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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.
401

System integration of electronic functionality in packaging application

Unander, Tomas January 2011 (has links)
Sensor applications are becoming increasingly important as products are now being requested to be more and more intelligent and safe. As the costs involved in sensor technology decrease its usage will spread to new market segments including new areas with products that have never previously used such functionalities, including, wood fibre based products for packaging, hygiene or graphical use. Currently there is a significant interest in developing technology that will allow packages to become interactive and be integrated with digital services accessible on the Internet. In this thesis, the system integration of a hybrid RFID based sensor platform is presented. This proposed platform provides a trade-off between the communication performance and its compatibility with international standards and also includes flexibility in on‐package customization, including the type and number of sensors. In addition it combines the use of traditional silicon based electronics with printed electronics directly onto wood fibre based materials so as to enable the possibility of creating smart packages. Together with the system integration of the sensor platform, five printed moisture sensor concepts that are designed to work with the sensor platform are presented and characterized. Firstly, there is a moisture sensor that shows a good correlation to the moisture content of wood fibre based substrates. The second one involves a sensor that detects high relative humidity levels in the air and the third is an action activated energy cell that provides power when activated by moisture. The fourth one deals with two types of moisture sensors that utilize silver nano-particles in order to measure the relative humidity in the air. The final one is a printable touch sensitive sensor that is sensitive to the moisture contained in the hand. A concept of remote moisture sensing that utilizes ordinary low cost RFID tags has also been presented and characterized. The main focus is thus on system integration to, by combining silicon based electronics with printed electronics, find the most low cost solution with regards to flexibility, sensor functions and still meet the communication standards. / När efterfrågan på mer intelligenta och säkra produkter ökar så ökar även intresset för olika typer av sensorer. När kostnaden för dessa sensorer sjunker så kommer användandet av dessa att utökas till nya marknadssegment som tidigare inte använt denna typ av funktionalitet, som tillexempel pappersbaserade förpackningar, hygienartiklar och papper för grafiskttryck. Det är för närvarande ett stort intresse att utveckla tekniker som tillåter förpackningar att bli interaktiva och integrerade med olika digitala tjänster kopplade till Internet. I denna avhandling så presenteras systemintegrationen av en RFID baserad sensor plattform som tillhandahåller en avvägning mellan kommunikationsprestanda, kompabilitet med internationella standarder och kundanpassningsflexibilitet. Där man direkt på förpackningen kombinerar fördelarna med traditionell kiselbaserad elektronik med trycktelektronik för att kunna skapa intelligenta förpackningar. I avhandlingen presenteras och utvärderas även fem trycka fuktsensorer som är designade att kunna användas tillsammans med sensor plattformen. Den första sensorn mäter fukthalten i cellulosabaserade substrat. Den andra kan detektera höga fukthalter i luften. Den tredje, som aktiveras vid en händelse, producerar en elektrisk ström när den blir fuktig. Den fjärde sensorn använder sig av silverbaserade partiklar i nanostorlek för att mäta fukthalten i luften. Den femte sensorn är en beröringskänslig sensor som ger utslag av fukten i handen. Utöver dessa sensorer så utvärderas även ett koncept med en fuktsensor som kan läsas av på avstånd. Fokus är således att på system integrationsnivå, med hjälp av att kombinera kisel elektronik med tryckt elektronik, hitta den mest kostnadseffektiva lösningen med avseende på flexibilitet, sensor funktionalitet och att även kunna möta kommunikationsstandarderna.
402

Highly Sensitive and Selective Gas Sensors Based on Vertically Aligned Metal Oxide Nanowire Arrays

