Dissertations / Theses on the topic 'Microsensors'
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McCarthy, Jeffrey J. "Potentiometric microsensors and telemetry." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39268.
Full textThe second phase of research focussed on the development of a pH sensitive radiotelemetric device that could eventually be used for the noninvasive monitoring of gastric pH. The first attempt used an ISFET as a variable resistor in a simple telemetry circuit. The drift in the pH dependent signal from this device was significant. The use of a differential sensor was studied as a possible way to minimize the effect of signal drift. This system measured the differential output of a pH ISFET and a pH insensitive ISFET. The pH insensitivity was due to an alkanethiol monolayer at the ISFET$ vert$solution interface.
It was shown that ISFETs are well suited for use as sensors in telemetry devices. The union of these previously independent research areas has been achieved.
Kerness, Nicole. "CMOS-based calorimetric chemical microsensors /." [S.l.] : [s.n.], 2002. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=14839.
Full textPathak, Shrey. "Piezoelectric microsensors for semiochemical communication." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/57210/.
Full textLin, Jenn-Yu Gary. "Sensor compatible digitizing techniques for integrated microsensors." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/22215.
Full textWeltin, Andreas [Verfasser], and Gerald A. [Akademischer Betreuer] Urban. "Multiparametric, flexible microsensors for in vivo application." Freiburg : Universität, 2015. http://d-nb.info/1119327407/34.
Full textMcCulloch, Scott. "Fibre optic microsensors for intracellular chemical measurements." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248617.
Full textSAUSER, FRANK EDWARD. "PACKAGING OF PRESSURE MICROSENSORS FOR CLINICAL APPLICATIONS." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109368416.
Full textSrinivas, T. A. S. "A free-standing microthermopile infrared detector." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259660.
Full textLazaro, Orlando. "CMOS inductively coupled power receiver for wireless microsensors." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51874.
Full textCho, SeongHwan 1974. "Energy efficient RF communication systems for wireless microsensors." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/29240.
Full textIncludes bibliographical references (p. 131-137).
Emerging distributed wireless microsensor networks will enable the reliable and fault tolerant monitoring of the environment. Microsensors are required to operate for years from a small energy source while maintaining a reliable communication link to the base station. In order to reduce the energy consumption of the sensor network, two aspects of the system design hierarchy are explored: design of the communication protocol and implementation of the RF transmitter. In the first part of the thesis, energy efficient communication protocols for a coordinated static sensor network are proposed. A detailed communication energy model, obtained from measurements, is introduced that incorporates the non-ideal behavior of the physical layer electronics. This includes the frequency errors and start-up energy costs of the radio, which dominate energy consumption for short packet, low duty cycle communication. Using this model, various communication protocols are proposed from an energy perspective, such as MAC protocols, bandwidth allocation methods and modulation schemes. In the second part of the thesis, design methodologies for an energy efficient transmitter are presented for a low power, fast start-up and high data rate radio.
(cont.) The transmitter is based on a [Epsilon]-[Delta] fractional-N synthesizer that exploits trade-offs between the analog and digital components to reduce the power consumption. The transmitter employs closed loop direct VCO modulation for high data rate FSK modulation and a variable loop bandwidth technique to achieve fast start-up time. A prototype transmitter that demonstrates these techniques is implemented using 0.25[mu]m CMOS. The test chip achieves 20[mu]s is start-up time with an effective data rate of 2.5Mbps while consuming 22mW.
by SeongHwan Cho.
Ph.D.
Leonte, Irina Ionela. "High frequency acousto-electric microsensors for liquid analysis." Thesis, University of Warwick, 2008. http://wrap.warwick.ac.uk/3681/.
Full textDing, Xiaoyi. "Mechanical properties of silicon films and capacitive microsensors." Case Western Reserve University School of Graduate Studies / OhioLINK, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=case1054842799.
Full textGarcia, Castro Fatima. "Deformation microsensors on flexible substrate for health applications." Thesis, Rennes 1, 2019. http://www.theses.fr/2019REN1S100.
Full textThis work focuses on the processing of mechanical sensors on flexible substrates. The devices are designed and optimized with the objective of detecting small deformations in real time. They can be applied for health signal acquisition, in particular small electrophysiological signals that can be detected by deformation, for example on the surface of the skin. The work includes the technological development of sensors made of microcrystalline silicon deposited by PECVD or ICPCVD on very thin flexible substrates (Kapton 25 µm thick). For each type of deposition, mechanical stress studies are presented, in particular through the determination of the gauge factor. The dynamic characterization of the sensors is carried out through the development of a specific test bench for reproducible real-time deformation measurements. The results make it possible to determine optimized geometries, capable of monitoring complex deformations in real time, up to ECG-type signals. Sensor matrices are also produced and tested
Menolfi, Christian Ivo. "Low noise CMOS chopper instrumentation amplifiers for thermoelectric microsensors /." Zürich, 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13583.
Full textAydemir, Akin. "Deep-trench Rie Optimization For High Performance Mems Microsensors." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608719/index.pdf.
