Dissertationen zum Thema „Détection de trace de gaz“
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James, Frank. „Développement d’un système de préconcentration miniaturisé pour la détection de gaz à l’état de trace/Application à la détection de COV et d’explosifs“. Thesis, Saint-Etienne, EMSE, 2015. http://www.theses.fr/2015EMSE0778/document.
Der volle Inhalt der QuelleIn order to overcome problems due to the conventional sensors detection limits, a preconcentration system is required. Accumulation of vapor(s) for detection is possible with an adsorbent and allows releasing them toward a detector, under the effect of a sudden rise of the temperature. Amplification of the concentration and the signal are obtained.This thesis continues the development of a preconcentrator for the detection of toxic gas and explosives. This preconcentrator is made of a silicon microcomponent filled with an adsorbent and a heater at its back. Two metal capillary allow ensuring the gas flow into the device. Various designs of preconcentrators were developed with different adsorbents to satisfy the requirements for volatile organic compounds (VOCs) and explosives applications.The optimization of adsorption and desorption phases is very important for the process.The coupling between a micro-chromatograph and a preconcentrator was conducted and showed the contribution of the microcomponent to the chromatography. Analysis of a VOCs mixture was achieved with initial concentrations in the order of 40 ppb, whereas the detection limit was of a few ppm. An enrichment factor of 800 was achieved.The advantage of using porous silicon was also demonstrated for the gas adsorption with low saturation vapor pressure. This result is interesting for explosive vapor préconcentration
Camara, El Hadji Malick. „Développement d'un micro-préconcentrateur pour la détection de substances chimiques à l'état de trace en phase gaz“. Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2009. http://tel.archives-ouvertes.fr/tel-00448980.
Der volle Inhalt der QuelleCamara, El Hadji Malick. „Développement d'un micro-preconcentrateur pour la détection de substances chimiques à l'état de trace en phase gaz“. Saint-Etienne, EMSE, 2009. http://tel.archives-ouvertes.fr/tel-00448980.
Der volle Inhalt der QuelleIn the field of gas detection, one major trend is to miniaturize analytical techniques. In such technological developments, the gas pre-conditioning is usually very important. This may involve, firstly, the modification of a gas mixture, for example to improve the selectivity of a detection device, secondly, the effect of preconcentration in order to increase the sensibility of the detector. Indeed, in some applicative environments the concentration of gas is too small and therefore a preconcentration unit at the entrance of the analytical device is needed. When a preconcenrator is used, the gas mixture to be analyzed flows through it and is accumulated during some time, then the mixture is desorbed by a temperature pulse and brought to the detector. This work presents the development of a gas preconcentrator based on a micro-channel in porous and non-porous silicon filled with an adequate adsorbent material by micro-fluidic process in open micro-device or by impregnation in close one. The particularity of this device is its applicability in the fields of atmospheric pollution monitoring (Volatiles Organic Compounds-VOCs) and explosives detection (nitroaromatic compounds). Various designs of micro-devices have been investigated and a special focus has been dedicated to the carbon adsorbent. The optimization of the device and its operation were driven by its future application in outdoor environments. The benefits of using porous silicon to ease the fixing of the carbon absorbent in the reactor and to modify the gas desorption kinetic are also investigated
Rouxel, Justin. „Conception et réalisation de cellules photoacoustiques miniaturisées pour la détection de traces de gaz“. Thesis, Reims, 2015. http://www.theses.fr/2015REIMS030/document.
Der volle Inhalt der QuellePhotoacoustic cells are optical sensors based on the absorption of photons by gas molecules. The pressure wave created by gas relaxation is proportional to the trace gas concentration. Furthermore the photoacoustic signal is inversely proportional to the cell volume. Thus cell miniaturization enables performances improvements. This work consists in designing, realizing and characterizing miniaturized photoacoustic cells, based on the differential Helmholtz resonator (DHR) principle. In a first phase, modeling by the finite element method of millimeter scale cells has shown that the miniaturization of this type of resonator should effectively improve the detection limit. Thus, the ambitious realization of a DHR cell on silicon by the use of microelectronic techniques has been attempted. However, this extreme miniaturization direction encountered design and fabrication difficulties which made the produced devices unusable. To overcome these difficulties, a miniaturization alternative, at the centimeter scale, using commercial MEMS microphones, has been carried out. Three cells have been built by different methods and have been tested for methane detection. The last cell generation can detect around 100 ppb of methane with a commercial interband cascade laser at 3.357 µm of wavelength. Finally, to anticipate the next cell generation fabrication, a geometry optimization has been performed by simulation. This optimization shows that a 43 % signal improvement, compared to the most performant cell already built
Gascon, Hélène. „Détection de traces de gaz par spectroscopie à diode laser : application au sulfure d'hydrogène“. Paris 6, 2001. http://www.theses.fr/2001PA066513.
Der volle Inhalt der QuelleBounaix, Fabrice. „Etude et réalisation d'un spectromètre haute sensibilité à diode laser pour la mesure de traces de gaz : application à la détection de la vapeur d'eau“. Grenoble 1, 1993. http://www.theses.fr/1993GRE10018.
Der volle Inhalt der QuelleElmaleh, Coralie. „Développement d’un prototype ultrasensible d’analyse de gaz dans le domaine submillimétrique“. Electronic Thesis or Diss., Littoral, 2024. http://www.theses.fr/2024DUNK0698.
Der volle Inhalt der QuelleThis thesis explores the technological development of a spectroscopic experiment in the submillimeter range, also known as Terahertz (THz). This spectral band stands out for its ability to precisely resolve molecular doublets, enabling clear and precise identification of complex gas mixtures, even when other wavelengths might fail.Although the THz region offers exceptional resolving power, spectrometers operating in this region often face sensitivity challenges due to the development of technology in this band. Thanks to an innovative approach, we have implemented the first Cavity Ring-Down Spectroscopy (CRDS) experiment capable of quantifying compounds to ppb precision. The study is concentrated between 550 GHz and 650 GHz, a window of the THz spectrum that not only offers unrivalled resolution and molecular sensitivity, but also possesses the ability to penetrate non-conducting materials while being non-ionizing. These properties position this technology at the cutting edge of analysis tools, promising a plethora of applications, from fundamental research to industrial applications
Mohsen, Yehya. „Conception et caractérisation d’une plate-forme microfluidique pour la détection sélective de traces d’un produit de dégradation du TNT dans l’atmosphère“. Thesis, Besançon, 2013. http://www.theses.fr/2013BESA2004/document.
Der volle Inhalt der QuelleThe objective of this study is to develop and characterize a micro-fluidic platform allowing theconcentration and the separation of a degradation compound of trinitrotoluene: the orthonitrotoluenerecognized as an explosive taggants. Tin dioxide gas sensors (SnO2) used here asdetectors suffer from a luck of selectivity and have an insufficient sensitivity toward most ofpollutants. For that, our original approach consists to work in front of a chemical gas sensor(SnO2), in particular, by developing on the one hand a gas micro-preconcentrator to improve thesensitivity and on the other hand, a chromatographic micro-column in order to overcome the luckof selectivity.First, various adsorbents have been studied and characterized for the ONT concentration. Theobtained results allowed to select three types of activated carbons (N, KL2 and KL3) and ahydrophobic zeolite DAY. Then, the micro-system devices have been realized on a siliconsubstrate and manufactured using the silicon/glass technology.The last part of this work is devoted to the evaluation of the platform performances in terms ofconcentration and separation of ONT. In particular, after the optimization of the experimentalconditions concerning the concentration and the elution of ortho-nitrotoluene, the couplingbetween the micro-fluidic platform and a tin dioxide gas sensor allowed on the one hand to showthat the detection limit of the ONT pollutant is lower than 365 ppb. In this case, a total desorptionof the analyte and a constant concentration factor were obtained with the zeolite DAY. On theother hand, the use of this type of platform allowed to obtain a good separation and detectionperformance of ONT in presence of interferent (toluene) and at high humidity rate
Richard, Lucile. „Développements de spectromètres ultrasensibles pour l'analyse de gaz par « optical feedback cavity enhanced absorption spectrocopy » dans le moyen infrarouge avec des lasers à cascades inter-bandes“. Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAY004/document.
