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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Proposta de sistema para registro eletrônico de ponto com gerenciamento remoto

Ana Paula Müller Giancoli 31 January 2011 (has links)
O presente trabalho propõe uma arquitetura de sistema para registro eletrônico de ponto baseado em software livre e capaz de atender os principais requisitos extraídos da portaria 1510 do Ministério do Trabalho. Essa arquitetura utiliza o sistema operacional Linux, a linguagem de programação Python, o framework Web Plone e o servidor de aplicações Zope, a fim de proporcionar, entre outros benefícios, a segurança, o acesso ao código fonte da aplicação e a independência de fornecedores. A validação é obtida por meio de testes práticos realizados em protótipo que adota os elementos do sistema. Os resultados satisfatórios obtidos nesses testes indicam que a aludida arquitetura é adequada para a aplicação em questão. / This study aims at proposing a system architecture for electronic clocking in and out based on free software to fulfill the main requirements extracted from the 1510 regulation from the Ministry of Labor. This architecture uses the Linux operating system; the Python programming language; the Web Plone framework and the Zope application server to provide, among other benefits, the security, the access to application source code, and the independence from suppliers. The validation is obtained though practical tests on prototypes that adopt the elements of the system. The satisfactory results obtained in these tests indicate that the aforementioned architecture is suitable for the application in question.
2

Preparation and evaluation of metal surfaces for use as photocathodes

Mistry, Sonal January 2018 (has links)
In linear accelerator driven 4th generation Free Electron Lasers (FELs), the final beam quality is set by the linac and ultimately by its photoinjector and photocathode. Therefore, to deliver cutting-edge beam characteristics, there are stringent requirements for the photocathode used in the photoinjector. Understanding how surface properties of materials influence photocathode properties such as quantum efficiency (QE) and intrinsic emittance is critical for such sources. Metal photocathode research at Daresbury Laboratory (DL) is driven by our on-site accelerators VELA (Versatile Electron Linear Accelerator) and CLARA (Compact Linear Accelerator for Research and Applications), a free electron laser test facility. Metals offer the advantage of a fast response time which enable the generation of short electron pulses. Additionally, they are robust to conditions within the gun cavity. The main challenge with metal photocathodes is to maximise their (relatively) low electron yield. In this PhD thesis, the goal has been to carry out an experimental investigation on alternative metals to copper, correlating surface properties with photoemissive properties. A range of surface analysis techniques have been employed: surface composition was investigated using X-ray Photoelectron Spectroscopy and Medium Energy Ion Scattering, Kelvin Probe apparatus and Ultra-violet Photoelectron Spectroscopy were used to measure work function, and Atomic Force Microscopy and Interferometric microscope provided images characterising surface morphology. The photocathode properties studied include: QE measured using a 265 nm UV LED source that was later upgraded to a 266 nm UV LASER, and Mean Transverse Energy measured using the Transverse Energy Spread Spectrometer. As a result of this work, Mg, Nb, Pb, Ti and Zr have all been identified as photocathode candidate materials, each exhibiting a QE greater than Cu. Additionally, surface preparation procedures for optimising QE from a selection of metals has been explored; the findings of these experiments would suggest that ex-situ Ar plasma treatment followed by in-situ heat treatment is well suited to remove surface contaminants without altering the surface morphology of the cathode. As part of this work, metallic thin films produced by magnetron sputtering have been produced; ultimately the chosen cathode metal will be deposited onto a cathode plug which will be inserted into the electron gun that will drive CLARA. Thus the preparation of metal thin films has been investigated and the effect of different substrate materials on the film properties has been explored. Preliminary experiments studying the effects of surface roughness on photoelectron energy distribution have been conducted; the findings have not been conclusive, thus further systematic studies are required.
3

Lactuca sativa L. : Evaluation écotoxicologique de rejets industriels complexes et de solutions synthétiques / Lactuca sativa L. : Industrial discharge waters and synthetic solutions ecotoxicological assement bioindicator

