Dissertations / Theses on the topic 'Microsensor'
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1
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.
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Byun, Albert Joonsoo. "Chemical Application of Silicon-Based Resonant Microsensor." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16296.
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The detection of volatile organic compounds in liquid is of interest for applications in public health, workplace safety and environmental monitoring. Traditionally, water samples were taken and analyzed in the laboratory using classical laboratory instrumentation. Current trends target real-time measurements using e.g. chemical microsensors built with microfabrication technologies. Among these, mass-sensitive chemical sensors, based on cantilever beams or surface acoustic devices, have shown substantial promise in gas-phase applications. In a liquid environment, the resonant microstructures typically suffer from high damping, which negatively affects the sensor resolution. In this work, a novel disk-type resonator developed at Georgia Tech was investigated as chemical microsensor for liquid-phase applications. The micromachined resonator vibrates in a rotational in-plane mode shape, reducing damping in a liquid environment. As part of the present research, a measurement setup with a custom-made flow cell for liquid-phase chemical measurements and a coating system to locally deposit polymer sensitive films onto the resonators were developed. To improve the film adhesion on the resonator surface in liquid, physical and chemical binding techniques were developed and tested on wafer samples. Polymers such as poly(4-vinylpyrrolidone), poly(ethylene-co-propylene) and poly(styrene-co-butadiene) were deposited using the custom-designed coating system onto the disk-type resonators. Liquid-phase measurements using tetrachloroethylene as the chemical analyte were performed. The experimental results are discussed, sources of problems are identified and recommendations for future research are made.
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Tang, David 1977. "Rotor speed microsensor for the MIT Microengine." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8554.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes 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.
4
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.
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Adams, Douglas Edward. "A high resolution capacitance-based lateral position microsensor." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/46050.
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Shih, Eugene Inghaw 1976. "An energy-efficient radio for wireless microsensor networks." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/86763.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 139-142).
by Eugene Inghaw Shih.
S.M.
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Phanaphat, Piyada 1978. "Protocol stacks for power-aware wireless microsensor networks." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8076.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 71-72).
In a distributed wireless sensor system, a need to prolong the lifetime of the network is crucial and limited by battery capacity. As communication traffic among sensor nodes is triggered by sensing events, the network can exploit these time-varying scenarios to obtain power savings by adjusting its operating conditions accordingly. A coherent design of application-specific network protocol stacks is the key. Specifically, embedding power aware features in the link layer and media access control (MAC) layer promises to extend the lifetime of the sensor network. The power-aware design will be illustrated on [mu]AMPS sensor node prototypes. With the integrated design framework, lower layers of the network stack provides configurable power-aware features to be controlled by higher network layers that maintain broaderview knowledge of the environment. TDMA has been chosen as a MAC Layer protocol for its inherited power-aware mechanism of radio shutdowns outside its TDMA slot and in absence of sensing events. Another level of power-aware features can be deployed in MAC ID and TDMA slot assignments. In a field of scattered sensor nodes, not all the nodes are in radio range of one another or of the base station. Hence, assigning N TDMA slots for the network of N sensor nodes that are not all in radio range will waste the receiver energy and link bandwidth. An algorithm for a re-use of MAC ID and MAC time slot is proposed based on the number of neighboring nodes. Hence, varying the number of neighboring nodes by varying the transmit power can optimize the system lifetime and bandwidth. An implementation of the Link and MAC infrastructure is completed. Power scalability is illustrated on [mu]AMPS node prototypes, with TDMA Media Access and a vehicle tracking application demonstration.
by Phanaphat Piyada.
M.Eng.
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Wang, Andrew Yu 1976. "Base station design for a wireless microsensor system." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86627.
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Hager, Jonathan M. "Development and calibration of a heat flux microsensor." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44640.
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The concept, design, fabrication, and calibration of a new type of layered heat flux gage is described. Using thin-film microfabrication techniques the gage design is able to combine many of the desireable characteristics of other previous gage designs to produce a gage that has a very small size, high frequency response, and the ability to measure very high heat flux rates. The heat flux microsensor incorporates a differential thermopile, a set of 100 differential thermocouple pairs connected in series across a thin thermal resistance layer. The gage is fabricated on a model surface without the need for additional adhesives. The design configuration allows the thermal insulating layer to remain very thin, while still retaining the high output typical of much thicker gages. The small overall thickness of the gage, less than 2 µm, gives it a fast time response with the capability of measuring heat transfer in transient flow conditions. The combination of small thickness and small surface dimensions, 1 mm by 1 cm, gives the microsensor negligible flow and thermal disruption.
The performance of a prototype microsensor deposited on Corning 7059 glass was measured. Steady-state calibrations were done using a convection calibration apparatus. The measured sensitivity (before amplification) was 0.164 mV per watt/cm². The output was linear over the range tested from 800 to 9000 watts/m². The unsteady response was tested using a continuous laser beam directed through a variable speed chopper wheel onto the gage surface. Results showed a frequency response of at least 1 kHz.Master of Science
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Lartz, Douglas John. "Feedforward temperature control using a heat flux microsensor." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06302009-040309/.
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Du, Hongtao. "Energy-constrained microsensor platform on-board image processing." Saarbrücken VDM Verlag Dr. Müller, 2007. http://d-nb.info/985423781/04.
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Daly, Denis Clarke. "An energy efficient RF transceiver for wireless microsensor networks." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34111.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 81-86).
A wireless microsensor network consists of a group of sensor nodes that are deployed remotely and used to relay sensing data to the end-user. Due to their remote deployment, large scale wireless sensor networks require a low-power, energy efficient transceiver that can operate for years on a single battery. Existing wireless transceivers designed for low-power wireless standards like IEEE 802.15.4 have difficulty meeting such stringent energy requirements. Thus, a custom on-off keying wireless transceiver for sensor networks has been designed in a 0.18-[micro]m CMOS process. Power savings are achieved by using an envelope detection based architecture that leverages SAW components and through advanced circuit techniques. The transceiver is power-aware, able to scale power consumption in response to operating conditions. Circuit optimizations are made in both high frequency and baseband circuits to minimize the number of off-chip components and to achieve optimal energy efficiency. A thorough comparison of radio-frequency tuned and untuned gain stages shows that untuned gain can offer energy efficiency advantages in many situations. The transceiver operates in the 900 MHz ISM band at a data rate of 1 Mbps. The receiver's sensitivity is scalable from -37 dBm to -71 dBm with power consumption ranging from 500 [micro]W to 2.4 mW.
(cont.) These power levels correspond to an energy per bit ratio of 0.5 to 2.4 nanojoules per bit, more than ten times smaller than the ratio of typical wireless receivers. The transmitter supports output power levels from -10 dBm to -1 dBm and has a maximum power efficiency of 11%.
by Denis Clarke Daly.
S.M.
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SIPPOLA, CLAYTON BRADLEY. "A CERAMIC CAPACITIVE PRESSURE MICROSENSOR WITH SCREEN-PRINTED DIAPHRAGM." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1146761953.
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Seo, Jae Hyeong. "Silicon-Based Resonant Microsensor Platform for Chemical and Biological Applications." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19835.
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The main topic of this thesis is the performance improvement of microresonators as mass-sensitive biochemical sensors in a liquid environment. Resonant microstructures fabricated on silicon substrates with CMOS-compatible micromachining techniques are mainly investigated. Two particular approaches have been chosen to improve the resolution of resonant chemical/biochemical sensors. The first approach is based on designing a microresonator with high Q-factor in air and in liquid, thus, improving its frequency resolution. The second approach is based on minimizing the frequency drift of microresonators by compensating for temperature-induced frequency variations.
A disk-shape resonant microstructure vibrating in a rotational in-plane mode has been designed, fabricated and extensively characterized both in air and in water. The designed resonators have typical resonance frequencies between 300 and 1,000kHz and feature on-chip electrothermal excitation elements and a piezoresistive Wheatstone-bridge for vibration detection. By shearing the surrounding fluid instead of compressing it, damping is reduced and quality factors up to 5800 in air and 94 in water have been achieved. Short-term frequency stabilities obtained from Allan-variance measurements with 1-sec gate time are as low as 1.1 10-8 in air and 2.3 10-6 in water. The performance of the designed resonator as a biological sensor in liquid environment has been demonstrated experimentally using the specific binding of anti-beta-galactosidase antibody to beta-galactosidase enzyme covalently immobilized on the resonator surface.
An analytical model of the disk resonator, represented by a simple harmonic oscillator, has been derived and compared with experimental results. The resonance frequency and the Q-factor of the disk resonator are determined from analytical expressions for the rotational spring constant, rotational moment of inertia, and energy loss by viscous damping. The developed analytical models show a good agreement with FEM simulation and experimental results and facilitate the geometrical optimization of the disk-type resonators.
Finally, a new strategy to compensate for temperature-induced frequency drifts of resonant microstructures has been developed based on a controlled stiffness modulation by an electronic feedback loop. The developed method is experimentally verified by compensating for temperature-induced frequency fluctuations of a microresonator. In principle, the proposed method is applicable to all resonant microstructures featuring excitation and detection elements.