Der volle Inhalt der QuelleThis work of these has made it possible to develop and characterize the use of instruments on the "OF-CEAS" technique in the mid-infrared for traces' detection in different mixtures in the gas phase. Inter-band Cascade Laser (ICL) is the latest innovation in semiconductor lasers in this spectral region. Compatibility of ICL with OF-CEAS offers new applications for compact and robust instruments with fast response time and a low detection limit. A demonstration of the good sensitivity and stability of the OF-CEAS instruments was performed with continua absorption measurements (water vapor and nitrogen). But also with the detection of a very low intensity quadrupole line of nitrogen (3x10-29 cm-1/(moléc cm-2). The main objective of this work was to develop an instrument dedicated to nitrogen oxide detection for the analysis of exhaled breath. The analyzer is presented at the sensitivity of 6x10-10 cm-1 in an acquisition of 180 ms. Its limit of detection on NO is at the state of the art, with short term (180 ms) limit of 50 ppt. It reaches the sub-ppt level (0.9 ppt) with 12 min of integration
Kinjalk, Kumar. „Long Wavelength QCLs for BTEX and Propane detection through QEPAS“. Electronic Thesis or Diss., Université de Montpellier (2022-....), 2023. http://www.theses.fr/2023UMONS079.
Der volle Inhalt der QuelleSensitive and selective sensing of BTEX and Propane is of great interest for environmental, biomedical, and petrochemical applications. However, detecting these compounds poses unique challenges due to potential interferences, either among themselves or from other compounds. This issue can be resolved by using laser spectroscopy in the long-wavelength mid-infrared spectral region (13-15 µm), where they exhibit highly discriminating absorption features. Yet, this wavelength range is almost unexplored due to the lack of suitable sources. This thesis aims to bridge this gap by developing high-performing long-wavelength QCLs and leveraging QEPAS for ultra-sensitive and selective detection.A novel design is proposed to improve the performance of long-wavelength InAs-based QCLs, which allowed us to demonstrate a record-breaking low threshold current density of 0.6 kA/cm2 at 300 K. Additionally, a novel insulation technique using SOG is also proposed to improve device stability issues provoked by the alteration of properties of photoresist insulation (typically used for InAs-based QCLs) at elevated temperatures. Subsequently, single-frequency DFB QCLs with SMSR > 20 dB and optical output power in the mW range operating in the continuous wave regime are developed, targeting the absorption lines of these gasses. Using these DFBs, a sensing system based on QEPAS is developed, calibrated, and characterized for Toluene, Benzene, and Propane detection. Exceptionally low detection limits of 113 ppb, 3 ppb, and 3 ppm are achieved in a pure nitrogen matrix over a 10-second integration time. The system maintains selectivity and robustness, even in complex gas mixtures. Finally, a 13.71 µm QCL is successfully coupled with a HCW, where optimal coupling conditions, beam quality, and loss are explored. The study confirms the efficient transmission of such wavelength through HCW with minimal loss and improved spatial beam quality
Bailly, Guillaume. „Développement de la transduction microonde appliquée à la détection d'ammoniac : du nanomatériau au capteur large bande, compréhension des mécanismes et influence des traces d'eau“. Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCK029/document.
Der volle Inhalt der QuelleThe main objective of this thesis is to propose an analysis of the microwave transduction specificities in the framework of ammonia sensing applications. The two main features of this transduction are its broadband characterization (1 to 8 GHz) as well as its sensitive materials (dielectrics). This transduction method is based on the interaction between a polluting gas and a sensitive material deposited on the surface of a microwave-specific propagating structure. The response of the sensor is not directly induced by the dielectric properties of the gaseous target molecule, but rather by those of the target species adsorbed on the surface of the sensitive material. This adsorption causes a modification of the sensor parameters measured by a vector network analyzer. Unlike more conventional transducers such as conductimetry, this principle works at room temperature with any type of material, including electrical insulators.The first work carried out during this thesis led to the development of a new experimental bench adapted specifically for the study of microwave gas sensors by measuring the S-parameters in reflection and transmission modes. This development includes the design of two new generations of sensors, coated with metal oxides (iron or titanium oxides) commercially available or synthesized during the study. The first sensor comprises interdigital circuits while the second sensor is a trapezoidal resonator. The latter is characterized by a series of frequencies of interest regularly distributed between 1 and 8 GHz. The association of a mass spectrometer with the measurement bench allowed to follow the adsorption and desorption behavior of the target species which is ammonia (10-100 ppm), but also the behavior of the vector gas conventionally used, argon, and water initially adsorbed on the sensitive material or intentionally added during the experiment. The objective is to study the role of water as interfering with the detection of ammonia, the main target species. A third molecule of interest, ethanol, was also used during the experiments in order to estimate the possible differences in the detected molecules behaviors. The experimental results were exploited using specific data processing protocols established during this thesis. Temporal treatments were carried out to study the kinetic behavior of the sensor, while spectral treatments allowed to apprehend the broadband aspect of the sensor response in the presence of pollutants.The first major result is the significant increase in sensitivity to ammonia, which significantly lowered the detection threshold to ammonia concentrations in the 10 ppm range. Titanium dioxide has been identified as a good candidate for ammonia detection, with reflection coefficient variations up to 6 dB for 300 ppm. The role of the water initially adsorbed on the sensitive material has been elucidated, showing that its influence is significant only during the first few minutes of the experiments. Thus, it is possible to detect ammonia in the presence of residual moisture. The processes induced by the gaseous exposures and particularly by the carrier gas were identified, and confirmed that the sensor response was solely due to its interaction with the target molecules. Another major result is the definition of the operating conditions that are necessary for the establishment of the selectivity. Our theoretical analysis clearly demonstrated the interest of broadband measurements in terms of discrimination of target molecules. This analysis has been tested in multitarget experiments using ammonia, water and ethanol. These observations allowed to establish the specifications of a new generation of microwave sensors, guaranteeing systematic discrimination between these three molecules
Mohsen, Yehya. „Conception et caractérisation d'une plate-forme microfluidique pour la détection sélective de traces d'un produit de dégradation du TNT dans l'atmosphère“. Phd thesis, Université de Franche-Comté, 2013. http://tel.archives-ouvertes.fr/tel-00943211.
Der volle Inhalt der QuelleMarais, Arthur. „Détection de traces d’éléments lanthanides par fluorescence en temps résolu : application industrielle au marquage anti contrefaçon et à l'analyse chimique“. Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1012/document.