Priac, Anne 27 November 2014 (has links)
Ce travail de thèse a concerné l’évaluation des impacts écotoxicologiques de rejetsindustriels complexes issus de la filière du traitement de surface et de solutionssynthétiques mono- et polycontaminées sur la laitue Lactuca sativa L. Il est ainsimontré que les résultats des tests écotoxicologiques de germination des semences delaitue reflètent la variabilité de la composition chimique des rejets et de leuramélioration après traitement d’abattement de la charge métallique et/ou organique.Ces tests ont également permis de classer selon leur toxicité croissante certains ETM(Fe, Cr, Co, Cu, B, Al, F, Ni, Cd, Ag, Zn, Sn) et quelques molécules organiques (4NP,NAP, DBP, NP9). En revanche, quelle que soit la qualité chimique du rejet testé, lestaux de germination des semences et les élongations des plantules (principalement leslongueurs racinaires) dépendent de la variété de laitue choisie pour le test. Cetteobservation s’applique aussi aux solutions synthétiques métalliques monocontaminées.Ainsi, pour un même rejet, la Batavia dorée de printemps apparait plus résistante auxpolluants que la Kinemontepas et la Grosse Blonde Paresseuse, et que l’Appia (CE50estimées respectivement à ~99, 59, 43 et 25 %). Ces différences intraspécifiquess’observent également pour la composition interne et les tendances d’enrichissement encertains nutriments et ETM, malgré la présence de Cd dans le péricarpe de semences“vierges”. / This thesis has explored the surface treatment DW and mono- and polycontaminatedsynthetic solution ecotoxicological impact assessment on lettuce Lactuca sativa L.Ecotoxicological seed germination bioassays reflect the DW chemical variability, theirchemical improvement after metallic and/or organic abatement, and also permit toclassify MTE (Fe, Cr, Co, Cu, B, Al, F, Ni, Cd, Ag, Zn, Sn) and POP (4NP, NAP,DBP, NP9) according to their increasing ecotoxicity. However, whatever the DWchemical quality, seeds germination rates and plantlets elongations (mainly rootelongations) depend on lettuce variety’s choice. It is also true for monometallicsolutions. Thus for the same DW sample, the Batavia dorée de printemps varietyappears to be more resistant to pollutant than the Kinemontepas and the GrosseBlonde Paresseuse varieties, and than the Appia variety (estimated EC50 respectively99, 59, 43 and 25 %). Despite the presence of Cd in virgin pericarp seeds, intraspecificdifferences occured as well when analyzing the inner plantlet compositions and thenutrients and MTE uptake patterns.
4

Développement de méthodes d’évaluation de la teneur en éléments trace pour la qualité sanitaire des récoltes / Development of assessment methods of the trace element content for the sanitary quality of crops