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Marzioch, Julia [Verfasser], and Gerald A. [Akademischer Betreuer] Urban. "Microsensor system for the metabolic monitoring in cancer cell culture." Freiburg : Universität, 2019. http://d-nb.info/118713337X/34.
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Kirshenblatt, Stacey Jenna. "Microsensor technology to evaluate patient adherence with removable oral appliances." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46921.
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Objective: The aim of this study was to evaluate the accuracy of three thermosensitive microsensors, which record “wear-time” of removable oral appliances (OA) used for orthodontics and obstructive sleep apnea therapy.
Methods: In vitro testing was undertaken for TheraMon (Sensor T, n=20), AIR-AID SLEEP (Sensor A, n=30) and DentiTrac (Sensor D, n=16) microsensors, which were placed in a water bath to simulate “wear-time” of OA. Logs of when the microsensors were placed in the water bath were compared to the time readouts from the microsensors. Trial 1 examined the accuracy of long durations of “wear” (7 hours/day). Trial 2 examined short durations of “wear” (2 hour intervals). Trial 3 tested the impact of different embedding materials on accuracy: acrylic, polyvinylchloride and thermoactive acrylic. In vivo testing included 14 volunteers who wore maxillary retainers embedded with Sensor A and D for 30 nights. Subjects’ logs of appliance usage were compared to the computed readouts from the sensors.
Results: In the in vitro phase, the median absolute deviation of the computed “wear-time” minus the logged time was 0.00 minutes for Sensor A and Sensor T in all trials. For Sensor D, the median deviation was 5.00 minutes in trial 1 and 3 and 10.00 minutes in trial 2. Sensor A was significantly more accurate than Sensor T and Sensor D in trial 1 (p<0.001). In trial 2, Sensor A and Sensor T were equal in accuracy but were significantly better than Sensor D (p<0.001). In trial 3, there was no effect of the material on the recording accuracies of Sensor A (p=0.13) and Sensor D (p=0.41); Polyvinylchloride was found to be significantly less accurate for Sensor T (p<0.05). In the in vivo phase, the median absolute deviation of Sensor A was 3.00 minutes and Sensor D was 5.00 minutes; there was no significant difference between Sensor A and Sensor D (p=0.45).
Conclusion: Sensor D tended to have the largest deviation in recording accuracy in in vitro testing using the water bath. All three microsensors have acceptable clinical accuracy and can be used to record “wear-time” of removable OA fabricated from different materials.
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Ickes, Nathan J. (Nathan Jeffrey) 1979. "Hardware and software for a power-aware wireless microsensor node." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8080.
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Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 143-144).
This thesis examines important issues in the design of hardware and software for microsensor networks, with particular attention paid to mechanisms for providing power awareness. The [mu]AMPS Revision 1 microsensor node is used as an example. The design of this node implementation is described in detail, including, in particular, the design of the pAMPS processor board and its power-scalable architecture. The operating system and application programming interface for the node is described. Finally, an analysis is made of the power consumed by each of the node's subsystems, and these results are used to assess the degree of power-awareness provided by the [mu]AMPS Revision 1 node.
by Nathan J. Ickes.
M.Eng.
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Demirci, Kemal Safak. "Chemical microsystem based on integration of resonant microsensor and CMOS ASIC." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/41182.
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The main topic of this thesis is the development of a chemical microsystem based on integration of a silicon-based resonant microsensor and a CMOS ASIC for portable sensing applications. Cantilever and disk-shape microresonators have been used as mass-sensitive sensors. Based on the characteristics of the microresonators, CMOS integrated interface and control electronics have been implemented. The CMOS ASIC utilizes the self-oscillation method, which incorporates the microresonator in an amplifying feedback loop as the frequency determining element. In this manner, the ASIC includes a main feedback loop to sustain oscillation at or close to the fundamental resonance frequency of the microresonator. For stable oscillation, an automatic gain control loop regulates the oscillation amplitude by controlling the gain of the main feedback loop. In addition, an automatic phase control loop has been included to adjust the phase of the main feedback loop to ensure an operating point as close as possible to the resonance frequency, resulting in improved frequency stability. The CMOS chip has been interfaced to cantilever and disk-shape microresonators and short-term frequency stabilities as low as 3.4×10-8 in air have been obtained with a 1 sec gate time.
The performance of the implemented microsystem as a chemical sensor has been evaluated experimentally with microresonators coated with chemically sensitive polymer films. With a gas-phase chemical measurement setup constructed in this work, chemical measurements have been performed and different concentrations of VOCs, such as benzene, toluene and m-xylene have been detected with limits of detection of 5.3 ppm, 1.2 ppm and 0.35 ppm, respectively.
To improve the long-term stability in monitoring applications with slowly changing analyte signatures, a method to compensate for frequency drift caused by environmental disturbances has been implemented on the CMOS chip. This method uses a controlled stiffness modulation generated by a frequency drift compensation circuit to track the changes in the resonator's Q-factor in response to variations in the environmental conditions. The measured Q-factor is then used to compensate for the frequency drift using an initial calibration step. The feasibility of the proposed method has been verified experimentally by compensating for temperature-induced frequency drift during gas-phase chemical measurements.
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Abercrombie, Matthew G. "Acoustic microsensor with optical detection for high-temperature, high-pressure environments." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/19467.
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Al-Khalifa, Sherzad. "Identification of a binary gas mixture from a single resistive microsensor." Thesis, University of Warwick, 2000. http://wrap.warwick.ac.uk/52652/.
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Increasing concern about the rapid escalation of environmental pollution has led to strong legislation to ensure, for example, that the emission of pollutants from vehicles and industries is controlled to an acceptable level. As a consequence, there has been a rapid expansion of research into developing more efficient and low-cost gas monitoring systems. Currently, commercial solid-state atmospheric gas detection systems are based on one sensor for each gas, while research systems are an array of sensors for the detection of multiple gases. In this research, techniques are developed whereby more than one gas is detected using a single resistive gas sensor. A novel modulated temperature technique was used to enhance the selectivity of the resistive SnO2 gas sensor. Fast Fourier transforms was used to extract the Fourier coefficients. These in turn were used as input to neural networks for training and subsequently for prediction purposes. The result has shown that a single doped SnO2 resistive microsensor can be used to classify binary gas mixture in air. The research objectives have been fulfilled in that a novel way in detecting the components and the concentration level of a binary gas mixture was developed. Additionally, a low-cost low-power intelligent gas monitoring system was designed. This included the design of a novel temperature/thermometer circuit.
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Wang, Andrew Yu 1976. "Lower power RF transceiver modeling and design for wireless microsensor networks." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33930.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 97-102).
The design of wireless microsensor systems has gained increasing importance for a variety of civil and military applications. With the objective of providing short-range connectivity with significant fault tolerance, these systems find usage in such diverse areas as environmental monitoring, industrial process automation, and field surveillance. The main design objective is to, maximize the battery life of the sensor nodes while ensuring reliable operations. To achieve this goal, the microsensor node has to be designed in a highly integrated fashion and optimized across all levels of system abstraction. For microsensor networks, the RF transceiver dominates the power consumption. The concept of transceiver power efficiency is introduced, which defines the ratio of RF transmit power to transceiver electronics power, to show that short-range RF transceivers have low transceiver power efficiency. A system energy model is developed to show that the battery life of the transceiver not only depends on its power consumption, but more importantly, on its energy dissipation over the operation cycle.
(cont.) Both the transceiver power efficiency and the battery life can be improved significantly by increasing the data rate, reducing the start-up time, and improving the PA efficiency. Increasing the data rate drives down the fixed energy cost of the transceiver. Reducing the start-up time decreases the start-up energy overhead. Improving the PA efficiency lowers the energy per bit cost of the power amplifier. The voltage controlled oscillator occupies a large fraction of the total energy budget in the operation of the microsensor transceiver. The design of integrated LC oscillators is investigated on both the system and the circuit design levels. On the system level, the phase noise requirement of the VCO as a function of the channel bandwidth and the data rate is derived. On the circuit level, the physical mechanisms of phase noise are examined and a low-power 5-GHz VCO is designed and fabricated in a 0.18-[mu]m SiGe BiCMOS process. A technique is proposed to trade off phase noise for a lower bias current through the sizing of the switching transistors. This VCO demonstrates a phase noise of -125dBc/Hz at 7mA core bias current and -llOdBc/Hz at 1.5mA, which exceeds the system phase noise requirement.
by Andrew Yu Wang.
Ph.D.
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Peabody, Hume L. "Evaluation of a Heat Flux Microsensor in a Transonic Turbine Cascade." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35495.
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The effects of using an insert Heat Flux Microsensor (HFM) versus an HFM deposited directly on a turbine blade to measure heat flux in a transonic cascade are investigated. The HFM is a thin-film sensor, 6.35 mm (0.250") in diameter (for an insert gage, including the housing) which measures heat flux and surface temperature. The thermal time response of both gages was modeled using a 1-D, finite difference technique and a 2-D, finite element solver. The transient response of the directly deposited gage was also tested against insert gages using an unsteady shock wave in a bench test setup and using a laser of known output. The effects of physical gage offset from the blade surface were also investigated. The physical offset of an insert HFM near the stagnation point on the suction side of a turbine blade was intentionally varied and the average heat transfer coefficient measured. Turbulence grids were used to study how offset affects the heat transfer coefficient with freestream turbulence added to the flow.
