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Pilloni, Raphael. "AGRONOMICAL AND PHYSIOLOGICAL STUDY OF THE RESPONSE OF SORGHUM AND PEARL MILLET CROPS TO HIGHER SOWING DENSITY IN THE SEMI-ARID TROPICS. ASSESSEMNT OF THE OPPORTUNITY FOR SUSTAINABLE INTENSIFICATION AND CONSEQUENCE FOR THE TRANSPIRATION RESPONSE TO EVAPORATIVE DEMAND OF THE CROPS". Electronic Thesis or Diss., Université de Montpellier (2022-....), 2022. http://www.theses.fr/2022UMONG051.
Pełny tekst źródłaIn the semi-arid tropics, sorghum and pearl millet or key source of income and calories. Sustainable intensification is therefore needed to ensure food security. These two cereals are largely grown in smallholder farming system and cultivated at low density, opening an avenue to increase yield through this agronomic management. Through field and lysimetric trials carried out in India and Senegal this work showed the possibility to increase significantly, the biomass and grain yield in both species, with the same irrigation regime and fertilization. We highlighted a lowering of the vapour pressure deficit (VPD) in the canopies of high density, resulting in an increase in water use efficiency of the crops. While both crops responded positively to increased density, there were also large specie differences in the genotypic variation of the response to density, namely a strong genotype x density interaction in sorghum for biomass and WUE, but none in pearl millet. The genotypic variation in the degree of WUE response found in sorghum and its link with biomass accumulation led to investigate putative differences in the transpiration response of the crops to the evaporative demand. We tested this hypothesis outdoors with canopy-grown sorghum plants in field and lysimeter experiments. The response of the evapotranspiration was measured against the evaporative demand. This response was linear and, with WUE, showed large genetic variation. WUE was surprisingly higher in genotypes with the highest transpiration response to the evaporative demand (Penman-Monteith). These genotypes were also those that allowed maximum light penetration into the canopy. This work opens the door to intensification, in the short term by increasing sowing density in drylands using sorghum and pearl millet cultivars that show a strong response to density, and in the medium term by selecting sorghum cultivars adapted to high density
N'Guimbi, Joseph. "Mesures et corrélations des tensions de vapeur d'alcools lourds". Lyon 1, 1990. http://www.theses.fr/1990LYO10200.
Pełny tekst źródłaGarreau, Dominique. "Contribution à l'étude des vibrations d'un ailetage basse-pression d'une turbine à vapeur". Toulouse, INPT, 1987. http://www.theses.fr/1987INPT114H.
Pełny tekst źródłaGarreau, Dominique. "Contribution à l'étude des vibrations d'un ailetage basse-pression d'une turbine à vapeur". Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37605286p.
Pełny tekst źródłaSever, Lionel. "Conception d'un ébulliomètre permettant la captation rapide des équilibres liquide-liquide-vapeur par turbidimétrie et mesure de tensions de vapeur dans la même cellule". Lyon 1, 1995. http://www.theses.fr/1995LYO10086.
Pełny tekst źródłaBiscay, Frédéric. "Modélisation moléculaire d'interfaces liquide-vapeur à haute pression et prédiction de la tension interfaciale". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2009. http://tel.archives-ouvertes.fr/tel-00725080.
Pełny tekst źródłaBiscay, Frédéric. "Modélisation moléculaire d'interfaces liquide-vapeur à haute pression et prédiction de la tension interfaciale". Phd thesis, Clermont-Ferrand 2, 2009. http://www.theses.fr/2009CLF21967.
Pełny tekst źródłaDhima, Aleksandër. "Solubilité des gaz naturels dans l'eau à pression élevée". Lyon 1, 1998. http://www.theses.fr/1998LYO19002.
Pełny tekst źródłaBlondel-Telouk, Agnès. "Conception et mise au point d'un dispositif statique pour la détermination de la masse molaire moyenne de coupes pétrolières par tonométrie : étude d'équilibres liquide - vapeur de quatre systèmes binaires". Lyon 1, 1994. http://www.theses.fr/1994LYO10141.
Pełny tekst źródłaATALLAH, FARIS SALIH. "Etude des mecanismes de transport d'une vapeur metallique a travers un gaz a basse pression". Limoges, 1990. http://www.theses.fr/1990LIMO0090.
Pełny tekst źródłaPauly, Jérôme. "Mesure et représentation des équilibres de phase vapeur-liquide-solide de mélanges paraffiniques sous pression". Pau, 2000. http://www.theses.fr/2000PAUU3008.
