Τα τελευταία χρόνια, υπάρχει έντονο ερευνητικό ενδιαφέρον για την φασματοσκοπία πλάσματος, η οποία βασίζεται στην μελέτη της ηλεκτρομαγνητικής ακτινοβολίας που εκπέμπεται όταν η ύλη βρίσκεται σε κατάσταση ολικού ή μερικού ιονισμού. Έτσι προκειμένου να δημιουργηθεί πλάσμα, απαιτείται να προσφερθεί στο ουδέτερο αρχικά δείγμα, ενέργεια σημαντικής ποσότητας. Κατά τη διεξαγωγή των πειραμάτων, την απαιτούμενη ενέργεια την παρείχαν δύο διαφορετικές πηγές: ένα laser Nd-YAG και ένας ηλεκτρικός σπινθηριστής. Οι φασματοσκοπικές αυτές μέθοδοι ονομάζονται Libs (Laser Induced Breakdown Spectroscopy) και Sibs (Spark Induced Breakdown Spectroscopy) αντίστοιχα. Στην παρούσα ειδική ερευνητική εργασία, οι τεχνικές αυτές εφαρμόζονται για την επαγωγή πλάσματος σε δύο διαφορετικά δείγματα: σε ατμοσφαιρικό αέρα και σε προ-αναμεμειγμένα μίγματα υδρογονάνθρακα-αέρα. Αρχικά λοιπόν, μελετήθηκαν ποιοτικά τα φάσματα εκπομπής πλάσματος επαγόμενου από τους δύο σπινθήρες για να συλλεχθούν πληροφορίες για το οξειδωτικό μέσο, εν προκειμένω του αέρα και στη συνέχεια, συγκρίθηκαν με τα φάσματα εκπομπής πλάσματος σε φλόγες. Επιπλέον, η φασματοσκοπία πλάσματος χρησιμοποιήθηκε για την μελέτη μιγμάτων με διαφορετική αναλογία καυσίμου προς οξειδωτικό μέσο το κάθενα, μέγεθος που εκφράζεται μέσω του λόγου ισοδυναμίας,φ. Τέλος, συσχετίστηκε η ολική ένταση της μοριακής ταινίας του ελεύθερου ριζικού κυανίου (CN), ενδιάμεσο προϊόν της καύσης, με το φ όπου και διαπιστώθηκε η γραμμική σχέση που συνδέει τις παραπάνω ποσότητες. Αποτέλεσμα αυτής της εργασίας αποτελεί το γεγονός ότι οι τεχνικές αυτές θα μπορούσαν να χρησιμοποιηθούν σαν διαγνωστικά εργαλεία για τη μελέτη φλογών άγνωστης περιεκτικότητας σε καύσιμο όχι μόνο στους εργαστηριακούς χώρους αλλά και σε in-situ περιβάλλοντα. / Over the past few years, there has been an intense research interest over the plasma spectroscopy, which is based on the study of the electromagnetic radiation propagated by matter in total or partial ionized state. Hence, in order to create plasma, it is necessary to provide the neutral sample with a significant amount of energy. During the experimental procedures, the required energy was provided by two different energy sources, a laser Nd-YAG and an electrical scintillator. The afore-mentioned spectroscopic methods are called Libs (Laser Induced Breakdown Spectroscopy) and Sibs (Spark Induced Breakdown Spectroscopy), respectively. In the present study, these techniques are applied to induce plasma in atmospheric air and in premixed flammable hydrocarbon-air mixtures. At first, the emission spectra of plasma induced by the two sparks were qualitatively analyzed in order to capture data concerning the oxidizing agent, namely the air. Then the spectra were compared to the spectra of the plasma in flame. Moreover, plasma spectroscopy was used to study combustible mixtures of different fuel concentrations, which are characterized by the equivalence ratio, φ. Finally, the total intensity of the molecular band of the free radical cyanogens (CN), known meta-stable product of the combustion was correlated to φ. This correlation demonstrates that the growth of the CN band with the amount of fuel in the mixture is evident and simple linear correlation exists between them. The major result of this study is the fact that these techniques could possibly be used as diagnostic and analytical tools for the study of flames of unknown fuel concentration, not only in the laboratory but also in field conditions.