Chen, Jiajun 17 December 2010 (has links)
Mimicking the biological olfactory systems that consist of olfactory receptor arrays with large surface area and massively-diversified chemical reactivity, three dimensional (3D) metal oxide nanowire arrays were used as the active materials for gas detection. Metal oxide nanowire arrays share similar 3D structures as the array of mammal's olfactory receptors and the chemical reactivity of nanowire array can be modified by surface coatings. In this dissertation, two standalone gas sensors based on metal oxide nanowire arrays prepared by microfabrication and in-situ micromanipulation, respectively, have been demonstrated. The sensors based on WO3 nanowire arrays can detect 50 ppb NO2 with a fast response; well-aligned CuO nanowire array present a new detection mechanism, which can identify H2S at a concentration of 500 ppb. To expand the material library of 3D metal oxide nanowire arrays for gas sensing, a general route to polycrystalline metal oxide nanowire array has been introduced by using ZnO nanowire arrays as structural templates. The effectiveness of this method for high performance gas sensing was first investigated by single-nanowire devices. The polycrystalline metal oxide coatings showed high performance for gas detection and their sensitivity can be further enhanced by catalytic noble metal decorations. To form electronic nose systems, different metal oxide coatings and catalytic decorations were employed to diversify the chemical reactivity of the sensors. The systems can detect low concentrated H2S and NO2 at room temperature down to part-per-billion level. The system with different catalytic metal coatings is also capable of discriminiating five different gases (H2S, NO2, NH3, H2 and CO).
403

Resilient Average and Distortion Detection in Sensor Networks

Aguirre Jurado, Ricardo 15 May 2009 (has links)
In this paper a resilient sensor network is built in order to lessen the effects of a small portion of corrupted sensors when an aggregated result such as the average needs to be obtained. By examining the variance in sensor readings, a change in the pattern can be spotted and minimized in order to maintain a stable aggregated reading. Offset in sensors readings are also analyzed and compensated to help reduce a bias change in average. These two analytical techniques are later combined in Kalman filter to produce a smooth and resilient average given by the readings of individual sensors. In addition, principal components analysis is used to detect variations in the sensor network. Experiments are held using real sensors called MICAz, which are use to gather light measurements in a small area and display the light average generated in that area.
404

Gas Detection Applications of Vertically Aligned Metal Oxide Nanowire Arrays

Su, Haiqiao 18 December 2014 (has links)
To build novel electronic noses for mimicking biological olfactory systems that consist of olfactory receptor arrays with large surface area and massively-diversified chemical reactivity, three dimensional (3D) vertical aligned ZnO nanowire arrays were employed as active materials for gas detection. ZnO nanowire arrays share 3D structures similar to mammalian olfactory receptor arrays, with thousands of vertical nanowires providing a high reception area which can significantly enhance the sensors’ sensitivity. Meanwhile, with different material decorations (such as SnO2, In2O3, WO3 and polymers), each array of nanowires can produce a distinguishable response for each separate analyte, which would provide a promising way to improve the selectivity. Both patterned grown well-aligned and wafer size random-distributed 3D nanowire array sensing devices are investigated. Several different types of gas sensors have been investigated in this dissertation. Metal oxide semiconductor gas sensors based on 3D metal oxides/ZnO vertical nanowire arrays have detected NO2 and H2S down to ppb level, and five gases of NO2, H2S, H2, NH3, and CO have been discriminated. Active self-powered gas sensors based on 3D metal oxides/ZnO vertical nanowire arrays have been successfully fabricated and worked well for H2S and NO2 detection. With the decoration by mixture of PEDOT polymer with metal oxide nanoparticles, ZnO vertical nanowire array gas sensors have fast response and recovery time as well as good sensitivity to volatile organic gases of acetone, methanol and ethanol. A novel ionization sensor also has been built by ZnO vertical nannowire arrays, and this device could be able to ionize air under safety operation voltage.
405

The development of dendrimer-gold composite based electrochemical immunosensor for the detection of cholera toxin in water

14 January 2014 (has links)
M.Tech. (Chemistry) / Please read abstract in the full-text document
406

Conception d'antennes pour biocapteurs implantables / Antenna designs for implantable biosensors