Faucher, Stéphane 18 December 2013 (has links)
Ce travail de recherche porte sur la mise en place d’outils permettant d’évaluer le transfert en éléments trace des sols agricoles vers les plantes. Il a été ciblé sur quatre éléments trace métalliques réglementés dans le sol et/ou la plante à savoir le cadmium, le cuivre, le plomb, le zinc, ainsi qu’un élément trace supplémentaire en voie de réglementation, l’arsenic. Dans un premier temps, un protocole d’échantillonnage a été développé afin de disposer d’un outil de diagnostic pré-récolte. Le cahier des charges a été défini de telle façon que ce protocole soit opérationnel, représentatif de la parcelle, applicable pour différentes parcelles et cultures et autorise une spatialisation de la concentration en éléments trace. Il est de type aléatoire stratifié afin de pouvoir couvrir la totalité de la surface étudiée. Dans un second temps, l’étude s’est portée sur le développement d’une méthode d’analyse des sols par électrochimie afin de disposer d’un outil d’évaluation de la biodisponibilité potentielle des éléments traces et donc du risque de transfert sol - plante. Pour ce faire, les concentrations des éléments sous leurs formes électrolabiles ont été déterminées par voltammétrie de redissolution anodique utilisant des électrodes sérigraphiées élaborées au laboratoire. La méthode a été développée et validée à partir d’une solution de sol de référence minéralisé. Elle a été par la suite appliquée à des solutions de différents sols agricoles obtenues par lixiviation selon un protocole normalisé (NF ISO 18772). / This study concerns the establishment of tools, which allow evaluating the transfer of trace elements from agricultural soils to plants. It focused on four metal trace elements regulated in soil and/or in plants, which are cadmium, copper, lead, zinc, as well as a trace element in the process of regulation, arsenic. First, a sampling protocol was developed in order to dispose of a tool of pre-harvest diagnostic. The specifications were defined such that this protocol is operational, representative of the parcel, applicable to various parcels and crops and authorizes a spatial distribution of the trace element concentration. It is based on random stratified type in order to be able to cover the whole of the considered area. Then, the study focused on the development of a soil analysis method by electrochemistry in order to dispose of a tool for assessing the potential bioavailability of trace elements and therefore the risk of the soil - plant transfer. For that, the electrolabile form concentrations of these elements were determined by anodic stripping voltammetry using screen printed electrodes produced at the laboratory. The method was developed and validated from a solution of a mineralized certified reference soil. It was subsequently applied to solutions of different agricultural soils obtained by leaching according to a normalized protocol (NF ISO 18772).
5

Diversités taxonomique et fonctionnelle des communautés microbiennes en lien avec le cycle du carbone dans un gradient de sols multi-contaminés / Taxonomic and functional diversity of microbial communities in relation to the carbon cycle in a multi-contaminated soil gradient

Lemmel, Florian 14 January 2019 (has links)
Les activités sidérurgiques du siècle dernier ont laissé derrière elles des sols de friches multi-contaminés. Cette multi-pollution a dû conduire à une adaptation des communautés microbiennes, pouvant impacter leurs diversités et in fine le fonctionnement des sols. Dans ce contexte, les objectifs de mes travaux de thèse étaient : i) d’étudier la diversité taxonomique des communautés microbiennes mais aussi leur diversité fonctionnelle en lien avec le cycle du carbone, ii) d’identifier les éventuels liens qui unissent ces deux diversités et iii) de comprendre comment les caractéristiques des sols et leur pollution pouvaient modifier ces liens. Une collection de sols présentant un gradient de pollution par des hydrocarbures aromatiques