Dissertations / Theses on the topic 'Cellulose – Effets du feu'
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Jamaladdeen, Rawaa. "Investigation on Wildfire Flashovers in the Mediterranean Climate Regions with Emphasis on VOCs Contributions." Electronic Thesis or Diss., Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2023. http://www.theses.fr/2023ESMA0015.
Full textRequests from the firefighting communities are increasing urging the scientific communities to create operational protective and preventive tools that help them understand extreme wildfire behaviors considering not only the atmospheric conditions but also topography, and vegetation characteristics. Thus, our objective was to provide answers to such requests by investigating the probable factors responsible for intensifying wildfire regimes to flashovers using numerical, and thermobiochemical experimental approaches. The numerical model is a gas dispersion model validating experimental data from wind tunnel tests to resolve the controversy of whether or not the volatile organic compounds (VOCs) accumulations in confined topographies end up inducing wildfire flashovers. It comprises a propagating fire front calculated using the Rothermel semi-empirical steady-state surface fire model, and Van Wagner transition to crown fire behavior criteria, with an integrated unsteady rate of VOC emissions simulating the ones evolving from the vegetation burning in the firefront. To synchronize our work with field input, thermochemical experiments were conducted on various Mediterranean vegetation species to examine their VOC emission rates in normal and stressful environmental conditions as they may end up defining different flammability scenarios in wildfires. First, two Mediterranean shrub species: Cistus albidus and Rosmarinus officinalis are explored for their VOC emissions and physiological changes after being subjected to abiotic stresses (drought and heat), using pyrolysis-gas chromatography and mass spectrometry (Py-GC/MS) analyses. Two other Mediterranean forest species: Quercus suber L. and Cupressus sempervirens horizontalis L. were investigated for their distinctive flammability characteristics using thermo-gravimetric and differential thermal analyses (TG/DTA), coupled with Py-GC/MS analysis to identify the gases emitted during the exo-thermic peaks. This step aims to better understand the flammability descriptors of these species as a part of a more efficient forest management strategy by which, favoring the plantation of certain lesser flammable species in silviculture measures may protect other more flammable but economically valuable species, from the dangers of wildfires and their extreme behaviors. Mediterranean vegetation species are important VOC emitters especially when provoked by external stresses during wildfires however, some biogenic VOCs (BVOCs), more particularly sesquiterpenes, are still not thoroughly covered for their flammability characteristics, such as their lower and upper flammability limits, auto-ignition temperatures, flashpoints, etc. Such a scientific lack we found it necessary to enrich by studying the flammability limits of β-Caryophyllene, one of the most important sesquiterpenes emitted from Mediterranean vegetation. Preliminary tests for measuring the vapor pressures of β-Caryophyllene are conducted in preparation for experimenting its flammability limits in a spherical bomb as future plans. The work in this thesis should be considered as the first step in a more global approach that should provide operational firefighting staff, with a comprehensive decision-making tool capable of shaping their forest management strategies from wildfire characteristics themselves and protecting wildlands and firefighters equally from the dangers and extreme behaviors of wildfire flashovers
Chollet, Benjamin. "Étude du comportement au feu de matériaux polymères contenant des bio-nanoparticules fonctionnalisées." Thesis, IMT Mines Alès, 2018. http://www.theses.fr/2018EMAL0004/document.
Full textThe growing desire to reduce the ecological footprint of plastic materials promotes the development of polymers and additives from renewable resources in order to limit their environmental impact. Flame retardants represent an important family of additives that play a crucial role in many fields where fire hazard is encountered. Thus this study aims at developing new flame retardant systems from biomass compounds to improve the fire behavior of polylactide (PLA), a bio-based polymer. Lignin and cellulose were chosen as pristine compounds. These compounds have been transformed into nanoparticles with adapted processes. Then, they were functionalized with phosphorous moieties or mixed with ammonium polyphosphate, and incorporated into polylactide with in internal mixer. Thermal, flammability and fire properties of these compounds were evaluated. The results obtained with some systems are promising
Banner, Philippe. "Les effets des nouvelles générations d'armes à feu sur l'appareil auditif." Université Louis Pasteur (Strasbourg) (1971-2008), 1985. http://www.theses.fr/1985STR1M300.
Full textChen, Jie. "Etude des effets de gravité et de pression sur les flammes de diffusion turbulentes représentatives d'incendie." Poitiers, 1994. http://www.theses.fr/1994POIT2267.
Full textLaforge, Vincent. "Effets vulnérants des armes à feu réglementaires : sept siècles de balistique lésionnelle." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0117.
Full textHow can a few grams of lead expelled with a few grams of powder remotely take out the toughest boor? Why can the same projectile kill one and spare the other? Since the 15th century, these questions frighten the fighter, intrigue the surgeon and stir the scientific community.Crossing historic data, medicolegal reports and scientific experiments, this study tries to answer these centuries-long questions. The consulted sources are mostly based on surgical writing but also explore books dealing with weapons, ammunition, tactics, given all these factors interneve in this, something definitive, drama that is the tumultuous encounter between a projectile and the particular target that the human body is. The results are mixed and often contradictory, opposing those who think a projectile-induced wound is a common wound and those who consider the igniting mechanism has to be taken into account to study and treat its effects efficiently. This work shows, apart from these polemics, the great diversity of firearms wounding effects, no ballistic trauma being strictly comparable to another. This non-reproductible specificity, aside from scientific experiments, rules out any formal and definitive answer regarding the effects of firearms projectiles. Being shot with a bullet remains an individual adventure with unpredictable consequences
Yaméogo, Urbain Gnourègma. "Le feu, un outil d'ingénierie écologique au Ranch de Gibier de Nazinga au Burkina Faso." Orléans, 2005. http://www.theses.fr/2005ORLE2087.