Der volle Inhalt der QuelleTime-resolved fluorescence is an advanced spectrophotometric analysis method which allows the selection of emitted luminescent photons on a time-based parameters. It is possible to extract the signal of long-lived luminescent species even in complex and polluted matrix from the industry. This type of analysis is especially fitted for the detection of lanthanide ions. During this thesis two technologies based on time-resolved analysis were designed to answer specific industrial problematics. The first one yields the residual concentration of chemical additives used during oil and gas extraction. The second one aims at protecting crude oils and refined fuels from counterfeiting. They both rely on the use of lanthanide complex and the measurement of their luminescent properties. A prototype of time-resolved spectrofluorimeter was also built to transfer the technologies from the laboratory to the industrial world
Maamary, Rabih. „Développements d'instrumentations lasers (QCL, DFG) dédiés à la métrologie d'espèces d'intérêt atmosphérique (CH₄, HONO)“. Thesis, Littoral, 2014. http://www.theses.fr/2014DUNK0376/document.
Der volle Inhalt der QuelleI report in this PhD thesis on the development of two mid-infrared laser spectrometers, based on difference-frequency generation (DFG) and quantum cascade laser (QCL), for application to trace gas monitoring. The DFG spectrometer (2.78 µm) was coupled with the QCL spectrometer (8 µm) to simultaneously measure nitrous acid (HONO) absorption spectra of the v₁ and v₃ bands respectively. Such crossing measurements allow us to determine experimentally, for the first time, the line strengths of 31 absorption lines of the ν1 band of trans isomer of nitrous acid that significantly impacts the air quality and climate change because of its crucial role in the atmospheric oxidation capacity. The QCL spectrometer is also deployed for continuous monitoring of methane (CH₄) during January 2013 in Dunkirk. Methane concentration variation is analyzed with the help of the simultaneously recorded meteorological parameters. In order to identify the sources of CH₄ emission, I developed an Isotope Ratio Laser Spectrometry (IRLS) technique to measure the isotopic ratio of ¹³CH₄/¹²CH₄. Preliminary results are presented
Laithier, Virginie. „Microsystème fluidique de détection de gaz pour l'environnement“. Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4308/document.
Der volle Inhalt der QuelleMy 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
El, Romh Mohamad Ali. „Oxydes sans plomb pour la détection de gaz : OSPÉGAZ“. Thesis, Littoral, 2016. http://www.theses.fr/2016DUNK0448/document.
Der volle Inhalt der QuelleToday gas detection, which now mainly uses optical sensors, electrochemical sensors based on lead, and catalytic sensors, is a very promising market (estimated at 3 billion euros) with a strong growth (10% per year). The need for new instrumentation systems dedicated to the monitoring of the air quality and to the detection of hazardous substances, requires the study and development of new sensors compatible with the European environmental standards : Restriction of the use of Hazardous Substances (RoHS) ; Registration, Evaluation and Authorization of Chemicals (REACh). The OSPÉGAZ project aims to develop innovative integrated instrumentations systems for the characterization of different environmental exposures linked to the actions recommended by the PNSE2 for proven health impacts. Our research project aims to develop innovating and cost-effective gas sensors containing lead-free oxides and dedicated to the detection of flammable gases and protection against toxic risks. The works of the thesis presented in this manuscript is a part of this project. The objectives were, firstly, to develop a new process for ink preparation in UDSMM laboratory, for the elaboration, electrical and physicochemical characterizations, of thick porous film, and secondly to make gas sensors based on these films. We chose to use the BaTiO3 (well-known material in literature) material as a first material in order to develop the process of thick film elaboration. After that, we chose the BaSrTiFeO₃ as gas-sensitive material, and we studied two compositions of Ba₁₋ ₓ Sr ₓ Ti₁₋yFeyO₃ with two different concentrations or iron : Ba₀.₈₅Sr₀.₁₅Ti₀.₉Fe₀.₁O₃ (BSTF 10%) and Ba₀.₈₅Sr₀.₁₅Ti₀.₉₈Fe₀.₀₂O₃ (BSTF 2%). Electrical characterizations were made in a wide range of frequency (100 HZ to 1 MHz) and temperature (25° C to 500° C). The dielectric properties as a function of temperature and frequency were studied using two different structures of capacitance : metal-insulator-metal (MIM) and interdigital electrodes (CID). Finally we have developed semi-conductor gas sensors based on BT, BST and BSTF (10% ; 2%) thick films. All our sensors were tested under different gases such as carbon monoxide CO (200ppm), hydrogen sulphide H₂S (50ppm) and sulfur dioxide SO₂ (20ppm), at various temperature, in the laboratory of SIMTRONICS SAS. We have measured the greatest relative sensitivity under H₂S (50ppm) gas ; 55.4% and 48% respectively for BSTF (10%) and BSTF (2%), at 450°C. Good relative sensitivity and very interesting dynamic responsesof BSTF show that the material has a great potential for the detection of gas. The optimization of the sensor geometry, iron rate and operating temperature should allow us to improve the performance of our demonstrators
Viatte, Camille. „Observations de la composition atmosphérique par mesures infrarouges en occultation solaire depuis la station d’izana (Tenerife) et la nouvelle plateforme Oasis à Créteil“. Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST1127/document.
Der volle Inhalt der QuelleIn the frame of atmospheric composition change related to human activities, homogeneous and continuous atmospheric measurements have to be performed. This is why a new observatory (called OASIS for Observation of the Atmosphere by Solar occultation Infrared Spectroscopy) has been installed on the roof of the University of Paris-Est in order to analyze concentrations and variations of key atmospheric trace species, such as ozone and carbon monoxide. Development of experimental methodology and adaptation of inversion code (PROFFIT) allow to retrieved total and partial columns of these gases. Results are compared to different data from ground-based (SAOZ for O3), satellites (IASI, GOME-2, OMI, for O3, and IASI and MOPITT for CO) and from atmospheric model calculations (REPROBUS for O3 and MOCAGE for CO). Very good correlations were found, showing that a middle resolution instrument, such as OASIS is able to monitor atmospheric trace gases with a good accuracy. Then, thanks to a measurements campaign (April-May 2009), realized at Izaña (Tenerife, clear atmospheric conditions) observatory which is equipped with high resolution spectrometer, we provide valuable information about the performance of various total column ozone measuring instruments from ground (Brewer) and space (IASI, OMI, GOME-2). All temporal O3 and CO variabilities (seasonal, day-to-day, diurnal and extreme events) observed at both sites, such as respective high and middle resolution instruments capabilities were discussed in details
Ngo, Kieu An. „Etude d'un système multiplicateur pour la détection sélective des gaz“. Aix-Marseille 3, 2006. http://www.theses.fr/2006AIX30018.
Der volle Inhalt der QuelleChemical sensors based on metallic oxide undergo a significant lack of selectivity to gases. To overcome this problem, we proposed a solution based on the electronic nose approach, i. E. The combination of several sensors with appropriate pattern recognition methods. A semi-automatic test bench including a matrix composed of several commercial gas sensors was carried out. We used two sensor heating procedures (isotherm mode and temperature modulation mode). Principal component analysis and artificial neural networks were used as pattern recognition techniques. The first heating procedure, applied to a six-sensor array, allowed to classify and to identify five toxic gases (CO, NH3, H2S, C2H2 and NO, each gas concentration was 100 ppm). Moreover, the quantification of gas in binary mixtures was satisfactory, with a RMSEPr value of about 10 %. The second heating procedure, applied to a four-sensor array, allowed to identify three reducing gases (CO, C2H2, and H2S) with concentrations varying from 25 ppm to 100 ppm
Wood, Thomas. „Application des techniques d’optique guidée à la détection de gaz“. Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4321/document.