Perrissol, Philippe 08 December 2015 (has links)
De tous temps, l'amélioration des moyens de guérison et de prévention des maladies a constitué un enjeu majeur de nos sociétés. Les possibilités offertes désormais par les technologies modernes ont permis de multiplier le nombre d'applications médicales mais toutes ces pratiques nouvelles ont un impact dans le domaine de l'expérimentation animale et impliquent aussi un suivi sanitaire à grande échelle. Le travail présenté dans cette thèse a pour but de moderniser la surveillance de l'état de santé des souris de laboratoire, et s'inscrit dans un projet collaboratif entre le LEAT et TIRO-MATOs. L’objectif est la conception d’un système capable de faciliter ce suivi au quotidien. Pour cela, la conception d'une antenne à 433MHz, connectée à un capteur de température, implantable dans une souris et intégrant notamment l'impact de l'environnement biologique a tout d’abord été étudiée. Après caractérisation des éléments obtenus, la faisabilité d’un système de géolocalisation est présentée. Afin de disposer également de la capacité d’identification des sujets, cette étude s’est poursuivie à 868 MHz (standard RFID). Dans cette partie, l’antenne interrogatrice placée sous la cage, a été plus particulièrement étudiée. Afin de comparer les différentes antennes obtenues, des mesures de puissance récupérées par le lecteur (RSSI) sont réalisées, utilisant pour cela des phantoms de souris spécialement mis au point pour cette étude. Les conclusions tirées par comparaison notamment avec les résultats de phantoms numériques ont permis de concevoir un dispositif de diversité à 4 antennes et de le tester en présence de un à quatre phantoms dans quatre différentes zone de la cage. / The improvement of the methods of cure and prevention of diseases has always constituted a major objective in our societies. The possibilities offered by modern technologies allow the multiplication of the number of medical applications but all these new practices have an impact on pre-clinical animal studies which require a large-scale health status follow-up. This work, which aims at modernizing the supervision of laboratory mice in an animal facility, is a collaborative project between the LEAT and TIRO-MATOs labs. The objective is the design of a system allowing to facilitate this follow-up for the researchers while leading to new research areas. Thus, we first studied the conception of an antenna working at 433MHz, connected to a mouse implanted temperature sensor, taking also into account the biological environment impact. After having characterized the obtained elements, the feasibility of a localization system has been studied. In order to identify several mice within a cage, the study has focused on using an UHF RFID (Radio Identification Frequency) standard (868 MHz). In this part, a reader antenna placed under the cage has been investigated. Different solutions have been proposed and compared thanks to the received power (RSSI level) recorded by the reader. For that purpose, mice “phantoms” have been specifically developed. The comparison of the different results obtained particularly with numerical mice “phantoms”, led to the conception of a reading diversity system composed of 4 antennas. This last system allows to detect the presence of up to four phantoms within a cage divided into four zones.
407

The new version of the Radiation Monitor system for the electronics at the CERN : electronic components radiation hardness assurance and sensors qualication / La nouvelle version du système de monitorage des radiations pour l'électronique au CERN : garantie de tenue aux radiations des composants électroniques et qualication des capteurs