polycycliques (HAP) et des éléments traces métalliques (ETM) a été étudiée. La diversité taxonomique des communautés bactériennes et fongiques a été obtenue par séquençage Illumina MiSeq et la diversité fonctionnelle métabolique a été estimée à l’aide des outils Biolog® et MicroResp™. La dégradation de deux substrats carbonés modèles, le phénanthrène (PHE) et la cellulose (CEL) marqués au 13C, a également été analysée par la technique de Stable Isotope Probing, qui en identifiant les microorganismes impliqués dans la dégradation de ces composés, permet de lier la diversité taxonomique à une fonction. Globalement, en sélectionnant les microorganismes, le niveau de contamination a modulé positivement ou négativement l’abondance relative de différents taxons bactériens et fongiques. Contrairement aux HAP, les ETM ont induit une diminution de la diversité fonctionnelle métabolique, mais aussi une tolérance accrue au zinc. Le potentiel fonctionnel de dégradation des HAP était positivement corrélé à la teneur en HAP des sols alors que les fonctions de dégradation du PHE et de la CEL étaient présentes dans tous les sols, quel que soit leur niveau de contamination. Les taux de dégradation de ces composés étaient positivement corrélés à l’abondance et la richesse microbienne, mais sans lien avec la pollution des sols. En outre, le taux de dégradation du PHE était expliqué par les abondances relatives des genres Massilia et Mycobacterium identifiés parmi les bactéries dégradantes. En conclusion, nous avons observé une diminution de l’intensité de dégradation de plusieurs composés carbonés, voire la disparition totale de la fonction, suggérant un possible dysfonctionnement du cycle du carbone dans certains des sols les plus pollués / The iron and steel activities of the last century have left behind multi-contaminated brownfields. This multi-pollution must have led to an adaptation of microbial communities, potentially impacting their diversities and ultimately the soil functioning. In this context, the objectives of my PhD thesis were: i) to study the taxonomic diversity of microbial communities, but also their functional diversity in relation to the carbon cycle, ii) to identify the possible relationships between these two diversities and (iii) to understand the impact of soil characteristics and pollution on communities. In this way, a collection of ten multi-contaminated soils, with both polycyclic aromatic hydrocarbons (PAH) and metallic trace elements (MTE) gradients, was studied. The bacterial and fungal taxonomic diversities were obtained using Illumina MiSeq sequencing and the metabolic functional diversity was estimated through Biolog® and MicroResp™ assays. The degradation of two model carbon substrates, namely 13C-labeled phenanthrene (PHE) and 13C-labeled cellulose (CEL), was also analyzed using Stable Isotope Probing technique, which, by identifying the microorganisms involved in the substrate degradation, allows to link function with taxonomic diversity. Overall, by selecting microorganisms, the contamination level positively and negatively modulated the relative abundance of different bacterial and fungal taxa. Unlike PAH, MTE induced a decrease of metabolic functional diversity, but also a greater zinc tolerance. The functional potential of PAH degradation was positively correlated with the PAH concentration in soils, while the PHE and CEL degradation functions were present in all soils, irrespective of their contamination level. Degradation rates of these compounds were positively correlated with microbial abundance and richness, but not linked to soil pollution. In addition, the PHE degradation rate was explained by the relative abundances of the Massilia and Mycobacterium genera, identified among the active PHE-degrading bacteria. In conclusion, we observed a decrease in the degradation intensity of several carbon compounds, or even the total disappearance of various functions, suggesting a potential dysfunction of carbon cycle in some of the most polluted soils
6

