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Draycott, Samuel Thomas. "On the re-creation of site-specific directional wave conditions." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/31472.
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Wave tank tests facilitate the understanding of how complex sea conditions influence the dynamics of man-made structures. If a potential deployment location is known, site data can be used to improve the relevance and realism of the test conditions, thus helping de-risk device development. Generally this data is difficult to obtain and even if available is used simplistically due to established practices and limitations of test facilities. In this work four years of buoy data from the European Marine Energy Centre is characterised and simulated at the FloWave Ocean Energy Research Facility; a circular combined wave-current test tank. Particular emphasis is placed on the characterisation and validation processes, aiming to preserve spectral and directional complexity of the site, whilst proving that the defined representative conditions can be effectively created. When creating representative site-specific sea states, particular focus is given to the application of clustering algorithms, which enable the entire spectral (frequency or directional) form to be considered in the characterisation process. This enables the true complex nature of the site to be considered in the data reduction process. Prior to generating and measuring the resulting sea states, issues with scaling are explored, the facility itself is characterised, and emphasis is placed on developing measurement strategies for the validation of directional spectra. Wave gauge arrays are designed and used to characterise various elements of the FloWave tank, including reflections, spatio-temporal variability and wave shape. A new method for directional spectrum reconstruction (SPAIR) is also developed, enabling more effective measurement and validation of the resulting directional sea states. Through comparison with other characterisation methods, inherent method-induced trade-offs are understood, and it is found that there is no absolute favourable approach, necessitating an application specific procedure. Despite this, a useful set of 'generic' sea states are created for the simulation of both production and extreme conditions. For sea state measurement, the SPAIR method is proven to be significantly more effective than current approaches, reducing errors and introducing additional capability. This method is used in combination with a directional wave gauge array to effectively measure, correct, and validate the resulting directional wave conditions. It is also demonstrated that site-specific wave-current scenarios can be effectively re-created, thus demonstrating that truly complex ocean conditions can be simulated at FloWave. This ability, along with the considered characterisation approach used, means that representative site-specific sea states can be simulated with confidence, increasing the realism of the test environment and helping de-risk device development.
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wang, menglin. "Building Information Modeling (BIM): Site-Building Interoperability Methods." Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-theses/1026.
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"Nowadays, many companies in the Architecture/Engineering/Construction (AEC) industry are using Building Information Modeling (BIM) in achieving a faster, sustainable and more economic project. Among the new developed concepts and BIM applications, two of the concepts most frequently used with the support of BIM technology in the planning, organization and scheduling of projects are 4D and 5D in which a 3D model is tied to its time execution (4D) at any point in time and its corresponding cost (5D). However, most of these applications concentrate on modeling the building but it does not include a corresponding modeling of the site in which the building is located. To date, there are few studies and systematic implementation of the site and the building integrated into one BIM model. This site-building integrated model can also be conceptualized as ¡°6D BIM¡± model. The benefit of integrating the site and building together into one model is that the building is no longer treated in isolation of its surround site but incorporates extremely helpful short-term and long-term information for the owner, designer, and builder regarding site topography, landscaping, access roads, ground conditions and the location of site utilities. Major existing research and technology issues that are preventing this site-building integration deal with functionality and interoperability of the BIM software, different orientation and coordination of building model and site model. The objectives of this thesis are to explore current organizational and technological issues preventing this integration, to investigate a feasible method to create a site-linked BIM model, and to discuss the benefits and limitations of bringing BIM concept to the site conditions. The research has been conducted by an extensive review on the literature related to the topic of interest published primarily by AEC. A review on current applications of Geographic Information Systems (GIS) has also been included because of the wider context provided by this technology to the specific topic of this research. Related BIM software developed by three different vendors ¡ªhas been discussed and compared to determine the level of feasibility and operational features of technological support necessary to implement the site-linked BIM model. A case study based on the design and construction of the WPI Recreational & Sports Center, currently under construction, was developed to explore and understand the details that are involved in creating a new site model and to link it with the existing 3D building model. What has been learned from the analysis of this case study is presented, discussed and analyzed in terms of benefits and limitations. Recommendations for future extensions from both the research aspect and the technology support aspect finally presented. These include the creation of 3D BIM Campus Map, which is one site model with several building models placed on it to facilitate future planning of new building and/or maintenance and operation of the current buildings and campus infrastructure. "
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Ashton, Philip. "A system designed to improve site investigation procedures and for the reduction of risk associated with uncertain site conditions." Thesis, University of Brighton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271975.
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Solomons, Wesley John. "Investigating the impact of site activities and conditions on concrete quality of in-situ and precast construction methods." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95942.
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Thesis (MEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Construction of structural concrete frames may take place by using either cast in-situ or precast methods. With the cast in-situ method, these elements are constructed on the construction site as needed. Precast construction on the other hand is more resembles a line. The elements are constructed in a precast yard in a systematic fashion and once completed, they are taken to the construction site where they are to be erected. This study identifies the aspects and attributes which influence the quality of concrete during the construction phase of these two construction methods. The study is independent from the conceptual or design phase. Information regarding these aspects and attributes were obtained from literature and from contractors in industry through interviews and site visits. The literature review also focuses on quality management techniques and factors that influence quality in the construction environment. The information obtained from the site visits and literature was used to design a survey which was sent out to a number of respondents. A comparison between in-situ and precast construction was made based on the results of the survey. The synthesis of the research findings can be used by project teams to help them decide on the choice between in-situ and precast construction. It was found that precast construction is better for durability, and fitness for purpose is less complex for the in-situ solution. Recommendations for future studies are provided at the end of the document.
AFRIKAANSE OPSOMMING: Konstruksie van beton struktuurrame kan plaasvind deur die gebruik van in-situ of voorafvervaardigde metodes. Met die in-situ metode, word hierdie elemente op die terrein gebou soos benodig. Tydens voorafvervaardigde konstruksie aan die ander kant is die konstruksie soortgelyk aan 'n produksielyn. Die elemente word gegiet in 'n voorafvervaardingsterrein in 'n sistematiese wyse, en sodra dit voltooi is, word dit na die konstruksie terrein geneem waar dit opgerig word. Hierdie studie identifiseer die aspekte en eienskappe wat 'n invloed op die kwaliteit van beton het tydens die konstruksiefase van hierdie twee konstruksie metodes. Die studie is onafhanklike van die konseptuele of ontwerp fases. Inligting rakende hierdie aspekte en eienskappe is verkry uit die literatuur en van kontrakteurs in die bedryf deur middel van onderhoude en besoeke. Die literatuur fokus ook op die gehalte, bestuurs-tegnieke en faktore van gehalte in die bou-omgewing. Die inligting is verkry deur ‘n vraelys wat aan 'n aantal respondente gestuur is. 'n Vergelyking tussen in-situ en voorafvervaardigde konstruksie is vervolgens gemaak op grond van die resultate van die opname. Die sintese van die bevindinge kan gebruik word deur projek spanne om hulle te help besluit oor die keuse tussen in-situ en voorafvervaardigde konstruksie. Die resultate dui daarop dat voorafvervaardigde konstruksie beter is vir duursaamheid, maar passing op terrein is minder kompleks vir die in-situ oplossing. Aanbevelings vir toekomstige ondersoeke word aan die einde van die studie gemaak.
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Yeoh, Kiang-Meng. "The significance of site conditions on adhesion strength of concrete patch repairs." Thesis, Queen's University Belfast, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296799.
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Du, Preez Anthony Adrian. "A site-based study of durability indexes for concrete in marine conditions." Master's thesis, University of Cape Town, 2002. http://hdl.handle.net/11427/5060.
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Includes bibliographical references.This dissertation comprises a site-based investigation into the ease at which durable concrete can be produced, using three extenders and four site-curing methods over four seasons in the Port of East London (Eastern Cape). GGBS, FA and CSF were selected as extenders as it is well established that these extenders enhance the durability properties of concrete, relative to plain unblended concretes. The test elements modelled two structural elements in the Port viz. a reinforced concrete retaining wall and mass concrete paving slabs. This was to facilitate possible future correlation or further study. For closer correlation, test elements were cast in close proximity of the actual retaining wall and likewise for the slabs.
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He, Yongtian. "Chromate reduction and immobilization under high pH and high ionic strength conditions." Columbus, OH : Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1047476794.
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Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains xix, 219 p.: ill. (some col.). Includes abstract and vita. Advisor: Samuel J. Traina, Environmental Science Graduate Program. Includes bibliographical references (p. 201-219).
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Ndingaye, Xoliswa Zandile. "An evaluation of the effects of poverty in Khayelitsha: a case study of site C." Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&.
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The study seeked to investigate an evaluation of the effects of poverty in Khayelitsha Site C. Poverty in this area has manifested in the conditions people live under and the social effects of such conditions in the life of Site C residents was assessed in terms of/or in relation to the following: levels of infant mortalitylevel of malnutrition
rate of school drop out due to lack of food and other resources
high level of alcohol abuse
lack of basic services and the shortage of toilets etc.
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Costanza, Jed. "Degradation of tetrachloroethylene and trichloroethylene under thermal remediation conditions." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08262005-021152/.
