La demande croissante d’électricité, notamment renouvelable, entraîne une croissance de l’éolien avec l’utilisation de pales en composite de plus en plus grandes. Pour réduire le cout de maintenance de ces structures composites, le suivi de santé structurel (SHM) au cours du temps permet d’évaluer le comportement de la structure, d’anticiper les dégradations et la maintenance. Dans ce cadre, le développement de capteurs, à base de résine époxy et de nanotubes de carbone, appelés Quantum Resistive Sensor (QRS), est présenté. Les QRS peuvent être attachés à la surface de la structure ou intégrés à cœur durant la séquence de drapage. Durant la polymérisation de la résine, le comportement électrique du QRS traduit l’évolution de la réticulation et de la température dans la structure. Suite au processus de fabrication, l’influence des paramètres extérieurs (température, humidité, vitesse de déformation, coefficient de Poisson…) sur les caractéristiques des QRS a été étudiée. Durant l’utilisation de la structure composite, les QRS ont également permis la détection et la propagation d’endommagements jusqu’à la fracture ultime. Les QRS représentent donc une solution potentielle comme capteurs SHM non intrusifs, permettant un suivi de la structure, de sa fabrication jusqu’à sa dégradation finale. / The growing demands for electrical energy, especially renewable, is boosting the development of wind turbines equipped with longer composite blades. To reduce the maintenance cost of such huge composite parts, the structural health monitoring (SHM) is an approach to anticipate and/or follow the structural behaviour along time. To do so, a proper instrumentation is necessary and has to be as less intrusive as possible. To this end, the development of carbon nanotube- epoxy Quantum Resistive Sensor (QRS) is presented. QRS can be as well glued on the surface or embedded in the core of the composite structure during the stacking sequence. During manufacturing, both the temperature and resin crosslinking can be detected with the change in the QRS electrical characteristics. Once the structural part is made, the effect of the external parameters (strain rate, temperature, humidity, Poisson ratio…) on the electrical characteristics of QRS has been studied. During the composite life, the QRS electrical behaviour has also demonstrate its capability to detect the initiation and propagation of damage until final failure. A non-intrusive monitoring with QRS of the structure life cycle, from manufacturing until final breakage is therefore possible.

A theoretical model is developed for calculating the sensitivity of resistive sensors based on aligned multiwall carbon nanotubes (MWCNT) embedded in the pores of alumina membranes. Aligned MWCNTs offer more surface area as each CNT acts as a landing site for detecting gas species. The MWCNTs behave as a p-type semiconducting layer; when the bus bar contacts are placed at either end of the top surface the resistance between the contacts responds to oxidizing (resistance decreases) and reducing gases (resistance increases). The model presented in this thesis aims to understand the device resistance dependence upon the MWCNT resistance, and the sensitivity dependence upon the device structure and design. The model was utilized for enhancing the sensitivity of MWCNT sensors for ammonia (30% sensitivity) and nitrogen dioxide (40% sensitivity) gases. Experimental results from sensitivity measurements are compared with theoretical predictions.