Full text#956
m depth for 1 &
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m opening for a dissolved wafer process (DWP) and to achieve 100 &
#956
m depth for 1 &
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m opening for silicon-on-glass (SOG) process. A number of parameters affecting the etch rate and profile angle are investigated, including the step times, etch step pressure, platen power, and electrode temperature. Silicon etch samples are prepared and processed in METU-MET facilities to understand and optimize the DRIE process parameters that can be used for the production of MEMS gyroscopes and accelerometers. The etch samples for DWP are masked using a photoresist, Shipley S1813. After the optimization process, vertical trench profiles are achieved with minimum critical dimension loss for trench depths up to 20 &
#956
m. Since the selectivity of the resist is not sufficient for 100 &
#956
m deep trench etch process, silicon dioxide (SiO2) is used as the mask for this process. At the end of the optimization processes, more than 100 &
#956
m depth for 1 &
#956
m opening with almost vertical sidewalls are achieved. In summary, this study provides an extensive understanding of the DRIE process for successful implementations of integrated MEMS sensors.
Siegesmund, Øyvind. "Development and electrochemical characterization of ultra-microsensors using nanotechnology." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-6851.
Full textScalera, Jonathan E. "Image Chipping with a Common Architecture for Microsensors (CAuS)." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34172.
Full textA notable shortcoming of these systems is the fact that they are battery powered. The use of a finite power source places an upper limit on the lifespan of such a system. Thus, a major thrust in the development and usage of these microsensor platforms lies in the conservation of their limited energy resources. In attempt to reduce power consumption and hence extend the system's lifespan, communication bandwidths are often limited. In order to reduce the required bandwidth, much of the signal processing necessary to achieve a desired functionality must be performed within the microsensor platform itself.
This thesis effort provides this crucial bandwidth reduction by implementing in hardware an algorithm
developed by the University of Maryland, which limits transmissions to the best view
Regions-of-Interest (ROI) data, on the CAuS platform by BAE Systems. The hardware implementation
was verified with a Matlab script that compared its results with those of the original
algorithm. It was shown that these implementations were consistent for all of the data sets tested.
Moreover, a subjective analysis, in which the detected ROIs were visually inspected, was performed
to corroborate the former quantitative results.
Master of Science
Zorlu, Özge. "Orthogonal fluxgate type magnetic microsensors with wide linear operation range." Konstanz Hartung-Gorre, 2008. http://d-nb.info/988140535/04.
Full textWalmet, Eric Robert. "In-situ monitoring of PMMA solution polymerization with dielectric microsensors." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/10036.
Full textSchmidt, Martin Arnold. "Microsensors for the measurement of shear forces in turbulent boundary layers." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/14781.
Full textLin, Qian. "A Plastic-Based Thick-Film Li-Ion Microbattery for Autonomous Microsensors." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1175.pdf.
Full textWu, Zhizhen. "Flexible Microsensors based on polysilicon thin film for Monitoring Traumatic Brain Injury (TBI)." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1512045589967871.
Full textFink, Klaus Michael. "Investigations of environmental degradation of materials by measurement of electrolyte parameters using microsensors and microelectrodes." Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1058210033.
Full textWang, Lin. "Design, analysis and testing of humidity microsensors produced in mitel 1.5[mu]m CMOS technology." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0015/MQ47841.pdf.
Full textFlamm, Hubert [Verfasser], and Gerald A. [Akademischer Betreuer] Urban. "Electrochemical microsensors for superoxide monitoring in cell culture = Elektrochemische Mikrosensoren fuer Superoxid-Monitoring in Zellkultur." Freiburg : Universität, 2014. http://d-nb.info/1123482217/34.
Full textMehta, Anjum. "MICROMACHINED ELECTROCHEMICAL SENSORS FOR HYDROGEN PEROXIDE AND CHLORINE DETECTION." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3464.
Full textM.S.M.E.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering
Ferrara, Lisa Anne. "The Development of an In Vivo Spinal Fusion Monitor Using Microelectromechanical(MEMS) Technology to Create Implantable Microsensors." Cleveland State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1234531155.
Full textLI, CHUNYAN. "A SPIRALLY-ROLLED FLEXIBLE POLYMER TUBE INTEGRATED WITH MICROSENSORS AND MICROFLUIDIC DEVICES FOR MULTIFUNCTIONAL SMART MICROCATHETERS." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1196111658.
Full textKumar, Abhishek. "Development, characterization and experimental validation of metallophthalocyanines based microsensors devoted to monocyclic aromatic hydrocarbon monitoring in air." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22635/document.
Full textThis PhD work is dedicated to investigate potentialities of phthalocyanines materials to realize a Quartz Crystal Microbalance (QCM) sensor for Benzene, Toluene and Xylenes (BTX) detection in air. The goal is to develop a sensor-microsystem capable of measuring BTX concentrations quantitatively below the environmental guidelines with sufficient accuracy. To achieve these objectives, our strategies mainly focused on experimental works encompassing sensors realization, sensing material characterizations, development of gas-testing facility and sensor testing for different target gases. One of the main aims is to identify most appropriate phthalocyanine material for sensor development. After comparative sensing studies, tert-butyl-copper phthalocyanine based QCM device is found as most sensitive and detail metrological characteristics are further investigated. Results show repeatable, reversible and high magnitude of response, low response and recovery times, sub-ppm range detection limit, high resolutions and combined selectivity of BTX gases among common atmospheric pollutants. Special focus is given to understand the gas/material interactions which are achieved by (a) XRD and SEM characterizations of sensing layers, (b) formalization of a two-step adsorption model and (c) assessing extent of diffusion of target gas in sensing layer. At last, possible ageing of sensor and suitable storage conditions to prevent such effect are investigated
Scaglia, Philipp, and Martin Zimdahl. "Treatment effects of van Beek activator comparing two wear-time prescriptions assessed by microsensors: a randomized clinical trial." Thesis, Malmö universitet, Odontologiska fakulteten (OD), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-19730.