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Thesis (Ph. D.)--Civil & Environmental Engineering, Georgia Institute of Technology, 2006.Pennell, Kurt, Committee Chair ; Lawrence Bottomley, Committee Member ; James Mulholland, Committee Member ; Carolyn Ruppel, Committee Member ; D. Webster, Committee Member. Includes bibliographical references.
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Wang, Yin-Han. "Taiwanese girls' self-portraiture on a social networking site." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/578/.
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An increasing number of young girls produce contents in social media on a everyday basis for the opportunities to express, explore and connect. Public misunderstanding and concern are about whether girls are being narcissistic and vain. Academic works address how girls exercise agency while negotiating structure in the construction of their gendered adolescent identities. This thesis is situated in relation to our hopes and fears about girls’ self-representation through digital media production, and examines the role that photographic self-portraiture plays in girls’ social relations, personal and gender identity work. The theoretical framework combines the perspectives of gender performativity and symbolic interactionism, supplemented by analyses of personal photography. This thesis chose as its case study the popular Taiwanese social networking site Wretch, and employed a mixed method of quantitative content analysis of 2000 self-portraits of teenagers to understand how they represent themselves, and qualitative online interviews with 42 girls aged 13-20 to learn about their relationships with self-portraiture. The content analysis shows that most teenagers represent themselves in a gender stereotypical manner, while some adopt non gender-specific styles to represent themselves as friendly, suggesting that teenagers may use ideals about femininity, masculinity and sociality as shortcuts to present themselves in a positive light. Interview findings reveal how girls use camera technologies and the affordance of SNS for visual self-disclosure, which isimportant for the development of theirinterpersonal relationships. The findings also suggest that self-portraiture is not simply an act of photographing a ‘reality’ of the self, but of formulating self-image(s) and identity in the process of making self-portraits. In self-portraiture, girls are constantly confronted with the ‘who am I’ question, and construct and revise their biographies as they manage an array of audiences from different contexts all collapsing in one space. Furthermore, selfportraiture creates a distance between the ‘I’ and the ‘me’, allowing one to ‘play’ with self-image(s) and identity. It creates a space for the negotiation of ideals and anxieties, for experiments with different subject positions that may be socially or individually rewarding, and it is through these seemingly casual endeavoursthat one gradually works out their position in the social world. The thesis contributes to the scholarship on girls’ media culture, and suggests current theoretical perspective be expanded in order to better understand different ways of ‘doing girlhood’.
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Whang, Jooho. "Migration of radioactive wastes from shallow land burial site under saturated and unsaturated conditions." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/16925.
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Yuan, Yu. "Performance of FRP-masonry joints under on-site conditions: influence of water and salts." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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Nowadays, masonry is still commonly found in building structures, but low bearing capacity and poor seismic resistance make it necessary to strengthen masonry buildings. Externally bonded fiber-reinforced polymer (FRP) composites have emerged as a valid technique since the past decades.
The aim of this study is to investigate the bond behavior of SRP-masonry joints considering the effects of water and salt. An experimental campaign was designed: SRP composite was applied to masonry blocks, which were previously subjected to an accelerated weathering protocol. Other SRP-masonry joints were suffered to moist condition, as well certain specimens were prepared as references. i) Direct shear tests were conducted to determine the bond behavior, while digital image correlation (DIC) is employed to obtain detailed displacement and strain information. ii) Pull-off tests were carried out to further investigate the local bond. iii) To give deeper understanding on what the part substrate properties played in debonding, supplementary tests were performed, including three-point bending flexural tests and Brazilian splitting tests. iv) In addition, ion chromatography provided the salts amount and distribution of salt-laden specimens, contributing to interpret the results from shear tests.
Furthermore, the theoretical bond strength prediction method suggested by the Italian Guidelines CNR DT 200/R1/2013 was calibrated by collected previous and current studies specifically for SRP composite, and then compared with the experimental results from this study, providing more consolidated knowledge on the bond strength between SRP and masonry blocks, and on the other hand validating the results gained in the shear tests conducted in this study.
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Smith, Jason Richard. "Seral stage, site conditions, and the vulnerability of understory plant communities to forest harvesting /." Burnaby B.C. : Simon Fraser University, 2005. http://ir.lib.sfu.ca/handle/1892/2024.
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Research Project (M.R.M.) - Simon Fraser University, 2005.Theses (School of Resource and Environmental Management) / Simon Fraser University. Research Project (School of Resource and Environmental Management) / Simon Fraser University.
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Teahan, James E. "An investigation of the legal criteria governing differing site conditions disputes on construction contracts." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/26022.
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Boyer, Mekelle McRae. "Spatial analysis of environmental conditions conducive to termite infestation for a half hectare site." [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1000108.
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Thesis (M.S.)--University of Florida, 2002.Title from title page of source document. Document formatted into pages; contains x, 71 p.; also contains graphics. Includes vita. Includes bibliographical references.
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Schulz, Matthias C., Jan Kowald, Sven Estenfelder, Roland Jung, Eberhard Kuhlisch, Uwe Eckelt, Ronald Mai, Lorenz C. Hofbauer, Christian Stroszczynski, and Bernd Stadlinger. "Site-Specific Variations in Bone Mineral Density under Systemic Conditions Inducing Osteoporosis in Minipigs." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-230646.
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Osteoporosis is a systemic bone disease with an increasing prevalence in the elderly population. There is conflicting opinion about whether osteoporosis affects the alveolar bone of the jaws and whether it poses a risk to the osseointegration of dental implants. The aim of the present study was to evaluate the effects of systemic glucocorticoid administration on the jaw bone density of minipigs. Thirty-seven adult female minipigs were randomly divided into two groups. Quantitative computed tomography (QCT) was used to assess bone mineral density BMD of the lumbar spine as well as the mandible and maxilla, and blood was drawn. One group of minipigs initially received 1.0 mg prednisolone per kg body weight daily for 2 months. The dose was tapered to 0.5 mg per kg body weight per day thereafter. The animals in the other group served as controls and received placebo. QCT and blood analysis were repeated after 6 and 9 months. BMD was compared between the two groups by measuring Hounsfield units, and serum levels of several bone metabolic markers were also assessed. A decrease in BMD was observed in the jaws from baseline to 9 months. This was more pronounced in the prednisolone group. Statistically significant differences were reached for the mandible (p < 0.001) and the maxilla (p < 0.001). The administration of glucocorticoids reduced the BMD in the jaws of minipigs. The described model shows promise in the evaluation of osseointegration of dental implants in bone that is compromised by osteoporosis.
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Rey, Agnés. "Creating a web site under project management conditions example of the web site of the "Freunde der Hebräischen Universität Jerusalem in Baden-Württemberg e.V." /." [S.l. : s.n.], 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11675467.
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Lynch, Erin S. "Feng Shui as a site design tool: Assessing conditions of human comfort in urban places." Thesis, The University of Arizona, 2003. http://hdl.handle.net/10150/292072.
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Feng Shui as a site design tool seeks a different spectrum of criteria in the observation and assessment of a site than that of contemporary site design. It is a method based on the understanding and observation of the energetic conditions within and surrounding a site. Energetic conditions are perceptible. It requires an additional level of awareness to be able to identify what it is that causes a space to feel the way it does. Feng Shui may provide the additional level of consideration that when incorporated in the design process, facilitates spaces that may more effectively fulfill their purpose and feel good to the people using them. This study assessed a variety of existing urban places in Tucson, Phoenix, Scottsdale, Tempe, and Sedona, AZ. for conditions of human comfort based on (1) Feng Shui principles, and (2) contemporary site design recommendations. Current research on the topic of Feng Shui is limited to its application in land planning. This qualitative study applied the principles of Feng Shui as criteria in the evaluation of urban spaces. Results of the study indicate that well designed places from a Feng Shui standpoint were also perceived as well designed from a contemporary site design vantage. The outcome suggests the value of incorporating Feng Shui as a tool in the site design process used by Western designers.
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Mahfouz, Tarek Said. "Construction legal support for differing site conditions (DSC) through statistical modeling and machine learning (ML)." [Ames, Iowa : Iowa State University], 2009.
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Langanke, Kristen L. "Response to Nitrogen and Salinity conditions in Rhizophora mangle Seedlings Varies by Site of Origin." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7048.
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Many coastal plant species thrive across a range of environmental conditions, often displaying dramatic phenotypic variation in response to environmental variation. We characterized the response of the critical foundation species Rhizophora mangle L. to full factorial combinations of salt and nitrogen (N). We used seedlings collected from five populations and measured traits related to salt tolerance and N amendment. The response to increasing salt included significant plasticity in succulence, leaf mass area (LMA), and root to shoot ratio (R:S). Seedlings also showed overall reduced maximum photosynthetic rate in response to N amendment, but this response depended on the level of salt and varied by site of origin of the seedlings. Seedlings from different sites also differed in height growth, LMA, R:S, and total dry biomass. Generally, survival was lower in high salt and high N, but the impact varied among sites. Overall, this study revealed significant trait plasticity in response to salt and N level, and differentiation of responses of seedlings among different sites. Seedling survival depended on maternal family for 3 of 5 sites showing variation within and among sites. Variation in trait plasticity and seedling survival in R. mangle may be important for future adaptation to a complex mosaic of environmental conditions.
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Schroder, Jason C. "Measurements of black carbon properties during cloud, biomass burning, and free tropospheric conditions at a marine boundary layer site and high elevation mountain site." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/51642.