Full textLoréal, Olivier. "Effets de la surcharge en fer sur la fibrogenese hepatique." Rennes 1, 1993. http://www.theses.fr/1993REN1B007.
Full textChatenet, Sarah. "An instrumented controlled-atmosphere cone calorimeter to characterize electrical cable behavior in depleted fires." Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R047.
Full textElectrical cable sheaths are the most abundant fire load in nuclear power plants and fire is the most frequent internal aggression (one fire outbreak per year and per nuclear unit in France). A fire is threatening by two means: the heat it releases that may drive a fire growth and the smoke it yields, composed of gases and aerosols, that may be toxic and corrosive and interact with components in the area. At advanced stages, confined fires become oxygen depleted and the combustion regime shifts towards under-ventilated and vitiated combustion with the production of unburnt species leading to a higher threat. To assess the potential hazard of a confined fire, it is then of high importance to quantify the heat release, the gases and the aerosols produced by electrical cable sheaths fires in oxygen depleted conditions. To do so, a bench scale apparatus known as the controlled-atmosphere cone calorimeter (CACC) has been developed. The apparatus has been primarily qualified with PMMA plaques. Representative materials of PVC based electrical cable sheath have been formulated and manufactured in the shape of plaque samples. These materials have been characterized in terms of fire parameters (heat release rate, mass loss rate), evolved gases and evolved aerosols under different oxygen concentrations in under-ventilated conditions thanks to the CACC/FTIR/ELPI coupling. Vitiation lowers the heat release rate and decreases the fuel mass loss rate while under-ventilation increases unburnt species and aerosols production
Chatenet, Sarah. "An instrumented controlled-atmosphere cone calorimeter to characterize electrical cable behavior in depleted fires." Electronic Thesis or Diss., Université de Lille (2018-2021), 2019. http://www.theses.fr/2019LILUR047.
Full textElectrical cable sheaths are the most abundant fire load in nuclear power plants and fire is the most frequent internal aggression (one fire outbreak per year and per nuclear unit in France). A fire is threatening by two means: the heat it releases that may drive a fire growth and the smoke it yields, composed of gases and aerosols, that may be toxic and corrosive and interact with components in the area. At advanced stages, confined fires become oxygen depleted and the combustion regime shifts towards under-ventilated and vitiated combustion with the production of unburnt species leading to a higher threat. To assess the potential hazard of a confined fire, it is then of high importance to quantify the heat release, the gases and the aerosols produced by electrical cable sheaths fires in oxygen depleted conditions. To do so, a bench scale apparatus known as the controlled-atmosphere cone calorimeter (CACC) has been developed. The apparatus has been primarily qualified with PMMA plaques. Representative materials of PVC based electrical cable sheath have been formulated and manufactured in the shape of plaque samples. These materials have been characterized in terms of fire parameters (heat release rate, mass loss rate), evolved gases and evolved aerosols under different oxygen concentrations in under-ventilated conditions thanks to the CACC/FTIR/ELPI coupling. Vitiation lowers the heat release rate and decreases the fuel mass loss rate while under-ventilation increases unburnt species and aerosols production
Blier-Langdeau, Ariane. "La réponse au feu des communautés végétales d'une tourbière ombrotrophe restaurée." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/35465.
Full textOmbrotrophic peatlands (bogs) are known to be Carbone sink partially because of their resistance and resilience to fire. In a global climatic change context with politics aiming toward a reduction of atmospheric Carbone emission, a quick restoration of every degrade peatlands is desirable. The Canadian horticultural industry developed a promising peatland restoration technique. More than 100 sites were restored in Canada and despite many success indicators, we still hope that restored peatlands are resistantandresilient to fire. Indeed, few studies assess an ecosystem response to a disturbance happening after restorationandnone evaluates the response to fire of restored peatlands. At the end of summer 2014, a fire occurred in a Southern Quebec bog, partially burning a ten years old restored sectoranda natural one nearby providing the first opportunity to study the response to fire of a restored peatland. This research is divided in two objectives: 1) determine if the peat accumulation potentialandplant cover are the same between the burnedandunburned parts of the restored sector one growing season after fireand2) compare the mosses strata recovery between the naturalandthe restored sectors. The phytobiomass production rate was similar between the burnedandunburned parts of the restored sectorandthe burned parts plant cover growths significantly during the first growing season after fire, even reaching a similar level as the unburned parts for some areas. Sphagnumhummocks of the restored sectors showed a better resistanceandrecovery than the one in the natural sector. Thus, this study shows a tendency to resilience to fire of restored ombrotrophic peatlands.
Giroud, Frédérique. "Contribution à la modélisation de la propagation des feux : approche multiphasique des feux de forêt. Développement d'un feu de propergol en milieu semi-confiné." Aix-Marseille 1, 1997. http://www.theses.fr/1997AIX11023.
Full textPascal, Nadine. "Quelques observations sur les effets d'une carence de fer sur la cellule végétale non chlorophyllienne." Grenoble 1, 1992. http://www.theses.fr/1992GRE10165.