The time constant of the directly deposited gage was measured to be 856 ms compared to less than 30 ms for the insert gages. Model results predict less than 20 ms for both gages and rule out the anodization layer (used for electrical isolation of the directly deposited gage from the blade) as the cause for the directly deposited gage's much slower time response. Offsets of ± 0.254 mm (0.010") at the gage location with an estimated boundary layer thickness of 0.10 mm (0.004") produced a higher average heat transfer coefficient than the 0.000" offset case. Using an insert HFM resulted in a higher average heat transfer coefficient than using the directly deposited gage and reduced the effects of freestream turbulence. To accurately measure heat transfer coefficients and the effects of freestream turbulence, the disruption of the flow caused by a gage must be minimized. Depositing a gage directly on the blade minimizes the effects of offset, but the cause of the slow time response must first be resolved if high speed data is to be taken.Master of Science
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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/.
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A pesquisa propôs avaliar o desempenho e o comportamento de reatores seqüenciais em batelada com biomassa suspensa e imobilizada, em escala de bancada, na remoção de compostos de nitrogênio. Tais sistemas foram testados como tratamento complementar de reatores sulfetogênico e metanogênico utilizados no tratamento de água residuária industrial com alta concentração de sulfato e amônia. Visou o desenvolvimento de uma estratégia de operação que viabilizasse o uso dos próprios constituintes da água residuária para a maximização da eficiência do tratamento. O estudo foi dividido em 3 etapas principais. Na etapa 1 (181 dias de operação), o reator com biomassa suspensa foi mantido com 4 fases alternadas aeróbio/anóxico e ciclo de 24 horas, e verificou-se a presença da desnitrificação endógena (eficiência de remoção de nitrogênio de 65 \'+ OU -\' 27%). Para a etapa 2 (127 dias de operação), o reator de biomassa suspensa foi submetido ao tempo de ciclo de 12 horas, com uma fase aeróbia (6 horas) e com posterior fase anóxica (6 horas). Nessa etapa adicionou-se efluentes dos reatores metanogênico e sulfetogênico, ricos em ácidos voláteis (ácido acético), com intuito de acelerar o processo desnitrificante. Os resultados obtidos foram baixos em termos de remoção de nitrogênio (42 \'+ OU -\' 21%). Para a etapa 3 (134 dias de operação), foram ensaiados vários meios suportes, através de técnica de microsensores de oxigênio dissolvido, a fim de verificar a formação de biofilme específico (nitrificante/desnitrificante) e optou-se pelo uso do carvão mineral no reator com biomassa imobilizada. Nesta última etapa, foi mantida a estratégia operacional adotada na etapa 2 (ciclo 12 horas), bem como a adição de parcela do afluente na fase anóxica. A remoção de nitrogênio, com períodos aeróbio e anóxico e ciclo de 12 horas, mostrou-se viável no reator com biomassa imobilizada (eficiência de remoção de nitrogênio de 72 \'+ OU -\' 13%). Ao final dos ensaios experimentais, realizaram-se modelagens cinéticas que permitiram a compreensão dos processos convencionais e não convencionais ocorridos nas várias etapas para remoção de nitrogênio, tais como desnitrificação em fase aeróbia e o processo ANAMMOX.The 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.
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Michener, Michael Douglas. "Measurements of thermal properties and blood perfusion using the heat flux microsensor." Thesis, Virginia Tech, 1991. http://hdl.handle.net/10919/41696.
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A thin-film heat flux sensor was used in two transient conduction applications. First it was used in a device for simultaneously determining the thermal conductivity, κ, and the thermal diffusivity, α, of solid materials. The device was heated and then touched to metal samples at room temperature. The thermal properties were characterized based on the heat flux response of the gage, and the change in temperature of the metal surface at a specified distance away from the gage. A finite difference program was developed and used to model the system response. The effect of α was most evident by the time delay in the temperature response on the metal surface. The effect of κ was most evident in the heat flux response after the first few seconds of contact.
In the second application, the gage was used in a probe that was cooled and then touched to biological materials. A numerical model was used to demonstrate the effect of tissue blood perfusion on the surface heat flux. Experimental tests were performed on live dogs. Both the numerical model and the experiments showed that increases in blood perfusion could be detected from the transient heat flux measurements. In both applications, this research forms the basis for instrumentation which will be able to measure κ, α, and blood perfusion.Master of Science
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Beach, Elvin R. III. "Picoliter Drop Deposition of Oxide Nanoparticles: A Route to High Performance Microsensor Arrays." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1249675063.
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Kieninger, Jochen [Verfasser], and Gerald A. [Akademischer Betreuer] Urban. "Electrochemical microsensor system for cell culture monitoring = Elektrochemisches Mikrosensor-System zum Zellkultur-Monitoring." Freiburg : Universität, 2012. http://d-nb.info/1114995657/34.
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Södergren, Simon. "Electrochemical microsensor with in-situ fabricated Ag/AgCl reference electrode for high-pressure microfluidics." Thesis, Uppsala universitet, Mikrosystemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-330913.
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Electroanalysis offers cheap and selective analysis of interesting solutions. However, one of the most common drawbacks is the accessibility for electrochemical sensing. By using high-pressure microfluidics with an integrated three-electrode system, new possibilities open for increased accessibility. Therefore, there is a need to fabricate sustainable reference surfaces into highly pressure tolerant microchannels. In this thesis, Ag/AgCl reference surfaces were in-situ fabricated in high-pressure microfluidic chips. This was performed by electroplating Ag on thin film Pt in microchannels and then chlorinating the silver into Ag/AgCl. Electroanalysis of ferrocyanide was carried out in a microfluidic chip using one of the in-situ fabricated Ag/AgCl references. The half-wave potential showed to be around +251 mV and the electrochemical water window was measured to 1400 mV with a range between -300 mV and +1100 mV. The obtained values show to be comparable to reference data of similar experiments performed elsewhere. For some applications of electrochemistry, a catalysis surface is beneficial. Nanoporous Pt black has proved to generate high catalytic performance in electrochemistry. Therefore, attempts have been carried out to fabricate Pt black onto Pt thin films, with the vision to succeed with such fabrication within microfluidic channels. To summarize, this project work has showed a possibility to in-situ fabricate Ag/AgCl reference surfaces. The project has also showed how to use such surfaces as reference electrodes for electroanalysis in high-pressure microfluidic chips. Lastly, new challenges and ideas to fabricate catalysis surfaces on thin film electrodes in flow channels have been presented. By this thesis, one more step has been taken to increase the accessibility for electroanalysis.
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Chawich, Juliana. "ZnO/GaAs-based acoustic waves microsensor for the detection of bacteria in complex liquid media." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCD012/document.