The aim of this diploma thesis is to focus on the resistance of concrete exposed to high temperatures especially with focus of resistance against explosive spalling as well as clarifying the mode of action of various types of polypropylene fibres. The theoretical part is an introduction to the issues of explosive spalling, its mechanisms and majority influencing factors. Further description of the processes taking place in the structure of concrete under extreme thermal load, distribution and size of pores in concrete, thermal load, temperature-time curves and their applications, methods of elimination of negative behaviour of concrete exposed to thermal loading (passive and active methods), mode of action of polypropylene fibres and more is also included in the theoretical part. The main aim of experimental part is to verify the function of polypropylene fibers of various Melt Flow Indexes (MFI) and dosage. Primarily, the test samples with content of the PP-fibers are compared to the reference sample without fibers. Secondarily, the samples with standard PP-fibers (with MFI 25) with dosage 2.0 kg/m3 are compared to samples with modified PP-fiber (with MFI 2500) of dosage 0.9 kg/m3. Photogrammetric images were used for evaluation and comparison of spalled surfaces and its depth. Determination of the softening temperature and melting point of the modified and standard PP-fibers was made by using a high temperature microscope video. The second part of the experimental work was to define concrete permeability at different temperatures and pressures. Permeability was measured at temperatures of 20°C, 90°C, 150°C, 175°C, 200°C, 225°C and 250°C and at pressure of 0.2, 0.4 and 0.6 MPa.

Les écosystèmes marins côtiers sont constament soumis à des pollutions, notamment aux hydrocarbures, du fait de leur localisation et de leurs caractéristiques environnementales. Le rôle clé des microorganismes dans la dégradation de ces polluants est aujourd’hui très bien décrit. Toutefois, les conditions d’oxygénation fluctuantes dans ces environnements côtiers, dues aux marées et aux activités de bioturbation de la macrofaune, influencent les communautés microbiennes.Ainsi, ce travail de thèse a eu pour objectif de caractériser, l’assemblage de communautés microbiennes hydrocarbonoclastes de sédiments marins côtiers soumises à des oscillations oxie/anoxie en présence de pétrole lors d’une expérience en bioréacteurs. L’adaptation des bactéries marines hydrocarbonoclastes notamment des genres Alcanivorax et Cycloclasticus vis-à-vis de ces variations d’oxygène a pu être investiguée par oligotypage. Des écotypes ont été identifiés en fonction des conditions d’oxygénation démontrant ainsi les capacités d’adaptation aux conditions oscillantes d’oxygène de ces deux genres. La structure des communautés archéennes (séquençage des transcrits du gène de l’ARNr 16S) n’a pas montré de modification évidente liée aux conditions d’oxygénation démontrant ainsi des capacités d’adaptation et/ou de résistance plus importantes chez ces microorganismes comparées aux communautés bactériennes. Enfin, les analyses métagénomiques ont mis en évidence une réponse fonctionnelle spécifique aux oscillations oxie/anoxie. Ainsi, ces travaux de thèse apportent de nouvelles connaissances sur l’influence des variations d’oxygénation sur les communautés microbiennes et par conséquent sur la dégradation des hydrocarbures au sein des écosystèmes marins côtiers. / Coastal marine ecosystems are constantly subject to pollution, particularly hydrocarbons, because of their location and their environmental characteristics. The key role of microorganisms in the degradation of these pollutants is now well described. However, fluctuating oxygenation conditions in these coastal environments, due to tides and macrofauna bioturbation activities influence microbial communities.Thus, this thesis work aimed to characterize the assembly of microbial hydrocarbonoclastic communities of coastal marine sediments subjected to oxic/anoxic oscillations in the presence of oil during a bioreactor experiment. The adaptation of MOHCB, particularly of Alcanivorax and Cycloclasticus genera, to these oxygen variations has been investigated by oligotyping. Ecotypes were identified according to the oxygenation conditions demonstrating adaptation capacities of these two genera to the oscillating oxygen conditions. The structure of archaeal communities (16S rRNA transcript sequencing) did not show any modification related to the oxygenation conditions thus demonstrating greater adaptation and/or resistance capacities in these microorganisms compared to the bacterial communities. Finally, metagenomics analyses revealed a specific functional response to oxic/anoxic oscillations. Thus, this thesis provides new insights into the influence of oxygenation variations on microbial communities and consequently on the degradation of hydrocarbons in coastal marine ecosystems.