Full textRichard, Jérôme Pascal Marie. "Interaction d'un brouillard d'eau avec un feu de nappe à l'échelle laboratoire : effets physicochimiques et influence sur le rayonnement." Poitiers, 2001. http://www.theses.fr/2001POIT2333.
Full textThe water mist is first characterized without flame : measurements of droplets diameters, droplets density and mass flow rate are performed. Then, the temperature field within the flame is established, without and then with water mist. Absorption fields and diffusion coefficients for two wavelengths are also determined in order to determine the relative contribution of absorption and diffusion processes. The knowledge of these experimental fields allows for the calculation of radiative flux towards the fuel surface with a Discrete Ordinates Method algorithm. Computed radiative flux values are compared with experimental values. Tomographic images of the mist-flame interaction flow are obtained. A PIV treatment of these images allows for the determination of droplets speed fields in order to get a better understanding of the dynamic interaction between the droplets and the flame. The study also shows that the introduction of steam within the flame has a chemical effect
Camillo, Anycée. "Etude multi-échelle du comportement au feu d'un siège et d'une paroi types issus d'un système de transport ferroviaire européen." Phd thesis, ISAE-ENSMA Ecole Nationale Supérieure de Mécanique et d'Aérotechique - Poitiers, 2013. http://tel.archives-ouvertes.fr/tel-00924616.
Full textLeslie, Michael Alan. "Effect of phytase and glucanase, alone or in combination, on nutritive value of corn and soybean meal fed to broilers." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Fall/Dissertations/LESLIE_MICHAEL_29.pdf.
Full textBertault, Jean-Guy. "Étude de l'effet du feu en foret semi-décidue de Cote d'Ivoire au sein d'un dispositif d'expérimentation sylvicole." Nancy 1, 1992. http://www.theses.fr/1992NAN10018.
Full textLe, Saux William. "Etude des feux de sodium en jet : modélisation par un code de calcul bidimensionnel (PULSAR 2.1)." Orléans, 1996. http://www.theses.fr/1996ORLE2076.
Full textLassus, Julie. "Risque d'inflammation de gaz imbrûlés au cours d'un incendie en milieu confiné-ventilé." Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aéronautique, 2009. http://www.theses.fr/2009ESMA0005.
Full textDuring an underventilated fire, oxygen concentration can become insufficient and a large quantity of unburnt gases can be produced. When these unburnt gases are removed through an extraction duct, a supply of fresh air from other ducts may produce a significant amount of a flammable mixture able to ignite. This ignition can occur with sufficient temperature level and species production. A series of experiments has been conducted in a room test with unburnt gas analysis in order to study the influence of several parameters on these criteria. Two main parameters appear: heat release rate and ventilation flow. Criteria on these factors are determined in order to predict conditions that lead to an ignition risk. Fire tests with a second fuel pan are also made to study the influence of thermal degradation of this second pan on ignition risk. A model for the estimation of this risk in the extraction duct is developed. It allows to obtain the flammability diagram of fuel mixture and to calculate produced species using oxygen concentration and temperature levels in extraction ducts
Bonnet, Véronique. "Analyse spatiale et fonctionnelle de la réponse des communautés végétales après incendie en Basse Provence calcaire." Aix-Marseille 3, 2001. http://www.theses.fr/2001AIX30065.
Full textOur study takes place within the context of fire cycle changes (frequency increase and size decrease), in lower calcareous Provence. The aim is to demonstrate and explain the changes occurring within post-fire vegetation at different organization levels and spatial and geographical contexts. The post-fire vegetation of four areas burned in 1997 has been studied using a diachronic method over 3 years. The goal is to determine vegetation patterns and structure, via a taxonomic or functional approach. Four additional areas burned in 1998 and 2000 were employed in order to study revegetation processes at local levels, with a particular interest in recolonization by seed rain and the seed bank. Our study has demonstrated a very high variability in floristic composition and structure during the first three years after a fire at the local level. This variability is due to certain fugitive taxa, which are mainly therophytic, ruderal and anemochoric species. In spite of these fugitive taxa, plant communities at the landscape level seem to be very stable. At the regional level, climatic, topographic and soil caracteristics seem to determine vegetation structure. This study confirms that plant communities in mediterranean regions are very stable in relation to fire, and in developing adaptations, such as vegetative sprouting. If mediterranean mattorals are, in these regions, a reference landscape, then fire could be considered as a simple parameter of plant community structure
Robert, Fabienne. "Comportement des bétons sous haute température et en cas d’incendie : caractérisation multi-échelle." Cachan, Ecole normale supérieure, 2008. http://www.theses.fr/2008DENS0046.
Full textThe full understanding of concrete structure behavior submitted to fire requires to study the phenomena at different scale, from micro scale to macro scale. The aim of this work is to understand the links between the phenomena observed at different scale. This study investigates the chemical phases’ transformation at high temperature thanks to different means of characterization of the microstructure (XRD, DSC, Environmental SEM …). It has been demonstrated that the increase in compressive strength at 200°C may be due to the formation of Katoite or Jaffeite. Moreover, the major part played by the stress state of the concrete elements on the spalling behaviour, between intermediate and full scale, has been put forward. The full scale tests have been done with Promethee Laboratory, new and innovative testing facility which allows to take into account the interactions during a fire between the tested element and the surrounding cold building. The tested element is as a result in a real mechanical and thermal stress state. This approach is based on a substructuring system. The hydraulic jacks forces will be time dependent and calculated taking into account both the deflected shape and the stiffness matrix of the cold surrounding building
Yue, Chao. "Fire simulation in the ORCHIDEE biosphere model : implications for global carbon fluxes." Versailles-St Quentin en Yvelines, 2014. http://www.theses.fr/2014VERS0016.