Submitted by FABIAN RODRIGO CASTRO FORERO null (fabiancastroforero@yahoo.com) on 2016-05-25T17:32:02Z No. of bitstreams: 1 castro_fr_me_ilha.pdf: 5058433 bytes, checksum: bf5b2af2ddbd3137fd6e825d60119c97 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-05-31T13:28:40Z (GMT) No. of bitstreams: 1 castro_fr_me_ilha.pdf: 5058433 bytes, checksum: bf5b2af2ddbd3137fd6e825d60119c97 (MD5) / Made available in DSpace on 2016-05-31T13:28:40Z (GMT). No. of bitstreams: 1 castro_fr_me_ilha.pdf: 5058433 bytes, checksum: bf5b2af2ddbd3137fd6e825d60119c97 (MD5) Previous issue date: 2016-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O pé é o órgão base da sustentação do corpo humano que está constantemente submetido a esforços para garantir a estabilidade deste. Analisando-se a distribuição de força na região plantar de indivíduos, pode-se inferir a respeito de patologias nos pés, problemas posturais e de equilíbrio. O estudo da distribuição de força na região plantar é feito com o baropodômetro, um equipamento composto por sistemas de hardware e software. Neste trabalho é apresentado o desenvolvimento de um baropodômetro implementado no Laboratório de Instrumentação e Engenharia Biomédica do Departamento de Engenharia Elétrica, UNESP – Campus Ilha Solteira, constituído por 120 sensores resistivos, tipo Force Sensing Resistor (FSR), dispostos matricialmente em duas plataformas, e por circuitos de aquisição de dados, comunicação e interfaceamento. Com as informações obtidas, por meio do software é possível identificar deformidades na região plantar e locais desta região submetidos a forças elevadas. Foram feitos testes em um grupo de 30 voluntários com diferentes faixas etárias e diferentes graus de escoliose. Inicialmente os voluntários foram divididos em dois grupos, sendo que o grupo G2 (45-78 anos) apresentou valores de estabiliometria maiores quando comparados com o G1 (13-30 anos). De forma similar, foi segmentada a mesma população (N=30) em dois grupos, segundo o grau de escoliose, GrA (0-9°) e GrB (10-32°). O grupo GrB mostrou maiores valores de estabiliometria do que o GrA e foi possível determinar que quanto maior o grau de escoliose menor a dependência das variáveis de estabiliometria com a idade. / The foot is the main support organ of the human body that is constantly subjected to efforts to ensure the stability of the body. Analyzing the distribution of force in the plantar region of individuals, it is possible to infer about feet pathologies, postural and balance problems, among others. The study of foot force distribution is made with the baropodometer, an equipment composed by hardware and software systems. This work describes the baropodometer developed at the Instrumentation and Biomedical Engineering Laboratory at the Department of Electrical Engineering, UNESP – Ilha Solteira, composed of 120 resistive sensors (Force Sensing Resistor - FSR) arranged in matrix on two platforms. Furthermore, acquisition and communication boards and software made in LabVIEW were developed. With the information obtained, with the software it is possible to identify deformities in the plantar region and sites of this region subjected to high forces. Tests in 30 volunteers with different ages and different scoliosis angles were made. Firstly, the volunteers were divided into two groups according to ages. The second group G2 (45-78 years old) had higher stabilometry values than first group G1 (13-30 years old). Secondly, the 30 volunteers were divided in two groups according scoliosis angles, GrA (0-9°) e GrB (10-32°). The GrB group showed higher stabilometry values than the GrA group, and it was possible to determine that the higher the degree of scoliosis the lower the dependency of stabiliometry variables with the age.

Orientador: Aparecido Augusto de Carvalho / Resumo: O pé é o órgão base da sustentação do corpo humano que está constantemente submetido a esforços para garantir a estabilidade deste. Analisando-se a distribuição de força na região plantar de indivíduos, pode-se inferir a respeito de patologias nos pés, problemas posturais e de equilíbrio. O estudo da distribuição de força na região plantar é feito com o baropodômetro, um equipamento composto por sistemas de hardware e software. Neste trabalho é apresentado o desenvolvimento de um baropodômetro implementado no Laboratório de Instrumentação e Engenharia Biomédica do Departamento de Engenharia Elétrica, UNESP – Campus Ilha Solteira, constituído por 120 sensores resistivos, tipo Force Sensing Resistor (FSR), dispostos matricialmente em duas plataformas, e por circuitos de aquisição de dados, comunicação e interfaceamento. Com as informações obtidas, por meio do software é possível identificar deformidades na região plantar e locais desta região submetidos a forças elevadas. Foram feitos testes em um grupo de 30 voluntários com diferentes faixas etárias e diferentes graus de escoliose. Inicialmente os voluntários foram divididos em dois grupos, sendo que o grupo G2 (45-78 anos) apresentou valores de estabiliometria maiores quando comparados com o G1 (13-30 anos). De forma similar, foi segmentada a mesma população (N=30) em dois grupos, segundo o grau de escoliose, GrA (0-9°) e GrB (10-32°). O grupo GrB mostrou maiores valores de estabiliometria do que o GrA e foi possível determi... