Дисертації з теми "Sources d'émission"
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Boisjoli, Mark. "Paramétrisation multisource et caractérisation des sources d'émission de l'expérience HERACLES 2001." Thesis, Université Laval, 2011. http://www.theses.ulaval.ca/2011/27847/27847.pdf.
Ogheard, Florestan. "Développement d'un système de mesure directe du débit d'émission de sources neutroniques." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00740509.
Salame, Thérèse. "Sources d’émission du carbone organique gazeux à Beyrouth." Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10108/document.
The atmospheric pollution related to the VOC still maintains a great interest since these species contribute to the formation of tropospheric ozone, peroxyacetylnitrate and secondary organic aerosols resulting in negative impacts on human health, climate and on the environment. In order to apply efficient control strategies, there is a need to identify the VOC emission sources, to determine their speciation and their contribution to VOC ambient levels. To date, there is a paucity of data regarding the VOC in the Middle East region (MEA) due to a lack of ground-based measurements leading to insufficient evaluation of air pollution in this region. In this work, we report the results of the first study regarding VOC in Lebanon, a developing country in the MEA region. The study is based on two intensive field measurement campaigns within the frame of the Emission and Chemistry of Organic Carbon in the East Mediterranean, Beirut (ECOCEM-Beirut) project conducted during summer 2011 and winter 2012 at a sub-urban site. Over 70 VOC from C2 to C16 have then been measured. First, we provide insights on the factors controlling VOC distribution. Then, VOC source profiles were determined with field measurements close to the main potential emitters. Finally, we identified the VOC factors, based on the sources profiles established previously, and quantified their relative contribution according to the season, by implementing the source receptor model PMF. The major sources were traffic-related emissions (combustion and gasoline evaporation) in winter and in summer. The modeled results showed an agreement with the local emission inventory regarding the load of the on-road mobile source
Dufresne, Marvin. "Sources et déterminants des composés organiques volatils à Marseille." Electronic Thesis or Diss., Ecole nationale supérieure Mines-Télécom Lille Douai, 2022. http://www.theses.fr/2022MTLD0007.
Volatil Organic Compounds (VOC) are key species because of their role as precursors of secondary pollutants such as ozone (O3) and secondary organic aerosols (SOA). However, the knowledge on VOC emissions remains insufficient, leading to high uncertainties on emission inventories and consequently on chemistry-transport models (CTM) which are crucial for the successful implementation of efficient air quality policies. This lack of information is all the more critical in the Mediterranean basin since this region is particularly affected by air pollution and climate change. In order to provide new knowledge on the sources and factors controlling VOC in this region, an 18-months field campaign took place from March 2019 to August 2020 in Marseille. It allowed to obtain a unique database of 70 non-methane hydrocarbon (NMHC) compounds for the study of the evolution of the VOC composition of the atmosphere of Marseille. The analysis of observations using the source-receptor model PMF (Positive Matrix Factorization), allowed to determine eight major NMHC emission sources for the measured compounds. Road traffic is the main emitter of these compounds in Marseille in all the seasons contributing to 40% of concentrations whereas residential heating contributes to 20% in winter. A sharp decrease of the NMHC emissions due to road traffic has been observed in Spring 2020 associated to the lockdown due to the sanitary crisis of Covid-19. An industrial source has been identified as high emitter of xylenes, species with a high potential on SOA formation. Global, regional and local emission inventories were compared to each other with the observations in the Marseille area. A high variability on the total VOC emissions but a very good agreement on the VOC emissions from road traffic. This comparison showed the chemical speciation of VOC emission sources is significantly higher for the inventories in the case of HCNM emitted by combustion (alkenes and aromatics) possibly due to an overestimation of residential heating. In addition, the study showed a difference in chemical composition for road traffic between the local emission inventory and observations
Salame, Thérèse. "Sources d’émission du carbone organique gazeux à Beyrouth." Electronic Thesis or Diss., Lille 1, 2014. http://www.theses.fr/2014LIL10108.
The atmospheric pollution related to the VOC still maintains a great interest since these species contribute to the formation of tropospheric ozone, peroxyacetylnitrate and secondary organic aerosols resulting in negative impacts on human health, climate and on the environment. In order to apply efficient control strategies, there is a need to identify the VOC emission sources, to determine their speciation and their contribution to VOC ambient levels. To date, there is a paucity of data regarding the VOC in the Middle East region (MEA) due to a lack of ground-based measurements leading to insufficient evaluation of air pollution in this region. In this work, we report the results of the first study regarding VOC in Lebanon, a developing country in the MEA region. The study is based on two intensive field measurement campaigns within the frame of the Emission and Chemistry of Organic Carbon in the East Mediterranean, Beirut (ECOCEM-Beirut) project conducted during summer 2011 and winter 2012 at a sub-urban site. Over 70 VOC from C2 to C16 have then been measured. First, we provide insights on the factors controlling VOC distribution. Then, VOC source profiles were determined with field measurements close to the main potential emitters. Finally, we identified the VOC factors, based on the sources profiles established previously, and quantified their relative contribution according to the season, by implementing the source receptor model PMF. The major sources were traffic-related emissions (combustion and gasoline evaporation) in winter and in summer. The modeled results showed an agreement with the local emission inventory regarding the load of the on-road mobile source
Blondel, Alodie. "Identification des sources intérieures de composés organiques volatils et estimation de leur contribution aux teneurs observées dans les logements français." Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10171/document.