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Black carbon is a subset of the total atmospheric aerosol population that is formed in the incomplete combustion of fossil fuels, biofuels, and biomass. This research focused on the properties of black carbon particles measured in the boundary layer and free troposphere, as well as the activation of black carbon particles by cloud droplets. The primary motivation for this research is to increase our understanding of the properties of black carbon under these different atmospheric conditions.
A single particle soot photometer was used to study properties of black carbon particles incorporated into cloud droplets at two field locations: 1) a marine boundary layer site, and 2) a high elevation mountain site. At both sites, a size dependence on the fraction of black carbon incorporated into cloud droplets was observed; and for small (<100 nm) diameters, black carbon was efficiently incorporated into droplets. In addition, at the marine boundary layer site, thick coatings were observed on the small diameter black carbon particles that were incorporated into the droplets, which was consistent with theory.
The single particle soot photometer was also used at a high elevation mountain site to investigate properties of black carbon from biomass burning and black carbon within the free troposphere. The average mass concentration of black carbon was found to be significantly higher (approximately 9x) during periods of biomass burning than within the free troposphere, yet had similar mass median diameters. Coating thicknesses of black carbon containing particles during the two subsets of data were also investigated. Average coating thicknesses for black carbon core diameters between 140 to 160 nm was 55 nm when sampling in the free troposphere, but approximately 32 nm when sampling air masses influenced by biomass burning.
The results presented in this dissertation increase our understanding of the properties of black carbon particles and how they vary as a function of location and type of air mass sampled. This information can be used to further constrain computer models that are used to predict how black carbon can affect climate.Science, Faculty of
Chemistry, Department of
Graduate
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Adjerid, Smaïl. "Contribution à l'identification des conditions optimales de sollicitation des revêtements phosphatés-lubrifiés." Valenciennes, 1995. https://ged.uphf.fr/nuxeo/site/esupversions/169e5879-2295-41fe-ad0e-9f45341fb297.
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Les revêtements de phosphate sont encore largement utilisés dans diverses applications du secteur de la mécanique. Cependant, concernant la lubrification et notamment, le domaine de la mise en forme à froid, ces revêtements peuvent présenter des caractéristiques physico-chimiques souvent aléatoires et pas toujours fiables. En effet, les performances tribologiques des couches phosphatées dépendent d'un très grand nombre de paramètres liés à l'élaboration du revêtement lui-même ou encore à ses conditions de sollicitation. L’étude réalisée a consisté à évaluer l'incidence de certains paramètres de traitement concernant la phosphatation au zinc et la phosphatation au manganèse à partir d'un test de grippage spécifiquement dédié. Les conditions de sollicitation telles la température et la vitesse de glissement ont également été étudiées, de même que les conditions de stockage après traitement. Il a été montre que la composition chimique et la structure métallurgique du substrat avaient une incidence notable sur la résistance au grippage des revêtements de phosphate, les structures hétérogènes présentant les performances optimales. Dans ce cas, l'attaque par l'acide phosphorique est plus facile et les sites de nucléation de cristaux de phosphate plus nombreux. L’usure affectant le frotteur en régime de lubrification mixte à l'approche du grippage a été caractérisée sur trois alliages revêtus ou non de nitrure de titane. Enfin, des études de cas ont permis de valider industriellement les possibilités de l'essai de grippage.
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Schiavon, Laurent. "Conditions de monotonie de la courbure pour les courbes et splines d'interpolation." Valenciennes, 2002. https://ged.uphf.fr/nuxeo/site/esupversions/ebd449f2-087e-4588-b4a1-bedcc9b86660.
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Pour une courbe, la courbure est une grandeur géométrique déterminante pour sa forme. Dans de nombreuses applications de la CAO (automobile, aéronautique), les courbes que l'on cherche à modéliser doivent être à courbure monotone, dans le but d'obtenir des formes aérodynamiques et esthétiques. Dans ce travail, nous apportons des solutions via les courbes polynomiales cubiques et rationnelles quadratiques (arcs coniques) quisont controlées par un ensemble de points (et de masses dans le cas rationnel)For a curve, the curvature is a deciding geometric feature for its shape. For some applications of CAD (automotive, aeronautics), it is important to maintain monotone curvature along the curve we aim to modelize in order to obtain aerodynamic and aesthetic shapes. In this work, solutions are given via the cubic polynomial curves and the quadratic rational curves (conic segments) which are controlled by a set of points (and weights in the rational case)
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Düthorn, Elisabeth [Verfasser]. "Influence of micro-site conditions and environmental gradients on tree-ring based climate reconstructions / Elisabeth Düthorn." Mainz : Universitätsbibliothek Mainz, 2015. http://d-nb.info/1079935584/34.
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Murphy, Stephen Thomas. "Modelling growth of volume sample and stem analysis trees with reference to site conditions in Wales." Thesis, Bangor University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494310.
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Concerns over sustainability and a move towards systems of forest management other than clearfelling have fuelled the search for flexible growth models that can be used in a wide variety of situations with wide generalisation. The Tyfiant Coed project was established to develop a distance dependent individual tree model based on earlier stand level approaches. The model is parameter parsimonious and the parameters are interpretable.
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Merrett, Greg Lee. "Groundwater redox conditions at a petroleum contaminated site, Kuils River, South Africa : pathways for BTEX biodegradation." Master's thesis, University of Cape Town, 2003. http://hdl.handle.net/11427/8588.
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Includes bibliographical references (leaves 84-88).A shallow sandy aquifer, contaminated by petrol from an underground storage tank, was studied to determine if intrinsic bioremediation of the hydrocarbons is taking place. Groundwater samples taken from 32 monitoring wells were analysed for NO₃-,NH₄+, Mn²+, Fe²+, SO₄²-, and ΣH₂S. Portable electrodes were used to make field measurements of electrical conductivity, redox potential, and pH. The variation and distribution of these redox-sensitive groundwater constituents show that bioremediation via NO₃- reduction, Fe³+ reduction, and SO₄²- reduction (and possibly methanogenesis in the most reduced part of the plume) is occurring. In some cases redox processes are taking place simultaneously resulting in redox zones that overlap. Iron and sulphate reduction are the dominant processes taking place.
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Ansari, Abderrahim. "Les conditions du développement régional et les transformations d'un site industriel : le cas des industries Couture Limitée /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1989. http://theses.uqac.ca.
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Lazzarotto, Ludovic. "Maîtrise des conditions de contact et de frottement en mise en forme par frappe à froid." Valenciennes, 1998. https://ged.uphf.fr/nuxeo/site/esupversions/2ab4c8fe-845a-4693-b6d7-338a45c4c812.
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Le comportement mécanique en surface des aciers phosphatés savonnés est étudié par le test de dureté Brinell. Une configuration de référence de l'essai est préconisée pour analyser l'influence du vieillissement des bains de traitement de surface et du temps de phosphatation. Les résultats servent de base à l'identification des lois de comportement rhéologiques au voisinage de la surface de l'acier revêtu. La procédure d'identification consiste à minimiser les écarts entre les pénétrations numériques et expérimentales. Cet apport permet de préciser les conditions de contact à l'interface pièce-outil. Ensuite, une méthodologie d'analyse des conditions de frottement caractéristiques des procédés de mise en forme est définie. Elle fait appel au test de compression-translation. Ce test de frottement met en œuvre un indenteur qui représente l'outil et un échantillon représentatif des lopins. L'indenteur frotte sur l'échantillon en créant une zone de déformation plastique localisée. L'essai est effectué dans des conditions optimales pour simuler la pression de contact, la déformation plastique et la température caractéristique du procédé de mise en forme. Une étape de validation basée sur un cas de tréfilage montre que le coefficient de frottement issu de l'essai de compression-translation est parfaitement utilisable pour la simulation éléments finis du procédé. La méthodologie d'analyse est ensuite utilisée pour caractériser le comportement tribologique des huiles de frappe à froid à partir de quatre critères de sélection : le coefficient de frottement, la longueur de frottement avant apparition de rayures et de fissures, et la rugosité résultante. Une dernière phase de développement permet de réaliser des essais consécutifs pour reproduire les sollicitations de la surface du lopin soumise à des opérations de mise en forme successives. Les résultats décrivent l'évolution du frottement en fonction des revêtements, de leur dégradation et des lubrifiants additionnels.
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Costache, Vlad. "Régulation traductionnelle en réponse à la fécondation et en conditions perturbées dans l’embryon d’oursin." Rennes 1, 2011. https://ecm.univ-rennes1.fr/nuxeo/site/esupversions/90a59e79-f757-41e0-8873-f8286ef854ee.