Full textAbstract:
Cette thèse s’inscrit dans le cadre d’une cotutelle internationale entre l’Université de Bourgogne Franche-Comté en France et l’Université de Sherbrooke au Canada. Elle porte sur le développement d'un biocapteur miniature pour la détection et la quantification de bactéries dans des milieux liquides complexes. La bactérie visée est l’Escherichia coli (E. coli), régulièrement mise en cause dans des épidémies d'infections alimentaires, et parfois meurtrière.La géométrie du biocapteur consiste en une membrane en arséniure de gallium (GaAs) sur laquelle est déposé un film mince piézoélectrique d’oxyde de zinc (ZnO). L'apport du ZnO structuré en couche mince constitue un réel atout pour atteindre de meilleures performances du transducteur piézoélectrique et consécutivement une meilleure sensibilité de détection. Une paire d'électrodes déposée sur le film de ZnO permet de générer sous une tension sinusoïdale une onde acoustique se propageant dans le GaAs, à une fréquence donnée. La face arrière de la membrane, quant à elle, est fonctionnalisée avec une monocouche auto-assemblée (SAM) d'alkanethiols et des anticorps anti-E. coli, conférant la spécificité de la détection. Ainsi, le biocapteur bénéficie à la fois des technologies de microfabrication et de bio-fonctionnalisation du GaAs, déjà validées au sein de l’équipe de recherche, et des propriétés piézoélectriques prometteuses du ZnO, afin d’atteindre potentiellement une détection hautement sensible et spécifique de la bactérie d’intérêt. Le défi consiste à pouvoir détecter et quantifier cette bactérie à de très faibles concentrations dans un échantillon liquide et/ou biologique complexe.Les travaux de recherche ont en partie porté sur les dépôts et caractérisations de couches minces piézoélectriques de ZnO sur des substrats de GaAs. L’effet de l’orientation cristalline du GaAs ainsi que l’utilisation d’une couche intermédiaire de Platine entre le ZnO et le GaAs ont été étudiés par différentes techniques de caractérisation structurale (diffraction des rayons X, spectroscopie Raman, spectrométrie de masse à ionisation secondaire), topographique (microscopie à force atomique), optique (ellipsométrie) et électrique. Après la réalisation des contacts électriques, la membrane en GaAs a été usinée par gravure humide. Une fois fabriqué, le transducteur a été testé en air et en milieu liquide par des mesures électriques, afin de déterminer les fréquences de résonance pour les modes de cisaillement d’épaisseur. Un protocole de bio-fonctionnalisation de surface, validé au sein du laboratoire, a été appliqué à la face arrière du biocapteur pour l’ancrage des SAMs et des anticorps, tout en protégeant la face avant. De plus, les conditions de greffage d’anticorps en termes de concentration utilisée, pH et durée d’incubation, ont été étudiées, afin d’optimiser la capture de bactérie. Par ailleurs, l’impact du pH et de la conductivité de l’échantillon à tester sur la réponse du biocapteur a été déterminé. Les performances du biocapteur ont été évaluées par des tests de détection de la bactérie cible, E. coli, tout en corrélant les mesures électriques avec celles de fluorescence. Des tests de détection ont été réalisés en variant la concentration d’E. coli dans des milieux de complexité croissante. Différents types de contrôles ont été réalisés pour valider les critères de spécificité. En raison de sa petite taille, de son faible coût de fabrication et de sa réponse rapide, le biocapteur proposé pourrait être potentiellement utilisé dans les laboratoires de diagnostic clinique pour la détection d’E. coliThis thesis was conducted in the frame of an international collaboration between Université de Bourgogne Franche-Comté in France and Université de Sherbrooke in Canada. It addresses the development of a miniaturized biosensor for the detection and quantification of bacteria in complex liquid media. The targeted bacteria is Escherichia coli (E. coli), regularly implicated in outbreaks of foodborne infections, and sometimes fatal.The adopted geometry of the biosensor consists of a gallium arsenide (GaAs) membrane with a thin layer of piezoelectric zinc oxide (ZnO) on its front side. The contribution of ZnO structured in a thin film is a real asset to achieve better performances of the piezoelectric transducer and consecutively a better sensitivity of detection. A pair of electrodes deposited on the ZnO film allows the generation of an acoustic wave propagating in GaAs under a sinusoidal voltage, at a given frequency. The backside of the membrane is functionalized with a self-assembled monolayer (SAM) of alkanethiols and antibodies anti-E. coli, providing the specificity of detection. Thus, the biosensor benefits from the microfabrication and bio-functionalization technologies of GaAs, validated within the research team, and the promising piezoelectric properties of ZnO, to potentially achieve a highly sensitive and specific detection of the bacteria of interest. The challenge is to be able to detect and quantify these bacteria at very low concentrations in a complex liquid and/or biological sample.The research work partly focused on the deposition and characterization of piezoelectric ZnO thin films on GaAs substrates. The effect of the crystalline orientation of GaAs and the use of a titanium / platinum buffer layer between ZnO and GaAs were studied using different structural (X-ray diffraction, Raman spectroscopy, secondary ionization mass spectrometry), topographic (atomic force microscopy), optical (ellipsometry) and electrical characterizations. After the realization of the electrical contacts on top of the ZnO film, the GaAs membrane was micromachined using chemical wet etching. Once fabricated, the transducer was tested in air and liquid medium by electrical measurements, in order to determine the resonance frequencies for thickness shear mode. A protocol for surface bio-functionalization, validated in the laboratory, was applied to the back of the biosensor for anchoring SAMs and antibodies, while protecting the top side. Furthermore, different conditions of antibody grafting such as the concentration, pH and incubation time, were tested to optimize the immunocapture of bacteria. In addition, the impact of the pH and the conductivity of the solution to be tested on the response of the biosensor has been determined. The performances of the biosensor were evaluated by detection tests of the targeted bacteria, E. coli, while correlating electrical measurements with fluorescence microscopy. Detection tests were completed by varying the concentration of E. coli in environments of increasing complexity. Various types of controls were performed to validate the specificity criteria. Thanks to its small size, low cost of fabrication and rapid response, the proposed biosensor has the potential of being applied in clinical diagnostic laboratories for the detection of E. coli
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Siman, Renato Ribeiro. "Reator de leito expandido em escala plena com zonas anaeróbia e aeróbia sobrepostas: remoção conjunta de matéria orgânica e nutrientes e estudo do comportamento microbiológico do biofilme, por respirometria e microsensor de OD." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-31102008-151843/.
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A presente pesquisa teve a intenção de desenvolver reator biológico de 159 \'M POT.3\' de volume total, com leito de carvões granulares (ativado e antracito) expandido e parcialmente aerado, para promover remoções de matéria orgânica e nutrientes (N e P) do esgoto sanitário, devido a manutenção de ambientes anaeróbio e aeróbio, estratificados ao longo da altura do reator e ao longo do biofilme cultivado em seu interior. Para avaliar o impacto das modificações operacionais no comportamento biológico dos microrganismos presentes no reator, foram aplicados métodos para análise das atividades nitrificante (ANE), desnitrificante (ADE) e metanogênica (PME), embasados em testes respirométricos padrões descritos na literatura. A estratificação reacional também foi estudada dentro de filmes biológicos com a ajuda de microsensores amperométricos de OD em testes de bancada. Assim, após 451 dias de operação, foi possível verificar remoções médias de \'DQO IND.F\', NTK e fosfato total de, respectivamente 78%, 56% e 42%, quando o reator foi operado por 66 dias com tempo de detenção hidráulica médio de 8,8 h, injetor de oxigênio puro, instalado após placa de orifício em linha de recirculação aerada, a qual funcionava pressurizada (3 a 4 bar) e com razão média de recirculação igual a 3, comparada à vazão de alimentação. Para o restante do período, no qual foram aplicadas taxas de carregamentos volumétricos médios de 0,74 \'+ OU -\' 0,28 kg\'DQO IND.F\'/\'M POT.3\'.dia; 0,17 \'+ OU -\' 0,07 kg NTK/\'M POT.3\'.dia e 0,05 \'+ OU -\' 0,02 kg\'PO IND.4\'POT.-3\'/\'M POT.3\'.dia, o sistema demonstrou remoções médias de 65 \'+ OU -\' 20% para \'DQO IND.F\', 25 \'+ OU -\' 21% para o NTK e 48 \'+ OU -\' 18% para o fosfato total, mesmo operado com tempo de retenção celular médio de 15 \'+ OU -\' 7 dias. Os testes respirométricos foram sensíveis para avaliar a atividade microbiana do material biológico coletado ao longo do reator, com os quais foram verificados PME médio de 0,25 mL\'CH IND.4\'/gSVT.h, para as amostras de material biológico coletado na região anaeróbia, ao fundo do reator; ANE variando entre 1,3 a 4,4 mg\'O IND.2\'/gSVT.h, para as amostras coletadas na região aeróbia, intermediária ao reator; e ADE variando entre 0,024 e 5,20 mg\'N IND.2\'/gSVT.h, para amostras coletadas, respectivamente, no fundo e no topo do reator. As análises do material líquido também corroboram com a idéia de estratificação dos ambientes aeróbio, no fundo do reator, e micro-aerado, em sua região intermediária superior, apontando para região com alto potencial de ocorrerem nitrificação e desnitrificação conjuntas no topo da sua zona reativa. O microsensor amperométrico de OD com ponta entre 10 e 30 \'mü\'m de diâmetro, confeccionados em laboratório especializado, se mostrou sensível para a observação do gradiente de concentração de oxigênio dissolvido dentro de filme biológico, suficientes para a formação de regiões aeróbia e anaeróbia em seu interior, cuja informação pode ser útil para a aprimoramento de reatores com biofilme, projetados para remoções combinadas de matéria orgânica e nutrientes. Entretanto, quando se pretende definir parâmetros cinéticos ou de transferência de massa, maior rigor deve ser dispensado na definição dos locais para a aplicação do sensor, nos quais sejam reduzidos os efeitos da heterogeneidade do agregado microbiano no ajuste da modelagem matemática aplicada aos pontos experimentaisThe current research aimed the development of a 159 \'M POT.3\' total volume biological reactor, with a expanded and partially aerated granular coal bed (activated and anthracite), to promote organic matter and nutrients (N and P) removal from wastewater due to the maintenance of anaerobic and aerobic environments, stratified throughout the height of the reactor and also all over the biofilm cultivated in its interior. Methods for the analyses of specific nitrifying activities (ENA), denitrifying (EDA) and methanogenic (EMA) were applied to assess the impact of the operational modifications in the biological behavior of microorganisms present in the reactor, based on standard respirometric tests found in literature. The reactional stratification was also studied inside the biological films with the help of DO microsensors in batch tests. Thus, after 451 of operation it was possible to verify mean \'COD IND.F\', TNK and phosphate removal of 78%, 56% and 42%, respectively, when the reactor was operated for 66 days with average hydraulic detention time of 8.8 h, pure oxygen injector which was installed after the aerated recirculation line which was working pressurized (3 to 4 bar) and with mean recirculation ratio equal to 3, when compared to the feeding flow. For the rest of the period where mean volumetric loading rates of 0.74 \'+ OR -\' 0.28 kg\'COD IND.F\'/\'M POT.3\'.day; 0.17 \'+ OR -\' 0.07 kgTNK/\'M POT.3\'.day and 0.05 \'+ OR -\' 0.02 kg\'PO IND.4\'POT.-3\'/\'M POT.3\'.day were applied the system demonstrated average removal of 65 \'+ OR -\' 20% for \'COD IND.F\', 25 \'+ OR -\' 21% for TNK and 48 \'+ OR -\' 18% for total phosphate, even when it operated with mean cellular retention time of 15 \'+ OR -\' 7 days. The respirometric tests were sensible enough to assess the microbial activity from the biological material collected throughout the reactor, and where mean PME of 0.25 mL\'CH IND.4\'/gSVT.h was verified for the samples of biological material collected in the anaerobic region, at the bottom of the reactor; ANE varying between 1.3 to 4.4 mg\'O IND.2\'/gSVT.h, for the samples collected in the aerobic region, reactor\'s intermediary; and ADE varying between 0.024 to 5.20 mg\'N IND.2\'/gSVT.h, for samples collected at the bottom and the top of the reactor, respectively. The analyses of the liquid material also support the idea of stratification of the aerobic environments, at the bottom of the reactor, and micro-aerated, in its superior intermediate region, pointing to the region as a high potential of occurring joint nitrification and denitrification at the top of the reactive zone. The DO amperometric microsensor, with tip between 10 and 30 \'mü\'m of diameter, produced in a special laboratory, is sensible to the determination of dissolved oxygen concentration gradient inside biological film, sufficient for the formation of anaerobic and aerobic regions in its interior, this information can be useful to the improvement of biofilm reactors, projected for the combined removal of organic matter and nutrients. However, when the definition of kinetic parameters or mass transference is intended more strictness must be applied when choosing the locals for microsensor application, where the effects of the microbial aggregate heterogeneity is reduced in the adjustment of the mathematical modeling applied to the experimental points.