Concepções sobre ciência e tecnologia de professores de ciências em formação continuada e seus planos de ensino / Conceptions on Science and Technology of in Service Formation Science Teachers and Their Teaching Plans

Silva, Daniela Fiorini da 16 May 2017 (has links)
Esta pesquisa se desenvolve no âmbito do ensino de ciências, no que tange à formação continuada de professores de Ciências e sequências didáticas. Objetivando-se obter um levantamento palpável sobre as concepções dos professores de Ciências sobre Ciência e Tecnologia (C&T), foram utilizadas duas ferramentas de coletas de dados: Uma enquete e sequências didáticas (SD) desenvolvidas pelos professores cursistas participantes do Curso de Especialização em Ensino de Ciências da Faculdade de Educação da USP no Programa Rede de Formação Docente (EEC-FEUSP-REDEFOR) durante o segundo ano de oferecimento, 2011-2012. O foco principal do presente estudo é sistematizar as concepções sobre C&T dos professores cursistas e observar como estas permeiam o desenvolvimento de SD, para que se obtenham subsídios e reflexões sobre os objetivos da educação científica, da formação de professores e do entendimento dos professores de ciências sobre as questões sócio científicas (QSC). A análise dos dados se desenvolveu utilizando duas abordagens, quantitativa e qualitativa, de forma a se complementarem. As análises estatísticas nomeadas análise multifatorial e de cluster, e abordagem qualitativa descritiva documental dos resultados sustentam a análise como um todo, interpretando os resultados obtidos, trazendo assim uma visão ampla do objeto de estudo que aponta a presença de dez tipos de concepções, 8 tipos de perfis de concepções sobre C&T que se traduzem nas SD em categorias sintéticas como: conhecimento científico prediz, reverte e evita problemas ambientais; conhecimento científico explica e viabiliza melhoria de vida; C&T beneficiam sociedade e ambiente; homem prejudica e desperdiça; preocupação simplória com a degradação ambiental; conteudismo; aproximação CTS e consciência de bem social global; funcionalidade e acesso ao conhecimento científico; conhecimento científico e visões alternativas, e finalmente, impactos do desenvolvimento científico e tecnológico no meio ambiente. A importância de se reconhecer tais variações e sentidos das concepções mais comumente expressas se revela à medida que configuram tópicos de discussão relevantes aos cursos de formação inicial e continuada de professores e a observação da forma como estas SD poderiam sintetizar concepções mais ricas de possibilidades de discussões em sala de aula. / This research develops in the scope of science teaching, in what concerns to in service formation science teachers and didactic sequences. In order to obtain a palpable survey on the conceptions of the teachers on Science and Technology (S & T), two data collection tools were used: a survey and didactic sequences (DS) developed by the teachers participating in the Specialization Course in Science Teaching of the Faculty of Education of USP in the Program of Teacher Education (EEC-FEUSP-REDEFOR), along the second year (2011-2012). The main focus of the present study is to systematize the conceptions about Science and Technology of the teachers and to observe how they permeate the development of DS, to obtain subsidies and reflections on the objectives of scientific education, teacher training and teachers\' understanding Sciences on socio-scientific issues (SSI). The analysis of the data was developed using two approaches: quantitative and qualitative, in order to complement each other. The statistical analyses named multifactorial and cluster analysis, and qualitative documentary descriptive approach of the results support the analysis as a whole, interpreting the results obtained, thus bringing a broad view of the object of study that points out the presence of ten types of conceptions, 8 types of profiles of S & T conceptions that translate into DS in synthetic categories such as: Scientific knowledge predicts, reverses and avoids environmental problems; Scientific knowledge explains and enables improvement in life; Society and Environment; Man harms and wastes; Simplistic concern with environmental degradation; Content; CTS approach and global social welfare awareness; Functionality and access to scientific knowledge; Scientific knowledge and alternative visions, and finally, Impacts of scientific and technological development on the environment. The importance of recognizing such variations and meanings of the most commonly expressed conceptions is revealed by the fact that they configure topics of discussion relevant to the initial and in service formation courses and the observation of how these DS could synthesize richer conceptions of possibilities for discussion In the classroom.
7

Concepções sobre ciência e tecnologia de professores de ciências em formação continuada e seus planos de ensino / Conceptions on Science and Technology of in Service Formation Science Teachers and Their Teaching Plans