Full textAim: The aim of this study was to evaluate the compliance and overjet changes among patients treated with the van Beek activator comparing a twelve- and eight-hours daily wear-time prescription. Material and methods: The study sample consisted of thirteen patients (4 boys and 9 girls) with a mean age of 10.0 years (SD = 0.9). All patients had a Class II malocclusion and were treated with the van Beek activator. Patients were randomly assigned to two groups with a wear-time of twelve and eight hours respectively. Compliance was measured with the aid of a microsensor (TheraMon®) built into the activator and the overjet and overbite were recorded after the first, third and sixth month. Results: The mean decrease in overjet among the 8 hours group after six months was 3.4 mm compared to the 3.5 mm overjet reduction recorded in the 12 hours group. The mean wear-time in the 12 hours group and 8 hours group were 8.2 hours (SD = 1.7) and 7.9 hours (SD = 2.6) per day respectively. The overall mean daily wear-time of all patients in both groups was 8.1 hours. Conclusions: The eight-hours prescription was easier to achieve compared to the twelve-hours. The van Beek activator was effective in Class II correction, no clinically significant difference in treatment effect was observed between the two wear-time prescriptions.
Suzuki, Takeharu, and n/a. "Integrated, Intelligent Sensor Fabrication Strategies for Environmental Monitoring." Griffith University. School of Microelectronic Engineering, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040813.131206.
Full textSuzuki, Takeharu. "Integrated, Intelligent Sensor Fabrication Strategies for Environmental Monitoring." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367295.
Full textThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Microelectronic Engineering
Full Text
Karavai, Olga. "Mapping local corrosion parameters using SVET and SIET." Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22052.
Full textLocalized corrosion, i.e., corrosion confined to local regions, is difficult to predict and control. In general, it appears as a result of heterogeneities, either in the metal or in the corrosive environment. One of the phenomenological features of localised corrosion is the development of specific environments close to active sites. In practice, the micro-environment near the metallic surface is different from that of the bulk medium and varies with time and conditions of the system under study. Localized electrochemical techniques based on the use of microelectrodes are well suited for in situ sensing the distribution of potential, current and chemical species in active zones, pores or defects. Most of the published work dealing with microelectrodes in corrosion is mainly exploratory and their use in a regular basis is still rare in corrosion research. This work presents the development and application of microelectrodes as experimental tools capable to assess local electrochemical reactions on metallic substrates immersed in aggressive solutions. Traditional electrochemical techniques used in corrosion research give the average response of the global activity of the whole surface not discriminating local effects and local chemistry. Therefore they are unable per si to properly characterize localized phenomena and the corresponding corrosion, inhibitive mechanisms and, sometimes, even to select the best protection methods. It is important to know local parameters such as pH, micro-galvanic effects, concentration of oxidizing (like O2) and aggressive (like Cl-) species, and formation of surface films. The Scanning Vibrating Electrode Technique (SVET) was used for local measurements of ionic currents in solution. The technique detects the potential distribution in solution associated to ionic currents in solution. For the analysis of the chemical species involved in the corrosion process, electrochemical microsensors were used in SIET (Scanning Ion Selective Electrode Technique) mode. Microelectrodes sensitive to pH, dissolved oxygen and metal cations (namely, Mg2+, Zn2+ and Cu2+) were developed and characterized. Work was also done with microeloectrodes sensitive to Al3+, but with less success. Then, they were used for investigating the reactivity on defects and corrosion inhibition on coated aluminium and magnesium alloys, detecting the micro-distribution of chemical species in solution close to the corroding surface of Zn, Cu and a Zn- Fe galvanic couple specimens. ix Limitations and difficulties exist for the use of these techniques in corrosion research due to the inherent reactivity of corroding metals, with the formation of corrosion products and sharp changes of pH, O2 and ionic strength along the samples surface. In spite of the difficulties, the results presented here demonstrate that the SVET/SIET mapping gives useful information for the quantification of electrochemical processes at the micro-level. The data are of prime importance for the modelling and simulation of corrosion mechanisms, selection of new corrosion inhibitors and development of ‘‘smart” coatings that suppress the corrosion processes.