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La traduction est une étape critique de la régulation de l'expression des gènes. Chez l'oursin, la fécondation induit une augmentation de la synthèse protéique, qui dépend essentiellement de la traduction d'ARN messagers maternels et qui est indispensable au déroulement des cycles cellulaires embryonnaires. Dans le cadre de cette thèse, le contrôle de la traduction a été étudié chez l'oursin dans deux situations : le contexte physiologique de la fécondation et le contexte de l'induction de l'apoptose. L'une des étapes limitantes de la traduction est l'initiation, qui fait intervenir le facteur d'initiation eIF2, responsable de l'apport de la méthionine initiatrice au niveau du ribosome. Lorsque la sous-unité α d'eIF2 est phosphorylée, la synthèse protéique globale est inhibée et la traduction sélective d'ARNm est stimulée. Dans les ovules non fécondés d'oursin, eIF2α est physiologiquement phosphorylé et la fécondation provoque sa déphosphorylation. En microinjectant dans les ovules un variant d'eIF2α mimant l'état phosphorylé, nous avons montré que la déphosphorylation d'eIF2α est nécessaire pour la première division mitotique chez l'oursin. Nous nous sommes intéressés au lien entre la phosphorylation d'eIF2α et l'induction de l'apoptose chez l'oursin. La traduction d'ARNm codant pour des protéines pro- ou anti- apoptotiques influence directement la survie des cellules. Le traitement au MMS provoque la phosphorylation d'eIF2α par la kinase GCN2, et induit ainsi l'apoptose dans les embryons. En fin, dans le but d'étudier comment la machinerie traductionnelle module le recrutement polysomal, nous avons analysé le traductome en réponse à la fécondation et après le traitement au MMS, par une approche de séquençage à haut-débit. L'analyse des transcrits nous permettra d'appréhender le réseau des gènes régulés au niveau traductionnel lors de la fécondation et de l'induction de l'apoptose dans les embryons d'oursinTranslation is a critical step in gene expression regulation. In sea urchin embryos, fertilization induces an increase in protein synthesis, which depends mainly on the translation of maternal messenger RNAs. This protein synthesis is essential for the first cell cycles. In this thesis, translational regulation in sea urchin embryos was studied in two situations: the physiological context of fertilization and the context of apoptosis induction. Initiation is one of the limiting steps of translation. In this context, the initiation factor eIF2 plays a key role. EIF2 is responsible for bringing the initiator methionine to the ribosome. When the α subunit of eIF2 is phosphorylated, global protein synthesis is inhibited and the selective translation of certain mRNAs is stimulated. In the sea urchin unfertilized eggs, eIF2α is physiologically phosphorylated and fertilization induces its dephosphorylation. By microinjecting a variant mimicking the phosphorylated state of eIF2α into the unfertilized eggs, we showed that dephosphorylation of eIF2α is required for the first mitotic division in the sea urchin. We were interested in the relationship between the phosphorylation of eIF2α and induction of apoptosis in the sea urchin. Indeed, the translation of mRNAs encoding proteins pro- or anti-apoptotic directly influences cell survival. Exposing embryos to MMS, a DNA-damaging agent, causes phosphorylation of eIF2α and apoptosis activation. We found GCN2 kinase involved in the phosphorylation of eIF2α in this situation. Finally, we analyzed the translatome in response to fertilization and after exposure to MMS. We conducted deep sequencing of transcripts that are present in polysomes. Analysis of these transcripts, following annotation, will allow a better understanding of the genes regulatory network at the translational level during fertilization and the induction of apoptosis in sea urchin embryos
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Kaim, Michael. "Propriété des lois des fonctionnelles définies sur des processus empiriques : conditions d'absolue continuité." Lille 1, 2005. https://ori-nuxeo.univ-lille1.fr/nuxeo/site/esupversions/84cb1190-42fd-40f5-98be-c62b7b9f88f4.
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Le but de ce travail est d'étudier la loi de processus empiriques transportés, et plus particulièrement, l'existence de densité. Deux types de transport sont étudiés : - Le transport de processus empiriques, empiriques pondérés, quantiles et séquentiels par des fonctionnelles de types intégrales ou suprémum, - Le transport de processus empiriques ponctuels par des fonctionnelles homogènes. Cette seconde partie se prolonge par l'étude de la convergence en variation totale des fonctionnelles des processus empiriques ponctuels, qui vérifient une condition forte de variation régulière, vers celles d'un processus ponctuel Poissonien. On se limite au cas des fonctionnelles satisfaisant une condition de locale dépendance.
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Nguyen, Khoa Van. "Étude des effets de site dus aux conditions topographiques et géotechniques par une méthode hybride éléments finis/éléments frontières." Phd thesis, Ecole des Ponts ParisTech, 2005. http://pastel.archives-ouvertes.fr/pastel-00001839.
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Ce travail de thèse a pour but de développer la méthode des éléments frontières (BEM) et la méthode hybride éléments finis/éléments frontières (FEM/BEM) pour l'élastodynamique et la poroélastodynamique, et d'appliquer ces méthodes aux études d'effets de site sismiques et d'interaction dynamique sol-structure. La première partie du mémoire aborde les problèmes théoriques. Les formulations, en domaine temporel, de la BEM et de la FEM/BEM peuvent tenir compte du caractère ouvert des espaces (semi-)infinis. En particulier, la FEM/BEM peut également prendre en compte des comportements matériels complexes. Ces formulations ont cependant des difficultés numériques pouvant limiter leur applicabilité en pratique il s'agit de la stabilité numérique du schéma temporel, de l'augmentation rapide du temps de calcul avec le nombre de pas de temps et de l'effet de la troncature de l'espace semi-infini. Des techniques, destinées à améliorer les performances de ces méthodes, sont alors proposées. Pour l'application de la BEM en poroélastodynamique, une expression a de la solution fondamentale temporelle est proposée, en faisant deux hypothèses l'accélération relative, par rapport au squelette, du fluide interstitiel est négligée et les constituants du milieu (grains solides et fluide) sont incompressibles. Cette solution approchée, en termes de déplacements et de pressions interstitielles, est adéquate pour les sols sous sollicitations sismiques. Toutes les formulations sont validées et intégrées dans le code de calcul HYBRID. La seconde partie de la thèse est consacrée à l'application de la BEM et de la FEM/BEM aux calculs sismiques. Les phénomènes physiques et les caractéristiques principales des effets de site bidimensionnels, dus aux conditions topographiques et géotechniques, sont présentés. On prouve théoriquement que les effets de site peuvent considérablement aggraver le potentiel destructeur du mouvement sismique, car ils amplifient le mouvement, prolongent la durée du séisme et provoquent des mouvements différentiels. Des études paramétriques sont effectuées et montrent l'influence significative sur le mouvement sismique en surface de plusieurs facteurs le contenu fréquentiel de l'excitation, le contraste d'impédance sédiment/substratum, la géométrie du relief ou du bassin (largeur, profondeur ou hauteur, pente, forme), l'épaisseur de la sédimentation, l'effet multicouche et la saturation en eau interstitielle. Une étude, portant sur l'interaction dynamique barrage/fondation, démontre la nécessité de tenir compte de l'effet de flexibilité de la fondation dans les calculs sismiques des barrages en terre.
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Pilz, Marco. "A comparison of proxies for seismic site conditions and amplification for the large urban area of Santiago de Chile." Phd thesis, Universität Potsdam, 2010. http://opus.kobv.de/ubp/volltexte/2011/5296/.
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Situated in an active tectonic region, Santiago de Chile, the country´s capital with more than six million inhabitants, faces tremendous earthquake hazard. Macroseismic data for the 1985 Valparaiso and the 2010 Maule events show large variations in the distribution of damage to buildings within short distances indicating strong influence of local sediments and the shape of the sediment-bedrock interface on ground motion.
Therefore, a temporary seismic network was installed in the urban area for recording earthquake activity, and a study was carried out aiming to estimate site amplification derived from earthquake data and ambient noise. The analysis of earthquake data shows significant dependence on the local geological structure with regards to amplitude and duration. Moreover, the analysis of noise spectral ratios shows that they can provide a lower bound in amplitude for site amplification and, since no variability in terms of time and amplitude is observed, that it is possible to map the fundamental resonance frequency of the soil for a 26 km x 12 km area in the northern part of the Santiago de Chile basin.
By inverting the noise spectral rations, local shear wave velocity profiles could be derived under the constraint of the thickness of the sedimentary cover which had previously been determined by gravimetric measurements. The resulting 3D model was derived by interpolation between the single shear wave velocity profiles and shows locally good agreement with the few existing velocity profile data, but allows the entire area, as well as deeper parts of the basin, to be represented in greater detail. The wealth of available data allowed further to check if any correlation between the shear wave velocity in the uppermost 30 m (vs30) and the slope of topography, a new technique recently proposed by Wald and Allen (2007), exists on a local scale. While one lithology might provide a greater scatter in the velocity values for the investigated area, almost no correlation between topographic gradient and calculated vs30 exists, whereas a better link is found between vs30 and the local geology. When comparing the vs30 distribution with the MSK intensities for the 1985 Valparaiso event it becomes clear that high intensities are found where the expected vs30 values are low and over a thick sedimentary cover. Although this evidence cannot be generalized for all possible earthquakes, it indicates the influence of site effects modifying the ground motion when earthquakes occur well outside of the Santiago basin.