Der volle Inhalt der QuelleIn a world suffering from increasing air pollution due to spiraling industrial activity, the detection of toxic gasses in the atmosphere is of paramount importance. The gas detector market is already well developed, and features a wide variety of detection technologies and techniques, each presenting its own set of intrinsic advantages and drawbacks. In this thesis, a combination of two or more technologies typically used independently has been studied in order to improve the global performances of gas detection systems. To this length, we have conceived and studied detector architectures based upon optical transduction systems, coupled with a material presenting a specific sensitivity to the target gas. More precisely, we have for the first time integrated a catalyst designed to accelerate the oxidation rate of chemical species (such as carbon monoxide or hydrogen) with an optical component capable of absorbing the heat generated by the oxidation reaction. The associated increase in temperature is translated to a variation of the optical intensity comprising the exit signal of the detector. The work carried out measuring the chromatic and temperature dispersion of the refractive index of the materials comprising the optical transduction component by guided mode techniques, ellipsometry and photometric techniques is presented. The optical probing of the electrical properties of semiconductor materials has also been studied, including the variations of these properties following interactions with oxidizing, reducing, or combustible gasses
Cachia, Maxime. „Caractérisation des transferts d’éléments trace métalliques dans une matrice gaz/eau/roche représentative d'un stockage subsurface de gaz naturel“. Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3006/document.
Der volle Inhalt der QuelleNatural gas represents 20% of energy consumption in the world. This percentage is expected to increase in the next years due to the energy transition. For economic and strategic concerns, and in to regulate energy demand between summer and winter, natural gas might be stored in underground storages like aquifers. Consequently, injection and drawing operations favour contact between gaseous, liquid and solid species and make possible transfer phenomena of chemical species from one matrix to another. In addition, even though natural gases are composed essentially of methane (70-90%vol), they can also show various metallic trace element concentrations (mercury, arsenic, tin…). According harmful effects of these compounds on industrial infrastructures and on environment, knowing impacts of natural gas composition on aquifer storage is crucial.The different tasks of this thesis are incorporated within such a context with the objective to characterize gases-waters-rocks matrices and their potential interactions, focusing on metallic trace elements.Therefore, we have focused a part of this PhD thesis on the optimisation of conditions of use (i) of a in EX zone 0 sampler device, working according to the principle of bubbling and (ii) of trapping methodology as well as analytic methods. This unique device allows metal sampling from natural gases up to 100 bar pressure. Its use on industrial sites has permitted to measure and monitor during several years the metallic trace element chemical compositions of a natural gas and also more limited biogas and a biomethane analysis. Indeed, these two last gases are designed to reduce fossil fuel consumption particularly natural gas one. Biomethanes are led to use the same transportation network and to be temporarily stored in the same way as natural gaz. In addition of the gaseous phase, we have taken interest in the water and the mineral phases to characterize their chemical composition evolutions in time, without identify specific transfer mechanisms in touch with gas storage activity
Erouel, Mohsen. „Etude sur les transistors organiques à vocation capteur de gaz : application à la détection de gaz nitrés“. Lyon, INSA, 2008. http://theses.insa-lyon.fr/publication/2008ISAL0040/these.pdf.
Der volle Inhalt der QuelleOrganic field effect transistors (OFETs) are now widely recognized for their potential applications in all fields of so-called "plastic electronics". The high development of those transistors is related to the possibility to use its on nitrous gas sensor elaboration. The development of those systems needs the use of adapted technologies, a low elaboration cost, working at low temperature, to be easy to transport, selective and stable. In this field, the objective of our work consists on developing organic transistors for nitrous derivates detection usually used on classical explosive system. The sensor elaboration needed the good realisation of many tasks. The first one consists on the selection of the dielectric allowing us to have a stable transistor. For this, two insulator materials were used: inorganic oxides with high dielectric value (Ta2O5, HfO2, ZrO2, Al2O3/ZrO2) deposited with a low temperature process and an organic insulating material, the polymethylmethacrylate PMMA deposited by spin-coating. Pentacene transistors using different dielectrics were elaborated in order to compare their electric efficiencies. The results analysis (morphologic and electric) permitted to understand the comportment of those systems under their general aspect in addition to the comportment of the used dielectrics. The study of the stability of the oligothienylenevinylenes derivatives based transistors selected for the detection of dinitrotoluen (DNT) was conduced. The measure of components derivates was realized by studies based on the stress influence following, humidity and temperature. Sensors responses to DNT vapour were followed. Detection is related to donor-acceptor reaction
Waly, Hashem. „Automated Fault Identification - Kernel Trace Analysis“. Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/28246/28246.pdf.
Der volle Inhalt der QuelleBaklouti, Linda. „Capteurs à base d'assemblages discontinus organisés pour la détection spécifique de gaz“. Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT198/document.
Der volle Inhalt der QuelleGas sensing and monitoring are important issues for both industrial safety and protection of the environment and human beings. Dihydrogen, is increasingly used as fuel and energy carrier but it is extremely flammable and explosive in a wide range between 4 and 75% in air.Similarly, ammonia is widely used in industry as a cooling gas or as a reagent for the chemical production of other compounds.This gas presents risks to the environment and to living beings and can form explosive mixtures with air within 15 to 28% by volume.Gas sensors, indicating the presence and /or quantification of these gases, are very important.In continuation of our work on resistive sensors based on discontinuous assembly of nano-objects, the aim of this thesis was to prepare resistive sensors for the detection of H2 and NH3.These sensors are based on 2D assemblies of complex compositions of nanoparticles. Three types of core-shell nanoparticles were synthesized: Au@ZnO, Au@SnO2 and Au@Ag. Different physicochemical techniques (UV-Visible / TEM / DRX etc.) were used to characterize the particles. The next step was to assemble them in compact monolayers. The films were obtained by Langmuir-Blodgett assembling technique. Then, they were transferred to the surface of a glass slide supporting interdigitated electrodes. Sensing performances of the as-fabricated resistive sensor were evaluated.Sensors based on Au@ZnO and Au@SnO2 nanoparticles were tested towards H2, while Au@Ag based sensors were tested under NH3.The sensors showed attractive performances in H2 and NH3 detection within wide concentration ranges. Another important contribution of this work is the understanding of detection mechanisms. Various analytical techniques such as TPD (Temperature Programmed Desorption) and TPR (temperature programmed reduction) were used for the discussion of the mechanisms involved
Rebière, Dominique. „Capteurs à ondes acoustiques de surface : application à la détection des gaz“. Bordeaux 1, 1992. http://www.theses.fr/1992BOR10626.
Der volle Inhalt der QuelleRisser, Christophe. „Caractérisation et réalisation d'instruments de détection de gaz par spectrométrie laser photoacoustique“. Thesis, Reims, 2015. http://www.theses.fr/2015REIMS001.
Der volle Inhalt der QuelleThis work presents the conception of a photoacoustic spectrometer dedicated to trace gas measurements using a differential Helmholtz resonator. The main component of the instrument is the cell, where a standing wave is produced by a laser excitation and is measured with microphones. The photoacoustic signal is proportional to the gas concentration and the cell shape mainly affects its amplification. A finite element method is used to find this characteristic by calculating the cell eigenmodes and eigenfrequencies.Key parameters of the cell are then calculated, including cell frequency, quality factor and cell constant. Unlike other infrared spectroscopy methods, sensitivity of photoacoustic spectrometers increases by miniaturization process. This particular phenomenon is experimentally verified and is in good agreement with the simulation.Modelization proves again its robustness to be used on an engineering process of the spectrometer. This tool allows to optimize resonator dimensions according to the application, favouring maximum signal, higher working frequency or reduced size. Many cells designed with the help of the simulation are presented, where the observed error with experiments is of the order of 15 %. Finally, today's trace gas applications need the measurement of at least two concentrations, simultaneously with detection limits down to the ppb level. A novel Helmholtz resonance mode is then found to allow multi-gas sensing.Finally, sensitivity is increased by multi-pass systems
Lefebvre, Anthony. „Simulation et conception de microsources infrarouges nanophotoniques pour la détection de gaz“. Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLO002/document.