Indoor atmospheres appear very rich in volatile organic compounds (VOC). These substances form a “dangerous mix” whose composition and effects on health remain still unknown. This complexity makes difficult the identification and the quantification of indoor sources on the indoor air quality. The purpose of this thesis is to establish qualitative and quantitative relationship between VOC indoor sources and the concentrations observed in French dwellings. The first axis of this work deals with the development of passive measurement to determine the formaldehyde (FA) and acetaldehyde emission rates of materials. This sampler was validated in laboratory, then used in-situ, in a batch of measurements carried out in student rooms. This diagnosis on site shows that the furniture and the building materials contribute equally to the indoor concentration in FA. The increase of the emissions is clearly influenced by the rise in the temperature. A balance mass model based on the measured emission rates led to a satisfying prediction of the FA concentrations in the 24 sampled rooms. The second axis deals with the analysis of the chemical profiles of 60 residences. From a “screening” of the VOC; homogeneous classes of chemical profiles associated with the dwellings could be established. Assumptions on the potential sources of these compounds were formulated and examined on the basis of the bibliography, the descriptive questionnaires of the dwellings and the emissions of materials and products present in indoor environment
Moradian, Zabihallah. "Application de la méthode d'émission acoustique pour la surveillance du comportement au cisaillement des joints actifs." Thèse, Université de Sherbrooke, 2011. http://savoirs.usherbrooke.ca/handle/11143/1961.
Klaver, Anne. "Estimation des propriétés optiques des poussières désertiques d'origines saharienne et sahélienne, à proximité de leurs zones sources d'émission, à partir de leurs propriétés physico-chimiques." Paris 7, 2012. http://www.theses.fr/2012PA077179.
By absorption and scattering of the solar and terrestrial radiations, mineral dust has a direct radiative effect. At the global scale, this direct radiative effet is currently estimated between -0. 56 and + 0. 1 W m⁻², which doesn't allow to say if the mineral dust cools or warms the Earth/Atmosphere System. The estimation of this effect still remains uncertain because of the limited knowledge concerning the optical properties of mineral dust (scattering and absorption) which are linked with their physico-chemical properties. My work is incorporated within the issues of the reduction of these uncertainties. It involved the study of the physico-chemical (mineralogical composition, size and shape) and optical (scattering, absorption and extinction coefficients, single scattering albedo and asymmetry parameter) properties of thé minéral dust coming from western Africa, observed in the framework of the African Monsoon Multidisciplinary Analysis (AMMA) program at Banizoumbou (Niger) station in winter and summer 2006. With an optical model, these observations have been used in order to perform closure studies of the optical properties. I tried to determine if it is possible to estimate the optical properties of the mineral dust based on the knowledge of their physico-chemical properties. I showed a good representation of the scattering and absorption coefficients by calculation (calculation/measurement discrepancy < 13 %). However, efforts have to be performed concerning the estimation of the absorption coefficient and single scattering albedo (calculation/measurement discrepancy up to 291 %)
Xiang, Yang. "Analyse dynamique en champ proche de la contribution des sources de composés organiques volatils, en région urbaine sous influence industrielle." Thesis, Littoral, 2011. http://www.theses.fr/2011DUNK0408.
Recently, sources apportionment of Volatile Organic Compounds (VOC) has been the subject of a great numbers of studies, in order to determine their contributions to atmospheric pollution. However, the dynamical behavior of atmosphere, within its micro-meteorological scale, has never been taken into account in the sources-receptor approach, yet it is the main factor to interpret near-field physic-chemical measurements of air pollution, in an urban area under industrial influences. The complexity of such a study area results from not only the emission modes and the various industrial activities, but also the meteorological phenomenon in multi-scale, which influences the dispersion and transport in a small scale (tipically several kilometers). With measurements of 85 VOC (including 23 oxygenated VOC) during several months, we have developed an innovative methodology, associating the results of the PMF (Positive Matrix Factorization) modeling and the meteorological parameters, in order to identify the sources and to understand their dynamical behaviors. By introducing the vertical turbulence for the first time in this kind of analysis, the temperature and the solar radiation, as parameters of factor analyses, two behaviors have been distinguished, leading to identify the emissions near ground and in the upper part of surface layer. In this way, we have labeled the sources according to their nature as well as their emission mode, and we have highlighted the aged air mass containing secondary pollutants
Delair, Laurent. "Caractérisation de sources plasmas dédiées à la simulation de rentrées atmosphériques et au traitement de polluants : arc soufflé basse pression et décharge de polluants." Rouen, 2004. http://www.theses.fr/2004ROUES052.
This work deals with the experimental study of two plasma sources : an original plasma torch (two anodic arc roots) which generates a low pressure nitrogen arcjet, and an atmospheric pressure gliding arc. The thermodynamic characteristics of the nitrogen plasma – densities and temperatures – are deduced from emission spectroscopy analysis, from its creation zone to its expansion zone. Mach number measurements are carried out at the torch exit. The study of the arc(s dynamic behaviour highlights an acoustic resonance frequency inside the arc chamber. The analysis of the gliding arc with emission spectroscopy reveals its non-equilibrium state and some abnormal ionic line broadenings in its creation zone due to plasma turbulence phenomena. Simultaneous high speed acquisitions of electrical signals and light intensity confirm its classical dynamical behaviour : ignition, lengthening, extinction. They also show the impulse behaviour of the arc column as it moves between the electrodes
Xiang, Yang. "Analyse dynamique en champ proche de la contribution des sources de composés organiques volatils, en région urbaine sous influence industrielle." Electronic Thesis or Diss., Littoral, 2011. http://www.theses.fr/2011DUNK0408.