Danzeca, Salvatore 02 April 2015 (has links)
La mesure des niveaux de rayonnement est une exigence essentielle dans le LHC et ses lignes d'injection afin de quantifier les effets des radiations sur l'électronique et de fournir une connaissance détaillée du champ de rayonnement. Le système de surveillance des rayonnements pour l'électronique au CERN, le "RadMon '', a été installé dans les zones critiques où l'équipement est ou sera placé. Les problèmes rencontrés au cours des dernières années d'utilisation du Radmon, et la nécessité d'améliorer la précision et la résolution des mesures a conduit au lancement d'une nouvelle conception du moniteur.Ce travail décrit l'architecture du nouveau RadMon (V6), sa fiabilité dans les environnements radiatifs et de la stratégie adoptée pour choisir et qualifier les capteurs utilisés pour surveiller le champ de rayonnement mixte des accélérateurs du LHC. Les directives du CERN ont été adoptées pour qualifier les composants RadMon sous rayonnement afin de développer une nouvelle architecture à la fois plus tolérante au rayonnement et plus polyvalente que celui de la version précédente. Dans ce contexte, les défis que les tests de rayonnement imposent pour mesurer les Single Event Upsets (SEUs) sur un composant complexe à signaux mixtes tels que le convertisseur analogique-numérique, ont conduit au développement d'une technique de test innovant, qui sera décrit dans cette thèse.L'environnement radiatif complexe du LHC impose un processus de qualification particulier qui sera décrit et discuté dans ce travail pour les RadFets (capteur dose ionisante) et les mémoires SRAM (capteur de fluence High Energy Hadrons).L'utilisation du RadFet dans un champ mixte de rayonnement a été étudié et analysé au moyen de sources de 60Co et de faisceaux de protons de différentes énergies.Les RadFets ont été ré-étalonné en étudiant le débit de dose, les sources de particules, la température, la guérison thermique en fonction de l'épaisseur d'oxyde. En outre, grâce à la nouvelle architecture de la RadMon, de nouvelles configurations de polarisation ont été testées pour améliorer la résolution.Deux types de mémoires SRAM avec des nœuds technologiques de 400 et 90 nm ont été testés et calibrés en suivant une méthode de qualification stricte qui comprend des tests protons,dans la plage de 30 à 400 MeV et neutrons, depuis les énergies thermiques jusqu'à des énergies intermédiaires (~ 14 MeV). La mémoire 90 nm améliore la précision et la résolution de la mesure de la fluence hadronique. En outre, l'utilisation simultanée des deux types de mémoires améliore la précision de la détection des neutrons thermiques par rapport à la version précédente, grâce à d'une procédure qui sera détaillée dans ce travail.Les efforts en vue de l'amélioration de la résolution des mesures de TID pour le nouveau RadMon conduisent à la recherche et à l'étude d'un nouveau type de dosimètre : le dosimètre a Grille Flottante (FGDOS). Le capteur intégrant une électronique complexe, une qualification complète sous rayonnement était nécessaire. Des tests en champ mixte, des tests au 60Co et des tests au protons ont été réalisés afin d'évaluer les performances et les problèmes potentiels du capteur. Dans ce contexte, un modèle analytique du capteur a été conçu pour démontrer que la structure à Grille Flottante pouvait être utilisée comme instrument de mesure du ‘charge yield' à température ambiante et sous des champs électriques faibles.La caractérisation de la tolérance au rayonnement du matériel, le processus de qualification et les étalonnages des capteurs ont considérablement amélioré la fiabilité globale et la qualité des mesures sur la nouvelle version du RadMon. Ces améliorations font du RadMon un instrument de référence pour la surveillance des rayonnements des champs mixtes complexes, tels que ceux rencontrés dans le LHC et sa chaîne d'injecteurs, mais aussi pour d'autres centres de recherche en physique des particules, comme JLAB aux États-Unis, J-PARC au Japon. / The measurement of the radiation levels is an essential requirement in the LHC and its injection lines in order to quantify radiation effects on electronics and provide a detailed knowledge of the radiation field. The radiation monitoring system for the electronics at CERN, the “RadMon'', was installed in critical areas where equipment is or will be placed. Issues experienced in the last years of Radmon operation, the obsolescence of a few fundamental components of the electronic board and the necessity to improve both the accuracy and the resolution of measurements led to the launch of a new design of the monitor.This work describes the architecture of the new RadMon (V6), its reliability in radiation environments and the strategy adopted to choose and qualify the sensors, used for monitoring the mixed radiation field of the LHC accelerators. The CERN guidelines were adopted to qualify the RadMon components under radiation in order to develop a new architecture both more tolerant to radiation and more versatile than that of the previous version. In this context, the challenges that radiation tests impose for measuring Single Event Effects (SEUs) on a complex mixed-signal component such as the Analog to Digital converter, led to the development of an innovative test technique, which will be described in this thesis.The reliability of the RadMon measurements strongly depends on the calibration of its sensors. The complex radiation environment of the LHC imposes a peculiar qualification process which will be described and discussed in this work for the RadFets (Total Ionizing Dose sensor) and the SRAM memories (High Energy Hadrons fluence sensor).The use of the RadFet in a mixed field radiation environment has been studied and analyzed by means of 60Co sources as well as proton beams at different energies.The RadFets have been re-calibrated by studying the dose rate, particle sources, temperature, annealing and fading effects as a function of the oxide thickness. Furthermore, thanks to the new architecture of the RadMon, new biasing configurations have been tested to improve the resolution.Two types of SRAM memories with technology nodes of 400 and 90nm have been tested and calibrated by following a strict qualification methodology which includes tests with protons in the range 30-400 MeV, and with neutrons from thermal energies up to intermediate energies (~14 MeV). The 90nm memory improves the accuracy and resolution of the hadron fluence measurement. Moreover, the simultaneous use of both types of memories permits an improvement on the accuracy of the thermal neutron detection with respect to the previous version, as a result of a procedure which will be detailed in this work.The efforts towards the improvement of the TID measurements resolution for the new RadMon lead to the research and study of a new type of dosimeter sensor: the Floating Gate dosimeter (FGDOS). The sensor embeds complex circuitry, thus a full radiation qualification was necessary. Mixed field radiation tests, 60Co and protons tests have been carried out in order to evaluate the performance and the possible issues of the sensor. In this context, an analytical model of the sensor was developed to prove that the floating gate structure can be used as charge yield measurement instrument at room temperature and at low electric fields.The radiation tolerance characterization of the hardware, the qualification and calibration process of the sensors have significantly improved the overall reliability and quality of the measurements of the new RadMon. These improvements turned it into a reference instrument for radiation monitoring of complex mixed fields, such as the one encountered in the LHC, its injectors chain, and other particle physics research centers, such as JLAB in US, J-PARC in Japan.
408