Daniela Fiorini da Silva 16 May 2017 (has links)
Esta pesquisa se desenvolve no âmbito do ensino de ciências, no que tange à formação continuada de professores de Ciências e sequências didáticas. Objetivando-se obter um levantamento palpável sobre as concepções dos professores de Ciências sobre Ciência e Tecnologia (C&T), foram utilizadas duas ferramentas de coletas de dados: Uma enquete e sequências didáticas (SD) desenvolvidas pelos professores cursistas participantes do Curso de Especialização em Ensino de Ciências da Faculdade de Educação da USP no Programa Rede de Formação Docente (EEC-FEUSP-REDEFOR) durante o segundo ano de oferecimento, 2011-2012. O foco principal do presente estudo é sistematizar as concepções sobre C&T dos professores cursistas e observar como estas permeiam o desenvolvimento de SD, para que se obtenham subsídios e reflexões sobre os objetivos da educação científica, da formação de professores e do entendimento dos professores de ciências sobre as questões sócio científicas (QSC). A análise dos dados se desenvolveu utilizando duas abordagens, quantitativa e qualitativa, de forma a se complementarem. As análises estatísticas nomeadas análise multifatorial e de cluster, e abordagem qualitativa descritiva documental dos resultados sustentam a análise como um todo, interpretando os resultados obtidos, trazendo assim uma visão ampla do objeto de estudo que aponta a presença de dez tipos de concepções, 8 tipos de perfis de concepções sobre C&T que se traduzem nas SD em categorias sintéticas como: conhecimento científico prediz, reverte e evita problemas ambientais; conhecimento científico explica e viabiliza melhoria de vida; C&T beneficiam sociedade e ambiente; homem prejudica e desperdiça; preocupação simplória com a degradação ambiental; conteudismo; aproximação CTS e consciência de bem social global; funcionalidade e acesso ao conhecimento científico; conhecimento científico e visões alternativas, e finalmente, impactos do desenvolvimento científico e tecnológico no meio ambiente. A importância de se reconhecer tais variações e sentidos das concepções mais comumente expressas se revela à medida que configuram tópicos de discussão relevantes aos cursos de formação inicial e continuada de professores e a observação da forma como estas SD poderiam sintetizar concepções mais ricas de possibilidades de discussões em sala de aula. / This research develops in the scope of science teaching, in what concerns to in service formation science teachers and didactic sequences. In order to obtain a palpable survey on the conceptions of the teachers on Science and Technology (S & T), two data collection tools were used: a survey and didactic sequences (DS) developed by the teachers participating in the Specialization Course in Science Teaching of the Faculty of Education of USP in the Program of Teacher Education (EEC-FEUSP-REDEFOR), along the second year (2011-2012). The main focus of the present study is to systematize the conceptions about Science and Technology of the teachers and to observe how they permeate the development of DS, to obtain subsidies and reflections on the objectives of scientific education, teacher training and teachers\' understanding Sciences on socio-scientific issues (SSI). The analysis of the data was developed using two approaches: quantitative and qualitative, in order to complement each other. The statistical analyses named multifactorial and cluster analysis, and qualitative documentary descriptive approach of the results support the analysis as a whole, interpreting the results obtained, thus bringing a broad view of the object of study that points out the presence of ten types of conceptions, 8 types of profiles of S & T conceptions that translate into DS in synthetic categories such as: Scientific knowledge predicts, reverses and avoids environmental problems; Scientific knowledge explains and enables improvement in life; Society and Environment; Man harms and wastes; Simplistic concern with environmental degradation; Content; CTS approach and global social welfare awareness; Functionality and access to scientific knowledge; Scientific knowledge and alternative visions, and finally, Impacts of scientific and technological development on the environment. The importance of recognizing such variations and meanings of the most commonly expressed conceptions is revealed by the fact that they configure topics of discussion relevant to the initial and in service formation courses and the observation of how these DS could synthesize richer conceptions of possibilities for discussion In the classroom.
8

Biomonitoring environnemental et sanitaire des sols pollués par les éléments traces métalliques / Sanitary and environmental biomonitoring of polluted soil by metallic trace elements