Using the attained knowledge on the basin characteristics, simulations of strong ground motion within the Santiago Metropolitan area were carried out by means of the spectral element technique. The simulation of a regional event, which has also been recorded by a dense network installed in the city of Santiago for recording aftershock activity following the 27 February 2010 Maule earthquake, shows that the model is capable to realistically calculate ground motion in terms of amplitude, duration, and frequency and, moreover, that the surface topography and the shape of the sediment bedrock interface strongly modify ground motion in the Santiago basin. An examination on the dependency of ground motion on the hypocenter location for a hypothetical event occurring along the active San Ramón fault, which is crossing the eastern outskirts of the city, shows that the unfavorable interaction between fault rupture, radiation mechanism, and complex geological conditions in the near-field may give rise to large values of peak ground velocity and therefore considerably increase the level of seismic risk for Santiago de Chile.Aufgrund ihrer Lage in einem tektonisch aktiven Gebiet ist Santiago de Chile, die Hauptstadt des Landes mit mehr als sechs Millionen Einwohnern, einer großen Erdbebengefährdung ausgesetzt. Darüberhinaus zeigen makroseismische Daten für das 1985 Valparaiso- und das 2010 Maule-Erdbeben eine räumlich unterschiedliche Verteilung der an den Gebäuden festgestellten Schäden; dies weist auf einen starken Einfluss der unterliegenden Sedimentschichten und der Gestalt der Grenzfläche zwischen den Sedimenten und dem Festgestein auf die Bodenbewegung hin. Zu diesem Zweck wurde in der Stadt ein seismisches Netzwerk für die Aufzeichnung der Bodenbewegung installiert, um die auftretende Untergrundverstärkung mittels Erdbebendaten und seismischem Rauschen abzuschätzen. Dabei zeigt sich für die Erdbebendaten eine deutliche Abhängigkeit von der Struktur des Untergrunds hinsichtlich der Amplitude der Erschütterung und ihrer Dauer. Die Untersuchung der aus seismischem Rauschen gewonnenen horizontal-zu-vertikal-(H/V) Spektral-verhältnisse zeigt, dass diese Ergebnisse nur einen unteren Grenzwert für die Bodenverstärkung liefern können. Weil jedoch andererseits keine zeitliche Veränderung bei der Gestalt dieser Spektralverhältnisse festgestellt werden konnte, erlauben die Ergebnisse ferner, die Resonanzfrequenz des Untergrundes für ein 26 km x 12 km großes Gebiet im Nordteil der Stadt zu bestimmen. Unter Zuhilfenahme von Informationen über die Dicke der Sedimentschichten, welche im vorhinein schon durch gravimetrische Messungen bestimmt worden war, konnten nach Inversion der H/V-Spektralverhältnisse lokale Scherwellengeschwindigkeitsprofile und nach Interpolation zwischen den einzelnen Profilen ein dreidimensionales Modell berechnet werden. Darüberhinaus wurde mit den verfügbaren Daten untersucht, ob auf lokaler Ebene ein Zusammenhang zwischen der mittleren Scherwellengeschwindigkeit in den obersten 30 m (vs30) und dem Gefälle existiert, ein Verfahren, welches kürzlich von Wald und Allen (2007) vorgestellt wurde. Da für jede lithologische Einheit eine starke Streuung für die seismischen Geschwindigkeiten gefunden wurde, konnte kein Zusammenhang zwischen dem Gefälle und vs30 hergestellt werden; demgegenüber besteht zumindest ein tendenzieller Zusammenhang zwischen vs30 und der unterliegenden Geologie. Ein Vergleich der Verteilung von vs30 mit den MKS-Intensitäten für das 1985 Valparaiso-Erdbeben in Santiago zeigt, dass hohe Intensitätswerte vor allem in Bereichen geringer vs30-Werte und dicker Sedimentschichten auftraten. Weiterhin ermöglichte die Kenntnis über das Sedimentbeckens Simulationen der Bodenbewegung mittels eines spektralen-Elemente-Verfahrens. Die Simulation eines regionalen Erdbebens, welches auch von einem dichten seismischen Netzwerk aufgezeichnet wurde, das im Stadtgebiet von Santiago infolge des Maule-Erdbebens am 27. Februar 2010 installiert wurde, zeigt, dass das Modell des Sedimentbeckens realistische Berechnungen hinsichtlich Amplitude, Dauer und Frequenz erlaubt und die ausgeprägte Topographie in Verbindung mit der Form der Grenzfläche zwischen den Sedimenten und dem Festgestein starken Einfluss auf die Bodenbewegung haben. Weitere Untersuchungen zur Abhängigkeit der Bodenerschütterung von der Position des Hypozentrums für ein hypothetisches Erdbeben an der San Ramón-Verwerfung, welche die östlichen Vororte der Stadt kreuzt, zeigen, dass die ungünstige Wechselwirkung zwischen dem Verlauf des Bruchs, der Abstrahlung der Energie und der komplexen geologischen Gegebenheiten hohe Werte bei der maximalen Bodengeschwindigkeit erzeugen kann. Dies führt zu einer signifikanten Zunahme des seismischen Risikos für Santiago de Chile.
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Hajdu, Melissa Anne. "Effect of culture conditions, donor source, and injection site on in vitro development of deoxyribonucleic acid microinjected porcine zygotes." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-12172008-063219/.
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CARDOSO, TIAGO LUIS. "STUDY OF THE LABOUR CONDITIONS OF RECYCLABLE COLLECTORS ON JARDIM GRAMACHO S SITE: AN ANALYSIS BASED ON ERGONOMIC ASPECTS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=29787@1.
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O Estudo das condições de trabalho dos catadores de materiais recicláveis do polo de Jardim Gramacho: uma análise com base em aspectos ergonômicos busca analisar as condições de trabalho dos catadores integrantes do polo de Jardim Gramacho no que diz respeito aos aspectos ergonômicos e os impactos do trabalho desempenhado na saúde laboral e pessoal, pois mesmo com a evolução dos requisitos legais, após décadas de aprimoramento das leis trabalhistas, ainda nos deparamos com questões adversas ao que determina a legislação. Neste contexto, a pesquisa teve como objetivo principal identificar os principais problemas que acarretam danos à saúde destes profissionais estigmatizados pela natureza de sua atividade e vitimados pela precarização de políticas públicas eficazes voltadas para a saúde do trabalhador informal. Para fundamentar o estudo, foi realizado levantamento bibliográfico e pesquisa de campo, além das técnicas de observação participante e escuta dos sujeitos por entrevistas semiestruturadas, com vistas a compreender o processo atual de trabalho, analisando pontos em que houvesse prejuízo à saúde do trabalhador. A análise foi conduzida por meio de ferramentas e métodos ergonômicos, os quais possuem fundamentação na legislação de saúde e segurança ocupacional. O estudo realizado situou-se na Cooperativa Mais Verde, a maior dentre as instaladas no Polo. Pela amostra de trabalhadores pesquisada foi possível comprovar um ambiente carente de medidas que contribuam com a saúde laboral. Enfim, são propostas algumas medidas para a reversão deste cenário, a fim de possibilitar mais qualidade de vida a estes sujeitos importantes na gestão de resíduos sólidos brasileira.The environmental issue and human welfare have become an increasingly challenging goal for today s society, as the scarcity of natural resources has overcharged the rulers as they search for renewable energy and consumption alternatives. Great reflections related of the life quality in Brazil have appeared in relation to welfare, especially in the case of the poor classes, such as recyclable waste collectors, who often face a subhuman working hour striving to obtain the basic survival conditions, leaving the comfort and welfare in their lives behind them. These factors were the motivation by the choice of this line of study — especially because the researcher is graduated in production and safety engineering, acting on issues related to labour wellfare in order to provide work environments that allow the execution of professional activities in harmony with the physical and psychological wellfare of workers. I m currently an employee of the multinational General Electric, a private institution that has different business segments on a global scale. I work in the aviation industry and I have the experience of working in an environment that aims, firstly, at the welfare of your employees — a factor that undoubtedly gave me even more background, theoretical and practical knowledge, as well as technical capacity to act in the present work. This study is not part of a joint initiative of the company mentioned above with this author; it is only an individualized academic study, conducted with the advice and guidance of a thesis supervisor, as a requirement for obtaining a master s degree in Urban and Environmental Engineering by PUC-Rio.
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Nguyen, Khoa-Van. "Etude des effets de site dus aux conditions topographiques et géotechniques par une méthode hybride éléments finis/éléments frontières." Marne-la-vallée, ENPC, 2005. https://pastel.archives-ouvertes.fr/pastel-00001839.
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Gazeaux, Jérôme. "Caractérisation du mouvement de rotation de l'air (swirl) en écoulement stationnaire dans un monocylindre diesel en fonction des conditions d'admission." Valenciennes, 2001. https://ged.uphf.fr/nuxeo/site/esupversions/de38a189-bc42-41c0-901b-285a04d6bfe1.
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Les normes actuelles d'environnement contraignent les constructeurs automobiles à concevoir de moteurs plus performants et moins polluants. L'un des paramètres entrant en considération pour l'amélioration de la combustion est l'aérodynamique interne propre au conduit d'admission, la chambre de combustion et au piston. Le choix s'est porté sur un moteur diesel à injection directe comportant un conduit d'admission générant à l'origine un important mouvement de rotation de l'air (swirl). Les caractéristiques de l'écoulement ont été modifiées par l'ajout de différents procédés technologiques qui ont permis de mesurer et comparer les degrés de swirl et coefficients de débit de chaque configuration. Les profils des vitesses de ces écoulements ont ensuite été caractérisés grâce à la vélocimétrie par images de particules dans plusieurs plans. A l'aide de ces données numériques, le degré de swirl instantané est redéfini et une évolution en trois dimensions de l'écoulement présentéeThe current standards of environment constrain the car manufacturers to design more powerful and less polluting engines. One of the main parameters for the improvement of combustion is internal aerodynamics generated by the admission pipe, the combustion chamber and piston. We choiced a direct injection diesel engine with a helical admission pipe generating a significant rotational movement of air in the cylinder(swirl). The flow characteristics were modified by the addition of various technological processes which made possible to measure and compare the degrees of swirl and discharge coefficients for each configuration. The profiles velocities were then characterized by laser velocimetry with images of particles in several plans. Using these numerical data, the instantaneous degree of swirl was redefined and a three dimensional analysis of flows presented
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Gradowski, Tomasz Aleksander. "The influences of geoclimatic site conditions, disturbance type and canopy composition on the composition of understorey vegetation of boreal mixedwoods." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58807.pdf.