Recently, sources apportionment of Volatile Organic Compounds (VOC) has been the subject of a great numbers of studies, in order to determine their contributions to atmospheric pollution. However, the dynamical behavior of atmosphere, within its micro-meteorological scale, has never been taken into account in the sources-receptor approach, yet it is the main factor to interpret near-field physic-chemical measurements of air pollution, in an urban area under industrial influences. The complexity of such a study area results from not only the emission modes and the various industrial activities, but also the meteorological phenomenon in multi-scale, which influences the dispersion and transport in a small scale (tipically several kilometers). With measurements of 85 VOC (including 23 oxygenated VOC) during several months, we have developed an innovative methodology, associating the results of the PMF (Positive Matrix Factorization) modeling and the meteorological parameters, in order to identify the sources and to understand their dynamical behaviors. By introducing the vertical turbulence for the first time in this kind of analysis, the temperature and the solar radiation, as parameters of factor analyses, two behaviors have been distinguished, leading to identify the emissions near ground and in the upper part of surface layer. In this way, we have labeled the sources according to their nature as well as their emission mode, and we have highlighted the aged air mass containing secondary pollutants
Rivera, Martinez Rodrigo Andres. "Validation and deployment of greenhouse gas sensors (CH4) for the characterization of industrial and urban sources." Electronic Thesis or Diss., université Paris-Saclay, 2022. http://www.theses.fr/2022UPASJ020.
This PhD aims at reconstructing atmospheric CH4 concentrations from voltage signals recorded by low-cost Metal Oxide Sensors (MOS) for the purpose of monitoring CH4 leaks from an industrial facility. Our strategy is based on the collocation of measurements by low-cost sensors and expensive very high accuracy instruments. The CH4 concentrations data from the high accuracy reference instrument are then used as a target variable to be reconstructed using MOS voltage and other predictors. The reconstruction is performed with both machine learning models and parametric models. It is applied to increasingly complex problems, including the reconstruction of: 1) smooth variations of ambient room air CH4 in a laboratory, 2) fast and large variations of CH4 during concentration spikes generated on a test bench in a laboratory with a typical signature similar to that observed for real world leaks, and 3) fast and large variations of CH4 observed in the field during a dedicated controlled release experiment. The first laboratory experiments revealed a high influence of H2O in MOS sensors, and the reconstruction with a Multilayer perceptron model showed good agreement between the references and the reconstructed room air concentrations (Chapter 2). The results of the second experiment (Chapter 3) showed the importance of the selection of the sensor's type in order to produce reconstructions of CH4 concentration with a 1 ppm accuracy (RMSE). We also discovered that the TGS 2611-C00 sensors provided a more accurate reconstruction of CH4 spikes than the TGS 2611-E00 ones. A parsimonious model training strategy allowed us to restrict the training set from 70% to 25% of the data without a degradation in the reconstruction of the CH4 spikes. Emission of controlled releases from reconstructed CH4 concentrations measured by MOS sensors and the inversion of a Gaussian atmospheric model (Chapter 4) were similar to those inverted from high accuracy reference data, with an average emission rate estimation error of 25% over 11 controlled releases and a location error of 9.5 m. The results of this PhD are the basis to explore advanced techniques based on machine learning to produce accurate estimates of CH4 concentrations, and study the information required by inversion modelling that produced best estimates of the emission rate and location of CH4 leaks
Adès, Julie. "L'impact du cadre réglementaire fédéral de réduction d'émissions de gaz à effet de serre de 2007 sur les choix des sources d'énergie de l'industrie québécoise des pâtes et papiers." Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/26836/26836.pdf.
Lamaison, Laure. "Caractérisation des particules atmosphériques et identification de leurs sources dans une atmosphère urbaine sous influence industrielle." Lille 1, 2006. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2006/50376_2006_156.pdf.
Ouerdane, Djamel. "Étude de l'influence de l'asymétrie de masse initiale sur la fragmentation des sources d'émission de particules chargées produites lors des réactions §5§8Ni+¹²C, [exposant]n [exposant]a [exposant]t Ti,¹§9§7 Au à 34.5 MeV/nucléon." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0015/MQ47536.pdf.
Vallée, Renaud. "Etude des modifications du taux d'émission spontanée de sources internes utilisées comme sondes des variations de densités locales d'états photoniques dans des matériaux aussi divers que des milieux désordonnés polymères ou inorganiques, des cristaux photoniques et des nanostructures plasmoniques." Habilitation à diriger des recherches, Université Sciences et Technologies - Bordeaux I, 2012. http://tel.archives-ouvertes.fr/tel-00700983.
Sezac, Laurent. "Mise en oeuvre de deux expériences de corrélations de particules légères : comportement à très faibles impulsions relatives (mesure avec un spectromètre magnétique) et influence de la violence de réaction sur les sources d'émission (mesurée avec le détecteur de neutrons Orion)." Grenoble 1, 1993. http://www.theses.fr/1993GRE10014.
Piot, Christine. "Polluants atmosphériques organiques particulaires en Rhône-Alpes : caractérisation chimique et sources d'émissions." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00661284.
Guerra, Davide. "Modélisation du transfert d'un aérocontaminant dans un local ventilé en champ proche d'une source d'émission accidentelle." Phd thesis, Toulouse, INPT, 2004. http://oatao.univ-toulouse.fr/7295/1/guerra.pdf.