Lévèque, Thibaut 24 October 2014 (has links)
Dans un contexte où les préoccupations environnement-santé sont croissantes à l’échelle globale. Améliorer la compréhension des mécanismes de biodisponibilité et d’(éco)toxicité des polluants métalliques persistants est un enjeu prioritaire, notamment en raison de leur omniprésence observée dans les écosystèmes en relation avec leur compartimentation et spéciation . Le ver de terre est utilisé pour évaluer la qualité des sols ; de plus cet organisme du sol de par ses activités de bioturbation a une influence sur les cycles biogéochimiques. Des tests d’écotoxicité en conditions contrôlées sur vers de terre ont donc été réalisés avec différents sols et espèces de vers. Puis une étude d’impact sur les communautés de vers a été effectuée sur un site pollué présentant un gradient de concentration. L’influence de la bioturbation du ver sur la phytodisponibilité des polluants a été étudiée grâce à des expériences en mésocosmes. Finalement, des mesures de bioaccessibilité des polluants ont été réalisées in vitro sur des sols et végétaux pollués dans différents contextes : friches industrielles, jardins potagers, terrain de sport. L’objectif étant d’étudier le lien entre biodisponibilité pour l’homme, caractéristiques des sols et contexte de pollution. Deux approches complémentaires ont été développées : recherche scientifique liés aux mécanismes et développement d’outils, de procédures pratiques utilisables par les gestionnaires et évaluateurs de risques. L’écotoxicité des métaux et métalloïdes (notés ETM) sur les vers de terre n’est pas simplement régie par leurs concentrations totales, mais dépend fortement des caractéristiques physico-chimiques des sols. Par ailleurs, l’analyse des communautés de ver de terre présentes sur un site contaminé permet d’évaluer la qualité des sols puisqu’on constate un impact sur les l’abondance, la diversité et le taux de juvénile des vers. De plus, la bioturbation du ver de terre augmente significativement la biodisponibilité des ETM pour les plantes potagères telles que la laitue. Finalement, la bioaccessibilité humaine des ETM est régi par de nombreux facteurs liés en particulier au contexte de pollution. Cette fraction bioaccessible des ETM est directement responsable de leur cytotoxicité sur les cellules intestinales. Ces différents résultats ont été complétés par des études mécanistiques (IR, EXAFS, XANES, µ-XRF). / In a context where environmental health concerns are globally increasing. Improve understanding of the mechanisms and bioavailability (eco) toxicity of persistent metals pollutants is a priority, especially because of their observed omnipresence in ecosystems in relation to their compartmentation and speciation. The earthworm is used to assess soil quality; moreover this soil organism through its bioturbation activities affects biogeochemical cycles. Ecotoxicity tests under controlled circumstances on earthworms have been conducted with different soils and worms’ species. Then an impact study on earthworms’ communities was conducted on a polluted site showing a concentration gradient. The influence of earthworms’ bioturbation on phytoavailability of pollutants was studied through experiments in mesocosms and Rhizotest. Finally, in vitro measures of pollutants bioavailability were performed on polluted soils and plants in different contexts: brownfields, gardens, sports field. The objective is to study the link between bioavailability for humans, soil characteristics, context of pollution and toxicity. Two complementary approaches have been developed: scientific research related to the mechanisms and development of tools, practical procedures which could be used by managers and risk assessors. Ecotoxicity of metals and metalloid (denoted ETM) on earthworms is not simply governed by their total concentrations, but strongly depends on the physico-chemical characteristics of soils. Furthermore, analysis of earthworm communities from a contaminated site can evaluate the quality of soil since seen an impact on the abundance, diversity and rate of juvenile worms. In addition, earthworms’ bioturbation significantly increases the bioavailability of ETM for vegetable plants such as lettuce. Finally, the human bioaccessibility of ETM is governed by many factors, in particular the context of pollution. The bioaccessible fraction of ETM is directly responsible for their cytotoxicity on intestinal cells. These results were complemented by mechanistic studies (IR, EXAFS, XANES, μ-XRF).
9

Gestion et valorisation des Mâchefers d’Incinération de Déchets non Dangereux (MIDND) : Etude du comportement des polluants inorganiques traces au cours de la maturation et en fonction de la granulométrie / Management et valorization of municipal solid waste incineration bottom ash : Studying the behavior of inorganic trace pollutants during weathering and as a function of particle size