Made available in DSpace on 2014-12-17T15:01:27Z (GMT). No. of bitstreams: 1 SidrakJP_DISSERT.pdf: 3365381 bytes, checksum: 55b6f324d82bc4f385aa87921831ed44 (MD5) Previous issue date: 2011-12-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This dissertation aims to assess the representativeness of the manual chilled mirror analyzer (model II Chanscope 13-1200-CN-2) used for the determination of condensed hydrocarbons of natural gas compared to the indirect methods, based on thermodynamic models equation of state. Additionally, it has been implemented in this study a model for calculating the dew point of natural gas. The proposed model is a modification of the equation of state of Peng-Robinson admits that the groups contribution as a strategy to calculate the binary interaction parameters kij (T) temperature dependence. Experimental data of the work of Brown et al. (2007) were used to compare the responses of the dew point of natural gas with thermodynamic models contained in the UniSim process simulator and the methodology implemented in this study. Then two natural gas compositions were studied, the first being a standard gas mixture gravimetrically synthesized and, second, a mixture of processed natural gas. These experimental data were also compared with the results presented by UniSim process simulator and the thermodynamic model implemented. However, data from the manual analysis results indicated significant differences in temperature, these differences were attributed to the formation of dew point of water, as we observed the appearance of moisture on the mirror surface cooling equipment / O presente trabalho de disserta??o tem por objetivo avaliar a representatividade do analisador manual de espelho refrigerado (Chanscope II modelo 13-1200-C-N-2) usado para a determina??o do condensado de hidrocarbonetos de g?s natural frente aos m?todos indiretos, fundamentados em modelos termodin?micos de equa??o de estado. Adicionalmente, tem sido implementado neste estudo um modelo para c?lculo do ponto de orvalho de g?s natural. O modelo proposto constitui uma modifica??o na equa??o de estado de Peng-Robinson que admite a contribui??o de grupos como estrat?gia para calcular os par?metros de intera??o bin?ria kij(T) com depend?ncia da temperatura. Dados experimentais do trabalho de Brown et al. (2007) foram utilizados para comparar as respostas de ponto de orvalho do g?s natural com os modelos termodin?micos contidos no simulador de processo UniSim e com a metodologia implementada neste estudo. Em seguida, duas composi??es de g?s natural foram estudadas, sendo a primeira uma mistura padr?o de g?s sintetizada gravimetricamente e, a segunda, uma mistura de g?s natural processado. Tais dados experimentais foram tamb?m comparados com os resultados apresentados pelo simulador de processo UniSim e pelo modelo termodin?mico implementado. No entanto, os dados do analisador manual indicaram diferen?as significativas nos resultados de temperaturas, sendo estas diferen?as atribu?das ? forma??o de ponto de orvalho de ?gua, j? que foi observado o aparecimento de umidade sobre a superf?cie do espelho refrigerado do equipamento

Algumas atividades antrópicas podem provocar alterações nos recursos naturais, seja ela no rio, no solo ou no mar. Os efeitos destas alterações podem ser observados na biota, na qualidade das águas, na disponibilidade de nutrientes, interferindo em todos os elementos que compõem o ecossistema, influenciando-o em maior ou menor grau. O presente estudo procurou determinar o efeito dos poluentes sulfato de zinco, cloreto de amônia, dodecilsulfato de sódio e benzeno, numa espécie bioindicadora marinha, el larvas de mexilhão (Perna perna), além de acrescentar dados sobre a biologia e analisar quimicamente a presença de hidrocarbonetos nos tecidos dos animais adultos e das larvas. Para tanto foram utilizados testes de toxicidade, estudos sobre a bioenergética (consumo de oxigênio e excreção de amônia), enzimas biomarcadoras e