Pollino, Laurence. "Etude des mécanismes en spectrométrie d'émission optique à source étincelles avec comptage des impulsions (SEO-CDI) permettant la mise au point d'un modèle de quantification des inclusions dans les aciers." Lyon 1, 1999. http://www.theses.fr/1999LYO19002.
Thabet, Hanen. "Validation de la chaîne d'émission pour la conception d'un capteur RF autonome." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4314.
This work joins in a project consisting in developing prototype of an autonomous and smart RF sensor allowing the realization of a wireless sensor network in an industrial environment. This thesis deals with the study, the design and the realization of the radio-frequency part of the transmitter using the 863-870 MHz ISM band and the CMOS AMS 0.35µm technology. This transmitter includes all the functions from the local oscillator to the power amplifier. The integrated circuit occupies a surface of 0.22mm² and consumes approximately 27mA under a supply voltage of 3.3V. Numerous innovative principles were implemented and validated. All these principles can be easily transposed into other standards of communication and in other frequency bands. The results of the post-layout simulation completely satisfy the specifications and confirm the simulations. Partial experimental characterization validates new architectures proposed
Meyer, Thibaut. "Gravure du verre de chalcogénure GeSbSe en plasma fluoré ou à base de méthane." Thesis, Nantes, 2019. http://www.theses.fr/2019NANT4064.
This study is focused on the etching of the GeSbSe chalcogenide glass in SF6, SF6/Ar et CH4/H2/Ar plasmas. This work is extended to the etching of pure elements Ge, Sb, Se along with binary materials GeSe2 et Sb2Se3. A part of this work is dedicated to the identification of fluoride, hydride and hydrocarbon etching products at the surface of the materials and inside the plasma. Mass spectrometry analysis shows rich spectra containing some unheard-of products.In fluorine-based plasmas, the surface composition affects the surface roughness and the etch rate. Inevitably, the formation of non-volatile fluorine products (SeSbFx) induces micromasking effects. This is the reason why we have sought to slow down the SeSbFx kinetic formation by adding Ar to SF6. Using that mixture, we managed to reduce the fluorine atomic concentration at the surface for high content of Ar (>90%) and for a lower pressure (<2mTorr). With such conditions, we obtained a smooth surface (<5nm), an acceptable etch rate (>50 nm/min) and a quasi-anisotropic profile. To free from non-volatile halogen products, we explored the CH4/H2/Ar chemistry. The latter efficiently etched the antimony while having viable etching characteristics. Surface analyses showed that the GexCyHz products are linked to the roughness for higher pressure (>3mTorr) and a significant CH4 content (>30%). In addition to the capacity to etch the GeSbSe glass, such plasma is a promising alternative
Depraz, Sebastien. "Etude expérimentale et modélisation des propriétés radiatives des mélanges gazeux de type CO2-N2 à très haute température en vue de l'application aux rentrées atmosphériques martiennes." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2011. http://www.theses.fr/2011ECAP0051/document.
Modeling of the radiation of CO2 above 2000 K remains a challenge for the prediction of radiative transfer at high temperatures, especially for the design of thermal protection of space vehicles entering the Martian atmosphere. The challenge for both the creation of databases that the development of models to perform calculations coupled between Aerothermodynamics and radiative transfer. Several spectroscopic databases have been developed in recent decades. Simulations of CO2-N2 mixtures at equilibrium showed that the IR emission of CO2 is important, if not predominant, up to 4000 K. But the experimental data to verify their accuracy at high temperature are few and limited to the low spectral resolution, at lower temperatures, or involve significant uncertainties. The main objective of this work is to provide experimental data at medium or high spectral resolution and high temperature in order to verify the accuracy of the theoretical foundations developed. The gas mixture at high temperature we measure the emission spectra is achieved through a microwave discharge through a stream of pure CO2. The temperatures reached (about 6000 K), the mixture is in local thermodynamic equilibrium (LTE) and mainly contains the following species: CO2, CO, O2 and O. The measurement of the spectra is carried out using a Fourier transform spectrometer in the infrared. The harmonic emission bands of CO in the region 3800-4400 cm-1 power allows accurate determination of the radial temperature field in the plasma. The theoretical CO2 emissions, both in emission coefficient or radiance integrated on an optical path, in the regions of 2.7 and 4.3 _m _m, is then calculated from the spectroscopic database and compared measures. The databases are based spectroscopic studied CDSD-4000 and recently published EM2C-1994 which is older. The results show that the latter is sufficient for combustion in conventional applications, typically requiring low spectral resolutions and temperatures below 2500 K, for which it was originally developed. However, based CDSD-4000 is generally in good agreement with experimental data, especially in the wings of bands indicating reliability for applications at very high temperatures. Although comparisons have revealed that the line positions for high energy transitions are unclear in this basis, the high degree of overlap of the lines in the regions 2.7 and 4.3 _m _m should greatly reduce the impact of this imprecision in practice. The other objective of this work concerns the difficulty of coupling between the calculations of radiative transfer and aerothermodynamics. Indeed, calculations of radiative transfer iv involving polyatomic molecules must take into account a large number of rovibronic transitions. Therefore, an approximate model of radiative properties (Statistics narrowband model) was developed and its accuracy has been studied for electronic systems optically thick carbon diatomic molecules encountered in problems of Martian atmospheric reentry. These systems are CO 4th positive, C2 Swan and CN violet. Various conditions to the non-LTE and LTE, and various mixtures have been studied for different regimes of line broadening. Comparisons with calculations "line by line" showed excellent agreement. The model parameters were tabulated in terms of two temperatures, Tg (vibrational temperature) and Tr (rotational temperature)
Ménézo, Sylvie. "Conception, réalisation technologique sur InP, et caractérisation d'une source d'émission multi-longueurs d'onde pour les applications WDM a 1. 5 micromètre." Lyon, INSA, 1999. http://www.theses.fr/1999ISAL0100.