Gonzales Ramirez, Maria-Lorena 04 December 2014 (has links)
L’enjeu actuel autour de la gestion des MIDND est de valoriser, dans la mesure du possible, les mâchefers sur les chantiers routiers à maîtrise d’ouvrage publique ou privée, tout en tenant compte de la réglementation en vigueur et en réalisant un suivi rigoureux dès l’élaboration jusqu’à leur mise en place. Un des freins de la valorisation des MIDND est relatif aux critères de qualité de plus en plus contraignants. Parmi les polluants potentiels qui peuvent entrainer des restrictions environnementales d’utilisation, les éléments trace métalliques (ETM), dont le comportement en fonction des paramètres que sont la maturation et la granulométrie reste peu connu, sont des plus préoccupants. Dans cette thèse, l’approche développée a permis de définir les conditions favorables au relargage des ETM suivants : Cu, Cr, Pb, Sb, Ni et Zn. La démarche scientifique s’articule autour de trois grands axes : Le premier axe concerne le développement d’une méthode de caractérisation pertinente des MIDND (notamment de la fraction organique et de la fraction minérale polluante) afin de pouvoir mieux juger de leurs qualités. La matrice initiale d’étude prélevée sur un site industriel ainsi que ses fractions granulométriques, ont été finement analysée, tant d’un point de vue physico-chimique qu’en ce qui concerne leur comportement environnemental. La modélisation géochimique basée sur ces données physicochimiques et de lixiviation permet d’identifier des phases majoritaires et de simuler le comportement du matériau dans la perspective de prévoir l’évolution du MIDND en conditions spécifiques de stockage ou de valorisation. Le deuxième axe décrit l’impact des conditions de maturation, et du fractionnement granulométrique sur l’évolution de la qualité des MIDND. Trois différentes conditions de maturation (naturelle sur plate-forme; accélérée sur petit tas; forcée) ont été étudiées. Les résultats montrent que les changements dans la composition chimique et minéralogique des MIDND étudiés et de leurs fractions granulométriques sont plus significatifs lorsque la maturation progresse. La maturation naturelle accélérée et la carbonatation forcée limite la lixiviation du Cu, du Pb et du Zn. Au contraire, la lixiviation du Cr, de Sb, des Cl- et des SO42- augmente lorsque le pH diminue. Le troisième axe est dédié à l’étude de l’utilisation des MIDND comme matière première secondaire dans un scénario de valorisation alternatif aux utilisations en sous-couches routières classiquement pratiquées. Le scénario consiste à incorporer les MIDND dans un coulis auto-compactant utilisable pour l’élargissement de chaussées ou le comblement de fossés. Une formulation a pu être définie. La conformité des performances mécaniques, géotechniques et environnementales aux spécifications d’usage normalisées, est encourageante pour les potentiels utilisateurs des MIDND en technique routière. / Current challenge of Municipal Solid waste Incineration (MSWI) bottom ash management lays in its valorization, mainly to be used in road construction projects. The process must take into account environmental regulations and conduct rigorous monitoring from production to utilization. One constraint in the assessment of MSWI bottom ash is related to quality criteria which is becoming more restrictive. Among potential pollutants that can cause environmental use restrictions are metal trace elements (MTE), whose behavior based on weathering and grain size is not yet well known and represent one of greatest concern. In this thesis, the developed research approach defined the favorable conditions for Cu, Cr, Pb, Sb, Ni and Zn release. The aforementioned approach is based on three pillars: The first pillar focuses on the development of a pertinent characterization method for bottom ash (including the polluting organic and mineral fraction) aiming at a better assessment of its properties. The initial study matrix, taken from an industrial site, was carefully analyzed from both, physico-chemical and environmental performances. Geochemical modeling based on physico-chemical and leaching data, allowed to identify the main mineral phases and to simulate material behavior with the purpose of predicting the evolution of MSWI bottom ash in specific storage or valorization conditions. The second pillar describes the impact of weathering conditions and size partitioning on MSWI bottom ash quality evolution. Three different weathering conditions (natural on industrial scale heap; accelerated on small heap; and forced) were studied. The results showed that changes in the chemical and mineralogical composition of MSWI bottom ash as well as in its size fractions are more significant when the weathering proceed. The natural accelerated weathering and the forced carbonation limited the leaching of Cu, Pb and Zn, whereas, the leaching of Cr, Sb, Cl and the SO42- increased as pH decreased. The third pillar focuses on the study of MSWI bottom ash alternative utilization as secondary raw material for the typically practiced road sub-layers construction. It consisted of incorporating MSWI bottom ash in a self-compacting material used for pavement sub-layer or coated road shoulders structures. A formulated material was obtained by mixing MSWI bottom ash, water and cement as a hydraulic binder. The results of the mechanical, geotechnical and environmental assessment are promising for MISWI bottom ash potential use in road construction.

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