Full textAnthropogenic biomass burning and wildfires release greenhouse gases (CO2, CH4, N2O), reactive gases (CO, NOx) and aerosols into the atmosphere, and contribute to regional and global climate change. In forest regions affected by fires, fire also legate a sustained long-term carbon sink during the postfire vegetation recovery. It is thus important to incorporate fire processes into Earth system models, to be able to quantify the large-scale fire contribution to the terrestrial carbon balance, and predict future fire-climate-vegetation feedbacks. In this thesis, the prognostic fire module SPITFIRE has been incorporated into the process-based dynamic vegetation model ORCHIDEE. Evaluation studies show that the fire model is capable of capturing the essential climatic and anthropogenic drivers of burned area in the 20th century, but the frequency and size of very large fires are underestimated. Fires are found to reduce on average the terrestrial carbon sink compared with a simulation without fire, with larger fire-induced sink reduction occurring during drier and warmer years. Model factorial experiments indicate that fires during the last three decades, combined with rising CO2 and climate effects on the vegetation, have contributed to most of the pan-boreal (45oN–90oN) carbon sink at early 20th century. At the site level, the postfire forest carbon sink in North American boreal forests, as observed by chronosequences of biometric measurements and of eddy-covariance CO2 fluxes, are ascribed to a combination of forest regrowth from fire recovery and atmospheric CO2 increase, i. E. , the postfire carbon sink is amplified by the CO2 fertilization effect on forest growth
Allard-Duchene, Anne. "Changements temporels de l'abondance du lièvre d'Amérique et de l'écureuil roux le long de successions forestières après feu et après coupe." Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28894/28894.pdf.
Full textTonnabel, Jeanne. "Évolution des traits d'histoire de vie dans les milieux soumis au feu : approches théoriques et empiriques, le cas des Leucadendron dans le Fynbos sud-africain." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20165/document.
Full textIn fire-prone environments, plants have developed a huge diversity of life history strategies that aresupposed to be adapted to different environmental conditions such as several fire regimes. My PhDproject aimed at explaining the large diversity of life history strategies of perennial plants, focusingon how intrinsic and extrinsic factors have shaped the evolution of those traits. I particularly ask, ifsuch knowledge can be used to understand the impact of future environmental changes onbiological diversity ? And finally, how does this apply to conservation policies and the maintenanceof such diversity? Because contrasted fire regimes have been suggested as a major selective factorinfluencing plant traits in fire-prone environments, I especially investigated the effect of the fireregime in terms of distribution probabilities of fire intervals. A model of optimization of resourceallocation for a serotinous non-resprouting plant predict that whenever maximal plant survivalprobability is low, the optimal strategy consists in reducing resource allocation to seed maintenancein the canopy, while increasing resource allocation to annual seed production. The model alsopredict that a low level of serotiny should evolve when the predictability of fire arrival is low, that iswhen there is a large variance in fire intervals. In order to test those predictions, I used comparativeanalyses along the newly reconstructed phylogeny of the Leucadendron genus. A bioinformaticspipeline allowed designing new nuclear markers, maximizing both polymorphism and probability oforthology that can be further used to construct the Leucadendron phylogeny. This approachgenerated seven new markers of which three contained a polymorphic 3'-UTR region. Life historytrait are further estimated along branches of this new phylogeny to assess whether life history traitswere labile across the evolutionary history of the genus. This analysis show that all five studiedtraits emerged independently several times and in correlation with one another. The joint evolutionof fire-related traits and ecological niches are finally studied to test hypotheses partly inspired byour theoretical work. Comparative analyses that account for phylogenetic uncertainty, traitreconstruction uncertainty and environmental intra-specific variability show that serotinous speciesevolved ecological niches characterised by less extreme climatic events than species havingunderground seed banks. Similarly, non-resprouting species evolved niches including less extremeclimatic events than resprouting species
Féjean, Jérôme. "Développement de liants et de composites minéraux : application à la protection incendie." Rennes, INSA, 2003. http://www.theses.fr/2003ISAR0011.
Full textSpǎtǎcean, Corneliu Adrian. "Propriétés du bois et qualité des sciages dans les pessières noires de seconde venue issues de coupe et de feu." Master's thesis, Université Laval, 2008. http://hdl.handle.net/20.500.11794/19759.
Full textThe objectives of this project were to evaluate the effects of stand origin on lumber grade yield, MSR yield and bending properties and to describe the variability of wood mechanical and physical properties at different hierarchical levels in black spruce. The results indicate that a similar percentage of lumber pieces are graded as No.2 and better in logged stands, but this percentage is 20% lower than in burned stand. The MSR grades yield in logged stands is similar to that from natural stands but partial-cut origin stand has less lumber in superior MSR class due to lower bending properties. For all properties studied the between stands variance is much less important than within stand variance. Moreover, inter-tree variance component of MOE and MOR are lower than intra-tree variance. The stands that showed a more important DBH variance and asymmetrical competition present more important inter-tree variance in wood mechanical properties.