A 10-wavelength 200-GHz channel spacing emitter for WDM applications is built by the monolithic integration on InP of a DBR laser array and a PHASAR. The source design and the technology conception, realization and characterization of the monolithic integration are reported, as well as the measured performances of the fabricated emitter. The CW -one channel at a time operation was performed: the source provides high mode stability with a rejection better than 32dB for all channels; the 2000Hz-channel spacing can be achieved with accuracy better than 250Hz. The monolithic source exhibits high speed characteristics through the direct modulation of the integrated lasers: the measured amplitude modulation (AM) bandwidth is equal to 6. 50Hz for a 70rnA continuous active current. The measured chirp for a 2. 50bit/s modulation is less than 1. 5À. Besides, the emitter is provided with a wavelength monitoring function ensuring the accuracy of any absolute emitted channel of the comb
Nistor, Magdalena. "Faisceau d'électrons créé dans une décharge transitoire à cathode creuse : distribution énergétique, rayonnement X, et ablation d'une cible solide." Paris 6, 2000. http://www.theses.fr/2000PA066353.
Carre, Martine. "Etude et amélioration du rapport signal sur bruit d'un spectromètre d'émission atomique à source plasma induit par haute fréquence à des fins d'analyse élémentaire." Lyon 1, 1991. http://www.theses.fr/1991LYO10128.
Piet, Jordan. "Gravure plasma du CdHgTe : étude de précurseurs non conventionnels pour application aux détecteurs infrarouges hautes performances de très faible pas." Thesis, Nantes, 2019. http://www.theses.fr/2019NANT4089.
This thesis investigates new gas mixtures for HgCdTe plasma etching with the objective to etch without substrate polarization : CH₃NO₂/H₂/Ar, CH₃OH/H₂/Ar and CH₄/NO₂/H₂/Ar. A first part on the analysis of these plasmas by electrostatics probes and optical emission spectroscopy shown that the substitution of methane by nitromethane or methanol has an effect on the chemical component of the etching. For these new mixtures, the formation of molecules such as CO and CN is correlated with the annihilation of the polymer deposit. The second part, about the etching of HgCdTe with these new precursors proved the ability to etch the substrate without bias with CH₃NO₂/H₂/Ar and CH₄/N₂O/H₂/Ar mixtures and thus reduce the material damages, especially the surface roughness. Further study using CH₄/N₂O/H₂/Ar plasmas shows in particular an increase of the etching rate at low bias up to a threshold, before it stagnates, corresponding to the transition from chemically dominant etching to physically dominant etching. In addition, the roughness is independent of the plasma excitation power, substrate temperature and etching time. Finally, trench etching revealed the chemical and isotropic etching at low bias with CH₄/N₂O/H₂/Ar and CH₃NO₂/H₂/Ar mixtures, but which, at higher bias, has a better lateral passivation than CH₄/H₂/Ar etching process
Le, Quang Huy Damien. "Spectroscopic measurements of sub-and supersonic plasma flows for the investigation of atmospheric re-entry shock layer radiation." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22462/document.
During planetary atmospheric entries, thermochemical non-equilibrium processes in the shock layer limit the reliability of aerothermal environment prediction. To improve prediction accuracy, non-equilibrium kinetic models are being developed. These models are experimentally assessed through the comparison with well characterized non-equilibrium experiments. For this purpose, the present work is dedicated to the thermodynamic characterization of non-equilibrium in high enthalpy reactive flows. Conversely to common studies that employ short duration facilities to investigate shock layer kinetics, we will assess the possibility of producing significant departure from equilibrium using radio-frequency and microwave stationary plasma flows, including supersonic plasma flows where vibrational non-equilibrium is strongly expected. Suitable spectroscopic diagnostics have been applied allowing future comparisons to be made between the microscopic description of the experiments and theoretical non-equilibrium models
Baudic, Alexia. "Caractérisation expérimentale et statistique des sources de Composés Organiques Volatils (COV) en région Île-de-France." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS537/document.
Volatile organic compounds (VOCs) play a key role within the atmospheric system acting as precursors of ground-level ozone and secondary organic aerosols (causing health and climatic impacts); hence the growing interest of better characterizing them. Significant uncertainties are still associated with compounds speciation, quantification and respective contributions from the different emission sources.This thesis proposes, through several laboratory and intensive field campaigns, a detailed characterization of VOCs and their main emissions sources within the Île-de-France region. We used methods based on the determination of speciation profiles indicative of road traffic, wood burning and natural gas sources obtained from near-field investigations (inside a tunnel, at a fireplace and from a domestic gas flue). These different source profiles were used as chemical fingerprints for the identification of the main VOC emission sources, which respective contributions were estimated using the Positive Matrix Factorization (PMF) source-receptor model applied to one-year VOCs (including NMHC+OVOC) measurements in Paris. This thesis allowed, for the first time, to evaluate the seasonal variability of VOCs and their main emission sources. Road traffic-related emissions are major VOC local/regional sources in Paris (contributing to a quarter of total annual emissions). The important impact of wood burning in winter (50 % of the VOC total mass) was observed. Results obtained from this approach were compared with the regional emissions inventory provided by the air quality monitoring network Airparif. Finally, a good agreement was found between our observations and the inventory for road traffic and wood burning-related sources.This independent assessment of inventories is of great interest because they are currently used as input data within air quality prediction models
Depraz, Sébastien. "Etude expérimentale et modélisation des propriétés radiatives des mélanges gazeux de type CO2-N2 à très haute température en vue de l'application aux rentrées atmosphériques martiennes." Phd thesis, Ecole Centrale Paris, 2011. http://tel.archives-ouvertes.fr/tel-00697001.