excreção de fósforo e nitrogênio. Com relação à biologia, foram encontrados indivíduos sexualmente maduros a partir de 26,1 e 27 mm de comprimento para fêmeas e machos, respectivamente, e há diferença, ainda que esta não seja estatisticamente significativa, entre ovócitos e larvas submetidos a ação de poluentes. A análise de hidrocarbonetos indicou que existe uma contribuição biogênica e petrogênica no litoral norte do Estado de São Paulo. Para as demais análises verificou-se que, quando comparados aos grupos controles, as larvas foram sensíveis e responderam aos diferentes poluentes, geralmente com inibição da atividade. / Some antropic activities may be the cause fo alterations in natural resources, being it river, soil or sea. These alteration effects may be observed in the biota, water quality, nutrients disponibility, interfering with all elements that are part of a ecosystem, with greater or lesser influence degree. The present study was directed to determine the effect of pollutants, such as zinc sulphate, ammonia chlorate, sodium dodecilsulphate and benzene, acting over larvae of a marine bioindicator, the mussel (Perna perna), besides adding data on biology and chemically analysing hidrocarbon presence in larvae and adult animal tissues. In order to obtain these results, toxicity tests were used and bioenergetic (oxygen consumption and ammonia excretion), biomarkers, phosphorus and nitrogen excretion, were studied. As for biology, individuals sexually mature were found starting with 26,1 and 27 mm length females and males, respectively, and there is difference between larvae and ovocites, although statistically not significant, submitted to pollutants action. The hydrocarbon analysis indicates a biogenic and petrogenic contribution to north coast of São Paulo State. For the other analyses the observed results, when compared to control groups, showed that larvae are sensitive, and responded to different pollutants, generally with activity inhibition.

A hipóxia ocorre quando a demanda de oxigênio molecular necessário para gerar ATP é insuficiente. Os genes ativados por hipóxia compreendem o gene Hif-1a (Hipóxia-fator induzível 1a), Vegf-a (fator de crescimento endotelial vascular a), Arnt e Vhl (von Hippel-Lindau). Neste estudo foram utilizadas linhagens de camundongos geneticamente selecionados para alta (AIRmax) ou baixa (AIRmin) resposta inflamatória aguda (AIR). Foram realizados testes biológicos para caracterizar as reações inflamatórias produzidas por Biogel e TPA, bem como o tipo PAH cancerígeno. Testamos a expressão de mRNA de genes de hipóxia e caracterização de polimorfismo da região codificadora do Hif-1a no cromossomo 12. Camundongos AIRmax demonstraram uma maior reação inflamatória que os AIRmin para biogel e TPA enquanto o inverso foi observado com o DMBA. Os conjuntos de dados de fenótipos, expressão gênica e polimorfismo candidatam a região do cromossomo 12, que contém, entre outros, o gene Hif-1a, como participante da regulação da AIR. / Hypoxia occurs when the demand for molecular oxygen necessary to generate ATP is insufficient. Genes activated by hypoxia comprise the Hif-1a gene (Hypoxia-Inducible Factor 1a), Vegf-a (Vascular Endothelial Growth Factor a), Arnt and Vhl (von Hippel-Lindau). In this study we used lines of mice genetically selected for high (AIRmax) or low (AIRmin) acute inflammatory response (AIR). We conducted biological tests to characterize the inflammatory reactions produced by Biogel and TPA, and the type PAH carcinogen. We tested the mRNA expression of genes of hypoxia and characterization of polymorphism of the coding region of Hif-1a gene on chromosome 12. We found that the mice AIRmax had greater intensity of the inflammatory reaction that AIRmin to biogel and TPA while the reverse was observed with the DMBA. The data sets of phenotypes, gene expression and polymorphism applying the region of chromosome 12 that contains, among others, the gene Hif-1a, as part of the regulation of AIR.