Nguyen, Ngoc Lien. "Étude et réalisation de J FET GaInAs/inP pour applications microoptoélectroniques." Paris 11, 1986. http://www.theses.fr/1986PA112374.
Full textGUELZIM, ABDERRAOUF. "Etude des effets de ventilation sur le rayonnement d'un feu et sur le mouvement des fumées induites par celui-ci dans une galerie." Poitiers, 1992. http://www.theses.fr/1992POIT2300.
Full textFavier, Véronique. "Étude de nouveaux matériaux composites obtenus à partir de latex filmogènes et de whiskers de cellulose : effets de percolation mécanique." Grenoble INPG, 1995. http://www.theses.fr/1995INPG0120.
Full textLussier, Jean-Martin. "Comparaison de la croissance de marcottes d'epinette noire adultes à celle d'individus issus de graines après feu /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1991. http://theses.uqac.ca.
Full textDurand, Hippolyte. "Fonctionnalisation de nanofibrilles de cellulose pour le développement de dispositifs médicaux biosourcés." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI021.
Full textIn line with the ever-increasing academic and industrial interest for wood derived nanocellulose, the present work investigated the chemical surface modification of cellulose nanofibrils (CNFs) for biomedical application. Drugs and pro-drugs of active principle ingredients (APIs) were covalently immobilized or adsorbed onto CNFs films or suspensions. For covalent immobilization, the first strategy selected calls for water-based and single step esterification of CNF films. The resulting materials demonstrated antibacterial activity against both gram-positive and gram-negative bacterial strains, with a prolonged contact-active effect. In the second strategy, CNFs suspensions were modified through a multistep reaction, involving amidation and click chemistry, still water-based. Highly innovative characterization tools, such as dynamic nuclear polarization (DNP) enhanced nuclear magnetic resonance (NMR), complemented well-established techniques to confirm the success of grafting. In parallel to covalent immobilization, an adsorption strategy was also adopted, on both CNFs films and suspensions. Then, the CNF films with grafted or adsorbed APIs were used for preparing 100% CNF medical devices for topical applications. Another component of this work used CNF suspensions with grafted or adsorbed APIs were embedded in collagen matrices to prepare model medical device of soft tissue repair implants. Antibacterial activity against both aerobic and anaerobic bacteria, together with controlled release properties were assessed confirming that such composites present the expected active properties, and can be used for the design of innovative medical devices.Key words: nanocellulose, cellulose nanofibrils, functionalization, medical devices, antibacterial activity, drug release
Filion, Jacques. "Distribution spatiale de la regénération d'épinette noire (Picea mariana (Mill.) BSP) 8 ans après un feu de forêt /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1994. http://theses.uqac.ca.
Full textDirckx, Olivier. "Éude du comportement photochimique de l'Abiès grandis sous irradiation solaire." Nancy 1, 1988. http://www.theses.fr/1988NAN10439.
Full textSolari, Maria-Eugenia. "L'homme et le bois en Patagonie et Terre de feu au cours des six derniers millénaires : recherches anthracologiques au Chili et en Argentine." Montpellier 2, 1993. http://www.theses.fr/1993MON20198.
Full textChenoufi, Norchen. "Étude des effets de la surcharge et de la déplétion en fer dans des cultures de cellule hépatique : toxicité, prolifération." Rennes 1, 1996. http://www.theses.fr/1996REN10202.
Full textPimont, François. "Modélisation physique de la propagation des feux de forêts : effets des caractéristiques physiques du combustible et de son hétérogénéité." Aix-Marseille 2, 2008. http://theses.univ-amu.fr.lama.univ-amu.fr/2008AIX22011.pdf.
Full textPhysical modelling of forest fire behaviour started about 10 years ago, with models solving Navier-Stokes equations, mass and energy balance for both the lower atmosphere and the fuel. The fuel is defined as a porous media, described through its physical characteristics and spatial structure. This work determines the spatial scale relevant for fuel description. It also entails to understand the effects of fuel heterogeneity on fire behaviour, as well as on radiative and convective transfers and the incident wind. These outputs improve the understanding of the effects of fuel structure on fuel-breaks, in order to improve their design. The fire behaviour model used and improved during this phd work is FIRETEC, developed at the Los Alamos National Laboratory (New Mexico, USA)
Jeffrey, Olivier. "Effets des coupes de récupération sur les successions naturelles de coléoptères saproxyliques le long d'une chronoséquence de 15 ans après feu en forêt boréale commerciale." Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/29941/29941.pdf.
Full textThis study aims to describe the natural state of communities of eight saproxylic beetle families known to be associated with burned forest from a sample done at stump level and in commercial black spruce (Picea mariana (Mill)) stands residual to salvage logging (natural state) from burns of 1995, 2003, 2005, 2007, 2009 and 2010. The study also aims to compare these communities to those found in salvaged black spruce stands distributed in burns of 1995, 2003, 2005 and 2007. Beetles were sampled during summer 2010 and over 6 000 specimens among the eight studied families were captured. In its natural state, four colonization phases have succeeded along the first five postfire years. Saproxylic beetle assemblages were affected by salvage logging for a period of seven years.
Jeffrey, Olivier, and Olivier Jeffrey. "Effets des coupes de récupération sur les successions naturelles de coléoptères saproxyliques le long d'une chronoséquence de 15 ans après feu en forêt boréale commerciale." Master's thesis, Université Laval, 2013. http://hdl.handle.net/20.500.11794/24631.