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Yi, Chen. "Development of a diffusional microtitration device and a carbon fiber microsensor for potential drug influx/efflux studies on single cancer cell." Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1058284676.
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Spratley, Jon Peter Frederick. "mechanical design of an injectable microsensor for neural connection within the motor cortex of the human brain." Thesis, University of Birmingham, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.532287.
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LI, 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.
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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.
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The humidity, temperature, wind speed/direction micro sensors can be manufactured individually, resulting in three individual substrates. The integration of the three sensors into a single substrate is a vital challenge to achieve an integrated intelligent sensor so called a multiple sensor. This requires the integration of process flows and is a major challenge because adequate sensor performance must be maintained. Polyimide was selected as a humidity sensing material for its compatibility with conventional integrated circuit fabrication technology, negligible temperature dependence and good resistance against contamination. Nickel was selected for the temperature and wind speed/direction sensor because of its useful temperature coefficient and the advantage of its cost. Since the known wet etchant for nickel requires hard-baked photoresist, a method which does not attack the polyimide while removing the photoresist must be developed. The method developed for etching nickel employs hard-bake-free photoresist. Other challenge was ensuring good thermal isolation for the wind speed/direction sensor fabricated on a silicon nitride layer preformed on top of a silicon wafer. Since silicon acts as a good heat sink, the silicon under the sensor was etched entirely away until the silicon nitride layer was reached. This structure achieved good thermal isolation resulting in small power consumption. This low power feature is essential for sensors deployed in fields where power access or replacement of power sources is restricted. This structure was compared with the structure created by polyimide plateau on a silicon nitride layer coated on a silicon substrate as a function of power consumption. Based on the examination of thermal isolation, the multiple sensor utilizing a MEMS technique was fabricated with a single-sided mask aligner. The characteristics of humidity sensors fabricated with polyimide were examined in detail with respect to variations of electrode structures, improvement of sensitivity, effect of process temperature, temperature and frequency dependence, and stability. The humidity sensor constructed with O2 plasma treated polyimide resulted an improvement in sensitivity and hysteresis. The investigation using XPS, FTIR and AFM concluded the chemical modification of polyimide played an important role in this improvement. The design, fabrication and results of a series of humidity sensors are quantified. There is always no unique packaging solution for sensors because of the application-specific nature of the sensors. This intelligent environmental monitoring system was designed to accommodate both an environmental sensor and its signal conditioning electronics circuitry (SICONEC) into a single package. The environmental sensors need direct exposure to the environment while SICONEC needs a sealed encapsulation to avoid environmental damage. A new style of packaging addressing these requirements was demonstrated using a hot embossing machine. The hot embossing machine was used to embed an integrated circuit (IC) in a bare die condition into a polycarbonate (PC) sheet. In this case, the IC was flipped down against the PC, which protects the front side of the IC from the environmental damages. In a test phase, a die containing operational amplifiers was embossed into the PC. A humidity sensor and surface mount resisters were placed on the same surface of the PC to test the validity of this new technique. Interconnection between the embossed die and the humidity sensor was established using bonding wires. Copper tracks were also used to ensure all electrical connections for the die, the humidity sensor and the resistors. The results clarified the method developed. Details of process methods, issues and further potential improvement are reported.
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Suzuki, Takeharu. "Integrated, Intelligent Sensor Fabrication Strategies for Environmental Monitoring." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367295.
Full textAbstract:
The humidity, temperature, wind speed/direction micro sensors can be manufactured individually, resulting in three individual substrates. The integration of the three sensors into a single substrate is a vital challenge to achieve an integrated intelligent sensor so called a multiple sensor. This requires the integration of process flows and is a major challenge because adequate sensor performance must be maintained. Polyimide was selected as a humidity sensing material for its compatibility with conventional integrated circuit fabrication technology, negligible temperature dependence and good resistance against contamination. Nickel was selected for the temperature and wind speed/direction sensor because of its useful temperature coefficient and the advantage of its cost. Since the known wet etchant for nickel requires hard-baked photoresist, a method which does not attack the polyimide while removing the photoresist must be developed. The method developed for etching nickel employs hard-bake-free photoresist. Other challenge was ensuring good thermal isolation for the wind speed/direction sensor fabricated on a silicon nitride layer preformed on top of a silicon wafer. Since silicon acts as a good heat sink, the silicon under the sensor was etched entirely away until the silicon nitride layer was reached. This structure achieved good thermal isolation resulting in small power consumption. This low power feature is essential for sensors deployed in fields where power access or replacement of power sources is restricted. This structure was compared with the structure created by polyimide plateau on a silicon nitride layer coated on a silicon substrate as a function of power consumption. Based on the examination of thermal isolation, the multiple sensor utilizing a MEMS technique was fabricated with a single-sided mask aligner. The characteristics of humidity sensors fabricated with polyimide were examined in detail with respect to variations of electrode structures, improvement of sensitivity, effect of process temperature, temperature and frequency dependence, and stability. The humidity sensor constructed with O2 plasma treated polyimide resulted an improvement in sensitivity and hysteresis. The investigation using XPS, FTIR and AFMconcluded the chemical modification of polyimide played an important role in this improvement. The design, fabrication and results of a series of humidity sensors are quantified. There is always no unique packaging solution for sensors because of the application-specific nature of the sensors. This intelligent environmental monitoring system was designed to accommodate both an environmental sensor and its signal conditioning electronics circuitry (SICONEC) into a single package. The environmental sensors need direct exposure to the environment while SICONEC needs a sealed encapsulation to avoid environmental damage. A new style of packaging addressing these requirements was demonstrated using a hot embossing machine. The hot embossing machine was used to embed an integrated circuit (IC) in a bare die condition into a polycarbonate (PC) sheet. In this case, the IC was flipped down against the PC, which protects the front side of the IC from the environmental damages. In a test phase, a die containing operational amplifiers was embossed into the PC. A humidity sensor and surface mount resisters were placed on the same surface of the PC to test the validity of this new technique. Interconnection between the embossed die and the humidity sensor was established using bonding wires. Copper tracks were also used to ensure all electrical connections for the die, the humidity sensor and the resistors. The results clarified the method developed. Details of process methods, issues and further potential improvement are reported.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Microelectronic Engineering
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Neumann, Hendrikje Marie [Verfasser]. "Prototyping of a Surface-integrated Mechano-optical Microsensor System for 3D Traction Force Measurements by DHM/DIC / Hendrikje Marie Neumann." Kiel : Universitätsbibliothek Kiel, 2019. http://d-nb.info/1197612440/34.
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Rohtlaid, Kätlin. "Fabrication, caractérisation et intégration de microactionneurs et de microcapteurs à base de polymères conducteurs électroniques." Thesis, Cergy-Pontoise, 2019. http://www.theses.fr/2019CERG1029.