A corrosão localizada, i.e., corrosão confinada a locais específicos, é difícil de prever e controlar. Em geral, ocorre como resultado de heterogeneidades tanto no metal como no ambiente corrosivo. Uma das características da corrosão localizada é o desenvolvimento de ambientes específicos junto das zonas activas. Na prática, o micro-ambiente junto da superfície metálica é diferente do do seio da solução, variando com o tempo e com as condições do sistema em estudo. Técnicas electroquímicas localizadas baseadas na utilização de microeléctrodos são convientes para medir a distribuição de potencial, intensidade de corrente e espécies químicas em solução junto de zonas activas, poros ou defeitos. Muito do trabalho que existe publicado sobre microeléctrodos em corrosão refere-se a trabalho exploratório que permanece numa etapa preliminar. A aplicação de microeléctrodos em estudo de corrosão numa base rotineira é ainda rara. Este trabalho apresenta o desenvolvimento e aplicação de microeléctrodos como ferramentas experimentais capazes de aceder a reacções electroquímicas locais em substratos metálicos imersos em soluções agressivas. As técnicas electroquímicas tradicionais usadas no estudo de corrosão dão resposta média do processo global em toda a superfície da amostra sem distinguir efeitos locais e a química local. Não são, portanto, adequadas para a descrição detalhada dos mecanismos de corrosão localizada, de processos de inibição e, por vezes, para a selecção dos métodos de protecção mais adequados. É importante conhecer parâmetros locais, como pH, efeitos micro-galvânicos, concentração de espécies oxidantes (como O2) e agressivas (como Cl-), formação de filmes superficiais. Neste trabalho usou-se a técnica do eléctrodo vibrante de varrimento (SVET) para medições locais de corrente iónica em solução. A técnica detecta a distribuição de potencial em solução, associada à corrente iónica. Para a análise de espécies químicas envolvidas no processo corrosivo, foram usados microsensores electroquímicos no modo SIET (Técnica de Varrimento de Eléctrodo Selectivo de Iões). vii Foram desenvolvidos e caracterizados microeléctrodos sensíveis a pH, oxigénio dissolvido e catiões metálicos (nomeadamente, Mg2+, Zn2+ e Cu2+). Trabalhou-se também no desenvolvimento de microeléctrodos sensíveis a Al3+, embora com menos sucesso. Os microeléctrodos foram utilizados na investigação da corrosão e inibição em defeitos induzidos em revestimentos protectores aplicados sobre ligas de alumínio e de magnésio, e na detecção da micro-distribuição de espécies químicas em solução perto de eléctrodos de zinco, cobre e de um par galvânico Zn-Fe. Este trabalho revela também as limitações e dificuldades na aplicação destas técnicas ao estudo de corrosão devido à inerente reactividade do processo corrosivo, com formação de produtos de corrosão e grandes variações de pH, O2 e força iónica ao longo da superfície de amostra. Apesar das dificuldades, os resultados aqui apresentados demonstram que o mapeamento por SVET/SIET fornece informações muito úteis para a quantificação de processos electroquímicos à micro-escala. Os dados são de primordial importância para a modelação e simulação de mecanismos de corrosão, selecção de novos inibidores de corrosão e desenvolvimento de revestimentos anticorrosivos “inteligentes”.
Spínola, Ana Lúcia Gerardi. "Biofilmes aeróbios para remoção de nitrogênio em células de fluxo, submetidos a diferentes velocidades superficiais e taxas de carregamento." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-04042010-170727/.
Full textThe post-treatment of anaerobic reactor effluents, such as the Upflow Anaerobic Sludge Blanket (UASB), in most applications, is necessary, since this kind of biological treatment promotes BOD removal ranging from 60 to 75% and it has low efficiency in nitrogen and phosphorous removal. Nitrogen removal is usually carried out in a conventional way through nitrification, followed by denitrification. Nitrification, as well as denitrification, can be achieved in suspended growth reactors, or in adhered growth reactors, however it is known that systems based on biofilms exert direct influence in substrate degradation rates and ease the retention of nitrifying bacteria in reactors. The main objective of this work is to follow the development of aerobic biofilms in flow cell type reactors for the nitrification of synthetic substrate simulating an UASB effluent, submitted to different superficial velocities (1, 4 and 8 m/h) and loading rates (0.25; 0.5 and 1.0 g N/\'M POT.2\' biofilm.day). The development of nitrifying biofilms was followed by microsensors profiles and an estimative of the most probable number of nitrifying bacteria (MPN). The best NTK removal efficiencies were obtained in flow cells operated with a lower loading rate (0.25 g N/\'M POT.2\' biofilm.day), which represents a lower level than the levels applied in literature for adhered growth reactors used for nitrification. Considering the flow cells with a lower loading rate, the cell that presented NTK removal close to 100% was the one with the lowest superficial velocity (1 m/h). However, these systems present low efficiency for complete nitrification, obtaining higher nitrite than nitrate production; they could then be used in nitrogen removal by short way. The DO microsensors were efficient for analyses of DO profiles inside nitrifying biofilms, showing great variations, while the biofilm developed itself, in the DO concentrations in the contiguous liquid and at the bottom of the biofilm.
Tsopela, Aliki Theodora. "Development of a lab-on-chip platform integrating electrochemical microsensors for the detection of water contaminants based on algal physiology monitoring." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30017/document.
Full textWater quality assessment has attracted wide attention during the last decades in order to find ways to control contamination of water bodies induced, in a big part, by agricultural and industrial activities. Although conventional techniques, such as chromatography are highly accurate and sensitive tools, increasing interest has been placed lately to powerful alternative techniques that can be used on field, are cost-effective and offer the possibility of conducting rapid analysis. The present work was therefore dedicated to the development of a lab-on-chip device for water toxicity analysis. It consists in a portable system for on-site detection and aims at offering the possibility of conducting double complementary detection: optical and electrochemical. Since the optical sensor is already validated, this study focused on the implementation of the algal-based, electrochemical biosensor for detection water contaminants. The basic detection principle consists in monitoring disturbances in metabolic activities of algae induced by the presence of the herbicides. Algal response is different for each herbicide concentration in the examined sample. The two selected herbicides affect algal photosynthetic activity and consequently induce modifications in the quantity of electroactive species, O2, H2O2 and H3O+/OH- ions related to pH, produced by algae. Prior to the development of the final lab-on-chip device, the detection principle as well as the electrode materials that were going to be integrated were validated using a simpler device that was implemented using a silicon-based fabrication technology and was characterized using simpler procedures. A silicon chip containing the integrated three-electrode electrochemical microsystem was fabricated. The performance of the microsystem was evaluated through electrochemical characterization and calibration was performed. Once validated, the aforementioned materials and configurations were used for the fabrication of the lab-on-chip devices. The lab-on-chip devices were further used in bioassays to detect the herbicides of interest. Special emphasis was placed on O2 monitoring as indicator of the presence of herbicide, as it is the element the most representative of variations in metabolic activities. A concentration-dependent inhibition effect of the herbicide on photosynthesis was demonstrated. Herbicide detection was achieved with a greater sensitivity and a range covering the limit of maximum acceptable concentration imposed by Canadian government
Sbartai, Amel. "Conception et développement de nouveaux microcapteurs chimiques pour la détection des métaux dans les eaux." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10226.