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Mehramiz, Mohammad Reza. "Nutrient contents of three Atriplex species (Atriplex cancensces, atriplex linearis and Atriplex polycarpa) under different management practices and site conditions." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282667.
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There are thousands hectares of abandoned farmlands in Arizona. Research on practical methods for establishing native plants and wildlife on abandoned farmlands is under way at the Desert Botanical Garden of Phoenix and the University of Arizona. This research is aimed at improving understanding of the primary variables affecting restoration of abandoned farmlands. These variables include: water treatments, planting dates, mulch and water catchment, seasonal planting and plant species composition. The objectives of the study is to investigate the effect of land restoration practices on nitrogen, protein, fiber (NDF and ADF), ash and dry matter contents of three Atriplex species under different management and site conditions. The amount of nutrient contents in Atriplex species growing on abandoned farmlands under irrigation and conservation practices is higher when compared to no irrigation or control in Casa Grande research site. Atriplex species growing under mulch and water catchment condition had significantly higher nutrient content compared to other treatments. Furthermore, seasonal planting in abandoned farmlands affected the nutrient contents of Atriplex cultivars at the University of Arizona farm. The Atriplex cultivar planted in the winter had higher nutrient contents when compared to those planted in the summer and irrigated with a sprinkler irrigation system for some cultivars. A better understanding of how these variables affect nutrient contents of Atriplex species used in this restoration study will play an important role in directing public interest towards the revegetation of abandoned farmlands in southern Arizona for food production.
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Wei, Xiao. "Experimental and numerical study of atmospheric turbulence and dispersion in stable conditions and in near field at a complex site." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1012/document.
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Un programme expérimental a été conçu afin d'étudier la dispersion des polluants sur un terrain complexe avec un accent mis sur des conditions stables qui restent délicates pour la modélisation numérique. Ce programme expérimental est mené sur le site du SIRTA dans la banlieue sud de Paris et consiste à mesurer en champ proche la turbulence et la dispersion des polluants. L'objectif de ce programme est de caractériser la structure fine de la turbulence et de la dispersion associée par des mesures à haute résolution temporelle et spatiale. Ensuite, ces mesures permettent de valider et d'améliorer la qualité de simulations CFD pour la turbulence et la dispersion sur un site fortement hétérogène. Le dispositif instrumental comprend 12 anémomètres ultrasoniques mesurant en continu la vitesse du vent et la température à 10 Hz, et 6 détecteurs à photo-ionisation (PID) mesurant la concentration de gaz à 50 Hz pendant des essais de traçage. Plusieurs périodes d’observations intensives (POIs) avec des rejets de gaz ont été réalisées depuis Mars 2012.Tout d'abord, une étude détaillée de l'écoulement du vent sur le site est réalisée, car l’écoulement doit être caractérisé et correctement simulé avant de simuler la dispersion des polluants. Cette étude est basée sur deux ans de mesures en continu et sur les mesures acquises durant les POIs. La forte anisotropie de la turbulence dans la couche de surface est caractérisée à l’aide du calcul des variances, des échelles de longueur intégrales et des spectres des trois composantes de la vitesse du vent. La propagation des structures turbulentes entre les capteurs est caractérisée en utilisant les corrélations de vitesse. Les spectres de vitesse montrent plusieurs pentes dans différentes zones de fréquence. En outre, l’analyse des données montre l’impact de l'hétérogénéité du terrain sur les mesures. La forêt au nord du site expérimental modifie la vitesse et la direction du vent pour un grand secteur nord. Il induit un fort cisaillement de la direction du vent et une décélération en dessous de la hauteur de la forêt. Les simulations numériques sont effectuées avec le code de CFD Code_Saturne en mode RANS avec une fermeture k-ε adaptée pour les écoulements atmosphériques et un modèle de canopée pour la forêt. Ces simulations reproduisent correctement les caractéristiques de l'écoulement moyen sur le site des mesures, en particulier l'impact de la forêt pour les différentes directions du vent et pour la stratification neutre et stable. Les résultats de simulation montrent aussi le cisaillement de direction du vent et l’augmentation de l’énergie cinétique turbulente induits par la forêt. Une étude de sensibilité montre que ces effets sur l'écoulement s’accentuent quand la densité foliaire augmente. L’étude de dispersion est réalisée pour plusieurs POIs. L’analyse des données de concentration montre la cohérence avec les mesures de campagnes précédentes réalisées dans des zones proches de la source. Les fluctuations de concentrations sont caractérisées à travers les séries temporelles, l'histogramme et l'analyse statistique des concentrations. Une zone inertielle peut également être identifiée dans les spectres de concentration. Ensuite, la dispersion des polluants est modélisée par les équations de transport pour la concentration et sa variance. La concentration moyenne est globalement en bon accord avec les mesures pour toutes les POIs étudiées. L’accord avec les mesures sur la position du maximum de concentration dépend de la précision de la rotation du vent simulée en-dessous de la hauteur de la forêt. Les fluctuations de concentration obtenues dans les simulations semblent être affectées de manière significative par la condition initiale et la modélisation du terme de dissipation. Une étude de sensibilité à la paramétrisation est ensuite présentéeAn experimental program has been designed in order to study pollutants dispersion at a complex site with a focus on stable conditions, which are still challenging for numerical modelling. This experimental program is being conducted at the SIRTA site in a southern suburb of Paris and consists in measuring, in near field, the turbulence and the pollutants dispersion. The aim of this program is to characterize the fine structure of turbulence and associated dispersion through high temporal and spatial resolution measurements. Then, these measurements allow to validate and improve the performance of CFD simulation for turbulence and dispersion in a heterogeneous field. The instrumental set up includes 12 ultrasonic anemometers measuring continuously wind velocity and temperature at 10 Hz, and 6 photo-ionization detectors (PIDs) measuring gas concentration at 50 Hz during tracer tests. Intensive observations periods (IOPs) with gas releases have been performed since March 2012.First of all, a detailed study of flow on the site is made, because it must be characterised and properly simulated before attempting to simulate the pollutants dispersion. This study is based on two years of continuous measurements and on measurements performed during IOPs. Turbulence strong anisotropy in the surface layer is characterized by calculating variances, integral length scales and power spectra of the three wind velocity components. Propagation of turbulent structures between sensors has been characterized with velocity correlations. Energy spectra show several slopes in different frequency regions. Also, data analyses show impact of terrain heterogeneity on the measurements. The forest to the north of experimental field modifies wind velocity and direction for a large northerly sector. It induces a strong directional wind shear and a wind deceleration below the forest height. Numerical simulations are carried out using the CFD code Code_Saturne in RANS mode with a standard k-ε closure adapted for atmospheric flows and a canopy model for the forest. These simulations are shown to reproduce correctly the characteristics of the mean flow on the measurements site, especially the impact of the forest for different wind directions, in both neutral and stable stratification. Simulations results also show the directional wind shear and the turbulent kinetic energy increase induced by the forest. A sensitivity study has been made for various values of forest density and shows that the typical features of canopy flow become more pronounced as canopy density increases. Pollutants dispersion study are made for several IOPs. Concentration data analysis shows a consistency with previous measurements made in a near-source region where the plume scale is smaller than the large-scale turbulence eddies. Concentration fluctuations are characterized through concentration time series, histogram and statistical analysis. The internal subrange can be observed in the concentration spectra. Next, pollutants dispersion are modelled by transport equations for concentration and its variance. The mean concentrations show a good agreement with measurements in values for all the IOPs studied, except that the position of the concentration peak depends on the accuracy of simulated wind rotation below the forest height. The concentration fluctuations obtained from simulations seem to be affected significantly by the initial condition and the modelling of the dissipation term. A sensitivity study to the parameterisation is then presented
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Michaut, Christophe. "L'influence du contexte universitaire sur la réussite des étudiants." Dijon, 2000. https://nuxeo.u-bourgogne.fr/nuxeo/site/esupversions/670fe9b4-cd4b-45e0-9029-20b5897285b7.