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Les polymères électroactifs (EAPs) sont capables de changer de forme et/ou de dimension en réponse à une stimulation électrique, mais aussi de générer un signal électrique en réponse à une stimulation mécanique. Ces matériaux flexibles et légers apparaissent comme des candidats prometteurs pour le développement de systèmes micro-électro-mécaniques (MEMS en anglais « Micro-Electro-Mechanical Systems). Le but de cette thèse est la fabrication et la caractérisation de microactionneurs et de microcapteurs à base de polymères conducteurs électroniques (PCEs) afin d'obtenir des dispositifs performants pour une intégration dans les microsystèmes.Premièrement, un procédé d’élaboration couche par couche récemment décrit pour les microactionneurs à base de PCEs, a été pris comme point de départ de cette thèse. L’optimisation de la polymérisation en phase vapeur du 3,4-éthylènedioxythiophène (EDOT) a ainsi été réalisée afin d'améliorer les propriétés électriques et électrochimiques des électrodes obtenues et ainsi d’améliorer les performances des microactionneurs résultants.Dans une deuxième partie, le poly(3,4-éthylènedioxythiophène):poly(styrène sulfonate) (PEDOT:PSS) a été choisi comme nouveau matériau d’électrode afin de développer un procédé couche par couche plus simple et reproductible. Des additifs réactifs polaires à base de poly(oxyde d'éthylène) (PEO) ont été incorporés à une dispersion commerciale de PEDOT:PSS pour élaborer des électrodes aux propriétés électriques, mécaniques et électrochimiques améliorées. Ces électrodes composites à base de PEDOT:PSS ont ensuite été utilisées pour fabriquer des microactionneurs tricouches performants. De plus, les propriétés de capteur de déformation mécanique de ces tricouches ont été démontrées pour la première fois à l'échelle microscopique.La troisième partie de ce travail décrit l’intégration complète de ces dispositifs électrostimulables à base de PEDOT:PSS selon des procédés totalement compatibles aux microsystèmes. Ce travail décrit pour la première fois l’élaboration des microdispositifs tricouches, leur intégration complète avec contacts électriques et leur fonctionnement sur substrat flexible sans aucun maniement manuel, permettant ainsi la conception de microsystèmes avec des configurations complexes. Les microsystèmes obtenus ont été caractérisés avec succès en tant que microactionneurs et microcapteurs.Enfin, des actionneurs linéaires et fonctionnant à l’air libre ont été développés par la combinaison d’électrodes à base de PEDOT:PSS présentant différentes propriétés physiques, Les propriétés électrochimiques et mécaniques de ces électrodes ont tout d’abord été étudiées en fonction de leur composition et leur niveau d'oxydation. A partir d’un modèle théorique, la meilleure combinaison d’électrodes a été utilisée pour l’élaboration couche par couche de dispositifs tricouches asymétriques. Les systèmes résultants ont présenté des déformations linéaires cohérentes avec la prédiction du modèle électromécanique. Par ailleurs la capacité de ces matériaux à détecter et quantifier une déformation linéaire a également été démontrée.Les travaux de cette thèse ont démontré une méthode d’élaboration simple et reproductible pour la fabrication de microactionneurs et de microcapteurs à base de PEDOT:PSS avec des performances élevées. Le procédé de microfabrication développé permet leur intégration complète dans les microsystèmes et ouvre des perspectives prometteuses pour le développement de PCE-MEMS flexibles et efficacesElectroactive polymers (EAPs) are able to change their shape and/or size in response to electrical stimulation, but also to generate electrical signal in response to mechanical stimulation. As flexible, and lightweight materials, they arise as promising candidates for the development of soft Micro-Electro-Mechanical Systems (MEMS) to move towards soft electronics. The goal of this thesis is the fabrication and characterization of microactuators and microsensors based on electronically conductive polymers (ECPs) to obtain efficient devices for further integration into microsystems.The recently elaborated Layer-by-Layer (LbL) process for fabricating ECP based microactuators was taken as a starting point of this thesis. The optimization of vapor phase polymerization of 3,4-ethylenedioxythiophene (EDOT) was studied in order to improve the electrical and electrochemical properties of the electrodes and as a result, the microactuators performances.As a next step, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was chosen as a new electrode material to develop more simple and reproducible LbL process. Polar reactive additives based on poly(ethylene oxide) (PEO) were incorporated to the PEDOT:PSS commercial dispersion to elaborate electrodes with improved electrical, mechanical and electrochemical properties. These PEDOT:PSS composite electrodes were then used to fabricate efficient trilayer microactuators. Additionally, the mechanical strain sensing of these trilayers was demonstrated for the first time on microscale.The integration of these PEDOT:PSS based microactuators was then performed according to a process fully compatible with microsystems. The process describes for the first time the complete elaboration of the trilayer microdevices, their full integration with electrical connections and subsequent operation on a flexible substrate without any manual handling, allowing the design of microsystems with complex configurations. The resulting microsystems were successfully characterized as microactuators and as microsensors.Finally, air-operating linear actuators have been developed by the combination of PEDOT:PSS based electrodes with different physical properties as predicted by a theoretical model. The electrochemical and mechanical properties of PEDOT:PSS based electrodes were first studied as a function of their composition but also of their the redox level. Best combination of electrodes was used to develop asymmetrical trilayer devices with simple LbL process. The resulting devices presented linear actuation with performances in the range of predicted values. Linear strain sensing ability of these materials was also demonstrated.The work of this thesis demonstrated a simple and reproducible elaboration method for fabricating PEDOT:PSS based microactuators and microsensors with high performances. The developed microfabrication process allows their full integration into microsystems and brings them closer to the development of soft and efficient ECP-MEMS
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Le, Borgne Brice. "Microcapteurs chimiques basés sur des couches nanométriques de silicium polycristallin : application à la détection de plomb." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S118/document.
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Ces travaux de thèse ont pour but de mettre en œuvre un capteur de plomb à base de nanostructures de silicium polycristallin. L'étude physique des structures de type nanorubans ou nanofils de silicium polycristallin a montré que ces derniers possèdent de faibles qualités cristallines mais des propriétés électriques suffisantes pour être utilisées comme éléments sensibles d'un capteur. Les nanorubans ont été fonctionnalisés par greffage spontané des sels de diazonium, capables de pré-concentrer des ions de plomb à la surface de la nanocouche. Cette fonctionnalisation a permis de détecter des traces de plomb, le capteur atteignant une limite de détection de 2.10-7 mol/L. Ces résultats montrent ainsi que la détection de plomb est possible avec des nanostructures de silicium polycristallin dont le procédé de fabrication est relativement bon marché. Le développement d'un transistor gate-all-around (GAA) à base de nanofils de silicium polycristallin est proposé dans cette thèse. Son utilisation avec deux grilles indépendantes a permis de caractériser électriquement et physiquement les nanofils de silicium polycristallin. Les caractéristiques électriques du transistor GAA sont par ailleurs encourageants pour une utilisation en tant que capteur pour diminuer la sensibilité et les limites de détection d'ions de plombThe aim of this research work is to implement a lead ions sensor based on polycrystalline silicon nanostructures. This material has been intensively studied by electrical and physical characterization. This study showed that structures such as polysilicon nanoribbons or nanowires have poor crystalline quality but satisfying enough electrical properties to be used as a sensor sensible elements. Nanoribbons have been functionnalized by spontaneous grafting of diazonium salts that enable lead ions trapping at the surface of these nanoribbons. Thanks to the functionnalization, sensor reached a limit detection as low as 2.10-7 mol/L. These results prove that sensing lead ions is possible thanks to low-cost polysilicon nanostructures. Development of a gate-all-around transistor based on polycrystalline silicon nanowires is proposed in this manuscript. It could lead to increase sensibility of that type of microsensors
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Perera, Reshani H. "Nitric Oxide Synthase in Confined Environments: Detection and Quantification of Nitric Oxide Released From Cells and Modified Liposomes Using a Sensitive Metal Catalyst-PEDOT Modified Carbon Fiber Electrode." Cleveland State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1297142093.
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Lin, 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.
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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.
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Syfte: Syftet med den här studien var att undersöka följsamheten och reduktionen av det horisontella överbettet vid behandling med van Beek-aktivator genom att jämföra en rekommenderad användningstid av tolv och åtta timmar per dag. Material och metod: Tretton patienter (4 pojkar och 9 flickor) ingick i undersökningsmaterialet med en medelålder på 10,0 år (SD = 0,9). Alla patienter var diagnostiserade med en Angle Klass II-bettavvikelse och behandlades med van Beek-aktivator. Patienterna var randomiserade i två grupper med två olika användningstider (8 timmar och 12 timmar). Följsamheten mättes med hjälp av en mikrosensor (TheraMon®) inbyggd i aktivatorn och det horisontella och vertikala överbettet registrerades efter första, tredje och sjätte månaden. Efter att datan var insamlad gjordes statistisk analys för att påvisa ifall statistisk skillnad fanns mellan grupperna.Resultat: Medelreduceringen i horisontellt överbett i 8-timmarsgruppen var efter sex månader 3,4 mm jämfört med hos 12-timmarsgruppen som var 3,5 mm. Medelanvändningstiden var i 12-timmarsgruppen och 8-timmarsgruppen 8.2 timmar (SD=1,7) och 7,9 timmar (SD=2,6) per dag respektive. Den genomsnittliga användningstiden för samtliga patienter var 8,1 timmar.Slutsats: Rekommendation av åtta timmar var enklare att uppnå jämfört med tolv timmar. Van Beek-aktivatorn var effektiv för korrigering av Angle Klass II-bettavvikelser, ingen klinisk signifikant skillnad i behandlingseffekt observerades mellan de två grupperna.Aim: 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.
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Laithier, Virginie. "Microsystème fluidique de détection de gaz pour l'environnement." Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4308/document.