Cruaud, Perrine. "Influence des communautés microbiennes sédimentaires sur la répartition faunistique dans les sites hydrothermaux et les zones d'émissions de fluides froids du bassin de Guaymas." Thesis, Brest, 2014. http://www.theses.fr/2014BRES0059/document.
Whereas the deep-sea environment is often considered to be a desert, hydrothermal vents andcold seeps provide “oases” of biological activity on the ocean floor. Vent and seep ecosystems support complex food webs based on microbial chemoautotrophic primary production. These hydrothermal vent and cold seeps ecosystems both release hydrocarbon- and sulfide-rich fluids,fueling various surface assemblages such as mat-forming giant bacteria or symbiont-bearinginvertebrates (e.g. bivalves, tubeworms). In the Guaymas Basin, the nearby presence at a few tens of kilometers of cold seeps and hydrothermal vents coupled with comparable sedimentary settings and depths offer a unique opportunity to assess and compare the microbial community composition of these ecosystems. Tobetter understand their overall functioning, we studied sedimentary microbial communities associated with cold seep and hydrothermal vent areas in the Guaymas Basin. The diversity of microbial communities inhabiting sediments was studied using high throughput sequencing (454pyrosequencing), combined with complementary approaches, such as FISH and quantitative PCR. This study reveals that sediments found in the Guaymas Basin were colonized by microbial communities typically found in these types of ecosystems. Our results revealed a high similarity between microbial communities composition associated with the cold seep and hydrothermal vent areas as a probable consequence of the sedimentary context. Nonetheless, thermophilic and hyperthermophilic lineages (e.g.: Thermodesulfobacteria, Desulfurococcales, etc) were exclusively identified in hydrothermally influenced sediments highlighting the strong influence of temperature gradients and other hydrothermally-related factors on microbial community composition. Furthermore, sediments populated by different surface assemblages show distinct porewater geochemistry features and are associated with distinct microbial communities. Indeed, in the sediments underlying microbial mats characterized by high methane porewater concentrations,microbial communities were dominated by anaerobic methane oxidizers (ANME), known to produce sulfide which provides high fluxes of sulfide to the seafloor. In contrast, sediment associated microbial communities underlying faunal assemblages were characterized by a lower biomass and lower methane porewater concentrations in sediments, limiting porewater sulfide concentrations. Without elevated and toxic sulfide concentrations, faunal assemblages can colonize the surface. Together, geochemical and microbial surveys indicate that porewater methane concentrations play an important role in the microbial community structure and subsequently in the establishment of the surface colonizers. Furthermore, presence and activity of the surface colonizers influence the underlying microbial communities probably because of modification of energy source availabilities. Finally, the existence of similar microbial populations between the two ecosystems also raises the question of their dispersal mechanisms. Our results support the hypothesis of a potential continuity among deep-sea ecosystems. In absence of physical borders, environmental conditions (temperature, specific compounds associated withhydrothermal fluids) might select specific and highly adapted microorganisms from the pool of microorganisms dispersed globally across the seafloor
Vallée, Christophe. "Dépôt à basse température de couches minces d'oxyde de silicium élaborées en plasma oxygène / organosilicié dans un réacteur hélicon." Nantes, 1999. http://www.theses.fr/1999NANT2011.
Chauvet, Laura. "Caractérisation expérimentale et optimisation d'une source plasma à pression atmosphérique couplée à un spectromètre de masse à temps de vol." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30302/document.
Since the beginning of the 2000's, new atmospheric pressure plasma sources have been developed. They allow the propagation of a cold plasma jet or plasma plume in open air (non-equilibrium plasma jets). Their particular properties (in terms of reactive species, low temperature and ability to extend in open air) make them useful tools in a large range of research fields such as biomedicine, decontamination and sterilization, nanomaterial synthesis and analytical chemistry. Among the plasma jet sources, some are based on a dielectric barrier discharge (DBD) configuration, which is the case of this study. This work proposes the experimental characterization of a plasma jet developed with the aim to be coupled with a Time-Of-Flight Mass Spectrometer (TOF-MS) in order to perform ambient chemical analysis. The source consists of a dielectric body surrounded by two electrodes. The source is fed by a discharge gas (helium or neon) and powered by a square alternative voltage. The main diagnostics are optical emission spectroscopy and imaging with an ICCD camera. The mass spectrometer has also been used as a diagnostic tool to identify the ions created by the jet interacting with the species present in ambient air. The jet has been studied for two gases, neon and helium, with different experimental conditions of flow rates and applied voltages. The mechanisms of the jet propagation in open air have been studied for both half periods of the voltage (positive and negative), where the passage between positive and negative streamers transited through a remnant ionized channel. The spatial and temporal distributions of the main radiative species were investigated independently for each streamer allowing the observation and identification of mechanisms responsible of the populating of the upper level of observed emissions. It was shown that the mechanisms differ according to the half period studied and also the type of gases (neon and helium) due to the difference between the energies of their metastable states. In order to lay the groundwork in ambient analytical chemistry with the plasma source, its ionization capability was evaluated. Firstly, the ions created by the jet in open air were identified and analyzed with the TOF-MS, secondly the analysis was performed with different volatile samples. The results highlighted that the jet initiated with neon as discharge gas is able to ionize as well as the jet initiated with helium. A semi quantitative study of one of the volatile samples has also been realized
Baudrillart, Benoit. "Etude du procédé de croissance de films de diamant nanocristallin par dépôt chimique en phase vapeur assisté par plasma micro-onde distribué, à basse température et basse pression." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCD051/document.