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Il existe entre les universités françaises des différences de réussite des étudiants. Cette thèse examine plus particulièrement l’influence du contexte d’enseignement sur la réussite. Les données portent sur plus de 1800 étudiants de première année de DEUG de trois sites universitaires (Dijon, Nantes et Toulouse) et de trois filières (Administration Economique et sociale, Psychologie et Sciences de la Vie). Même lorsque sont contrôlées les caractéristiques individuelles des étudiants, des écarts significatifs de réussite persistent entre les établissements. A l’origine de ces écarts se trouvent des modes inégaux d’organisation pédagogique et des pratiques différenciées de sélection des étudiants. A partir d’une enquête auprès de 155 responsables pédagogiques, on constate que sur de nombreux points (curricula, mode de gestion, dispositifs d’aide aux étudiants), l’organisation pédagogique des premiers cycles universitaires se différencie. Les Facteurs organisationnels influant sur la réussite sont peu nombreux. Toutefois, une durée annuelle plus importante des enseignements et l’organisation semestrielle du DEUG sont deux éléments associés positivement et significativement à la réussite des étudiants. Par ailleurs, cette recherche montre que les universités pratiquent une sélection reposant tantôt sur la scolarité antérieure des étudiants tantôt sur leur implication dans les études. Ainsi, en Sciences de la Vie, la réussite dépend avant tout de la qualité du parcours scolaire des étudiants alors qu’en Psychologie, les étudiants vont davantage se différencier selon le temps qu’ils consacrent à leurs études, leur assiduité, etc. En AES, le mode de sélection varie selon les universités. Certaines favorisent les « meilleurs » étudiants tandis que d’autres privilégient l’investissement dans les étudesNoticeable differences can be observed between French universities with regard to the general success level. This thesis examines, more particularly, in which manner the educational context influences the success of students. The data covers more than 1800 first-year DEUG students over three different universities (Dijon, Nantes and Toulouse), and three subjects, i. E. Economic and social administration, Psychology and Biology. Significant differences still persist between establishments, even when the students’ individual characteristics are controlled for. Such disparities originate from unequal educational methods and from different means of selecting students. A questionnaire sent to 155 university heads of departments exams indicates that the educational organization of first and second year students vary on numerous levels (curricula, different modes of management, proposed methods of student help with). Educational factors influencing the general success level are not numerous. However, two elements, i. E. A longer educational period overt the year and the six-monthly DEUG organization, are positively and significantly associated to general achievement. Besides, this thesis shows that universities will select their students both on their previous schooling, while in Psychology, students will differentiate themselves according to the time dedicated to their studies, their own diligence, and so forth. In AES the mode of selection can vary from one university to the next. Some favour the “best” students while others privilege dedication to studies
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Sow, Ousmane. "Analyse thermodynamique d'un système de dessalement par distillation avec apport solaire : recherche des conditions optimales de fonctionnement en régime variable." Valenciennes, 2003. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/f9106e6d-4483-41c4-b3cc-0fcde7ffff70.
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Sur les installations de dessalement classiques, opérant par changement de phase, (multi-flash, multiple effets,. . . ) se posent toujours les problèmes du rejet d'une forte quantité d'eau non saturée en sels et du colmatage du sel sur les composants de l'installation. La solution classique bien connue à ce jour permettant d'éviter ces problèmes, consiste à introduire des substances chimiques de prétraitement de l'eau salée. La présente thèse rend compte par une simulation sur un système à multiple effets qu'une régulation sur le débit d'alimentation pourrait être une alternative pour réduire aux mieux ces pertes d'eau, et par conséquent le coût de la production. Une analyse thermodynamique a permis d'évaluer les énergies mises en jeu ainsi que les pertes exergétiques du système. Celle-ci sera suivie d'une modélisation en régime dynamique. Une comparaison à un système non régulé permet d'évaluer les performances du système. Enfin une étude de faisabilité donne une idée sur sa mise en œuvreWith traditional desalination plants, operative by phase shift (vapour compression mechanical, multi-flash, multiple effects. . . ) Two major problems arise: the rejection of a large quantity of water non-satured in salt and the build up of salt in all the installation components. The traditional solution to overcome these problems consists in introducing chemical substances for the pre-treatment of salted water. The present thesis proposes through analysis multipurpose system desalination, that a regulation on the rate of feed could be an alternative method to reduce this water loss, and consequently the production cost. This analysis allows us to evaluate energies brought into the system and the exergetical losses. A modeling in dynamical mode will follow this analysis. A comparison with a system not controlled makes it possible to evaluate the performances of the system. Finally a feasibility study gives an idea on its implementation
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Girard, Jean-Marc. "Contribution à l'évaluation de la charge de travail du conduteur automobile : une approche explorative multivariée." Valenciennes, 2007. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/ed765a6c-84db-4003-bb80-0696975e0b8b.
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Les avancées en matière de puissance de calcul, d'intégration et de coûts ont permis aux constructeurs automobiles et aux équipementiers de proposer aux conducteurs de nouveaux outils afin de les protéger et les aider quotidiennement dans leur conduite. La multiplication de ces systèmes n'est pas sans poser de problème puisque les capacités du conducteur ne sont pas extensibles. Les travaux présentés dans cette thèse proposent une méthodologie pour la construction d'un estimateur temps réel de la charge de travail. Ceci dans deux buts : - évaluer les systèmes ainsi que leurs interactions avec le conducteur ; - permettre aux systèmes de bénéficier d'un diagnostic de l'état du conducteur afin qu'ils adaptent l'aide fournie en fonction des capacités instantanées du conducteur. La méthodologie est basée sur la mise en correspondance, au sein de la même analyse, de données objectives issues des enregistrements de la performance de la conduite et des données subjectives issues d'une évaluation de la charge de travail du conducteur. Les données sont collectées au cours d'une expérimentation durant laquelle le sujet est soumis à différents niveaux d'exigence. Après avoir validé le protocole expérimental en terme de charge de travail et de performance aux tâches secondaires, une analyse exploratoire multivariée est menée sur les différents indicateurs. Cette analyse a permis de déterminer les variables les plus pertinentes permettant de distinguer les différents contextes de conduite - selon la vitesse, la densité de trafic et la réalisation de tâches secondaires - tout en faisant le parallèle avec la charge de travail du conducteurEveryday improvements in computing power, integration and cost allow the car manufacturers and the equipment suppliers to offer new tools to the driver in order to protect and help him in his driving. However, the increasing number of such systems becomes problematic as the driver capacities are not extensible. The work presented in this thesis proposes a methodology for the design of a real-time workload estimator, this with two aims : - to assess the systems and their interactions with the driver; - to allow the systems to profit from a diagnosis of the driver state so that they adapt the provided assistance according to the instantaneous capacities of the driver. Methodology is based on the connection, within the same analysis, between objective data resulting from the recordings of the driving performance and subjective data resulting from workload assessment. The data are collected during an experimentation in which the subject drives under several levels of driving task demands. After the validation of the experimental protocol according to the workload and the secondary task performance, a multivariate exploratory analysis is carried out on the various indicators. This analysis allows to determine the most relevant variables making it possible to distinguish the various driving contexts - according to the speed, the density of traffic and the execution of secondary tasks - while focusing on the relation with the driver workload
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Andreasen, Mie, Karsten H. Jensen, Darin Desilets, Marek Zreda, Heye R. Bogena, and Majken C. Looms. "Cosmic-ray neutron transport at a forest field site: the sensitivity to various environmental conditions with focus on biomass and canopy interception." COPERNICUS GESELLSCHAFT MBH, 2017. http://hdl.handle.net/10150/623933.
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Cosmic-ray neutron intensity is inversely correlated to all hydrogen present in the upper decimeters of the subsurface and the first few hectometers of the atmosphere above the ground surface. This correlation forms the base of the cosmic-ray neutron soil moisture estimation method. The method is, however, complicated by the fact that several hydrogen pools other than soil moisture affect the neutron intensity. In order to improve the cosmic-ray neutron soil moisture estimation method and explore the potential for additional applications, knowledge about the environmental effect on cosmic-ray neutron intensity is essential (e.g., the effect of vegetation, litter layer and soil type). In this study the environmental effect is examined by performing a sensitivity analysis using neutron transport modeling. We use a neutron transport model with various representations of the forest and different parameters describing the subsurface to match measured height profiles and time series of thermal and epithermal neutron intensities at a field site in Denmark. Overall, modeled thermal and epithermal neutron intensities are in satisfactory agreement with measurements; however, the choice of forest canopy conceptualization is found to be significant. Modeling results show that the effect of canopy interception, soil chemistry and dry bulk density of litter and mineral soil on neutron intensity is small. On the other hand, the neutron intensity decreases significantly with added litter-layer thickness, especially for epithermal neutron energies. Forest biomass also has a significant influence on the neutron intensity height profiles at the examined field site, altering both the shape of the profiles and the ground-level thermal-to-epithermal neutron ratio. This ratio increases with increasing amounts of biomass, and was confirmed by measurements from three sites representing agricultural, heathland and forest land cover. A much smaller effect of canopy interception on the ground-level thermal-to-epithermal neutron ratio was modeled. Overall, the results suggest a potential to use ground-level thermal-to-epithermal neutron ratios to discriminate the effect of different hydrogen contributions on the neutron signal.
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Cherki, Abdelkrim. "Prise en compte des imprécisions de modélisation en calculs de structures : Application aux conditions aux limites imprécises et à la localisation de défauts de modélisation." Valenciennes, 1998. https://ged.uphf.fr/nuxeo/site/esupversions/474e9b39-832a-400e-a219-db000db4c112.