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Les travaux menés durant cette thèse ont abouti à la fabrication d'un microsystème fluidique de détection de gaz innovant portatif, bas coût et incluant un pompage thermique. Le microcapteur de gaz utilisé est inséré dans un microcanal. Un chauffage intégré permet au microcapteur de bien fonctionner. Il permet aussi la création du phénomène de thermal creep qui est à l'origine de l'écoulement du gaz à détecter le long du canal vers le microcapteur. Le gradient de température le long du canal et les dimensions sont des paramètres essentiels de l'étude.Des simulations microfluidiques et thermiques ont permis de définir les dimensions du microcanal ainsi que les matériaux les plus adéquats. Deux types de microsystèmes ont ensuite été réalisés. Le dispositif de chauffage intégré a été calibré afin d'étudier le gradient thermique réel. Une étude des performances du microcapteur sous ammoniac a été réalisée. Nous avons pu notamment déterminer la température optimale de détection. Puis des tests dans une cellule de détection ont été réalisés avec le microsystème completMy thesis work led to develop an innovative fluidic microsystem for gas detection. It is portable, cheap and has an integrated thermal pumping. The gas microsensor used is inserted into a microchannel. Its integrated heater allows the well detection. It also allows the creation of thermal creep phenomenon, which is at the origin of the gas flow along the channel which will be detected by the microsensor. The choices of both microchannel dimensions and the temperature gradient are the most important parameters. Thus, microfluidic and thermal simulations were performed to define the microchannel dimensions and the most suitable materials natures. Two microsystems were processed with clean room technologies. The integrated heater was calibrated to study the real thermal gradient. A study of the performance of the microsensor was performed under ammonia. We could include determining the optimal temperature sensing. Then the microsystem was studed using in a special detection cell
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Gentles, Jeremy A., Christine L. Coniglio, Michael T. Mahnken, Joshua M. Morgan, Matthew M. Besemer, and Christopher J. MacDonald. "The Demands of a Single Elimination Collegiate Tennis Tournament." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/3971.
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Despite the considerable body of literature describing the demands of tennis, little is known about the accumulated physiological and mechanical loads associated with collegiate tennis tournament play. While microsensors have been used extensively to quantify demands in a variety of sports, particularly accelerometry and GPS sensors, limited data exists describing the demands of tennis match play using such microsensors (1,2).
Aim. The purpose of this study was to use heart rate sensors and triaxial accelerometers to investigate the physiological and mechanical loads associated singles and doubles' tennis play during a single elimination collegiate tennis tournament.
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Lale, Ahmet. "Développement de transistors à effet de champ à base de nanofils de silicium pour la détection en phase liquide." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30175/document.
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Les transistors à effet de champ sensibles aux ions (ISFET) sont des composants électroniques conçus pour fonctionner en phase liquide. Pour résumer, ce sont des MOSFET dont la grille métallique est remplacée par une membrane isolante ionosensible. Au début des années 2000, ces composants ont évolué avec l'introduction des premiers dispositifs à base de nanofils de silicium. Grâce à leurs faibles dimensions, ces capteurs ont ouvert de nouvelles perspectives, comme par exemple, l'étude des métabolismes intracellulaires. L'objectif de cette thèse a été de développer et d'étudier un capteur de type ISFET, à base de nanofils de silicium, ayant comme couche sensible l'alumine Al2O3. Les premiers travaux ont porté sur l'intégration de films minces d'alumine Al2O3 dans un procédé de type MOSFET. Ce matériau devant être déposé sur des nanofils de silicium, la technique de dépôt successif de couches moléculaires (Atomic Layer Deposition ALD) a été retenue. Cette méthode offre la possibilité de déposer des films d'épaisseur homogène tout autour des nanofils. Après l'étude de l'ALD-Al2O3, la deuxième grande partie de ce projet a consisté à développer, en utilisant les techniques de la microélectronique, des structures innovantes à base de nanofils de silicium. Des transistors constitués d'un seul nanofil, et d'autres constitués de réseaux parallèles de nanofils ont été réalisés. Ces capteurs ont été intégrés dans des canaux microfluidiques, permettant ainsi de localiser précisément le liquide sur les nanofils, mais aussi de pouvoir travailler en micro/nanovolumes. La dernière partie de ce projet a consisté à caractériser ces capteurs en phase liquide. Les différentes configurations ont montré leurs avantages et inconvénients en termes de transconductance, courants de fuite, pentes sous le seuil, sensibilités au pH et aux ions interférents (Na+ et K+). Les caractérisations se sont avérées excellentes et laissent entrevoir des perspectives intéressantes pour des applications biologiques. Les principales innovations de ces capteurs concernent : l'utilisation de nanofils suspendus, la réalisation d'une gaine isolante ionosensible bicouche SiO2/Al2O3 tout autour des nanofils, la variation du dopage le long des nanofils ce qui a conduit à la réalisation de jonctions N+/P/N+, et l'intégration des capteurs dans des canaux microfluidiques couvertsIon-sensitive field effect transistors (ISFET) are electronic components designed to operate in liquid phase. To summarize, they are MOSFET-based devices whose metal gate is replaced by an ionosensitive insulating layer. In the early 2000s, these components evolved with the introduction of the first device based on silicon nanowires. Thanks to their small dimensions, these sensors opened up new perspectives, such as the study of intracellular metabolisms. The aim of this thesis was to develop and study a type of ISFET sensor, based on silicon nanowires, with Al2O3 alumina as sensitive layer. The first part of this work was focused on the integration of thin alumina Al2O3 films in a MOSFET process. This material had to be deposited on silicon nanowires, that is why Atomic Layer Deposition (ALD) was used. This method allows to deposit films with uniform thickness all around nanowires. After the study of ALD-Al2O3, the second major part of this project was to develop innovative structures, based on silicon nanowires, using microelectronics methods. Transistors consisting of a single nanowire, and others consisting of parallel networks of nanowires were fabricated. These sensors were integrated in microfluidic channels, allowing to precisely locate the liquid on nanowires and also to work in micro/nanovolumes. The last part of this project consisted in characterizing these sensors in liquid phase. The different configurations showed their advantages and disadvantages in terms of transconductance, leakage currents, slopes below the threshold, sensitivities to pH and interfering ions (Na+ and K+). The characterizations proved to be excellent and suggest interesting prospects for biological applications. The main innovations of these sensors are: the use of suspended nanowires, the realisation of a bilayer SiO2/Al2O3 ion-sensitive sheath all around the nanowires, the doping variation along the nanowires which led to the realization of N+/P/N+ junctions, and the integration of sensors into covered microfluidic channels
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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.
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The use of ion-selective field-effect transistors (ISFETs) as potentiometric microsensors was investigated. In the first stage, an instrument was designed and built to operate an array of ISFETs. A microcomputer was used for instrument control and acquisition of data.The 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.
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Zribi, Aymen. "Fluxmètre thermique : conception, modélisation, réalisation et caractérisation. Mesures de températures et de densités de flux thermiques." Thesis, Besançon, 2016. http://www.theses.fr/2016BESA2085/document.
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En vue d'applications futures dans le domaine de la récupération d'énergie à basse température à partir de microsystèmes, la connaissance des transferts thermiques aux parois est d'une grande importance. Ces mesures sont réalisées à l'aide de capteurs spécifiques qui permettent de connaître le flux thermique total échangé entre la paroi sur laquelle ils sont installés et le milieu environnant. Cette étude se situe dans le cadre du développement de fluxmètres thermiques a gradient répondant aux contraintes liées aux machines thermiques de type micro-moteur Stirling. Six types de fluxmètres thermiques à sondes à résistance ont été développés à partir de différents matériaux, géométries et formes de capteurs. Une étude électrothermique, prenant en compte l'effet d'auto-échauffement, a été menée et validée expérimentalement. Les techniques de fabrication et de caractérisation, opérés majoritairement en salle blanche, ont permis de réaliser de nombreux capteurs à couches minces. Des supports spécifiques pour ces capteurs ont été développés. Ces capteurs de flux thermique, dont les résistances ont été étalonnées par rapport à une sonde de référence de haute précision, permettent également la mesure de la température. Pour mesurer la densité de flux thermique, deux méthodes ont été testées. La première méthode est indirecte : elle consiste à mesurer le gradient de température à l'aide de deux sondes à résistance en platine. La deuxième méthode est directe : elle repose sur un étalonnage en flux. Enfin, l'influence de l'intrusion des capteurs sur le répartition des flux thermiques dans la pièce à mesurer, avec ou sans support spécifique, a été étudiéeFor future applications in the field of low-temperature energy have sting in microsystems, knowledge of wall heat transfer is of great importance. These measurements are carried out using specific sensors which makes possible to know the total heat flux exchanged between walls and the surrounding environment. This study concerns the development of a gradient heat flux sensor compliant with their requirements associated with thermal machines such as micrometric Stirling engines. Six types of heat flux sensor with resistance temperature detector have been developed from different materials, with various geometries and shapes of sensing elements. An electro thermal study, taking into account the self-heating effect, was carried out and experimentally validated. The fabrication and characterization techniques, mainly carried out in clean rooms, allowed to produce numerous thin-film sensors. Specific housings for these sensors have been developed. These heat flux sensors, whose resistances have been calibrated with a highly accurate reference probe, also allow measuring the temperature. To measure the heat flux density, two methods were tested. The first method is indirect : it consists in measuring the temperature gradient using two platinum resistance probes. The second method is direct : it is based on heat flux calibration. The calibration and measurement benches have been modeled. Then, the experimental and numerical results have been compared. Finally, the influence of the sensor intrusion on the thermal fluxes distribution in the investigated sample, with or without a specific housing, has been studied
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Kerness, Nicole. "CMOS-based calorimetric chemical microsensors /." [S.l.] : [s.n.], 2002. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=14839.