Der volle Inhalt der QuelleJoule-heated suspended microhotplates can be used as infrared sources in cheap, low-consumption spectroscopic gas sensors. To enhance the very low efficiency of first generation structures, both their thermal and optical designs have to be optimized.The implementation of frustrated plasmonic resonators on top of the membrane grants both spectral and angular control of its emissivity. It is thus possible to make it radiate only at the frequencies absorbed by the gas under study, and in the solid angle of the detector. This leads to an increase in useful radiated power while the overall electrical consumption is decreased. Dynamical studies of membrane heating provide welcome insight on the relationship between membrane radius, heating time and energy consumption per measurement. The existence of a compromise is demonstrated in order to maximize the radiative efficiency, and its physical interpretation is detailed.Eventually, membranes fabricated in LETI’s clean room were characterized to measure their electrical, optical and mechanical properties. The implementation of such sources in a CO2 prototype sensor led to state-of-the-art results, with a few dozen ppm sensitivity with a power consumption of only one milliwatt
Favard, Alexandre. „Multicapteurs intégrés pour la détection des BTEX“. Electronic Thesis or Diss., Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0123.
Der volle Inhalt der QuelleOutdoor air quality is subjected to the law LAURE since 1996. In 2008, the european directive 2008/50/EC introduced measurement requirements and thresholds that should not be exceeded for certain pollutants on a european scale. According to several toxicological and epidemiological studies, air pollution causes respiratory failure, asthma, cardiovascular diseases and cancers. In Europe, air pollution is responsible for more than 300 000 early deaths a year.Volatile organic compounds (VOCs), particularly benzene, toluene, ethylbenzene and xylenes (BTEX compounds) are proven pollutants and play a major role in the degradation of indoor and outdoor air quality. This thesis is dedicated to the development of a metal oxide based multi-gas sensor for the detection of traces of BTEX within the framework of the SMARTY project (SMart AiR qualiTY). A complete electrical characterization system was designed and implemented for the detection of sub-ppm concentrations of BTEX.Based on the state-of-art, several materials were selected (WO3, ZnO, SnO2). The electrical characterizations of the selected sensitive layers were carried out under dry air and under different humidity levels in the presence of BTEX and interfering gases (NO2, CO2). Tungsten oxide (WO3) exhibits the best performance in the presence of moisture and is chosen for the technology transfer that accompanies the new patented AMU transducers. The WO3-based multi-sensor has a lower limit of detection (LOD) of 1 ppb at 50% relative humidity and effectively detects and quantifies BTEX
Biben, Christophe. „Contribution à l'étude d'un dispositif de détection de chocs sur conduites de gaz enterrées“. Toulouse, ENSAE, 1996. http://www.theses.fr/1996ESAE0011.
Der volle Inhalt der QuelleRahmani, Meryem. „Analyses Raman multispectrales exaltées pour la détection de molécules sous forme de trace“. Electronic Thesis or Diss., Le Mans, 2024. http://www.theses.fr/2024LEMA1004.
Der volle Inhalt der QuelleIn recent decades, the use of phytosanitary products commonly called pesticides has increased. These substances have become increasingly present in our environment, accumulating in soil, air and water. Even at very low concentration these products represent a danger to human, plant and animal health. For all these reasons it is important to regulate the use of phytosanitary products by prohibiting the use of certain of these substances and by strengthening regulations to set Maximum Residue Limits (MRLs) as low as possible. It is also necessary to develop new methods for detecting and identifying trace pollutants because conventional techniques require large laboratory capabilities which are not compatible with on-site analyses.In my PhD. work, we have used Surface Enhanced Raman Scattering (SERS) to detect and identify trace molecules. We studied and analyzed the performance of three commercial DRES substrates (Hamamatsu, SERSitive and Ocean Insight) for the detection and identification of a model molecule at concentrations of the order of 10-6 M and 10-8 M. We compared the Raman responses from the Raman maps recorded on their surfaces at two incident wavelengths. We have also developed and optimized efficient nanorough metallic substrates to detect and identify molecules with a detection limit of 10-9 M. We will present the experimental protocol used to fabricate our nanorough gold substrates. The topographical properties of the surfaces were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to better understand the reason of SERS properties of the substrates. The optical responses of our nanorough substrates were studied in the near field by electron photoemission (PEEM) and in the far field by Raman spectrometry after putting them in contact with solutions containing molecules at very low concentrations. We compared the spectral response, intensity distributions, and stability under laser beam, of gold nanorough substrates and the most efficient substrate among the three commercial DRES substrates by analyzing the Raman spectra at a concentration of 10-8 M.The stability of the Raman response of the commercial SERS substrates and our optimized nanorough substrates was studied over time, for a period of several months. The effectiveness of the substrates decreases over time and it is no longer possible to detect the presence of the molecules after several months. In my PhD work we have tested a method that makes it possible to improve the Raman performance of these aged substrates. The performance of these improved substrates was studied by analyzing Raman intensity distributions from imaging containing several hundred spectra. Finally, we used the gold nanorough substrates to detect molecules present in a binary mixture of model molecules at a concentration of 10-8 M. We analyzed the Raman maps using chemometric tools, namely Component Analysis. Principal (ACP), and Multivariate Curve Resolution (MCR)
Laugel, Guillaume. „Combustion catalytique de gaz inflammables à l’aide d’oxydes métalliques : application à la détection de fuites dans des turbines à gaz“. Strasbourg, 2009. http://www.theses.fr/2009STRA6097.
Der volle Inhalt der QuelleTo avoid risks of explosion and pollution in industrial combustion installation, such as gas turbines, the detection of residual explosive gases is required. Therefore, in collaboration with General Electric, the work of this thesis was focused on the development and the study of catalytic systems which can be integrated in a future fabrication of a gas sensor. The principle of these sensors is based on the measurement of the gas concentration as a function of the increase in temperature produced by the heat of combustion reaction on the catalytic surface. The combustion of different hydrocarbons (methane, n-butane, isooctane, n-decane) and oxygenated compounds (carbon monoxide, ethanol, methyl octanoate) that are commonly used in gas turbine units was studied. In this type of installation, recent regulations have implemented a sensor response to detect a concentration as low as 5% of the LEL (Lower Explosive Limit) for the above studied fuels. To fulfill this demanding application constraint, the fuels must be introduced at very low concentration (500 – 6250 ppm) during the catalytic tests. Simple and mixed metal oxides based on manganese, iron and cobalt were chosen as catalysts. Perovskites LaBO3 (B = Mn, Fe, Co) and substituted perovskites La0,8A’0,2BO3 (A’ = Ba or Sr and B = Mn or Co) and LaB0,8B’0,2O3 (B = Mn or Co and B’ = Fe or Cu) were prepared using a sol-gel process. Simple oxides and perovskites LaBO3 were supported on a mesoporous silica SBA-15 and on ceria according to the “two-solvents” method. A complete set of physico-chemical characterisations of the different catalysts was realized using several techniques (XRD, TPR, TPD-O2, EPR, NMR, XPS spectroscopy, etc. ) to correlate the structure of the materials with their catalytic activities
Delpha, Claude. „Contribution au développement d'un système multiplicateurs de gaz : application à la détection de gaz réfrigérant Forane 134a et de gaz carbonique dans une atmosphère conditionnée humide“. Metz, 2000. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2000/Delpha.Claude.SMZ0031.pdf.