Pełny tekst źródłaCacciuttolo, Quentin. "Apport de la pression sur les performances d'une cellule d'électrolyse de la vapeur d'eau à haute température". Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066610/document.
Pełny tekst źródłaIn order to improve the industrial attractiveness of high temperature steam electrolysis (HTSE), the increase in the operating pressure is one of the most promising solutions. In this context, this study is dedicated to the analysis of the pressure influence on the electrochemical reactions occurring in HTSE. A Model and experimental results dealing with the effect of pressure increase have been carried out. Concerning the cathodic side model, the limiting current density due to the lack of steam is shifted towards higher steam conversion rates by increasing the operating pressure. Regarding the anodic side, a negative thermodynamic effect is predicted by Nernst equation but no negative effect appears at high current density. Furthermore, the overpressure at the oxygen electrode decreases with the operating pressure (and so the risk of delamination is reduced). At the same time, experimental studies on three electrodes cell until 30 bars have been lead on the oxygen electrode. A positive effect of the pressure on the oxygen side performances has been observed. This gain in performance could be explained by three different mechanisms. The mechanic effect of pressure increase contact inside the electrode. Furthermore, high pressure improves gas circulation and adsorption/desorption kinetics at the surface of electrode
Le, Courtois Véronique. "Evaporation d'une coupe méthacrylique en film mince mécaniquement agité". Vandoeuvre-les-Nancy, INPL, 1989. http://www.theses.fr/1989NAN10023.
Pełny tekst źródłaKasehgari, Hossein. "Mesure des faibles tensions de vapeur par la méthode statique : application à l'étude d'hydrocarbures peu volatils". Lyon 1, 1992. http://www.theses.fr/1992LYO10153.
Pełny tekst źródłaViton, Christophe. "Tensions de vapeur et enthalpies de vaporisation des n-alcanes compris entre le n-décane et le n-eicosane : résultats expérimentaux et corrélations". Lyon 1, 1995. http://www.theses.fr/1995LYO10072.
Pełny tekst źródłaRigal, Philippe. "Equation d'état de Sanchez-Lacombe : mise au point d'une méthode par contribution de groupes pour le calcul des propriétés thermodynamiques des corps purs". Aix-Marseille 3, 2002. http://www.theses.fr/2002AIX30029.
Pełny tekst źródłaA good modelling of thermodynamic properties of pure compounds is a crucial step in industrial processes. In conditions of a large range of temperatures and pressures, equation of state is required. Parameters of equations of state are estimated by methods using experimental data, like fitting or critical specification methods, or by group contribution method when experimental data are not available. We study the Sanchez-Lacombe equation of state. This equation of state derived from the lattice fluid theory. It can be used for light components to polymers. We develop a method based on group contribution for modelling vapor pressures, saturated liquid volumes and vaporization enthalpies of hydrocarbons of intermediate molecular weights. We extend this method to aliphatic alcohols
Sainct, Florent. "Etude de la réactivité de décharges électriques nanoseconde à la pression atmosphérique dans la vapeur d'eau". Phd thesis, Ecole Centrale Paris, 2014. http://tel.archives-ouvertes.fr/tel-01020267.
Pełny tekst źródłaBureau, Nathalie. "Interactions entre fluides de gisement et fluides de forage". Lyon 1, 2002. http://www.theses.fr/2002LYO10130.
Pełny tekst źródłaGetachew, Sawaya Terufat. "Etude de systèmes biphasiques d'intérêt pétrolier : hydrocarbures peu volatils, mélanges eau-méthanol et eau-méthanol-chlorure de sodium". Lyon 1, 1998. http://www.theses.fr/1998LYO10193.
Pełny tekst źródłaSasse, Karim. "Détermination de faibles tensions de vapeur d'hydrocarbures lourds et corrélation des résultats par une équation d'état". Lyon 1, 1988. http://www.theses.fr/1988LYO10105.
Pełny tekst źródłaDehan, E. "Silicium partiellement oxydé obtenu en phase vapeur à basse pression à partir de Si2H6 et de N2O". Toulouse, INSA, 1995. http://www.theses.fr/1995ISAT0021.
Pełny tekst źródłaThomas, Nathalie. "Différents aspects de l'étude du dépôt chimique en phase vapeur sous pression réduite du disiliciure de tungstène". Grenoble INPG, 1992. http://www.theses.fr/1992INPG0119.
Pełny tekst źródłaBousquet, Angélique. "Dépôt de couches minces par plasma pulsé radiofréquence et basse pression en mélange hexaméthyldisiloxane / oxygène". Nantes, 2005. http://www.theses.fr/2005NANT2084.