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The foot is the main support organ of the human body that is constantly subjected to efforts to ensure the stability of the body. Analyzing the distribution of force in the plantar region of individuals, it is possible to infer about feet pathologies, postural and balance problems, among others. The study of foot force distribution is made with the baropodometer, an equipment composed by hardware and software systems. This work describes the baropodometer developed at the Instrumentation and Biomedical Engineering Laboratory at the Department of Electrical Engineering, UNESP – Ilha Solteira, composed of 120 resistive sensors (Force Sensing Resistor - FSR) arranged in matrix on two platforms. Furthermore, acquisition and communication boards and software made in LabVIEW were developed. With the information obtained, with the software it is possible to identify deformities in the plantar region and sites of this region subjected to high forces. Tests in 30 volunteers with different ages and different scoliosis angles were made. Firstly, the volunteers were divided into two groups according to ages. The second group G2 (45-78 years old) had higher stabilometry values than first group G1 (13-30 years old). Secondly, the 30 volunteers were divided in two groups according scoliosis angles, GrA (0-9°) e GrB (10-32°). The GrB group showed higher stabilometry values than the GrA group, and it was possible to determine that the higher the degree of scoliosis the lower the dependency of... (Complete abstract click electronic access below) / Mestre

Des capteurs MEMS variés peuvent être fabriqués dans une technologie CMOS standard associée à une ou plusieurs étapes de gravure supplémentaires. Dans ce contexte, le micro-usinage du substrat par la face avant permet la fabrication de capteurs résistifs bas coût, basés sur des effets piezorésistifs ou thermiques, mais non optimaux en terme de bruit et de consommation. Cependant, au lieu d'envisager une optimisation technologique du procédé, ce travail s'est plutôt concentré sur le design du capteur et de son interface électronique afin d'améliorer les performances ci-dessus. L'objet de cette thèse est un accéléromètre convectif 3 axes basé sur une topologie initialement prévue pour des mesures suivant 2 axes, dans le plan de la puce, et utilisant une mesure de température différentielle. La mesure de l'accélération dans la direction perpendiculaire au plan de la puce, sans ajouter de structure supplémentaire, est donc étudiée ainsi que l'interface électronique associée. L'originalité de la mesure suivant ce 3ème axe réside dans la mesure de la température de mode commun de la structure existante. Cette étude est réalisée par l'intermédiaire de modélisations multi-physiques et électriques du capteur, de la conception et de la simulation de l'interface électronique et enfin de la caractérisation d'un prototype complet. / In the field of MEMS, various sensors can be manufactured using a standard CMOS technology and subsequent etching techniques. In this context, The Front-Side Bulk Micromachining (FSBM) approach allows the fabrication of low-cost resistive transducers based on either piezoresistive or thermal effects. Nevertheless, such fabrication method leads to non-optimized devices in terms of noise and power consumption. Instead of constraining fabrication technology, and in order to keep fabrication costs as low as possible, this work focuses on sensor design and electronic interfaces to address both issues. In this thesis, the device under study is a 3-axis CMOS thermal accelerometer. The sensor is based on a topology that was primarily introduced for 2-axis measurements only (in-plane acceleration, xy), using differential voltage across sensing thermistors. This work addresses the overall sensing performance by using dedicated front-end electronic and also investigates an opportunity to measure out-of-plane acceleration without the requirement of an additional device. The third axis (z) is provided by measuring a shift in the common-mode temperature, which is clearly an original approach. The study is carried out by means of both physical and electrical modeling of the transducer, electronic design and simulation, and prototype characterization.