Full textBroadbent, Heather Allison. "Development of a CTD system for environmental measurements using novel PCB MEMS fabrication techniques." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001328.
Full textBouhadda, Ismaïl. "Élaboration et réalisation de transistors à effet de champ à canal microfluidique intégré dédiés à la détection en milieu liquide." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S131/document.
Full textThis work presents the achievement of specific and original electronic devices (Field effect transistor with microfluidic channel), dedicated to the detection of chemical and biochemical species in liquid. This device relies on the technologies of suspended gate transistor, developed in IETR, with a major improvement in the structure by adjunction of a microfluidic channel integrated in the structure. This structure named transistor with integrated microfluidic channel must enable to guarantee the flow of liquid under the gate, while keeping the high sensitivity of the SGFET. This architecture also allows increasing its robustness and reliability while requiring only a very small amount of chemicals solutions. Microchannels with good mechanical properties were fabricated by surface micromachining using different materials as a sacrificial layer. These channels have been integrated into a FET and microfluidic accesses (inlet / outlet) were provided by making openings via the front face. Electrical tests showed good functioning of these sensors with high sensitivity of pH measurement. However in this case, liquid flow is mainly achieved by capillarity. An improvement on the architecture of the structure was made with opening on the rear face. A good behaviour with high sensitivity of pH measurement was presented. Finally, a hybrid structure containing one opening access in the front face and one on the rear face was elaborated and the injection of the solution was successful
Wither, Sandra, and Sofia Myllenberg. "Treatment effects and adherence of van Beek activator during the first year comparing two wear-time prescriptions assessed by microsensors: a randomized clinical trial." Thesis, Malmö universitet, Odontologiska fakulteten (OD), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-19676.
Full textAim: The aim of this study was to evaluate the adherence and the changes in overjet among patients treated with the van Beek activator during the first year, comparing two wear-time prescriptions; 8 hours and 12 hours. Materials and methods: The study sample consisted of 20 patients, 9 girls and 11 boys, with a mean age of 10.0 years. All patients were diagnosed with a class II malocclusion and were treated with the van Beek activator. The patients were randomized into two groups with different wear-time prescriptions; 8 hours and 12 hours. The level of adherence was measured with the aid of TheraMon®, a microsensor embedded in the activator. The adherence, overjet and overbite were recorded after 3, 6, 9 and 12 months of treatment. Results: In both groups, a reduction of both overjet and overbite was observed. There was no significant difference between the 8- and 12-hour group for overjet and overbite reduction. The adherence, on the other hand, was better in the 8-hour group during the whole 12-month period. Conclusions: A wear-time prescription of 8 hours per day displayed a higher level of adherence than 12 hours in the present trial. No clinically significant differences in treatment effects were detected between an 8-hour and 12-hour wear-time prescription. The level of adherence is higher during the first 6 months of a treatment and is then reduced between 6-12 months.
Gonzalez, Beatriz Cruz. "Construção de microssensores e sua aplicação para estudo de biofilme empregado no tratamento de água residuária." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-10072009-115724/.
Full textThe goal of the current research was the construction of amperometric and potentiometric microsensors to measure dissolved oxygen (DO), hydrogen sulfide (\'H IND.2\'S\'), nitrite, nitrate, ammonium and pH in biofilms applied at wastewater treatment. The biofilms that were analyzed with the constructed microsensors were grown at the surface of flat-plate reactors, which were operated in five distinct experiments under different operational conditions. The growth media that had total Kjeldahl nitrogen (TNK) of 40 ± 10 mg/L and carbon oxygen demand (COD) of 90 ± 5 mg/L was used as feed of the flatplate reactors during the experiments. The reactors were inoculated with sludge originating from activated sludge reactor located in Rio Claro (SP). Alkalinity, pH, COD, \'NO IND.3\'POT.-\', \'NO IND.2\'POT.-\' analyses of the affluent and effluent of the reactors were carried out for the accompaniment of the operational conditions of the flat-plate reactors. Concomitantly to the last ones, microprofiles of DO, pH, nitrate and ammonium were obtained in the biofilms. The DO microsensors constructed showed a good performance when they were applied to measure oxygen concentrations in the microenvironments in biofilms. Ammonium and pH microelectrodes allowed the verification of the variations of pH and ammonium concentrations in the direction from the bulk liquid to the biofilm that occurred at the flatplate reactors. The nitrate microsensor has not presented selectivity for its primary ions (\'NO IND.3\'POT.-\') and it was evidenced that the same one detected the concentration of nitrate and nitrite (\'NO IND.X\'POT.-\'). The nitrite microsensor could not be constructed since the membrane that would be used was not available in the market. The \'H IND.2\'S\' microelectrodes had shown efficiency in measuring aqueous solutions with different concentrations of dissolved \'H IND.2\'S\'; however these devices were not applied in biofilms.
Ono, Alexandre Fernandes. "Estratégias de operação de reatores aeróbio/anóxico operados em batelada sequencial para remoção de nitrogênio de água residuária industrial." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-18092007-100009/.