Full textCette étude vise à décrire l’état naturel des communautés de huit familles de coléoptères saproxyliques, reconnues pour être associées aux brûlis, à partir d’un échantillonnage fait au niveau des souches et à l’intérieur de peuplements commerciaux d’épinettes noires (Picea mariana (Mill)) résiduels à la coupe de récupération (état naturel) provenant de brûlis de 1995, 2003, 2005, 2007, 2009 et 2010. L’étude vise également à comparer ces communautés à celles retrouvées dans des peuplements d’épinettes noires récupérés et répartis dans les brûlis de 1995, 2003, 2005 et 2007. Les coléoptères ont été inventoriés durant l’été 2010 et plus de 6 000 spécimens répartis dans les huit familles étudiées ont été capturés. À l’état naturel, quatre phases de colonisation se sont succédées pendant les cinq premières années après feu. Les assemblages des communautés de coléoptères saproxyliques sont quant à eux altérés par la récupération et ce, pour une période d’au moins sept ans.
This study aims to describe the natural state of communities of eight saproxylic beetle families known to be associated with burned forest from a sample done at stump level and in commercial black spruce (Picea mariana (Mill)) stands residual to salvage logging (natural state) from burns of 1995, 2003, 2005, 2007, 2009 and 2010. The study also aims to compare these communities to those found in salvaged black spruce stands distributed in burns of 1995, 2003, 2005 and 2007. Beetles were sampled during summer 2010 and over 6 000 specimens among the eight studied families were captured. In its natural state, four colonization phases have succeeded along the first five postfire years. Saproxylic beetle assemblages were affected by salvage logging for a period of seven years.
This study aims to describe the natural state of communities of eight saproxylic beetle families known to be associated with burned forest from a sample done at stump level and in commercial black spruce (Picea mariana (Mill)) stands residual to salvage logging (natural state) from burns of 1995, 2003, 2005, 2007, 2009 and 2010. The study also aims to compare these communities to those found in salvaged black spruce stands distributed in burns of 1995, 2003, 2005 and 2007. Beetles were sampled during summer 2010 and over 6 000 specimens among the eight studied families were captured. In its natural state, four colonization phases have succeeded along the first five postfire years. Saproxylic beetle assemblages were affected by salvage logging for a period of seven years.
Salmon, Fabien. "Simulation aéro-thermo-mécanique des effets du feu sur les parois d'un milieu confiné : application à l'étude des thermo-altérations de la grotte Chauvet-Pont d'Arc." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0041/document.
Full textIn 1994, the discovery of the Chauvet-Pont d'Arc cave (Ardèche, France) revealed singularanthropogenic thermal marks on walls. They are the witnesses of high intensity prehistorical firescarried out deep in the cavity. The thermoluminescence evaluation of the heating ages is consistentwith the earlier period of human occupation between 37,000 and 33,500 years ago. The archaeologistsidentified two kinds of thermo-alterations : colour changes and spallings. The colour changes resultfrom high-temperature chemical reactions in limestone, turning rock red or grey. Ex situ tests showedthat red colour happens after heating at 250oC for ten minutes while at least 350oC is necessary forgrey. Spalling stems from high stresses in rock due to restrained thermal expansion and thermohydricprocesses. In addition, part of the walls near thermo-altérations is still covered with soot. From theseclues, this investigation aims to characterize the fires of the Megaloceros Gallery which is located inthe deep part of the cave. Estimating the amounts of wood, the fires number and the ability tosupply the hearths could help make assumptions about the function of these fires.For the sake of conservation, only simulation can reproduce fires in the cave geometry withoutrequiring any reconstruction. This study is to set up a numerical modelling of fires in confinedgeometries and the induced thermal impacts on walls. A fluid-structure coupling is then developedfrom two free open source codes : OpenFOAM and Cast3m. The former manages the simulation offire scenarios through the FireFOAM tool. The latter handles the thermo-mechanical calculations inthe rock mass. To extend the initial scope of FireFOAM, some numerical models have beenimplemented in the code. This relates to soot deposit, danger assessment, thermocouple correctionand a thermal boundary condition. In addition, some modelling requirements improving the qualityof the results are detailed in the manuscript. The advanced model is then validated on experimentalfires in a former limestone quarry which has dimensions close to the Megaloceros Gallery ones. Thesame fuel (pinus sylvestris) as the one identified in the cave is burnt. The combustion led to similarthermo-alterations as those observed in the Chauvet-Pont d'Arc cave. Spallings and colour changesoccurred on the ceiling and walls of the quarry. The comparison with simulation is carried out thanksto the measurement of temperatures, velocities, soot deposits, gases and particles concentrations.The numerical model is then applied to the simulation of fires in the Megaloceros Gallery geometry.All the impacted areas of this gallery are considered and the scenarios that may have occurred arespecified. This investigation then provides an overview of the fires locations and intensities in thispart of the cave. Moreover, the compatibility with living conditions is indicated for the most powerfulfires. These information could help for archaeologists in the understanding of the functions of these fires
Dias, de Moraes Poliana. "Influence de la température sur les assemblages bois." Nancy 1, 2003. http://www.theses.fr/2003NAN10157.