Pagrindinis darbo tikslas – sukurti plačiajuostį rezistorinį jutiklį, skirtą didelės galios mikrobangų impulsams matuoti, kurio jautrusis elementas pagamintas iš n-tipo Si yra įmontuotas H tipo bangolaidyje. Rezistorinis jutiklis turėtų pasižymėti plokščia jautrio dažnine charakteristika, jo varža neviršyti 1 k, o stovinčios bangos koeficientas būti mažesnis nei 1,5. Disertacijoje yra pateikiami teoriniai elektrinio lauko pasiskirstymo bangolaidinėje sekcijoje su rezistorinio jutiklio jautriuoju elementu viduje modeliavimo baigtinių skirtumų laiko skalėje metodu rezultatai, kai jautrusis elementas yra talpinamas standartiniuose H tipo bangolaidžiuose WRD250 ir WRD840. Modeliavimo metu buvo ieškoma tokių jautriojo elemento matmenų ir savitosios varžos, kad rezistorinis jutiklis tenkintų aukščiau paminėtus reikalavimus. Disertacijoje taip pat aprašomi trijų skirtingų rezistorinių jutiklių, kurių optimalūs matmenys buvo surasti iš modeliavimo rezultatų, eksperimentiniai tyrimai. Buvo nustatytos šių jutiklių jautrio dažninės charakteristikos, jutiklių atsako signalo priklausomybė nuo mikrobangų galios ir stovinčios bangos koeficientas. Sujungus sukurtąjį jutiklį su plačiajuoste ruporine antena buvo atlikti mikrobangų galios tankio (elektrinio lauko stiprio) matavimai atviroje erdvėje. Pateikti disertacijoje internetinių maršrutizatorių ir šviesolaidinių konverterių elektromagnetinio atsparumo tyrimai, kuriuose rezistoriniai jutikliai naudojami elektrinio lauko stipriui... [toliau žr. visą tekstą] / The main goal of the thesis was the development of a resistive sensor, a sensing element of which made from n-type Si is mounted in a double ridge waveguide. Developed sensor was devoted for the measurement of high power microwave pulses. The sensor should meet the following requirements: its resistance should be lower than 1 k, a voltage standing wave ratio has been set < 1.5, and the frequency response of the sensor should be as flat as possible. In the thesis the results of theoretical calculation of electromagnetic fields inside waveguide segment with the sensing element of the resistive sensor mounted in the standard double ridged waveguides WRD250 and WRD840 are presented. Calculations have been performed using finite-difference time-domain method. The dimensions and specific resistance of the sensing element from the modeling results were chosen for the sensor that meets the requirements mentioned above. Corresponding sensors have been manufactured and their characteristics have been investigated experimentally. The sensitivity dependence on frequency, output signal dependence on microwave pulse power and voltage standing wave ratio were determined. Connecting the sensor to a wide band horn antenna the microwave pulse power density (electric field strength) in free space was measured. Resistive sensors were used for electric field strength measurement in the immunity against microwave radiation tests on internet routers and media converters demonstrating possible... [to full text]

The main goal of the thesis was the development of a resistive sensor, a sensing element of which made from n-type Si is mounted in a double ridge waveguide. Developed sensor was devoted for the measurement of high power microwave pulses. The sensor should meet the following requirements: its resistance should be lower than 1 k, a voltage standing wave ratio has been set < 1.5, and the frequency response of the sensor should be as flat as possible. In the thesis the results of theoretical calculation of electromagnetic fields inside waveguide segment with the sensing element of the resistive sensor mounted in the standard double ridged waveguides WRD250 and WRD840 are presented. Calculations have been performed using finite-difference time-domain method. The dimensions and specific resistance of the sensing element from the modeling results were chosen for the sensor that meets the requirements mentioned above. Corresponding sensors have been manufactured and their characteristics have been investigated experimentally. The sensitivity dependence on frequency, output signal dependence on microwave pulse power and voltage standing wave ratio were determined. Connecting the sensor to a wide band horn antenna the microwave pulse power density (electric field strength) in free space was measured. Resistive sensors were used for electric field strength measurement in the immunity against microwave radiation tests on internet routers and media