Les activités industrielles, la production d’énergie le transport et l’urbanisation ont engendré de sérieux problèmes environnementaux qui ont des effets néfastes non seulement pour les divers écosystèmes, mais aussi pour la santé des Humains. Il existe plusieurs méthodes de réhabilitation des sites contaminés. Les méthodes dites conventionnelles consistent le plus souvent à excaver, transporter et entreposer des sols dans des sites d’enfouissements, alors que d’autres technologies utilisent des traitements physico-chimiques ou l’incinération des polluants. Les inconvénients majeur de ces méthodes en sont le coût élevé, l’émission des gaz à effet de serre et la destruction des habitats. Cependant, plusieurs technologies ont émergé ces dernières décennies. Parmi ces technologies émergentes, la phytoremédiation est une méthode prometteuse et dont l’efficacité devienne de plus en plus reconnue. La phytoremédiation consiste à utiliser des plantes et les microbes qui leurs sont associés pour dégrader, extraire ou stabiliser les polluants du sol aussi bien organiques qu’inorganiques. Parmi les microbes associés aux racines des plantes, on trouve les champignons mycorhiziens arbusculaires (CMA) dont le rôle en phytoremédiation a été montré. Cependant, la diversité et les changements des structures des communautés de ces champignons dans des sites hautement contaminés et en association avec les populations des plantes qui poussent spontanément dans ces sites demeurent méconnues. L’objectif de mon projet de maitrise consiste à étudier la diversité et la structure des communautés des CMA dans les racines et les sols rhizosphériques de trois espèces de plantes Eleocharis elliptica, Populus tremuloides et Persicaria maculosa qui poussent spontanément dans des bassins d’une ancienne raffinerie pétro-chimique. J’ai échantillonné trois individus par espèce de plante dans trois bassins qui ont montré des concentrations différentes des polluants pétroliers. J’ai utilisé l’approche de la PCR conventionnelle, le clonage et le séquençage en ciblant le gène 18S de l’ARN ribosomique autant sur des échantillons de racines et des que sur ceux de sols rhizophériques. J’ai analysé au minimum 48 clones par échantillon. L’analyse de la diversité Beta a montré que la structure des communautés des CMA était significativement différente selon les biotopes (racines et sols rhizosphèriques) et les concentrations de contaminants pétroliers. Mes résultats ont montré que l'identité de la plante et la concentration de contaminants ont fortement influencé la structure des communautés de CMA. J’ai aussi observé qu’en plus de l’effet des facteurs biotiques et abiotiques mentionnés ci-dessus, plusieurs OTUs de CMA sont corrélés soit positivement ou négativement entre eux et aussi avec différents types de polluants d'hydrocarbures pétroliers. Cette étude a permis de comprendre les facteurs qui influencent les changements des structures des communautés des CMA et pourrait nous aider à améliorer l’efficacité de la phytoremédiation avec des plantes indigènes poussant spontanément sur des sites hautement contaminés par des hydrocarbures pétroliers. / Industrial activities, energy production, transportation, and urbanization have led to serious environmental problems that have negative effects not only for the natural ecosystems, but also for the human health. Several methods of rehabilitation of contaminated sites such as conventional methods consisting on excavation, transportation and storage of contaminated soils in landfills (known as Dig and Dump), as well as other technologies that use physical and chemical treatments or incineration of polluted soil pollutants, have been largely utilized. However, these methods are very costly and not environmental-friendly because of greenhouse gas emission and destruction of habitats. Several green technologies have emerged in recent decades. Among these emerging technologies, phytoremediation is a promising method whose effectiveness becomes increasingly recognized worldwide. Phytoremediation uses plant and their associated microbes to degrade, uptake or sequestrate organic and inorganic pollutants. Arbuscular mycorrhizal fungi (AMF) are among microbes that live intimately with plant root where they form a symbiosis known as arbuscular mycorrhiza. The objective of my master project was to study the diversity and changes of community structure of AMF in roots and rhizospheric soils of three native plant species Eleocharis elliptica, Populus tremuloides and Persicaria maculosa growing in petroleum-contaminated sedimentation basins of a former petro-chemical plant. I used conventional PCR, cloning and sequencing approach targeting 18S rRNA gene to investigate AMF community structure. I analyzed at minimum 48 clones for each sample. Beta diversity analyses showed that AMF community structure was significantly different across biotopes (roots and rhizospheric soils) and different concentrations of petroleum hydrocarbon contamination. Our results showed that plant identity and concentrations of petroleum hydrocarbon contaminations strongly influenced the AMF community structure as well as the inter-specific relationship among AMF taxa. Moreover, with consideration of both biotic and abiotic factors, we found that several AMF OTUs showed positive and negative correlations between each other and also with petroleum hydrocarbon pollutants. My study brings us in-valuable information to apply AMF for the phytoremediation in the future.