Impact of Ligand Shell Architecture on Structure and Reactivity of DNA Aptamer-Linked Gold Nanoparticle Assemblies

Baldock, Brandi 27 October 2016 (has links)
DNA-functionalized gold nanoparticles (DNA-NPs) have enormous potential as building blocks for materials due to their ability to specifically recognize and respond to target molecules and surfaces. The ability of DNA aptamers to adopt different conformations and bind either complementary DNA sequences or analyte molecules allows them to mediate nanoparticle assembly or disassembly, generating selective colorimetric responses. Aptamer-mediated nanoparticle assembly and disassembly is sensitive to the nanoparticle ligand shell composition and structure, yet these topics have not been extensively explored. In this dissertation, a method for determining the ligand shell composition of DNA-NPs is described and a framework for understanding the impact of the DNA assembly arrangement and recognition strand density upon aptamer-mediated nanoparticle assembly and disassembly is developed. Design rules for creating sensors with desired properties are elucidated, leading to creation of sensors with improved detection limits and quantification ranges. A technique was needed to determine the number of DNA strands of any base composition attached to gold nanoparticles (AuNPs) of any core size. A rapid, convenient and inexpensive method to quantify the number of label-free DNA strands attached to AuNPs was therefore developed. This technique was extended to determine two different DNA sequences bound to AuNPs using UV-visible and fluorescence spectroscopy. Based on the results of quantifying the ligand shells of DNA-NPs functionalized with two sequences, disulfide-terminated DNA non-specifically adsorbs and then rearranges to specifically bind the gold surface. The position of the AuNPs and DNA strands within DNA-NP assemblies had a profound influence on their ability to assemble and sense adenosine. Assemblies designed for large inter-AuNP spacing were stable but unable to sense adenosine. Assemblies designed for short inter-AuNP spacing were unstable until the DNA ligand shell was diluted. AuNPs functionalized with the fewest number of aptamers produced assemblies with the lowest detection limit and apparent disassociation constant and the largest analyte quantification range. Increasing the number of aptamer strands per AuNP increased the cooperativity of the AuNP disassembly response to adenosine. This dissertation includes previously unpublished co-authored material.
409

Estudo e desenvolvimento de sensores e dispositivos utilizando nanoestruturas alotrópicas de carbono / Study and development of sensors and devices based on nano-structured carbon allotropes