Full textThe purpose of this research was to evaluate the performance and the behavior of sequential batch reactors with suspended and immobilized biomass, in benches scale, for the nitrogen composite removal. Such systems had been tested as sulphetogenic and methanogenic reactors complementary treatment, used in an industrial waste water treatment with high sulphate and ammonia concentrations. The research aimed for the development of an operation strategy that could make possible the use of the proper waste water constituent for the improvement of the treatment efficiency. The study was divided into 3 main stages. In stage 1 (181 days of operation), the reactor with suspended biomass was kept with 4 alternating phases aerobic/anoxic and a 24-hour cycle was used, and the endogenous denitrification was verified (nitrogen removal efficiency of 65 \'+ OU -\' 27%). For stage 2 (127 days of operation), the suspended biomass reactor was submitted to a cycle of 12 hours, with an aerobic phase (6 hours) and posterior anoxic phase (6 hours). In this stage effluent of the methanogenic and sulphetogenic reactors, rich in volatile acid (acetic acid), was added to accelerate the denitrify process. The achieved results had been low in terms of nitrogen removal(42 \'+ OU -\' 21%). For stage 3 (134 days of operation), some supports media was tested through dissolved oxygen microsensors technique, in order to check the specific biofilm formation (nitrificant/denitrificant) and the mineral coal was opted to be used in the immobilized biomass reactor. In this last stage it was adopted an operational strategy similar in stage 2 (12 hours cycle), as well as the addition of part of the affluent in the anoxic phase. The nitrogen removal, with aerobic and anoxic periods and 12 hours cycle, revealed feasible in the reactor with immobilized biomass (nitrogen removal efficiency of 72 \'+ OU -\' 13%). In the end of the experimental tests, kinetic modelings were done and had allowed the understanding of conventional and not conventional processes occurred in the stages for nitrogen removal, such as desnitrification in aerobic phase and ANAMMOX process.
Gonzalez, Beatriz Cruz. "Geração de energia elétrica a partir de eletrodos imersos em sistema do tipo célula a biocombustível composta por reator anaeróbio e reator aeróbio operados em série alimentado com esgoto sanitário." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-02102013-153024/.
Full textThis research aimed mainly to verify the technical feasibility of employing a system called biofuel cell for treating wastewater and generating electricity at the same time. The biofuel cell, in lab scale, adopted consisted of an anaerobic followed by an aerobic reactor, aiming the removal of carbonaceous organic matter and nitrification. Each reactor had an area of 0.6275 m2 and useful volume of 24.0 L. The biofuel cell was fed with sanitary wastewater with hydraulic retention time of eight hours (in both modules). In each reactor was installed an electrode immersed, and the two electrodes were connected by a wire conductor. The capability of the system to generate electricity from the chemical and biochemical reactions that occurred along the electrodes and in biofilms attached to them was verified. The biofuel cell operation was divided into five Phases, named I, II, III, IV and V, and the main factor that distinguished these Phases consisted of the electrode material. Carbon fiber felt and graphite plate were adopted as the anode of the cell (on anaerobic reactor). Stainless steel plates (AISI 316) and stainless steel meshes (AISI 316) were used as the cathode (on aerobic reactor). Monitoring system were carried out with physicochemical analyzes of the influent, anaerobic effluent and aerobic effluent and for monitoring the electricity production it was used a potentiometer coupled with a specific software. DO, pH and redox potential microsensors were employed as auxiliary tools for monitoring the growth and development of biofilms attached to the electrodes of the biofuel cell. The results concerning the treatment of wastewater were COD efficiencies removal of (74.4 ± 17.1)% and nitrification of (65.8 ± 21.0)%, throughout the five Phases. The amount of the higher power density observed was 107.0 mW.m-2 occurred when the anode of the biofuel cell consisted of graphite plate and cathode of stainless steel mesh (AISI 316) type 20, on Phase V . The dosage of ferric chloride and the placement of plastic midia on the aerobic module of the system for automatic cleaning of the cathode, conducted on Phase V, were considered positive for the improvement in obtaining electricity. By combining the results related to power generation and application of microsensors it was concluded that the development of thick biofilms on the electrodes of a biofuel cell is a negative factor in their energy efficiency. It was also concluded that the biofuel cell is technically feasible to treat sanitary wastewater and to generate electricity, but actually, based on the knowledge we have about this technology, its adoption in large scale is still not economically feasible.
Didier, Pierre. "Développement d’un système à ondes acoustiques pour le suivi rhéologique de la polymérisation de protéines. Application à la maladie d’Alzheimer." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLN016/document.
Full textThe development of new biocompatible systems for monitoring protein polymerization processes is a key issue for understanding the molecular mechanisms of detection and for early treatment of so-called conformational diseases such as Alzheimer's disease or prion diseases. In these pathologies, proteins or fragments lose their structure and then assemble themselves into ordered fibers within aggregates. The molecular mechanisms of the conformational changes of a protein and its polymerization into amyloid fibers are still largely unknown. Understanding these mechanisms and diagnosis are closely related to the availability of an efficient analytical concept for the ex vivo monitoring of these phenomena.To address this problem, a microsystem has been developed for the detection and monitoring of polymerization of tau and Aß peptide, the main biomarkers of Alzheimer's disease. The microsensor is based on the propagation of acoustic high frequency waves that extract the rheological properties of the target environment. By measuring complex impedance of the biosensor, a dedicated signal processing allows the extraction of viscoelastic parameters (viscosity and elasticity). The study and development of this microsystem involve multidisciplinary expertise in instrumentation: development and design and modeling of biosensors, signal conditioning and solving associated inverse problems.First, the sensor has been optimized to improve its sensitivity and allow tracking of polymerization. Work on the feasibility of the system showed the ability to discriminate protein solutions of different concentrations. Since the purpose of the detection system is the simultaneous detection of different biomarkers responsible for Alzheimer's disease, a multi-electrode sensor for the detection of these different analytes has been developed. The optimization of the sensor, the microfabrication processes and chemical surface treatments are also developed in this work
Oldenziel, Weite Hendrik. "Application of a glutamate microsensor to brain tissue construction, evaluation and application of a glutamate microsensor /." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2006. http://irs.ub.rug.nl/ppn/297660691.