Pełny tekst źródłaThis work concerns the Plasma Enhanced Chemical Vapour Deposition (PECVD) of thin films, at low pressure (3mTorr) and low temperature (<100°C), in Hexamethyldisiloxane (HMDSO)/ oxygen pulsed plasmas in a radiofrequency helicon reactor. The kinetics of charged species and of some neutral active species is investigated by Langmuir probe and optical emission spectroscopy time-resolved measurements. The film analysis by ellipsometry, infrared spectroscopy and gravimetry shows inorganic SiO2-like and plasma polymers SiOxCyHz films can be deposited with a fixed gas mixture depending on the pulse parameters. The structure and deposition rate are linked to the creation and loss times of oxygen atoms. The reduction of ion bombardment in pulsed plasma also allows to reduce the compressive stress and to improve the electrical properties of SiO2-like films, as demonstrated by nano-indentation, Newton's ring method, and C(V) and I(V) measurements on MOS structure
Viguier, Françoise. "Ecoulements diphasiques lors de la vidange d'un réservoir de gaz liquéfiés sous pression. Comparaison Eau - CFC11-CFC113". Paris, ENMP, 1992. http://tel.archives-ouvertes.fr/tel-00844457.
Pełny tekst źródłaAinous, Nédal. "Réalisation d'un appareil d'analyse en ligne pour l'étude des équilibres liquide-vapeur : application à la récupération assistée des bitumes". Lyon 1, 2005. http://www.theses.fr/2005LYO10232.
Pełny tekst źródłaSavin, de Larclause Isabelle. "Dépôt organosilicie par plasma froid basse pression et pression atmosphérique sur substrats microstructurés". Toulouse 3, 2008. http://thesesups.ups-tlse.fr/870/.
Pełny tekst źródłaThis PhD works is part of an industrial project on ophthalmic optic, developed by the company Essilor. The aim is to prepare a technological step in the apprehension of the optical function of the glass and in their production. The innovative idea is based on the introduction of some actives functions in the glass, thanks to its discretisation. To do so, Essilor turns toward the microlectronic technologies, and especially the plasma technologies. The thematic treated here is the deposition of a thin film by plasma on a microstructurated substrate. In order to obtain a quality of the film homogeneous on the whole microstructure, the coating must be conformal, i. E. It must have a thickness, composition and structure constant on all the microstructure parts. Thus, the issue of this PhD is the understanding of the mechanisms which control this property, through the use of two different processes, a microwave ECR low pressure plasma and an Atmospheric Pressure Townsend discharge. The effect of process parameters (power, substrate polarisation, temperature, gas mixture) on the conformity was studied. This allowed checking the significance of the shadow effect at low pressure and to bring out the main role of the ions. At atmospheric pressure, although mean free pass is lower compared to the microstructure size, the coating is mainly concentrated on the superior regions of the microstructure. In order to understand this phenomena, reactive mass transfer simulation and electrical field simulation was done. The diffusion seems to be responsible, and these effects are accentuated by the repartition of the electrical field at the surface. The predominance of one of these phenomena (diffusion or field effect) changes in function of the process conditions
Mansour, Carine. "Spéciation des espèces soufrées dans les générateurs de vapeur des centrales nucléaires à réacteur à eau sous pression". Phd thesis, Paris 6, 2007. http://pastel.archives-ouvertes.fr/pastel-00005107.
Pełny tekst źródłaDali, Yacoub. "Etude expérimentale de l'oxydation des alliages de zirconium à haute pression de vapeur d'eau et modélisation des mécanismes". Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 2007. http://tel.archives-ouvertes.fr/tel-00341747.
Pełny tekst źródłaL'oxydation de deux familles d'alliages a été étudiée sous vapeur d'eau (pression comprise entre 100 millibars et 100 bars) : les alliages de type Zircaloy, dont la composition est basée sur celle du Zircaloy-4 et ceux de type Zr-x%Nb à différentes teneurs en niobium (0,2 ; 0,4 et 1%). Nos objectifs pour ces deux familles d'alliage étaient de comprendre les différences de réactivité de ces matériaux entre la basse et la haute pression de vapeur d'eau, en estimant les variations de la vitesse avec cette variable et l'influence de chaque élément d'addition sur la vitesse. Pour les alliages au niobium, une analyse approfondie de la ségrégation du niobium en surface a également été menée.
Au cours de ce travail, une thermobalance à suspension magnétique a été développée et mise en œuvre pour suivre in-situ l'oxydation à haute pression (jusqu'à 50 bars). Cette expérimentation est, à notre connaissance, unique en son genre. Au cours de cette étude, un large domaine de pression a ainsi été balayé en associant expérimentations en thermobalance (0,1-10 bars) et en autoclave (10-100 bars).