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Le mémoire est constitué de deux parties. La première est consacrée à la prise en compte des imprécisions sur les conditions aux limites cinématiques lors d'une analyse statique de structures par la méthode des éléments finis. La seconde concerne la prise en compte de l'imprécision sur les caractéristiques modales expérimentales pour la localisation de défauts dominants de modélisation dans les modèles éléments finis. L’imprécision est traitée au moyen du formalisme flou. Malgré des progrès effectués sur la représentativité des modèles durant ces dernières années, subsistent certains verrous comme par exemple des difficultés à modéliser certaines situations physiques telles que encastrements, liaisons soudées ou boulonnées. Ces liaisons sont couramment idéalisées par des supports fixes ou des extrémités articulées. De telles idéalisations perdent leur validité dans bien des applications du monde réel. En effet, une structure montée dans un mur est rarement encastrée. Dans ce type de cas, on se rend compte qu'il sera difficile de quantifier les conditions réelles du montage. De plus, des imprécisions sur les conditions aux limites peuvent mener à de réelles erreurs de modélisation. Pour cela, nous proposons un outil d'analyse permettant de prendre en compte l'imprécision sur les conditions aux limites cinématiques. L’outil est basé sur l'exploitation combinée des techniques d'analyse statique classiquement employés en éléments finis et du formalisme flou pour représenter l'imprécision sur les déplacements imposés. La deuxième partie est consacrée au traitement des imprécisions de mesure en dynamique de structures et plus particulièrement à la localisation de défauts de modélisation dans un processus de recalage modal. Nous présentons tout d'abord la méthode de recalage développée au LMA, Besançon. Nous proposons ensuite une extension de la méthode en y implantant un algorithme de résolution de système d'équations linéaires floues permettant ainsi d'étendre le potentiel de cette méthode. Chaque partie est illustrée par des exemples d'application numérique.
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Entrup, Alex K. "Restoration of a wet longleaf pine (Pinus palustris) savanna in southeast Louisiana: Burning toward reference conditions." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2068.
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This study quantifies the changes in vegetation composition and structure of a fire-excluded Pinus palustris (longleaf pine) wetland savanna restoration site in southeastern in comparison to a proximate contemporary reference site. The restoration site was invaded by hardwood species and off-site pines, and never underwent extensive soil disturbance. The restoration treatments involved logging across portions of the site and the reintroduction of fire across the entire site. All species present in 10m2 quadrats were recorded prior to treatment and throughout the 17 year study at reference and treatment sites. The community composition of both logged and unlogged sites converged over time, and became more similar to the reference site. We conclude that logging of off-site pine coupled with the reintroduction of frequent fires can be effective in restoring ground cover in remnant longleaf pine savannas withdisturbance.
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Bouchard, Pierre. "Cinquième intervention archéologique sur le site de l'îlot Hunt à Québec (CeEt-110) : étude socio-économique des habitants d'après la collection archéologique, 1850-1900." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0028/MQ51114.pdf.
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Delignon, Gaëlle. "Urbanisme et architecture balnéaires de Saint-Malo-Paramé : l'invention d'un site (1840-1940)." Rennes 2, 1998. http://www.theses.fr/1998REN20008.
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A partir du second empire, la pratique des bains de mer est lancée en France par des membres de l'aristocratie, sur le modèle anglais, et investit le rivage malouin des 1840. Un type nouveau de quartier se développe à partir du point de convergence de la plage, avec son établissement de bains, son grand hôtel, son casino et ses cabines mobiles. Les activités navales et halieutiques séculaires ne tardent pas à être remplacées par des pratiques ludiques et saisonnières. Durant le dernier quart du 19e siècle, l'intervention d'un fondateur promoteur parisien, sur les zones dunaires de Paramé, donne naissance a une ville nouvelle au plan régulier. L'espace est structure par des édifices fédérateurs, comme les hôtels de voyageurs, le casino et la digue promenade. Les points forts, qui fondent le chapelet des sites de villégiature de la cote d'Emeraude au tournant du siècle, sont relies entre eux par des réseaux, comme le chemin de fer, le bac, ou le tramway. Si l'estivant est au départ loge chez l'habitant, il souhaite très vite occuper une habitation individuelle, appelée villa, qui elle seule peut satisfaire son désir de contact avec l'élément maritime. La villa balnéaire présente en effet des particularistes liées au site, a la pratique nouvelle de la domesticité, mais aussi aux références de l'architecture domestique savante. La production de villas en série de la période éclectique laisse place, au lendemain de la première guerre mondiale, a l'épanouissement de la villa régionaliste, qui concerne tout autant les maîtres d'oeuvre parisiens que les locaux. L'architecture balnéaire, peut, à la suite du recensement exhaustif mené sur les habitations balnéaires du site de Saint-Malo, être considérée comme une branche de l'architecture domestique a part entièreFrom the middle of the 19th century, the British sea-bathing practises are imported in France, mainly by members of the aristocracy. From 1840, in Saint-Malo, new urban areas are growing outside of the walls, from the focal point of the beach, with bathing machines, a grand hotel and a casino nearby. The ancient shipping and fishing activities are quickly replaced by new seasonal leisure practises. At the end of the 19th century, Parame, the rural extension of Saint-Malo, is discovered by a powerful banker who turns the unbuilt and sandy site of the village into a new town, based on a regular grid. The urban space is based on the centre formed by remarkable buildings, like palaces, casinos and piers. The group of resorts of the emerald coast are linked, at the turn of the century, equally by boat, by train or by tram. The tourist requires an individual house, which is the only way to create a new relationship with the maritim environment. Therefore, the villa presents some specific points, in relation to the landscape, to the new practise of domesticity, and to the theory in the field of domestic architecture. The series of villas built during the eclectic period give way, after first world war, to a regional production, trying to mix rural and modern influences. As seaside architecture is indeed a branch of domestic architecture, and considering the perfect present conservation state of the villas of Saint-Malo, these must be preserved by individuals, as well as councils
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Pak, Sun. "Adaptation, combustion et limites pauvres d'un moteur à allumage commandé au gaz naturel obtenu par conversion d'un diesel faible puissance." Valenciennes, 1994. https://ged.uphf.fr/nuxeo/site/esupversions/1d663861-db36-4829-9d80-aa7826a05ebe.
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Un moteur diesel faible puissance a était converti en A. C. Puis alimenté au gaz naturel. Les caractéristiques générales de la combustion (délais, durées de combustion, dispersion cyclique) ont été étudiées en fonction du rapport air-gaz, de l'avance à l'allumage, et du type de bougie ainsi que les performances du moteur. Pour le comportement en mélange très pauvre, nous avons déterminé les limites opératoires, analyse le déroulement de la combustion et observe les variations de pression. En utilisant un générateur de turbulence en forme de cône, nous avons reculé les limites pauvres et réduit la dispersion cyclique et la pollution estimée en fonction de la richesse du mélange, de l'avance à l'allumage, de la vitesse et de la charge du moteur. A la fin de l'étude, nous donnons les conditions opératoires optimum pour différentes charges et vitesses.
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Pilz, Marco [Verfasser], and Jochen [Akademischer Betreuer] Zschau. "A comparison of proxies for seismic site conditions and amplification for the large urban area of Santiago de Chile / Marco Pilz. Betreuer: Jochen Zschau." Potsdam : Universitätsbibliothek der Universität Potsdam, 2010. http://d-nb.info/1014619106/34.
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Pourcelot, Laurent. "Les reacteurs de fission naturels du gabon. Contribution a l'etude des conditions de stabilite d'un site naturel de stockage de dechets radioactifs (2 ga)." Université Louis Pasteur (Strasbourg) (1971-2008), 1997. http://www.theses.fr/1997STR13007.
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Les reacteurs de fission naturels d'oklo sont constitues d'un coeur d'uraninite (60% d'u), hote des produits de fission, entoure d'une gangue argileuse. Les etudes geologiques, mineralogiques et geochimiques des reacteurs naturels ont pour objet de modeliser le comportement des produits de fission dans un site de stockage naturel. Le reacteur 10, situe dans la mine d'oklo, constitue un exemple de confinement exceptionnel des produits de fission, depuis 2 ma. Dans le reacteur 9, localise dans la carriere d'oklo, les migrations sont plus importantes. Le reacteur 13 a subi une influence thermique consecutive a une intrusion doleritique, survenue un milliard d'annees apres l'arret des reactions. Des etudes mineralogiques, chimiques et isotopiques des mineraux, nous ont permis de caracteriser les transferts thermiques et les variations des potentiels redox des fluides. Les chlorites vermiculisees du reacteur 9, a forte teneur en al et forte hydratation, sont attribuees a des conditions d'alteration. Les compositions isotopiques de l'oxygene tres enrichies en #1#8o confirment cette hypothese. Dans le reacteur 10, au contraire, les temperatures de cristallisation des chlorites mg et al (sudoites), estimees en utilisant le geothermometre de l'oxygene et confirmees par un geothermometre chimique, temoignent de conditions hydrothermales. L'etendue des migrations des terres rares fissiogeniques est plus importante dans le reacteur 9 que dans le reacteur 10 due a une phase d'alteration supergene. Nous avons trace les conditions redox des fluides contemporains du refroidissement du reacteur et de l'intrusion doleritique par les analyses des isotopes c et o des calcites. Enfin, nous avons discute l'impact des evenements thermiques et de l'alteration supergene sur le comportement des produits de fission des reacteurs d'oklo, consideres comme des sites naturels de stockage de dechets radioactifs.