Full textThe more generalized use of wood for building raises concern for fire safety. The current standards require the structure stability for a minimum time to ensure the building evacuation and the fire fight. Considering that the fire endurance of wood is well-known, the stability requirement is mainly reduced to the understanding of the behaviour of wood joints on fire. The aim of this work is to study the behaviour of single-dowel timber joints and it is divided into three parts. The first part is a study of the influence of temperature on the modulus of elasticity and on the embedding strength in a range between 20 and 300 °C. In the second part the wood charring and the influence of a metallic dowel embedded in wood, is studied. In the third part, the fire behaviour of single-dowel wood joints is tackled. The first two studies have provided mechanical and thermal data to allow the development of a model to simulate the joint behaviour and its fire endurance before fracture
Schaffhauser, Alice. "Impacts de la récurrence des incendies sur la végétation, son inflammabilité et sa combustibilité. Application à la Provence cristalline (Massif des Maures, Var, France)." Aix-Marseille 3, 2009. http://www.theses.fr/2009AIX30008.
Full textA better understanding of the dynamic equilibrium between the vegetation and the fire recurrence is useful for Mediterranean ecosystems sustainability. The impacts of fire recurrence on vegetation, its flammability and fire behaviour, have been studied on a 50 years fire history on acidic soils in South-Eastern France (massif des Maures, Var department, France). A vegetation mosaics was described according to fire mosaics. Five classes of fire recurrence were defined, from zero to four fires with different time intervals. Time elapsed since last fire then the number of fires are the most important factors in observed modifications. Species and functional analyses confirm the resilience of most species which have been selected by a long fire history. However, some plant traits are negatively affected by fire recurrence, such as competitive strategy and zoochory. A resilience threshold can be estimated around three to four fires in 50 years. In high maquis, a very structurative species (Erica arborea L. ) dominates the stand and decreases light and space for the other species. Its cover and long life duration entail a decrease in the functional diversity, leading to a slackening in dynamics. Flammability experiments on non-disturbed litters show significant differences between the facies. The most flammable are the high maquis and medium maquis with a high biomass, characterized by very high values of combustibility and vertical propagation ability. Fire behaviour simulations indicate contrasts between low and open formations and high and dense formations. High maquis, medium maquis and cork-oak woodlands on maquis lead to high fire intensity and rate of spread. Fire recurrence mainly impacts on vegetation structure and subsequently fire behaviour. These data are useful to predict the relationships between fire and vegetation in a climatic and disturbance change context
Fantin, Natalie. "Croissance juvénile des arbres mères comparée à celle de jeunes semis d'épinette noire (Picea Mariana (Mill) B.S.P.) issus de graines après un feu sur un même site /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1999. http://theses.uqac.ca.
Full textKiss, Laurence. "Impact des incendies sur les communautés de gastéropodes terrestres en basse Provence calcaire." Aix-Marseille 3, 2002. http://www.theses.fr/2002AIX30084.
Full textFire is a major disturbance within Mediterranean ecosystems, but its consequences on land snail communities and their subsequent recolonisation patterns are little studied. The aims of the present study are: (1) to define the short-; middle- and long-term impact of fire on land snail communities, (2) to analyse the consequences of successive fires during a short period of time on malacofaunas, and (3) to reveal the patterns of post-fire recolonisation within these communities. Land snail communities are highly resilient. Although fire induces a drastic reduction of their abundance, species richness is little affected and all the ecological groups are represented within the first post-fire year. Malacofaunas do not show patterns of post-fire succession. In fact, recolonisation patterns are complex and depend on diffuse refuges, located within burned areas and which are due to varying fire severity, but also on the biogeography and history of the sampling sites
Chorao, Charlène. "Etude du métabolisme de Rhodococcus rhodochrous lors de la photobiodégradation du 2-aminobenzothiazole : effet de l'immobilisation des cellules et rôle du fer." Phd thesis, Clermont-Ferrand 2, 2008. http://www.theses.fr/2008CLF21880.
Full textHamdani, Devarennes Siska. "Etude fondamentale du comportement au feu de composites silicones : stabilité thermique, résidus sous pyrolyse et tests calorimétriques." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20023/document.
Full textThis PhD work has been devoted to the study of the thermal behavior of silicone composites. A preliminary review on the flame retardancy of silicone reported numerous works devoted to the development of thermally-resistant silicone composites or silicone polymers used as flame retardant agents in other organic polymer matrices. The first part of our experimental work highlighted the key role of macromolecular chain immobilization, through the synergy of platinum and silica, in generating high ceramized residue content after thermal gravimetry. The second part of this work was dedicated to the study of silicone composites filled with either calcium or aluminum-based fillers. The filler nature (non hydrated, water releasing or hydroxyl groups on the surface), the morphology and the particle size strongly influenced the thermal behavior of silicone composites. The analyses on composites residues after extreme pyrolysis showed that the formation of new crystalline structures and the absence of water release favored the residue ceramization. The investigation on fire reaction of silicone composites finally granted their outstanding properties to the matrix thermal stability and/or a barrier layer formation
Badalato, Nelly. "Structure de déchets lignocellulosiques : effets sur la colonisation, les communautés microbienne et les performances de méthanisation, caractérisés par des approches fonctionnelles et haut-débit." Electronic Thesis or Diss., Paris, AgroParisTech, 2014. http://www.theses.fr/2014AGPT0002.