Les couches d'oxyde formées ont ensuite été caractérisées par différentes techniques telles que le MEB, le MET-HR, la DRX, l'ESCA, la marco- et microphotoélectrochimie (MPEC et mPEC), le SIMS après échange isotopique en H218O.
Pour les alliages de la famille du Zircaloy, nous avons confirmé le rôle prépondérant des précipités Zr(Fe,Cr)2 sur la résistance à la corrosion des gaines, et validé la croissance de la vitesse d'oxydation du zirconium quasi-pur avec la pression partielle de vapeur d'eau. A l'opposé de la très grande stabilité cinétique du Zircaloy-4, dont la vitesse est indépendante de la pression de vapeur d'eau et donc contrôlée par la diffusion de l'oxygène dans la couche, nos résultats nous ont conduits à proposer une étape limitante de réaction d'interface dans le cas du zirconium pur, associée à une forte dégradation de la couche liée à une croissance des grains catalysée par la vapeur d'eau, à l'origine des décohésions entre des amas de cristallites. Les précipités Zr(Fe,Cr)2 , au travers de la dissolution du fer dans la matrice de zircone environnante, pourraient, en stabilisant la zircone quadratique, assurer l'intégrité de la couche.
Pour les alliages Zr-x%Nb et plus particulièrement pour l'alliage Zr-1%Nb, la vitesse d'oxydation est dépendante de la pression partielle de vapeur d'eau. A cela s'ajoute un accroissement sensible de la ségrégation en niobium à la surface, mise en évidence par ESCA, sous la forme Nb2O5, mise en évidence par MPEC. La vitesse d'oxydation et la ségrégation en niobium montrent toutes deux une dépendance homographique en fonction de la pression. L'originalité de l'exploitation de ces résultats réside essentiellement dans la proposition d'un mécanisme simple prenant à la fois en compte la ségrégation et l'oxydation. Une étape limitante de diffusion des ions hydroxydes adsorbés dans la couche externe de l'oxyde permet de décrire la majorité des résultats expérimentaux obtenus sur les alliages Zr-x%Nb.
Lucile, Floriane. "Etude thermodynamique des équilibres liquide-vapeur des systèmes complexes CO2-eau-impuretés à haute pression. Expérimentation et modélisation". Thesis, Pau, 2012. http://www.theses.fr/2012PAUU3042/document.
Pełny tekst źródłaProduction of carbon dioxide from burning fossil fuel participates in the global warming. This issue generates a growing interest for CO2 capture and storage from oxy fuel combustion. Before the sequestration step, the CO2 has to be purified from impurities. Separation processes require a good knowledge of thermodynamics properties of phase equilibria. In this context a new experimental device was designed and set up in the LaTEP to allow the study of the solubility of gas mixture involved in CO2 capture and storage processes (CO2, O2, NOx, SO2). The apparatus was, first, validated by studying the CO2-water system in the temperature range from 293.15 K to 393.15 K and at pressure up to 5 MPa. Then, the CO2-water-NaOH was studied because few data are available in the scientific literature. Experimental data obtained was compared with a model developed in this work. This model is based on a thermodynamic description of physical chemical phenomena occuring in a vapour liquid system. Two model of activity coefficient are compared (Pitzer and electrolyte-NRTL). The last step of this study is the parameter optimization for e-NRTL
Khir, Tahar. "Contribution à l'étude du retard à la condensation dans la détente d'une vapeur légèrement surchauffée d'un fluide frigorigène". Paris 12, 1987. http://www.theses.fr/1987PA120003.
Pełny tekst źródłaCarneiro, Rafaela Lorenzato. "Caracterização da capacidade fotossintética e da condutância estomática em árvores de Pinus caribaea var. hondurensis e de Pinus taeda em Itatinga, São Paulo". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-10092013-170745/.