Full textByun, Albert Joonsoo. "Chemical Application of Silicon-Based Resonant Microsensor." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16296.
Full textTang, David 1977. "Rotor speed microsensor for the MIT Microengine." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8554.
Full textIncludes bibliographical references (p. 123-127).
This thesis presents the design, fabrication, and testing of a temperature-based sensor for measuring rotor speeds in the MIT MEMS micro gas turbine engine. The MIT microengine is a gas combustion engine made by micromachining and bonding six silicon wafers. The sensor is a boron-doped polysilicon resistor with a serpentine geometry that is thermally isolated from the substrate. The sensor is designed to measure the rotor rpm by responding to the heat flux fluctuations on the wall above the compressor blade tips. This thesis investigates the feasibility of this approach. The sensor development process involved fabricating stand-alone devices (which have only the sensor and contact pads and not integrated with other microengine components) and testing them using a furnace and a shock tube. The furnace test characterized the stability with thermal cycling and annealing. The shock tube test characterized the dynamic response. The temperature coefficient of resistivity (TCR), 0.009/K , and the room temperature resistance, ~9 kohms, measured in the furnace characterization experiments were approximately 50% less and 300% more than the predicted values, respectively. These discrepancies may be due to the fabrication process conditions, such as ion implant dose, polysilicon deposition temperature, and anneal conditions. The time constant, 9-10 [mu] sec, measured from the shock tube experiments matched predicted values to within 20-40% depending on the model used to estimate the convective heat flux into the sensor. However, the sensor's amplitude response was less than predicted values by approximately 10 - 75% perhaps due to the simplicity of the models used to estimate the convective heat flux. The experimental results suggest that this concept is viable as a microengine rpm sensor. Some design changes are suggested which should improve sensor performance.
by David Tang.
S.M.
Kim, Ho-Young 1971. "Microsensor development for the study of droplet spreading." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40244.
Full textWang, Ron-wen, and 王榮文. "Microsensors By CMOS Technology." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/40890740454120796200.
Full text國立臺灣大學
電機工程學系
85
In this thesis, two integrated microsensors are designed and implemented. Thesis two sensors are CMOS infrared (IR) thermopile sensor and CMOS 2D vertical Hall sensor, both are integrated with on-chip readout circuits.The IR sensor is characterized by its ease of operation, requirement of no bias, wide spectral response and being fabricated by standard IC process.Though itis always not the optimal process for sensor, considerable sensor proformancestill can be obtained by using this industrial IC process and minimal post-process micromachining steps. On the other hand, the 2D vertical Hall sensor is outstanding for its ability to measure two-dimensional magnetic fieldsimultaneously, its ability to adjust sensitivity by maskless post-processmicromachining and active carrier confinement arrangement. The maximal absolutesensitivity value of the 2D Hall sensor is approximately 34 mV/T, which is higher than that reported by other researchers in 1996. Through empirical study of teh design, fabrication and measurement of these sensors, some experiences are gained. Therefore, in this thesis, some observations are also offered to hopefully help the interested researchers successfully implement their desired sensors.
Silva, Cátia Samanta Ribeiro. "Polymeric microsensors using microtechnologies." Doctoral thesis, 2016. http://hdl.handle.net/1822/42537.
Full textThe work present here aims to combine advanced and specialized polymeric materials and microtechnologies with silicon based microtechnologies to develop an innovative concept for a thermal convective accelerometer with improved performance while also overcoming existing limitations. Thermal convective accelerometers have a transduction mechanism based in heat transfer by convection over a working fluid. The thermal accelerometer is a relatively recent technology and although research focused in improving many properties, parameters and processing techniques, thermal accelerometers still present some drawbacks regarding the power consumption caused by thermal losses through the fabrication material (typically silicon based) and limited third sensing dimension (planar silicon based microtechnologies). New developments towards the optimization of the existing thermal accelerometers may limit the power consumption and allow an easy integration of a Z-axis sensitive dimension. The methodology from the development of a concept to the actual fabrication and characterization requires a series of steps that need to be followed in a sequential way, namely: design and simulation analysis of the device concept (considering the electrical, thermal and fluidic domains), based on CAD and FEM techniques (using a FSI approach); development (project and simulation analysis) of tools based on CAD and CFD techniques; definition and optimization of a fabrication methodology (combination of polymeric and silicon based microtechnologies); and a full characterization of the fabricated device (sensitivity, bandwidth, dynamic range, and power). A three-axes thermal convective accelerometer was fully manufactured containing two main components: a polymeric based external structure fabricated my means of microinjection moulding technology that generates an isolated chamber from outside influences while supporting the second component, a polymeric flexible membrane that sustains and protects the metallic heating and sensing elements fabricated by microtechnologies. The proposed solution for the fabrication of a three-dimensional polymer based thermal accelerometer based in convection is innovative and the main contribution will be the use of polymeric materials not commonly used in microsystem technology and in electronic and instrumentation systems that are suitable to solve the main problems related to the current stateof- art of thermal accelerometers. Fabricated accelerometers were fully tested and characterized presenting a XY-axes sensitivity around 8 mV/g, a Z-axis sensitivity of 2.2 mV/g, and a 4 Hz bandwidth for a power of 45 mW. Thermal tests performed show that the heater can sustain up to 280 ºC without overheating the remaining structures and damaging the device. The developed technology has huge potential for functional highly complex threedimensional geometries at the micro-scale.