Silva, Guilherme de Oliveira 10 July 2018 (has links)
Um desafio central na área das ciências da saúde e biomédica tem sido o desenvolvimento de testes clínicos embasados em novas tecnologias que resultem em medidas precisas, com resultados consistentes mais rápidos que os convencionais, e ao menor custo possível. Os esforços atuais têm se concentrado em integrar a análise de materiais biológicos a componentes de circuitos integrados compatíveis com a indústria de semicondutores existente. Nesse contexto, esse trabalho apresenta duas contribuições a partir do uso de materiais nanoestruturados alótropos do carbono. Primeiramente, demonstramos como o desempenho de um sensor de pH embasado na tecnologia EGFET (Extended Gate Field Effect Transistor) pode ser controlado com a incorporação de grafenos, com diferentes graus de funcionalização, a eletrodos de FTO (Fluorine doped Tin Oxide). Os eletrodos de FTO foram modificados através da deposição dos materiais nanoestruturados de carbono via eletroforese. O desempenho dessas amostras como sensor de íons H+ mostrou dependência quanto ao tempo de deposição e composição tampão utilizado, tendo seu desempenho aumentado em até 24%, atingindo uma sensibilidade máxima de 67 mVopH-1 para tampão fosfato. A segunda contribuição desse trabalho trata-se da combinação das informações obtidas com um arranjo de dispositivos de NTFETs (Nanotubes Field Effect Transitors) decorados com nanopartículas metálicas e análise de discriminantes lineares, empregados na classificação de diferentes populações celulares. O método proposto foi capaz de identificar e classificar corretamente entre as linhagens de células cancerígenas B16 (melanoma), 3LL (carcinoma) e 3L4 (linfoma), além de distingui-las corretamente de suas contrapartes saudáveis. Adicionalmente, utilizamos esse conjunto de dados para classificar uma população celular desconhecida, demonstrando uma possível utilidade clínica da metodologia desenvolvida. / A central challenge in the biomedical field has been the development of new approaches for clinical tests based on microelectronic technologies, aiming trustful and precise results, faster and cheaper than the standard techniques. Current efforts have focused on integrating the analysis of biological samples and integrated circuit components compatible with the standard semiconductor industry. In this context, the present work gives two contributions on the usage of carbon nanostructure allotropes. First, we show how the performance of pH sensors based on EGFET (Extended Gate Field Effect Transistor) can be tuned with the integration of graphene nanosheets, with different degrees of functionalization, into FTO (Fluorine doped Tin Oxide) electrodes. The FTO electrodes were modified through EPD (electrophoretic deposition) of the carbon nanomaterials. The device performance as pH sensor showed dependence on the time of deposition and buffer composition, increasing up to 24% compared to the bare FTO electrode and reaching a maximum sensitivity of 67 mVopH-1 for phosphate buffer. The second contribution of this work regard the combination of the data gathered using an array of NTFETs (Nanotube Field Effect Transistors) decorated with metal nanoparticles and LDA (Linear Discriminant Analysis) to distinguish among different cell populations. The proposed method correctly classifies among the cancer cell lines B16 (melanoma), 3LL (carcinoma), and 3L4 (lymphoma), as well as cancer cells from their healthy counterparts. Additionally, we demonstrated a possible application of the method correctly classifying blind samples.
410

Saving resources through smart farming : An IoT experiment study

Jonarv Hultgren, Susanne, Tennevall, Philip January 2019 (has links)
Context: Smart farming, agritech, is growing in popularity and is starting to develop rapidly with some already existing technology that is implemented in agriculture for both industrial and private use. Objectives: The goal of this thesis is to investigate the benefits and issues with implementing technology in agriculture, agritech. In this thesis the investigation and research is performed by conduction a literature study and an experiment. Realization: A prototype was created to monitor the soil moisture level and calculating the average soil moisture value, then water the plants when needed. This was then compared to a manually watered pot to investigate if agritech could reduce the water usage when maintaining plants. Results: The result of the experiment indicates that it is possible to improve the use of resources such as human labor, time spent on maintaining the plants and water usage. Conclusions: The conclusion of this thesis is with the help of agritech, human workers can spend more time on other tasks and maintain the technology implemented. Instead of observing the plants to see if they need watering and watering them manually. Water usage may also be minimized with the help of sensors that make sure the plants only get watered when needed by constantly checking the soil moisture level.

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