Pełny tekst źródłaThe campaigns were conducted in trees with five years old of Pinus caribaea var. hondurensis and Pinus taeda in control plots (no fertilization and no irrigation) and fertilized and irrigated plots during summer and winter of 2012 to characterize the physiological variables: i) maximum photosynthetic capacity (Amax), ii) Photosynthesis throughout the day (A); iii) Changes in stomatal conductance (gs) in relation to the increase in vapor pressure deficit (VPD), and iv) Maximum rates of carboxilization (Vcmax) and maximum rates of electron transport (Jmax) based on A/Ci curves. The study was conducted in the project Potential Productivity of Pinus in Brazil, located at the Experimental Station of ESALQ/USP in Itatinga-SP. Three average trees per plot were chosen for physiological evaluations, performed with the LiCor 6400XT. The Amax measurement was performed in the middle third of the crown, in two branches per tree and two positions per branch, taken from 8 to 10am. To get the response of A and gs with increasing VPD, the measurements continued every hour, from 11 am to 3 pm. At the end of the measurements, the needles were collected for determination of specific leaf area (SLA) and leaf nitrogen (N). The A/Ci curves were performed in three trees, one branch per tree and two positions per branch were taken from 8 am to 12 pm. At five years, the Pinus caribaea var. hondurensis showed two-fold the wood volume of Pinus taeda. Both physiological measurements showed similar results between treatments for each species. Amax values were higher during summer, and Pinus caribaea var. hondurensis shower greater sensitivity compared to Pinus taeda. A and gs throughout the day showed higher variation in Pinus caribaea var. hondurensis. The average values of Amax for summer and winter were 8.2, 4.8 ?mol m-2 s-1 and 6.75, 6.3 ?mol m-2 s-1 for Pinus caribaea var. hondurensis and Pinus taeda, respectively. There was a reduction of A and gs with the increasing of DPV, for both campaigns for the Pinus caribaea var. hondurensis and only in winter campaign for Pinus taeda. Thus, the two species have different behaviors in response to climatic changes. The two species showed a positive relationship between photosynthesis and transpiration, with Pinus caribaea var. hondurensis showing greater water use efficiency. The average SLA and needle nitrogen were 9.6 m² kg-1, 10.1g kg-1 and 10 m² kg-1, 13.4g kg-1 for Pinus caribaea var. hondurensis and Pinus taeda, respectively. Photosynthetic parameters in Pinus taeda was higher in both campaigns, with average values of Vcmax and Jmax greater than in Pinus caribaea var. hondurensis, related to higher concentration of needle nitrogen. There was no relationship between tree biomass growth and leaf-level measurements of photosynthesis, indicating that other processes at crown level, use and allocation of photosynthates should be investigated to explain the difference in growth.
Werner, Andrzej. "L'influence de la pression sur la température d'ébullition peut être une cause de l'instabilité d'un générateur monotubulaire de vapeur". Doctoral thesis, Universite Libre de Bruxelles, 1985. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/213620.
Pełny tekst źródłaHenda, Redhouane. "Dépôts de nitrure de silicium par procédés chimiques en phase vapeur à basse pression et à faible bilan thermique". Toulouse, INPT, 1994. http://www.theses.fr/1994INPT035G.
Pełny tekst źródłaAdama, Maiga Mahamadou. "Modèles multi-bulles pour la cavitation : Équation d'évolution pour la pression". Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10092/document.
Pełny tekst źródłaThis thesis work concems the modelling of cavitation, a phenomenon by which almost empty bubbles are formed in a liquid in depression. The study of cavitation gave several models in literature almost all of these models disregard the interactions between the bubbles and the rise of pressure which results in certain phases of the evolution of the cavitation, as observed in experiments by Franc et al. (1995) and Ohl (2002). ln our work, we propose a new evolution model in the size of the bubbles, in which two non-identical bubbles are localized in a controlled expansion volume. The presence of two bubbles introduces an instability in which the exchange of void seems to be an additional degree of autonomy. Our model includes the possibility for many small bubbles to disappear or not depending on whether there is lower or not than the critical radius. According to the model, there can be many collapses of small bubbles as soon as the phenomenon of cavitation appears which is in accordance with the experimental observation of a noise in the appearance zone of Buogo et al (2002). The model reveals the pressure as an unknown factor of the problem for which we have highlighted an independent evolution equation of that density. The comparison of the size of the bubbles and the pressure depending on the time obtained with the model is in accordance with the measurements carried out in 2002
Abou-Naccoul, Ramy. "Pressions de vapeur et de sublimation de composés organiques et inorganiques : mesure et modélisation". Thesis, Lyon 1, 2011. http://www.theses.fr/2011LYO10083.