Full textLignocellulosic materials have a high energy potential and are abundant, especially in municipal solid waste and their methanization is a promising waste-to-energy bioprocess. However, owing to their highly complex and heterogeneous structure, they are recalcitrant to anaerobic conditions and the use of pre-treatments is usually required to improve their biodegradation yields. Besides, lignocellulose colonization by cellulolytic microorganisms is a key step for an efficient biodegradation. In this context, the PhD work aimed to better understand the factors affecting waste colonization, to establish the link between lignocellulosic waste colonization and its biodegradation efficiency and to characterize more precisely the mechanisms and interactions within the biomass. A transversal approach was developed, combining cultures of model pure strains and lab-scale methanization microcosms with a complex biomass. Integrated approaches were applied to these studies, combining high-throughput analyses (metagenomics/(meta) proteomics), physico-chemical monitoring of bioconversion and finally physico-chemical characterization of substrates. The main results highlight the important role of lignocellulosic materials chemical and micro-and macro -structural features for their recalcitrance, their biodegradation efficiency and the response of the microbial compartment. The first global quantitative proteomic study on the cellulolytic model Clostridium cellulolyticum was conducted. Results showed an increased biodegradation rate of the facial tissue compared to cotton. This enhanced biodegradation was associated to a particular metabolic profile, a faster and more extensive colonization and finally a quantitative modulation of the cellulasic system. On the other hand, study of lignocellulosic waste methanization confirmed the good agreement between this more realistic system and the above-described model system. It also provided new information about the effects of substrate on microbial community structure. Noticeably, Bacteroidia members predominated in the presence of tissue and a high proportion of Spirochaetes members was observed in the presence of cotton. Finally, study of the effects of wheat straw and cardboard dry grinding revealed the limitations of these pretreatments on biodegradation efficiency. Main key points were a moderate positive effect of wheat straw fine grinding, and the sensitivity of the microbial communities to substrate surface characteristics, as evidenced by the emergence of different microbial communities according to the applied mechanical pretreatment. In conclusion, this work brings new perspectives to the study of lignocellulosic waste recalcitrance by addressing both the structural, functional and ecological aspects. These results contribute to the core fundamental knowledge on bioprocesses. They confirm that the lignocellulosic materials are specific among non-hazardous waste and require the implementation of adapted specific processes
Pham, Duc Toan. "Analyse par le calcul à la rupture de la stabilité au feu des panneaux en béton armé de grandes dimensions." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1073/document.
Full textIn this contribution, an original and comprehensive method aimed at designing vertical concrete walls submitted to fire loadings, is proposed and developed, with a special emphasis on high rise panels used in industrial buildings. Indeed, when subjected to high thermal gradients, such slender structures exhibit quite significant out-of-plane movements, resulting in an eccentricity of the gravity loads and thus to bending moments in addition to the pre-existing compressive forces. It is such a change of geometry, which is all the more pronounced as the panel is tall, combined with a temperature-induced degradation of the constituent materials strength properties, which may explain why an overall collapse of the structure may occur, well prior to buckling instability. The proposed approach is fundamentally based on the theory of yield design. This theory is first applied to the determination of an interaction diagram, characterizing the fire resistance of a reinforced concrete panel cross-section. It is then implemented as a design method for analysing the stability of the panel in its previously calculated deformed configuration. The whole procedure is explained in full details in the simplified situation when the high rise panel can be modeled as a one-dimensional beam, leading to the exact determination of a dimensionless factor characterizing the stability of the panel. The method is then extended to deal with a more realistic, but somewhat more complex, configuration of a rectangular panel. Some preliminary results, which need to be further validated in a subsequent work, are finally produced. As a necessary complement to the mostly theoretical and computational approach presented in this work, a series of four-point bending tests has been performed on reduced scale slabs placed in a furnace. The results of these tests partially validate the predicted interaction diagram of a fire loaded panel section
Do, Thi Hong Tuoi. "Effet de l'éthanol sur la prolifération et la différenciation cellulaires dans la lignée de l'hépatome humain HepaRG : interrelations avec les métabolismes du fer et les polyamines." Rennes 1, 2010. http://www.theses.fr/2010REN1B143.
Full textIn the human hepatoma hepaRG cell line, we analyzed ethanol effect on cell proliferation and differentiation in relation with iron and polyamines metabolism. Ethanol induced a decrease in cell proliferation wich was associated to necrosis/apoptosis. An effect on cell differentiation was also observed : hepatocyte nucleus area increase, decrease of HC/BC ratio percentages, overexpression of hepatocyte specific markers. The mechanisms of ethanol effect are related to its metabolism, lipid peroxydation and disorders in iron and polyamine metabolisms. Ethanol effect on cell proliferation/differentiation was enhanced by the presence of exogenous iron or an inhibitor of ODC. Iron chelators protect against the toxic effect of ethanol and a reversion of its antiproliferative effects was observed in the presence of exogenous putrescine. The dysfunction in iron and polyamines metabolisms may be one of the underlying mechanisms of ethanol effect
Laplanche, Karine. "Etude du comportement au feu des assemblages de structures bois : approche expérimentale et modélisation." Phd thesis, Clermont-Ferrand 2, 2006. https://theses.hal.science/docs/00/69/39/99/PDF/2006CLF21665.pdf.
Full textLaplanche, Karine. "Etude du comportement au feu des assemblages de structures bois : approche expérimentale et modélisation." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2006. http://tel.archives-ouvertes.fr/tel-00693999.
Full textDesanghere, Sylvain. "Détermination des conditions d'échauffement de structure extérieure à un bâtiment en situation d'incendie." Phd thesis, Rouen, INSA, 2006. http://www.theses.fr/2006ISAM0010.
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