Der volle Inhalt der QuelleThe development of gas multisensor systems (electronic noses) has now an increasing interest in many field of application. In the field of atmospheric anti-pollution control our study consists in the main detection of a refrigerant gas Forane 134a and carbon dioxide in a humidity controlled atmosphere. We first give the state of the art on electronic noses and gas sensors, and then we present to justify our choice for array of tin dioxide (SnO2) sensors from FIGARO Engineering Inc. We mention the main constraints for their use allowing us to define the experimental set-up useful to their study. We show the importance of this set-up by noting the errors and other lack of precision which can be induced in the measurements if a good control is not correctly operated. Afterwards, we give the characterization results of the chosen sensor types for the different possible atmospheres : dry or wet synthetic air mixed with various concentrations of our two target gases R134 and CO2 and their mixture. We underline the reducing type response of the sensor in presence of humidity or R134a, and the oxidising type response CO2. We also show the influence of the relative humidity on the alone or mixed studied gases. From this characterization two main representative variables are extracted : the steady-state conductance and the conductance dynamic slope. The system learning data base is then built and we show that the association of the reference gas conductance as a variable with the two other types allow us to reduce the drift effects during the treatment with multivariate data analysis methods (Principal Component Analysis and Discriminant Factorial Analysis). Finally we propose decisive laws for the identification of the target gases and also their possible quantification. These laws allowed us the successful identification (more than 99%) of unknown test cases
Grossel, Agnès. „Spectrométrie infrarouge et détection de gaz à l'aide de lasers à cascade quantique“. Reims, 2007. http://theses.univ-reims.fr/exl-doc/GED00000774.pdf.
Der volle Inhalt der QuelleThis Ph. D thesis was realised in the Infrared Laser Spectroscopy team at the Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA) in REIMS. The purpose was to study some possible applications of quantum cascade lasers for the detection of very weak concentrations of gases and for the measurements of molecular parameters. It consists of three parts. First a rapid overview of nowadays infrared sources and gas detection methods is presented. This overview outlines the great interest of quantum cascade lasers that were chosen for this work. The second part deals with measurements methods of molecules spectroscopic parameters with diode laser and quantum cascade laser. Such methods were applied for the measurements of atmospheric molecules spectroscopic parameters : carbon dioxide and nitrous oxide. Such measurements were linked to a real need for analysis of atmospheric measurements. The N2O measurements were done for the inversion of atmospheric pro_les recorded by the SPIRALE instrument of the Laboratoire de Physique et Chimie de l'Environnement (LPCE) and the CO2 parameters were used to verify LIDAR measurements recorded by the Laboratoire de Meteorologie Dynamique (LMD) of Palaiseau. The QCL were also used for high sensitivity measurements of gas concentration. They were coupled with a photoacoustic sensor developed by the GSMA and this system was optimized to obtain detection limits in the ppb or tens of ppb range for several atmospheric molecules : methane, nitrous oxide, nitric oxide
Favard, Alexandre. „Multicapteurs intégrés pour la détection des BTEX“. Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0123/document.
Der volle Inhalt der QuelleOutdoor air quality is subjected to the law LAURE since 1996. In 2008, the european directive 2008/50/EC introduced measurement requirements and thresholds that should not be exceeded for certain pollutants on a european scale. According to several toxicological and epidemiological studies, air pollution causes respiratory failure, asthma, cardiovascular diseases and cancers. In Europe, air pollution is responsible for more than 300 000 early deaths a year.Volatile organic compounds (VOCs), particularly benzene, toluene, ethylbenzene and xylenes (BTEX compounds) are proven pollutants and play a major role in the degradation of indoor and outdoor air quality. This thesis is dedicated to the development of a metal oxide based multi-gas sensor for the detection of traces of BTEX within the framework of the SMARTY project (SMart AiR qualiTY). A complete electrical characterization system was designed and implemented for the detection of sub-ppm concentrations of BTEX.Based on the state-of-art, several materials were selected (WO3, ZnO, SnO2). The electrical characterizations of the selected sensitive layers were carried out under dry air and under different humidity levels in the presence of BTEX and interfering gases (NO2, CO2). Tungsten oxide (WO3) exhibits the best performance in the presence of moisture and is chosen for the technology transfer that accompanies the new patented AMU transducers. The WO3-based multi-sensor has a lower limit of detection (LOD) of 1 ppb at 50% relative humidity and effectively detects and quantifies BTEX
Matei, Ghimbeu Camelia. „Elaboration et caractérisation de couches mince d'oxydes métalliques pour la détection de gaz polluants atmosphériques“. Thesis, Metz, 2007. http://www.theses.fr/2007METZ050S/document.
Der volle Inhalt der QuelleThe demand of simple, small, low cost and performing gas sensors for the detection of pollutant gases is of great interest taking into consideration the health and environmental problems. For this purpose we decided to develop thin films of metal oxide semiconductors which present a good affinity to many pollutant gases, but, which, however present a problem of cross-sensitivity and, additionally, which must work at elevated temperatures. These thin films (SnO2, Cu-doped SnO2, WO3, In2O3, Sn-doped In2O3 and ZnO) have been deposited on Pt- partially coated alumina using a novel innovative technique, i.e., Electrostatic Spray Deposition allowing easy deposition parameter (temperature, flow rate, time etc.) variation. Homogeneous, nano-structured films with desired porous morphology have been obtained as revealed by Scanning Electron Microscopy and Transmission Electron Microscopy techniques. The microstructure studied using Energy Dispersive X-ray Analysis, X-ray Diffraction respectively Raman spectroscopy methods showed that we have successfully obtained the desired crystallinity and a good purity of the films for gas sensor use. The sensing performance of the films to different oxidizing and reducing pollutant gases (H2S, SO2 and NO2) has been yet evaluated. From all the studied films, the 1% Cu-doped SnO2 ones proves to be the most sensitive for the detection of H2S at low operating temperatures and furthermore present no cross-sensitivity for the two other gases. WO3 films presents the highest sensitivity to NO2 at 150°C compared with all the other composition films, but unfortunately the NO2 response interferes with the H2S response. To avoid this ambiguity, we can use ZnO films, which present a very high sensitivity to NO2 compared to SO2 and H2S response. Additionally, all the films were almost insensitive to SO2. On the base of these results we can propose the conception of a competitive miniaturized sensor array dedicated to detect and to quantify a H2S/NO2 mixture
Zadnik, Martin. „Détection du cliquetis pour moteur automobile“. Toulouse 3, 2007. http://thesesups.ups-tlse.fr/206/.
Der volle Inhalt der QuelleKnocking in automobile engines is a parasite phenomenon of abnormal combustion with several harmful consequences. This thesis is concerned with new techniques of knock sensor signal processing whose aim is to improve the detection. We first analyse the knock signal properties by means of time-frequency methods. Further on, the use of neural networks is considered in order to try to reconstruct the in-cylinder pressure signal, since this one better indicates the phenomenon. In the main part of the thesis, different knock detectors are studied, based on a parametric signal model. We propose various robust methods, on one hand to reduce the computational cost and on the other hand to assure a processing that is tolerant to imprecisely known knock- specific resonant frequencies. We derive theoretical detection performance of different detectors as well as apply these detectors on real signals
Erades, Laurent. „Nanoparticules d'oxydes semi-conducteurs : synthèse, caractérisation et application à la détection sélective de gaz“. Toulouse 3, 2003. http://www.theses.fr/2003TOU30031.
Der volle Inhalt der QuelleSaadi, Lama. „Etude de l'adsorption des molécules simples sur WO3 : application à la détection des gaz“. Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4346/document.