Pełny tekst źródłaFor a few years, we have attended an increasing importance of the long-term effects of the chemical pollutants on the environment and human health. It is thus necessary to study not only their ecotoxicological properties but also their physico-chemical properties such as the vapor pressure (or volatility) and aqueous solubility. In Addition, the introduction of the regulation REACH (Registration, Evaluation and Authorization of CHemicals) in June 2007 whose main objective is a better knowledge of the environmental and medical properties of chemical substances has increased the necessity of compound characterization. From an industrial point of view, the determination of the vapor pressure of the pure substances is an essential data in many unit operations such as purification and separation. Thus, we improved an apparatus with saturation of inert gas existing at the laboratory. Once the good performance of the apparatus checked (by measurement of the vapor pressure of a reference compound: phenanthrene) we studied N-alkanes ranging between C30 and C60 and 8 polycyclic aromatic hydrocarbons in a broad temperature range (20 to 320°C) and of pressure (10-1 Pa with 10-7 Pa). The obtained results were compared with the literature when available. In addition, determination of the vapor pressure of inorganic compounds of industrial interest : zirconium tetrachloride (ZrCl4) and the hafnium tetrachloride (HfCl4) was also undertaken. The experimental results of polyaromatic hydrocarbons have allowed us to improve a cubic equation of state (derivative of Peng-Robinson EOS) whose parameters are estimated by a method of contribution of groups developed by Rauzy-Coniglio. The predicted vapor pressures were in good agreement with the experimental values
Bellec, Aurélien. "Étude de la sublimation partielle de mélanges énantiomériquement enrichis". Rennes 1, 2009. http://www.theses.fr/2009REN1S064.
Pełny tekst źródłaThe aim of this work is the study of the sublimation of enantiomerically enriched compounds. Different chiral organic compounds (amino acids, carboxylic acids and amide) were sublimed under reduced pressure (0. 1 mbar) and at low temperature. Mixtures are made from the appropriate weight of enantiomers (mixtures of D+L) or from the racemic and the enantiomer (mixtures of DL+L (or D)). For each compound, enrichments but also depletions in the enantiomeric excesses of partial sublimates were observed. The determination of this ee for three amino acid (alanine, leucine, proline) for various ee of the starting material led to curves showing similar data for all the ee of the sublimates of the same amino acid. To better understand the behaviour of compounds during sublimation, several experiments were conducted: with a 13C labeled amino acid and analysis by NMR spectroscopy, by the use of two sublimation apparatus, etc. The analysis of the results showed differences with the literature and current knowledge that led us to propose a new interpretation of the phenomenon, based on the intrinsic characteristics of compounds: the saturated vapour pressure of each component (DL, L ou D)
Alaoui, Mohammed. "Utilisation des silanes (SiH4, Si2H6) comme sources de silicium dans les procédés de dépôts chimiques en phase vapeur à faible pression (LPCVD)". Mulhouse, 1991. http://www.theses.fr/1991MULH0182.
Pełny tekst źródłaLanquetin, Roger. "Spectrométrie de Fourier de flammes à basse pression et analyse des spectres d'émission de la vapeur d'eau à haute température". Paris 13, 1997. http://www.theses.fr/1997PA132030.
Pełny tekst źródłaCayet, Stephan. "Densite des especes dans un jet a basse pression de plasma air-vapeur d'eau en proportions variables. Experiences et modelisation". Paris 11, 1993. http://www.theses.fr/1993PA112358.
Pełny tekst źródłaValorso, Richard. "Développement et évaluation d’un modèle explicite de formation d’aérosols organiques secondaires : sensibilité aux paramètres physico-chimiques". Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST1126/document.
Pełny tekst źródłaFine aerosols have an important impact on health, visibility and climate. Secondary Organic Aerosols (SOA) represent an important fraction of fine aerosol composition. SOA are formed by nucleation or condensation onto pre-existing particles of gaseous species formed during the oxidation of emitted volatile organic compounds (VOC). VOC oxidation implies a huge number of secondary intermediates which are potentially involved in SOA formation. In order to study SOA formation, it is necessary to develop chemical schemes describing explicitly the formation and condensation of the gaseous secondary intermediates. The LISA has thus developed in collaboration with NCAR (National Center of Atmospheric Research) a generator of explicit chemical schemes : GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere). This work aims at testing (i) the reliability of GECKO-A to simulate observed SOA concentrations in Atmospheric Simulation Chamber (ASC) and (ii) exploring the SOA sensitivity to physico-chemical parameters such as saturation vapour pressures, chamber walls effects or kinetics rate constants. In order to assess GECKO-A's chemical schemes, the model has been confronted to chamber experiments performed to study SOA. Saturation vapour pressure (Pvap) is the key parameter controlling the gas/particles partitioning of organic compounds The three Pvap estimation methods considered as the more reliable in the literature have been implemented in GECKO-A. Pvap estimated by the three methods differs highly, up to several orders of magnitude. Despite of these discrepancies, simulated SOA concentration and speciation show a low sensitivity to the method used to estimate the Pvap. Moreover, none of the methods were able to make the model fit the observations. SOA concentration is systematically overestimated of a factor 2. Semi volatile organic compounds deposition on a chamber walls has been investigated. The implementation of this process in the model leads to a significant decrease of the simulated SOA concentrations, up to factor of 2. Simulated SOA yields are in good agreement with measured SOA yields. The hypothesis of a misrepresentation of some gaseous processes has then been investigated through sensitivity tests. SOA formation sensitivity to COV+ OH reactions rate constants has been explored. Results exhibited a high sensitivity to the rate constants estimations (regarding the rate constants values estimation, as well as the determination of the OH attack sites). The estimated alkoxy radicals decomposition rate constants have also been tested. This test showed however no significant impact on the simulated SOA yields
Ṭāha, ʿUṯmān. "Commande automatique robustesse du générateur de vapeur REP". Vandoeuvre-les-Nancy, INPL, 1993. http://www.theses.fr/1993INPL1280.
