finally conducted on thick-film piezoresitive strain gauges and piezoelectric gauges manufacturing by a screen-printing process with cermet and polymer pastes. We characterize these tranducers with the goal of used them as an alternative of conventional foil strain gauges.

This work covers an area of heavy metals detection by miniaturized thick film sensors. Working electrode of these sensors was fabricated using thick film paste that was prepared as a nanocomposition of carbon nanotubes powder, suitable vehicle and a thinner. The response of fabricated electrodes to cadmium and lead ions was measured using differential pulse voltammetry in an acetate buffer solution using a three electrode sytem. The results were compared with the carbon electrode made from special commercial thick film polymer paste. Finally the possibility of working electrode surface activation with nitric acid and heavy metals on real biological sample detection is described here.