This PhD thesis focuses on the understanding and the control of the nanocrystalline diamond (NCD) film growth process by distributed antenna array microwave plasma-assisted chemical vapor deposition. Two approaches were followed to reach these objectives: a « material » study aiming at studying the nucleation and growth mechanisms and the characteristics of the synthesized NCD films; a « plasma » study focusing on the diagnostics of H₂/CH₄/CO₂ low-pressure discharges used for NCD growth.Concerning the first part of this work, ex situ characterization techniques, such as scanning and high resolution transmission electron microscopy, atomic force microscopy, Raman spectroscopy, X-ray diffraction, UV-visible reflectometry, and in situ, such as laser reflectance interferometry, were used to study the nucleation density, morphology, topography, microstructure, purity, and growth rate of NCD films. The influence of some process parameters, such as chamber pressure, substrate position, gas composition, surface temperature, microwave power and ex situ substrate pretreatment, has been studied for silicon. The synthesis of NCD down to a substrate temperature as low as 130 °C has been thus investigated. The feasibility of NCD growth at this temperature on a polymeric material such as polytetrafluoroethylene (PTFE) has been demonstrated. The growth of NCD films on other kinds of substrates such as silicon nitride and stainless steel was also examined.Concerning the second part of this work, the diagnostics of the deposition plasma was carried out by optical emission spectroscopy and infrared absorption spectroscopy using wavelength-tunable laser diodes and external cavity quantum cascade lasers as radiation sources. The influence of the experimental conditions, in particular of the microwave power and the pressure in the chamber, on the concentration of the methyl radical CH₃, the diamond growth precursor, and of five stable molecules (CH₄, CO₂, CO, C₂H₂, C₂H₆), as well as on the degree of dissociation of H₂ and the kinetic, vibrational and rotational temperatures of the species, was studied. The high degree of dissociation of gas precursors, for a relatively low gas temperature of a few hundred degrees, indicates that the plasma chemistry is mainly governed by electronic processes. The considered distributed microwave plasma system nevertheless allows to produce some growth and etching species in amount comparable to conventional NCD growth processes, while permitting low temperature synthesis process
Samaké, Abdoulaye. "Processus de transfert vers l'atmosphère et de l'impact sanitaire des émissions biogéniques particulaires." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAU025/document.
Airborne particles (called « PM » for Particulate matter") are nowadays at the core of societal concerns because of their major impact on public health and their strong participation in climate change. Organic matter (OM) generally represents the first mass component of PM but it is still poorly understood, in particular the organic fraction from primary biogenic origin (PBOA). Some specific primary sugars are proposed as molecular tracers to study the atmospheric transport processes as well as to estimate the contribution of PBOAs to the total mass of PM. However, knowledge is still very limited about their spatial and temporal distributions (i.e., daily, seasonal and annual cycles), their main emission sources, or the environmental factors that drive their atmospheric concentrations. Moreover, although the understanding of the oxidative potential (OP) —a proxy of the health effect of PM— inherent in the chemical component of aerosols has progressed quite well in recent years, the contribution of this PBOA fraction is still very poorly understood. These aspects constitute the main objectives of this thesis work. From a methodological point of view, our questions were addressed by an interdisciplinary approach, which involved the statistical exploitation of a large database and the coupling of specific field campaigns with the implementation of an innovative experimental strategy developed for the simultaneous study of the chemical and microbiological characteristics of the samples collected.In a first work based on the exploitation of a large database, we showed that PBOAs constitute a very important fraction of PM in France, regardless of the typology of the environment, contributing on average to 13 ± 4% of the annual MO in PM10. We observed a synchronous temporal trends in both concentrations and ratios between primary sugars species for sites located in the same geographical region (up to an inter-site distance of about 200 km). These observations indicate that the PBOA source is very spatially homogeneous over distances consistent with those of large ecosystem types. This observation was then validated by an experimental approach based on two annual field sampling studies that allowed us to demonstrate (i) that daily changes in atmospheric concentrations of primary sugars are drived by only a few regionally variable atmospheric microbial taxa; and (ii) that these taxa come from local and regional flora for study sites that are directly influenced and not by agricultural activities, respectively. Finally, in the framework of the OP study, our results demonstrated (i) that all the tested model bioaerosols have a significant intrinsic OP, which is comparable for some species to the model atmospheric chemical components known for their high redox reactivity; and (ii) that they can significantly influence the OP of chemical PM models or sampled under real ambient conditions.This work provides a different look into the mass importance of PBOAs and new insights into the dominant sources and processes leading to their introduction into the atmosphere, as well as the influence of environmental factors on these processes. Alltogether these results argue for a systematic consideration of PBOAs in atmospheric chemistry models for better prediction of air quality
Al, Haj Rachad. "Hydrogeochemical study of Abu Ali watershed’s groundwater (Lebanon)." Electronic Thesis or Diss., Université de Lille (2018-2021), 2021. http://www.theses.fr/2021LILUR052.