Pełny tekst źródłaChammam, Abdeljelil. "Étude de décharges haute pression mercure et mercure hallogénure alimentés par des courants rectangulaires et pulsés". Toulouse 3, 2005. http://www.theses.fr/2005TOU30002.
Pełny tekst źródłaThe present work deals with feeding, the design and experimental study of mercury discharge lamps of high pressure 400 W, one of which was doped in thallium iodine. A pulsed power supply was measured using the results of simulation obtained by coupling a model of mercury discharge lamp of high pressure with a circuit software. The conception of the model as well as the practical achievement of the pulsed power supply have been done in the laboratory. After having electrically validated the acting of the coupling of feeding with the lamp, we measured energetic spectrical flow and the luminous flow as well as total lightings of lines resolved in time. The latter results led to the determination of temperature for the pseudo continued and pulsed modes. Comparing these measurements with those obtained through a "fluid" calculating code enabled us to evaluate, characterise and analyse the dynamic behaviour of the studied discharges and also indicate the limits of the models. We have particularly noticed that the more intense the impulsions are, the shorter the establishment time is and the longer the relaxation time becomes. This phenomenon is almost the same for a lamp doped in thallium iodine, though times, especially relaxation times, are of considerable increase. Infact, we can relate this effect to the presence of metastable levels of thallium and the snaring of its resonance rays. The influence of impulsions on the radiation is important for the ultra-violet part of the spectrum. In the impulsion regime, efficiency increases and can reach 30%. These results can open new perspectives to the production of ultra-violet radiation in industrial applications
Marrichi, Ana Heloisa Carnaval. "Caracterização da capacidade fotossintética e da condutância estomática em sete clones comerciais de Eucalyptus e seus padrões de resposta ao déficit de pressão de vapor". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-13042009-144513/.
Pełny tekst źródłaThis study aimed to characterize the physiological variables related to photosynthesis, in seven commercial Eucalyptus clones with high productivity, by evaluating maximum photosynthetic capacity (Amax), and the response of photosynthesis (A), stomatal conductance (gs) and transpiration (E) to Vapor Pressure Deficit (VPD). A trial was installed in 2004, at ESALQ/USP, with the clones that were part of BEPP Project (Brazil Eucalyptus Potential Productivity), and each plot had 49 plants (7x7) in a 3 m x 2.7m spacing. We measured tree height or DBHs and three average trees were selected for measurements, at 16 and 36 months. The sample to estimate Amax was: two crown positions (2 and 3), two branches per tree and two leaves per branch. The measurements which were taken from 8 to 10 am (low VPD). To get the response of A and gs to VPD measurements continued hourly, from 11 am to 3 pm, on the leaves from the first branch and position 2. At the end of the measurements leaves were collected for specific leaf area (SLA) and nitrogen (N) determination. Additionally, at 16 months, A/Ci curves were established, and parameters Vcmax, Jmax and VTPU were estimated through the program Photosyn Assistant. The curves were done for 2 trees per clone, at superior crown positions (2 and 3) and inferior ones (4 and 5). The physiological measurements and A/Ci curves were made using LiCor-6400. The results showed that Amax was similar for positions 2 and 3. There was variation among clones, but not consistent between ages, and all the clones had high Amax at 16 months (between 26 and 31 µmol m-2s-1, with an average of 29 µmol m-2s-1), decreasing at 36 months (between 19 and 26 µmol m-2s-1, with an average of 22 µmol m-2s-1). SLA and N were also similar between positions 2 and 3 and higher at younger age (11,1 versus 8,3 m²kg-1, 29,6 versus 21,1 gN kg-1;), what may be associate with Amax decrease. A, gs and E also showed lower values at age 36, for all the clones (23 versus 18 µmol m-2s-1; 0,41 versus 0,26 mol m-2s-1; 9,2 versus 6,1 mmol m-2s-1). All clones showed sensitivity to VPD, reducing gs and A with increasing VPD. However, the clones showed different sensitivities and all of them were less sensitive to VPD at age 36, highlighting a selection potential of genetic materials for water stress. In general, higher photosynthesis values were associated with higher transpiration, showing the necessity to know the water conditions of sites when planting genetic materials with high productivity. Vcmax, Jmax and VTPU were greater for superior positions compared to inferior ones, and were not different among clones. Due to a similarity in SLA, N and physiological and biochemical traits between positions 2 and 3, no distinction on future photosynthesis measurements between these positions is needed. Finally, there was not a direct relation between stem growth and photosynthesis, at both ages, showing that photosynthesis at crown level by itself can not capture all the ecophysiological processes related to wood productivity, being necessary the integration with studies related to carbon allocation inside the plant.