converters demonstrating possible... [to full text] / Pagrindinis darbo tikslas – sukurti plačiajuostį rezistorinį jutiklį, skirtą didelės galios mikrobangų impulsams matuoti, kurio jautrusis elementas pagamintas iš n-tipo Si yra įmontuotas H tipo bangolaidyje. Rezistorinis jutiklis turėtų pasižymėti plokščia jautrio dažnine charakteristika, jo varža neviršyti 1 k, o stovinčios bangos koeficientas būti mažesnis nei 1,5. Disertacijoje yra pateikiami teoriniai elektrinio lauko pasiskirstymo bangolaidinėje sekcijoje su rezistorinio jutiklio jautriuoju elementu viduje modeliavimo baigtinių skirtumų laiko skalėje metodu rezultatai, kai jautrusis elementas yra talpinamas standartiniuose H tipo bangolaidžiuose WRD250 ir WRD840. Modeliavimo metu buvo ieškoma tokių jautriojo elemento matmenų ir savitosios varžos, kad rezistorinis jutiklis tenkintų aukščiau paminėtus reikalavimus. Disertacijoje taip pat aprašomi trijų skirtingų rezistorinių jutiklių, kurių optimalūs matmenys buvo surasti iš modeliavimo rezultatų, eksperimentiniai tyrimai. Buvo nustatytos šių jutiklių jautrio dažninės charakteristikos, jutiklių atsako signalo priklausomybė nuo mikrobangų galios ir stovinčios bangos koeficientas. Sujungus sukurtąjį jutiklį su plačiajuoste ruporine antena buvo atlikti mikrobangų galios tankio (elektrinio lauko stiprio) matavimai atviroje erdvėje. Pateikti disertacijoje internetinių maršrutizatorių ir šviesolaidinių konverterių elektromagnetinio atsparumo tyrimai, kuriuose rezistoriniai jutikliai naudojami elektrinio lauko stipriui... [toliau žr. visą tekstą]

Volatile organic compounds (VOCs) in air and heavy metal ions, anions, microorganism in water are environmental contaminants that require detection at certain low concentrations to avoid detrimental effects. Analytical instruments can accurately determine the concentration and composition of the contaminants at trace levels. However, these methods require skilled personnel to operate. Hence sensors should have fast response, low maintenance and easy to handle. In the present work, environmental monitoring sensor for volatile organic compounds, anion and E. coli was developed. The sensor is resistive sensor architecture with organic nanocomposite as sensing layer. The conjugated organic molecule with receptor moieties that can interact and exhibit affinity to each of the analyte was designed and synthesized. A new conducting polymer for sensing toluene, aldehyde is designed and fabricated. The sensor shows highest sensitivity and selectivity for targeted analyte. The sensor response is explained by molecular dynamics simulation. The solubility parameter of the new polymers is calculated by molecular dynamics and is used for elucidation of rationale of the mechanism for selectivity. The interaction energy of the sensing layer calculated by simulation is higher for targeted analyte than that for other analytes. The adsorption of vapors on the sensing layer results in volumetric change of the sensing layer. The effect can be experimentally determined by monitoring the thickness of the film and the change in the parameters such as mass change, capacitance, resistance change, refractive index change that occurs due to absorption of vapors in the polymers. Here, laser Doppler vibrometry, a non contact method is used to measure the displacement occurring due to interaction of a new polymer film with analyte vapors. A sensor for real time monitoring of nitrate ion concentration in water is fabricated. A new conjugated polymer is designed for selection of nitrate is used as a sensing molecule. The sensor is tested for various concentrations of nitrate ions and possible interferents effect. An organic nanocomposite based resistive sensor is designed and fabricated to detect E. coli in water. The organic molecule with receptor groups was selected such that receptor group would interact and exhibit affinity to the functional groups present on outer membrane of the cell wall of the E. coli. The resistance change is caused due to interaction and is because of E. coli acting as p-dopant to sensor molecule. The electrostatic interaction between positively charged amine groups on sensor molecule and negatively charged E. coli is believed to be the interaction mechanism. This work demonstrates that the conjugated molecules with suitable moieties can bind with analyte like VOCs, heavy metal ions, anions, microorganism, that can be used as sensing element in resistive sensor architecture.