O trabalho aqui apresentado tem como intuito combinar materiais e microtecnologias poliméricas avançadas e especializadas com microtecnologias à base de silício para o desenvolvimento de um conceito inovador para um acelerómetro térmico convectivo com um desempenho melhorado superando também as limitações existentes. Os acelerómetros térmicos convectivos tem um mecanismo de transdução baseado na transferência de calor por convecção através de um fluído funcional. O acelerómetro térmico é uma tecnologia relativamente recente e embora os estudos científicos se tenham focado na otimização de diversas propriedades, parâmetros e técnicas de processamento, os acelerómetros térmicos ainda apresentam algumas desvantagens relativas ao consumo energético provocado pelas perdas térmicas através do material de fabrico (normalmente à base de silício) e também uma terceira dimensão sensível limitada (microtecnologias planares à base de silício). Novos desenvolvimentos no sentido da otimização dos existentes acelerómetros térmicos podem limitar o consumo energético e permitir uma integração mais fácil da dimensão sensível do eixo dos ZZ. A metodologia desde o desenvolvimento do conceito até à atual fabricação e caracterização requere uma série de etapas que necessitam de ser seguidas de uma forma sequencial, nomeadamente: projeto e análise por simulação do conceito do dispositivo (considerando os domínios elétrico, térmico, e fluídico), com base em técnicas CAD e FEM (através de uma abordagem FSI); desenvolvimento (projeto e análise por simulação) de ferramentas com base em técnicas CAD e CFD; definição e otimização de uma metodologia de fabrico (combinação de microtecnologias de polímeros com microtecnologias à base de silício); e uma caracterização completa do dispositivo fabricado (sensibilidade, largura de banda; gama dinâmica, e energia). Um acelerómetro térmico convectivo com três eixos foi inteiramente fabricado contendo dois componentes principais: uma estrutura externa à base de polímeros fabricada através da tecnologia de moldação por microinjeção gerando uma câmara isolada de influências externas que suporta o segundo componente, uma membrana polimérica flexível que sustem e protege os elementos metálicos de aquecimento e sensoriais fabricados por microtecnologias. A solução proposta para o fabrico de um acelerómetro térmico polimérico tri-dimensional baseado em convecção é inovativa e a principal contribuição consiste no uso de materiais poliméricos não comumente utilizados na tecnologia de microsistemas e na electrónica e instrumentação de sistemas que são adequados para solucionar os principais problemas relacionados com o atual estado da arte dos acelerómetros térmicos. Os acelerómetros fabricados foram testados e caracterizados apresentando uma sensibilidade de cerca de 8 mV/g para os eixos XY e 2.2 mV/g para o eixo ZZ, e uma largura de banda de 4 Hz para uma energia de 45 mW. Foram realizados testes térmicos demonstrando que a resistência de aquecimento consegue suportar até 280 ºC sem sobreaquecimento das restantes estruturas e sem danificar o dispositivo. A tecnologia desenvolvida apresenta um grande potencial para geometias tri-dimensionais altamente complexas e funcionais à escala micro.
Portuguese Fundação para a Ciência e a Tecnologia (FCT), for the financial support under the PhD scholarship SFRH/BD/78372/2011). The work was supported by FEDER through COMPETE and national funds through FCT in the framework of the project PTDC/EEA-ELC/099834/2008. The author would like to acknowledge the doctoral program in Science and Engineering of Polymers and Composites for supporting this work.
Chen, Ya-Hui, and 陳雅惠. "The Study of Mutiple Pressure Microsensors." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/47147874835077983081.
Full text逢甲大學
自動控制工程學系
89
Based on silicon micro-fabrication technology, the piezoresistive bridge-type pressure microsensors are designed. A chip includes sixteen microsensors in the designed membrane to form four Wheatstone-bridges. The pressure sensing theory of microsensors do follow piezoresistive effect, i.e. the resistivity variation is proportional to diaphragm deflection that is induced from applied pressure. The proposed microsensor can obtain more information from a micro-point measurement simultaneously. The physical dimension of the piezoresist-type sensors is about 6.5mm×6mm×0.7mm. The sensors integrated sensing elements and pre-processing circuits are fabricated by using MEMS techniques. The developed pressure sensors are following the procedures of simulation, design, fabrication, and test. The optimal design of microstructure and related sensing response analysis were simulated by the finite element method. The simulated sensor sensitivity is about 77.17μV/V/mmHg. Both responses of sensitivity and stress are related to the diagragm thickness and the length of the sensing resistors. The maximum pressure measurement range of the microsensors is designed up to 300mmHg, and the optimum stress response is achieved about 0.417MPa/mmHg. The three-dimensional microstructures are realized by anisotropic wet-etching technology. The piezoresistors are formed by offering N-type boron impurity diffusion whose sensitivity can be improved by controling process parameters. The resistance deviation of the silicon-based piezoresistive pressure microsensors with contact mesa is less than 3%. The sensor nonlinearity is less than 2% at temperature range from 25℃ to 55℃. The compound microsnesors developed in the research can supply more medical treatment information for auxiliary clinical research. They can also apply in various-type of force pressure measurement systems to improve equipment efficiency.