Chosson, Raphaël. "Étude expérimentale et modélisation du comportement en fluage sous pression interne d'une gaine en alliage de zirconium oxydée en atmosphère vapeur". Thesis, Paris, ENMP, 2014. http://www.theses.fr/2014ENMP0092.
Pełny tekst źródłaDuring hypothetical Loss-Of-Coolant-Accident (LOCA) scenarii, zirconium alloy fuel cladding tubes creep under internal pressure and are oxidized at high temperature (HT). Claddings become stratified materials: zirconia and oxygen-stabilized alpha phase, called alpha(O), are formed on the outer surface of the cladding in beta phase.The strengthening effect of the oxidation on the cladding creep behavior under internal pressure was highlighted at HT. In order to model this effect, the creep behavior of each layer must be known.This study focused on the characterization of the creep behavior of the alpha(O) phase at HT, through axial creep tests performed under vacuum on model materials containing from 2 to 7 wt.% of oxygen, representative of the alpha(O) phase. The strengthening effect and the embrittlement due to oxygen on the alpha(O) phase creep behavior at HT was quantified and creep laws were identified.Relevance of the creep laws for each layer, identified in this study or from the literature, is discussed. Then, a finite elements model, describing the oxidized cladding as a stratified material, is built. Based on this model, a fraction of the experimental strengthening during creep is predicted
Clément, Charles. "Évolution des profils de teneur en humidité, de température et de pression au cours du séchage sous vide en vapeur surchauffée". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60626.pdf.
Pełny tekst źródłaMokbel, Ilham. "Mesure des tensions de vapeur entre 10-3 et 1400 mmHg par la méthode statique : amélioration d'un appareil de mesure existant : étude de composés purs et de deux systèmes binaires". Lyon 1, 1993. http://www.theses.fr/1993LYO10265.
Pełny tekst źródłaAraoud, Zouhour. "Etude du régime dynamique d'un plasma de décharge électrique dans la vapeur de mercure". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/651/.
Pełny tekst źródłaThe present work deals with the modelling of the high-pressure-mercury lamp during the last phase of the warm-up period. Simulation is carried out in the frame of Local Thermodynamic Equilibrium using a time-dependent two-dimensional computational fluid model. After validation from comparison with literature results, this model is used to analyse the dynamic behavior of a high pressure mercury discharge lamp, to describe the evolution of various results during this phase and to measure the effect of the convection. Two models have been compared. The first takes into account of the convection and the second neglects it. We proved that the convection slows down the warm-up phase while increasing mercury losses behind the electrodes and the time of evaporation of the quantity of mercury. In the electric discharge, the influences of several parameters such as the current and the geometry of the burner are studied. Their incidences on the thermalisation of the discharge were examined. It was found, in one hand, that the warm-up of a high pressure mercury lamp is accelerated by amplifying the current or the inter-electrodes length with constant current. On the other hand, an increase in the diameter slows down it
Leborgne, Hervé. "Modélisation de l'évaporation à haute pression de gouttes multicomposants dans le code Kiva II". Rouen, 1999. http://www.theses.fr/1999ROUES046.
Pełny tekst źródłaViguier, Françoise. "Écoulements diphasiques lors de la vidange d'un réservoir de gaz liquéfiés sous pression. Comparaison Eau - CFC11-CFC113". Phd thesis, Ecole Nationale Supérieure des Mines de Saint-Etienne, 1992. http://tel.archives-ouvertes.fr/tel-00844457.
Pełny tekst źródłaHamedi, L'Habib. "Dépôt LPCVD de couches minces de silicium dopé bore in-situ : effet de la pression sur la microstructure et les propriétés électriques". Rennes 1, 1989. http://www.theses.fr/1989REN10036.
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