The Karoo Basin of South Africa holds an estimated 906 billion to 11 trillion cubic meters of unconventional shale gas within the shales of the Whitehill and Collingham formations of the Ecca Group. Evaluation of this potential resource has been limited due to the lack of exploration and a scarcity of existing drill core data. In order to circumnavigate this problem this study was undertaken to evaluate the potential target horizons exposed in outcrops along the southern portion of the Karoo Basin, north of Grahamstown in the Eastern Cape Province. Detailed field logging was done on the exposed Whitehill and Collingham formations as well as a possible conventional sandstone (turbidite) reservoir, the Ripon Formation, along road cuttings of the Ecca Pass. Palaeocurrent data, jointing directions and fossil material were also documented. Samples were analysed for mineralogy, porosity, permeability, and total organic carbon content (TOC). The extensively weathered black shales of the Whitehill Formation contain a maximum TOC value of 0.9% and the Collingham Formation shales contain a maximum TOC value of 0.6%. The organic lithic arkose sandstones of the Ripon Formation are classified as ‘tight rock’ with an average porosity of 1% and an average permeability of 0.05 mD. The Whitehill Formation in the southern portion of the Karoo Basin has experienced organic matter loss due to low grade metamorphism as well as burial to extreme depths, thus reducing shale gas potential. The Ripon Formation is an unsuitable conventional reservoir along the southern basin boundary due to extensive cementation and filling of pore spaces.

No description available.

This work includes two unrelated areas of research. The first portion of this work involved combusting densified refuse derived fuel (dRDF) with coal and studying the effect that Ca(0H)2 binder had on reducing polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) emissions. The second area of work was directed at developing nondestructive infrared techniques in order to aid in the analysis of postage stamp adhesives. With Americans generating 150-200 million tons a year of Municipal Solid Waste (MSW) and disposing of nearly ninety percent of it in landfills, it is easy to understand why American landfills are approaching capacity. One alternative to landfilling is to process the MSW into RDF. There are technical and environmental problems associated with RDF. This work provides some answers concerning the amount of PAH and PCB emissions generated via the combustion of RDF with coal. It was found that the Ca(OH)2 binder greatly reduced both the PAH and the PCB emissions. In fact, PAH emissions at the ten-percent level were reduced more by using the binder than by the pollution control equipment. If the Ca(0H)2 binder can reduce not only PAH and PCB emissions, but also other noxious emissions, such as acid gases or dioxin, RDF technology could soon be the answer to the current landfill problems. The second portion of this work focused on developing a method to analyze stamp adhesives nondestructively. Using this method, it was fairly easy to differentiate among the three different types of adhesives that have been used by the United States Postal Service: gum arabic, dextrin, and polyvinyl alcohol. Differences caused by changes in chemicals added to the adhesives were also detected. Also, forgeries were detected with as much success, if not more, than by conventional methods. This work also led to the construction of equipment that allows large samples to be analyzed by reflectance infrared methods.