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Pathak, Shrey. "Piezoelectric microsensors for semiochemical communication." Thesis, University of Warwick, 2012. http://wrap.warwick.ac.uk/57210/.
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Chemical communication plays vital role in the mediating the behaviour of an organism living in the “odour space”. The mechanisms by which odours are generated and detected by the organism has evolved over thousands of years and thus the potential advantages of translating this system into a fully functional communication system has opened new avenues in the area of multi-disciplinary research. This formed the basis of the Biosynthetic Infochemical Communications project – iCHEM whose central aim was to develop a new class of communication technology based on the biosynthesis pathways of the moth, S. littoralis. This novel infochemical communication system would consist of a “chemoemitter” unit which would generate a precise mix of infochemicals which after travelling through the odour space would be detected by a complementary tuned detector – the “chemoreceiver” unit comprising of a ligand specific detection element and an associated biophysical model functioning similar to the antennal lobe neuron of the moth. This combined novel system will have the capability of communicating by the help of chemicals only, in the vapour or liquid phase. For the work presented in this thesis, the novel concept of infochemical communication has been examined in the vapour and liquid phase by employing piezoelectric microsensors. This has been achieved and demonstrated throughout the thesis by employing chemo-specific acoustic wave microsensors. For vapour phase assessment, quartz crystal microbalance, were coated with different organic polymer coatings and incorporated in a prototype infochemical communication system detecting encoded volatiles. For liquid phase assessment, shear horizontal surface acoustic wave (SH-SAW) microsensors were specifically designed and immobilised within Sf9 insect cells. This GPCR based whole cell biosensing system was then employed to detect ligand specific activations thus acting as a precursor to the development of a fully functionalised OR based signalling system, thus contributing to the growing field of communication and labelling technology.
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Cordero, Álvarez Rafael. "Subcutaneous Monitoring of Cardiac Activity for Chronically Implanted Medical Devices." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS020.
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L'objectif de cette thèse de doctorat est le développement de capteurs et d'algorithmes pour une meilleure surveillance de l'activité cardiaque dans un défibrillateur cardioverteur implantable sous-cutané (S-ICD), et plus précisément pour améliorer la spécificité de détection des tachyarythmies dangereuses telles que la tachycardie ventriculaire (TV) et la fibrillation ventriculaire (FV) dans le S-ICD. Deux schémas de détection TV/FV indépendants ont été développés dans ce but : l'un de nature électrophysiologique et l'autre hémodynamique. Le schéma de détection électrophysiologique repose sur un ECG spécial qui a été enregistré le long d'un dipôle «court» situé au-dessus du grand pectoral inférieur gauche. Ce dipôle court maximise le rapport R/T et le rapport signal/bruit chez 9 volontaires sains. En théorie, cela devrait réduire le risque de détections faussement positives de TV/ FV simplement en raison de la taille, de l'emplacement et de l'orientation du dipôle, indépendamment de toute autre méthode de traitement du signal. Le schéma de détection hémodynamique repose quant à lui sur les vibrations cardiaques enregistrées par deux prototypes de capteurs accéléromètres triaxiaux. Les vibrations cardiaques sous-cutanées mesurées ont été caractérisées, validées physiologiquement et optimisées via leur filtrage le long de bandes passantes spécifiques et leur projection le long d'un référentiel spécifique patient. Le premier algorithme au monde indépendant de détection de FV par vibration cardiaque a été développé en opérant sur ces signaux optimisés. Les mêmes prototypes d'accéléromètre se sont également avérés capables d'enregistrer des accélérations respiratoires et de détecter l'apnée. Enfin, un dernier prototype de sonde sous-cutanée composite, composé de trois électrodes, d'un accéléromètre bi-axial et de connecteurs d'appareil standard. Ce prototype est capable d'enregistrer l'ECG dipolaire court, les vibrations cardiaques et les accélérations respiratoires. Cette sonde prototype a été implantée dans un quatrième et dernier animalThe aim of this doctoral thesis was the development of sensors and algorithms for the improved monitoring of cardiac activity in the subcutaneous implantable cardioverter-defibrillator (SICD). More precisely, to improve the detection specificity of dangerous tachyarrhythmia such as ventricular tachycardia (VT) and ventricular fibrillation (VF). Two independent VT/VF detection schemes were developed for this: one electrophysiological in nature, and the other hemodynamic. The electrophysiological sensing scheme relied on a special ECG that was recorded along a short dipole located above the lower left pectoralis major. This short dipole maximised R/T ratio and signal-to-noise ratio in a total of 9 healthy volunteers. In theory, it will reduce the risk of false positive VT/VF detections simply by consequence of the dipole size, location, and orientation and independently of any further signal processing methods. The hemodynamic sensing scheme relied on cardiac vibrations recorded from two tri-axial accelerometer prototype sensors. These subcutaneous cardiac vibrations were characterised, physiologically validated, and optimised via their filtering along specific bandwidths and projection along a patient specific reference frame. The world’s first independent cardiac vibration VF detection algorithm was developed operating on these optimised signals. The same accelerometer prototypes were also shown to be able to record respiratory accelerations and detect apnoea. A final subcutaneous lead prototype was developed capable of recording the short dipole ECG, cardiac vibrations, and respiratory accelerations. It consisted of three electrodes, a bi-axial accelerometer, and industry-standard device connectors. The prototype lead was implanted in a fourth and final animal
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Srinivas, 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.
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Peng, Tao. "Conception et réalisation de micro-capteurs à magnéto-impédance pour le contrôle non destructif." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112407/document.
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La capacité à détecter des micro-défauts ou des défauts profonds dans les pièces métalliques constitue un enjeu important pour l'industrie de l'aéronautique ou du nucléaire. La technique de contrôle non destructif (CND) par courant de Foucault est souvent utilisée pour cette application. Cette thèse s’inscrit dans le cadre d'une collaboration ayant pour but la réalisation et l'intégration de micro-capteurs de champ magnétique basés sur l’effet de magnéto-impédance (MI) à des systèmes de détection par CND. Ces micro-capteurs de structure multicouche (ferromagnétique/conducteur/ferromagnétique) ont été élaborés en salle blanche par dépôt de films minces. Un traitement thermique sous champ magnétique a ensuite permis d’optimiser les propriétés du matériau et d’induire des anisotropies dans le plan des couches ferromagnétiques. Une méthode basée sur la double démodulation d’amplitude du signal de mesure a été proposée pour la caractérisation dynamique des capteurs. Les paramètres importants tel que la géométrie, l’anisotropie et la fréquence d’excitation ont été étudiés afin d’optimiser les caractéristiques. Les résultats ont montré la nécessité de polariser les capteurs en champ. Nous avons donc étudié la possibilité de réaliser, grâce à une technique de micromoulage épais, un microsolénoïde 3D et des travaux préliminaires sur l’intégration d'un capteur dans le microsolénoïde par transfert de film ont été effectués. Enfin, une étude théorique a été réalisée en tenant compte des résultats obtenus expérimentalement. Pour cela, le modèle de Landau-Lifshitz-Gilbert (LLG) a été implanté dans un code de calcul électromagnétique par éléments finis permettant de calculer l’impédance du capteur en fonction du champ magnétique appliquéThe capability to detect micro-defects or buried flaws in the metallic parts is an important issue for the aerospace or nuclear industry. The technique of nondestructive testing (NDT) by eddy current is widely used for these applications. This thesis is part of collaboration project aimed at the realization and integration of magnetic field microsensors based on the magneto-impedance (MI) effect for the NDT detection systems. These multilayered structure microsensors (ferromagnetic/conductor/ferromagnetic) were realized in the clean room by thin film deposition method. A post-annealing step with magnetic field was then used to optimize the material properties and to induce magnetic anisotropy in the ferromagnetic layers. A method based on the double amplitude demodulation was proposed for the dynamic characterization of the sensors. The important parameters such as the geometry, the anisotropy and the driven frequency were studied in order to optimize the characteristics. The results showed that a bias field is necessary for the application. Therefore, we have investigated the possibility to realize, through thick micromoulding technique, a 3D microsolenoid and preliminary work on integrating a sensor in the microsolenoid by film transfer has been carried out. Finally, a theoretical study was investigated by taking into account the results obtained experimentally. For this purpose, the model of Landau-Lifshitz-Gilbert (LLG) has been implemented in an electromagnetic finite element calculation program in order to determine the impedance of the sensor as a function of the applied magnetic field