Groundwater is an important natural resource heavily impacted by human activities which can degrade its quality. The Mediterranean basin is water stressed environment and subject to strong anthropogenic pressure. This makes groundwater the main water resource for several Mediterranean countries, including Lebanon. This thesis aims to study the hydrogeochemical characteristics of groundwater in the Abu Ali watershed, located in northern Lebanon, and to compare them with the hydrogeochemical characteristics of groundwater in the Mediterranean region. The first chapter of this thesis is a hydrogeochemical meta-analysis study of the Mediterranean region, while the second and third chapters focus on Abu Ali’s watershed in order to analyze the hydrogeochemical characteristics and assess its groundwater quality.In the first chapter, information about the studies and concentrations of major, minor ions and isotopes were taken from 123 Mediterranean hydrogeochemical studies. Then, the data was analyzed qualitatively and quantitatively. In fact, a disparity in the distribution of study topics was observed. In addition, the dominant hydrochemical facies are Ca-Cl in the Quaternary and Ca-HCO3 in the “Jurassic and Cretaceous” and “Tertiary”. In addition, the main geochemical process modifying the groundwater’s chemistry is the evaporation in Quaternary and Tertiary aquifers, and rock-water interaction in Jurassic and Cretaceous aquifers. Finally, 29% and 15.3% of aquifers are polluted by nitrates and at least one of the minor ions respectively.In the second chapter, 65 groundwater’s samples were collected from Abu Ali’s watershed between the wet and dry seasons of 2019 and 2020. The physicochemical parameters and concentrations of 9 major ions were measured. The data has been analyzed. The results show that Ca-HCO3 with Ca-Mg-HCO3 and rock-water interaction are the main hydrochemical facies and geochemical process respectively. In addition, hierarchical cluster analysis and PCAs divide samples into 5 groups affected by high sulphate concentrations, agricultural activity, low values of physicochemical parameters and major ions, reverse ions exchange and moderate chemical composition. Finally, the comparison with other studies in the Mediterranean basin indicates that Abu Ali's study does not represent any extreme value compared to the published data. In the last chapter, different indices and plots were calculated and constructed from the same 65 samples’ concentrations. In addition, the concentrations of 24 minor ions were measured by ICP-OES. For domestic use, some samples have concentrations higher than the limits for TDS, nitrates, arsenic, antimony, thallium and lead. According to RSC, Donen plot and magnesium ratios, 4, 10 and 7 samples respectively were considered inappropriate. Meanwhile, based on sodium percentages and Kelly’s ratios, the majority of samples are excellent. The Wilcox diagram indicates that 13 samples, located from low to medium elevation, were considered good to acceptable. In addition, the same samples represent a high salinity risk according to the USSL diagram. Ultimately, most of the samples were considered suitable for irrigation.Finally, this work presents a primary assessment of average hydrogeochemical characteristics of groundwater in the Mediterranean region and a baseline hydrogeochemical assessment of groundwater in Abu Ali basin. More comparative Mediterranean studies, focusing on seasonal variations and different types of aquifers are essential for advancement in the field of hydrogeochemistry. In addition, isotopic and microbiological studies of Abu Ali’s groundwater are needed in order to analyze the groundwater’s origin and assess the risk of Abu Ali’s groundwater respectively
Perraudeau, Amélie. "Couches mésoporeuses de TiO2 déposés par PECVD à la pression atmosphérique en vue d'applications photovoltaïques." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0092.
An atmospheric pressure chemical vapor deposition process equipped with an axial injection torch was chosen for the TiO2 thin films synthesis. A dynamic deposition mode, i.e. moving the substrate holder in front of the plasma jet, was developed to cover a square centimeter surface. Towards the integration of the titania films as the active layer in DSSCs, a porous columnar structure crystallized under the anatase phase was required. The optical emission spectroscopy analysis of the discharge, without and with titanium precursor, provided information about the huge thermal flux transferred to the substrate by the plasma, thanks to gas temperature from 3000 to 4000 K, at distances between 5 and 15 mm from the nozzle. The atomic relative densities estimation, mainly of nitrogen, oxygen and titanium, combined with the process parameters influence on the film microstructure highlighted several growth mechanisms. From these results, a microstructure diagram was built to predict more easily the morphology and the crystallinity of the TiO2 films deposited on silicon substrates, as a function of microwave power and torch-substrate distance. Optimized conditions were found for the synthesis of thin films matching the DSSC active layer specifications. The process parameters were then adapted to replicate the microstructure on glass/FTO substrates, confirming the microstructure diagram, even though the thin film did not fulfill the requirements. Perovskite solar cells were finally made to investigate the interest of the layers developed on silicon substrates
Tran, Tan Vinh. "CARACTÉRISATION ET MODÉLISATION DES PLASMAS MICRO-ONDE MULTI-DIPOLAIRESAPPLICATION À LA PULVÉRISATION ASSISTÉE PAR PLASMA MULTI-DIPOLAIRE." Phd thesis, 2006. http://tel.archives-ouvertes.fr/tel-00139610.