Der volle Inhalt der QuelleThe team of micro sensors at IM2NP mainly focuses onthe development of gas sensors based on measurement in conductancevariation in presence of gas. The material used as sensitive element istungsten oxide (WO3) thin film. The objective of present thesis is to studythe surface properties of WO3 in its reconstruction c(2x2), obtained bycleavage along the [001] direction. This study is also followed by a gapanalysis using ab initio calculations based on DFT in both LDA andGGA approximations. Then, the adsorption of molecules of simple gases((O3, COx NOx) for these surfaces (more or less rich in oxygen), is performed.To simulate these systems, we have chosen the SIESTA code based onDFT which is used for the larger number of atoms as compared to other codes
Maulion, Geoffrey. „Conception, fabrication et caractérisation de composants photoniques innovants appliqués à la détection de gaz“. Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS063/document.
Der volle Inhalt der QuelleFor about a decade, gas detection has known a tremendous interest, due to several reasons: environmental issues, public health, people and building safety, etc... This trend, triggered a spectacular and sustainable need of gas detection means improvement and development, which has grown with both standards sophistication and scope extension. As a matter of fact, the number of research projects related to this particular topic increased: PEPS ANR project, begun in 2010, is one of them. This research project, which is the acronym of Pellet Photonique Sensor, aim at developing a photonic multigas detection system based on thermo-optical effect, thanks to the combination of on one hand, catalitic nanopowders which react selectively with the target gas (hydrogen or carbon monoxide) and on the other hand, an high sensitive to refractive index variations planar photonic component. This thesis manuscript mostly treats of the photonic component design (choice and optimization)
Le, Lirzin Youen. „Capteurs pour la détection de gaz neurotoxiques utilisant une transition d'ancrage de cristaux liquides“. Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2024. http://www.theses.fr/2024IMTA0399.
Der volle Inhalt der QuelleRecent use of neurotoxic agent in terrorist attacks or their threat in chemical warfare requires the development of a lightweight and efficient chemical sensor. Abbott et al. designed a gas sensor using copper ions (Cu2+) coordinated with nematic liquid crystals (LC) anchoring them in a homeotropic orientation. When the surface is exposed to organophosphorus gas (with P=O bond), the crystal structure evolves from homeotropic to planar orientation due to preferential coordination forces of the organophosphorus gas toward Cu2+. The difference can be observed between crossed polarizers. Few technological challenges should be pointed out : when copper ions are coated on the substrate, LC dewetting occurs and increase with surface ions concentration. Furthermore, copper ions dissolve in LC over time, eventually leading to an electric double layer locking the transducer in one orientation or the other. Here, we present the stabilization method and the fabrication technique to further increase the lifetime of sensors. These include grid formation, surface functionalization, jet printing and storage strategies. Both electrical and optical measurement of LC transition have been performed. A concentration up to 1 ppm of the simulant DMMP has been successfully detected. Finally, the need for a wearable device motivate the development of an optical transducer to perform on-field measurement
Matei, Ghimbeu Camelia. „Elaboration et caractérisation de couches mince d'oxydes métalliques pour la détection de gaz polluants atmosphériques“. Electronic Thesis or Diss., Metz, 2007. http://www.theses.fr/2007METZ050S.
Der volle Inhalt der QuelleThe demand of simple, small, low cost and performing gas sensors for the detection of pollutant gases is of great interest taking into consideration the health and environmental problems. For this purpose we decided to develop thin films of metal oxide semiconductors which present a good affinity to many pollutant gases, but, which, however present a problem of cross-sensitivity and, additionally, which must work at elevated temperatures. These thin films (SnO2, Cu-doped SnO2, WO3, In2O3, Sn-doped In2O3 and ZnO) have been deposited on Pt- partially coated alumina using a novel innovative technique, i.e., Electrostatic Spray Deposition allowing easy deposition parameter (temperature, flow rate, time etc.) variation. Homogeneous, nano-structured films with desired porous morphology have been obtained as revealed by Scanning Electron Microscopy and Transmission Electron Microscopy techniques. The microstructure studied using Energy Dispersive X-ray Analysis, X-ray Diffraction respectively Raman spectroscopy methods showed that we have successfully obtained the desired crystallinity and a good purity of the films for gas sensor use. The sensing performance of the films to different oxidizing and reducing pollutant gases (H2S, SO2 and NO2) has been yet evaluated. From all the studied films, the 1% Cu-doped SnO2 ones proves to be the most sensitive for the detection of H2S at low operating temperatures and furthermore present no cross-sensitivity for the two other gases. WO3 films presents the highest sensitivity to NO2 at 150°C compared with all the other composition films, but unfortunately the NO2 response interferes with the H2S response. To avoid this ambiguity, we can use ZnO films, which present a very high sensitivity to NO2 compared to SO2 and H2S response. Additionally, all the films were almost insensitive to SO2. On the base of these results we can propose the conception of a competitive miniaturized sensor array dedicated to detect and to quantify a H2S/NO2 mixture
Brecq, Guillaume. „Contribution à la caractérisation thermodynamique du cliquetis dans les moteurs à gaz : application à de nouvelles méthodes de détection“. Nantes, 2002. http://www.theses.fr/2002NANT2064.
Der volle Inhalt der QuelleAlrammouz, Rouba. „Conception et réalisation d’un système de détection de gaz à faible coût sur substrat flexible“. Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS134.
Der volle Inhalt der QuelleCurrent concerns for environmental protection and public health focus on air quality in industries, cities and households. Nowadays, paper-based gas sensors are of increasing interest due to their low cost, biodegradability, flexibility and applications in e-textiles, e-dressings and e-packaging.Graphene oxide is a derivative of graphene with exceptional electrical, mechanical and thermal properties. Graphène oxide is a promising material for the development of low-cost room temperature gas sensors.In this context, this thesis aims to integrate a graphene oxide sensing layer inside a porous paper substrate for humidity and ammonia detection. The first part of this work focuses on the fabrication, functionalization and optimization of capacitive porous gas sensors on paper. A new local reduction process of graphene oxide into electrodes is introduced. The process is hot-plating, a low cost technique compatible with large scale productionThe second part of this work studies the humidity and ammonia sensing capabilities of the sensors. Graphene oxide on paper exhibits a high sensitivity towards ammonia, with humidity as an interfering gas. The local reduction of graphène oxide into electrodes, and its functionalization with zinc oxide increased the sensitivity and selectivity of the device towards humidity. The fabricated sensors exhibit a good repeatability, reproducibility and flexibility
Mas, Adrien. „Etude et développement de caméras infrarouge multispectrales à acquisition simultanée pour la détection de gaz“. Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASP001.
Der volle Inhalt der QuelleThe accidental emission of gas in an industrial platform or the use of chemical weapons can have dramatic consequences. Bertin Technology commercialize an infrared multispectral camera using an array of uncooled detectors and called Second Sight allowing the detection of numerous gas. However, the temporal acquisition of spectral images is a limitation for a use on mobile platforms (vehicles, drones...). Therefore, the purpose of my PhD was to study several concepts of snapshot multispectral cameras using a single array of uncooled detectors. I worked on two concepts of optical architectures: a kaleidoscope-based design and a multichannel design inspired by the TOMBO architecture. The kaleidoscope-based camera can use optimally the focal plane array while having an important aperture and a great range of Fields of View. However, it has an important footprint and the implementation of the multispectral function is not obvious. By comparing, the multichannel architecture can be very compact and easily adaptable for multispectral applications but a compromise between its aperture and its Field Of View is necessary. Following these studies, the TOMBO multichannel design was chosen as the successor of the Second Sight and I could make a first demonstrator. Finally, a radiometric model was developed to compare the different cameras and I showed that the TOMBO camera could have better performances than the Second Sight thanks to its snapshot feature
Bizet, Laurent. „Spectrométrie laser avec sources moyen infrarouge largement accordables et application à la détection de gaz“. Thesis, Reims, 2019. http://www.theses.fr/2019REIMS010/document.
Der volle Inhalt der QuelleThe field of gas detection is interesting for many applications such as monitoring of air pollution, explosives detection, breath analysis, etc. Tunable laser spectrometry allows to create compact instruments with high performances (selectivity, spectral and temporal resolution). Mid-Infrared (Mid-IR) region can be accessed with the use of Quantum Cascade Laser (QCL). In this region, absorption lines of the molecules of interest are more intense, which improves the devices sensitivity. The work presented in this thesis is focused on the development of QCL-based gas detection devices. First part presents the use of new Mid-IR sources such as multiplexed QCL array and coherent QCL array. Second part is focused on the development of an intracavity setup and a detection technique based on the QCL voltage measurement. This technique does not need the use of an optical detector and can be performed whatever the laser wavelength
Gorintin, Louis. „Etude et réalisation de transistors à nanotubes de carbone pour la détection sélective de gaz“. Phd thesis, Palaiseau, Ecole polytechnique, 2011. https://pastel.hal.science/docs/00/69/50/13/PDF/These_Louis_Gorintin.pdf.
Der volle Inhalt der QuelleThis work focuses on sensor based on carbon nanotube field effect transistors (i. E. CNTFETs) modulated chemically. This new generation of sensors has many advantages: compact and inexpensive, they can be integrated in ultrasensitive and autonomous detection systems. The civilian security market is targeted, particularly punctual and network detection of warfare and explosive agent. In order to achieve a scalable and highly reproducible fabrication, which is not possible for a single carbon nanotube transistor, we propose to achieve CNTFETs using random mats of Single Wall carbon nanotubes (CNT). The first part of our work has dealt with the development of a deposition method of CNT mats using an airbrush technique assisted by an automated robot. Commercial carbon nanotubes powders are dispersed in a specific solvent and then deposited randomly by atomization of micro droplets on a hot substrate. The random mats obtained with this technique are extremely uniform (density) and allow to achieve arrays of CNTFETs with reproducible electrical characteristics. The second part has concerned the development of an array of CNTFETs with different metal electrodes (platinum, palladium, gold, nickel, titanium) to address the problem of selectivity of this kind of device. We identify a sort of electronic fingerprinting exploiting the specific interaction of each gas with each metal/SWCNTs junction. This interaction changes in an extremely specific way the transfer characteristics of the CNTFETs. We have demonstrated a sensitivity and selectivity to ammonia, nitrogen dioxide, and dimethyl methylphosphonate (sarin gas simulant) and hydrogen peroxide. These devices, thanks to their relatively low cost fabrication and high selectivity, have the potential to strike the market within a few years
Gorintin, Louis. „Etude et réalisation de transistors à nanotubes de carbone pour la détection sélective de gaz“. Phd thesis, Ecole Polytechnique X, 2011. http://pastel.archives-ouvertes.fr/pastel-00695013.
Der volle Inhalt der QuelleDonero, Laeticia. „Développement de micro-capteur et de nano-matériaux pour des applications de détection en milieu liquide“. Thesis, Nantes, 2017. http://www.theses.fr/2017NANT4003/document.
Der volle Inhalt der QuelleThis thesis is carried out within the framework of a partnership between two laboratories: IMN (Institute of Materials of Nantes), specialized in the elaboration of materials and IETR (Institute of Electronics and Telecommunications) specialized in microtechnologies and microsensors. The objective of this work is to develop original microsensors integrating nanomaterials, in order to obtain charge sensors with high sensitivities, especially in liquid media. The microsensors developed at the IETR are based on "bottom gate" and dual gate field effect transistors. Initially, we focused on the optimization of the technological process of the sensors to obtain the best electrical characteristics for our applications. Detection measurements using different pHs are explored. A second part of the project, carried out at the IMN, was the development of nanomaterials: carbon nanotubes and nanoporous carbon thin films. The studies have focused on the growth of carbon nanotubes deposited by PECVD and on the development of nanoporous layers. The last layers are obtained by depositing copper / carbon composite thin films by magnetron cathodic cosputtering followed by chemical etching of the copper. Subsequently, preliminary tests of integration of these carbon nanomaterials as well as of silicon nanowires were carried out to confirm the compatibility of the synthesis processes with the operation of the device
Possas, Abreu Maira. „Conception et développement des réseaux de capteurs MEMS en silicium et en diamant pour la détection de vapeurs“. Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1062/document.
Der volle Inhalt der QuelleSmart multi-sensor systems for gas detection (or electronic noses), are already deployed in areas as diverse as cosmetics and food industry, environment monitoring and military and medical purposes. The ongoing collaboration within the European SNIFFER Project, focused on the development of an innovative electronic nose-like system based on MEMS sensors combined with olfactory bioreceptors for the detection of illicit substances. In another context and, within an internal approach to ESIEE-Paris, we have also chosen to expand the topic to design a multi-sensor system for application in volatile organic compounds detection.Thus, in view of improving these technologies through the use of MEMS sensors, this manuscript comprehensively investigates the design, fabrication and characterization of silicon and diamond resonant micro-cantilevers sensors, and also presents a proof of concept of a multi-sensor system for gas detection. To date, silicon has been used as a building block of micro sensors, whose features are very well known and argued extensively in the literature. On the other hand, diamond as a unique material in terms of its superior physical and chemical properties, has been received attention in microelectronics. Although the realization of diamond MEMS sensors has been presented before, it has been never compared to silicon MEMS gas sensors. Therefore, to establish elements of comparison for the two technologies, this thesis aimed to use these two competitive materials as a building block of micro-cantilever based MEMS gas sensors.Firstly, we set up specific micro-machining processes for the realization of diamond patterns that have been previously developed in our laboratory in order to optimize them for a fully clean room compatible manufacturing, independent of changes in diamond synthesis conditions. We have, for the first time, realized diamond micro-cantilevers with integrated polysilicon gauges. The Young's modulus of diamond was characterized using two different methods resulting in the best case of the value as 1080 GPa. Then, the mass sensitivity of silicon and diamond microcantilevers was evaluated. In the best case, for sensors presenting very similar resonant frequencies, the silicon microcantilever have a sensitivity of 89 Hz / ng whereas for the diamond microcantilever, the sensitivity is 212 Hz / ng. It has been also observed that the impact of adding mass on the beam quality factor was more critical to the silicon structures for low mass load cases.Finally, a proof of concept for the use of the multi-sensor system based on silicon and diamond micro-cantilevers for the detection of volatile organic compounds was established. We demonstrated the detection of several compounds in concentrations of the order of tens of ppm in a fully automatic way and without the use of measuring instruments. The results of these detections form a database from which we resulted in the discrimination of the compounds tested by applying multivariate statistical methods
Madon, Lydie. „Etude d'un dispositif destiné à la détection en continu d'aérosols métalliques dans l'air“. Toulouse 3, 1996. http://www.theses.fr/1996TOU30035.
Der volle Inhalt der QuelleBlet, Vincent. „Etude d'un capteur à membrane gazeuse pour la détection d'espèces sensibles au pH“. Vandoeuvre-les-Nancy, INPL, 1990. http://www.theses.fr/1990INPL031N.
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