O presente estudo, composto por 2 experimentos in situ, buscou avaliar o efeito da irradiação com laser de CO2 no controle da progressão de lesões de erosão e, posteriormente, analisar a influência da abrasão em superfícies irradiadas e erodidas. No primeiro experimento, 56 fragmentos de incisivos bovinos (5x3x2.5mm) tiveram suas superfícies de esmalte divididas em 4 áreas: 1. Hígida (área de referência); 2. Erosão inicial; 3. Tratamento (irradiado ou não com laser de CO2); 4. Após fase in situ. O desafio erosivo inicial foi realizado com ácido cítrico 1% (pH=2,3) por 5 minutos, 2x/dia, por 2 dias. Os espécimes foram divididos em 2 grupos de acordo com o tratamento da superfície: irradiados com laser de CO2 ( λ= 10,6 m; 0,5 W) e não irradiados. Após um período de lead-in de 2 dias, 14 voluntários usaram um dispositivo intraoral palatino contendo 2 espécimes (irradiado e não irradiado), em 2 fases intraorais de 5 dias cada. Seguindo um desenho cross-over, durante a primeira fase, metade dos voluntários imergiu seu dispositivo em 100mL de ácido cítrico por 5 minutos, 3x/dia, enquanto a outra metade usou água deionizada (controle). Os voluntários foram cruzados quanto aos desafios na segunda fase. O desgaste do esmalte foi determinado quantitativamente por um perfilômetro óptico e a morfologia da superfície do esmalte foi avaliada qualitativamente por microscopia eletrônica de varredura. ANOVA a três critérios para medidas repetidas mostrou que não houve interação significativa entre desafio erosivo e irradiação com laser de CO2 (p=0,419). O desafio erosivo aumentou significativamente o desgaste do esmalte (p=0,001), independente de ter sido realizada ou não a irradiação com laser de CO2. Não houve diferença no desgaste do esmalte entre os espécimes irradiados e não irradiados (p=0,513). No segundo experimento, o preparo e seleção dos espécimes de esmalte bovino, a indução das lesões de erosão iniciais e os tratamentos foram realizados como no primeiro experimento. Após um período de 2 dias de lead-in, 12 voluntários usaram um dispositivo palatino contendo dois espécimes irradiados e dois não irradiados, em duas fases intraorais de 5 dias cada. Seguindo um protocolo split-mouth, os voluntários imergiram extraoralmente, durante 5 minutos, os dispositivos em ácido cítrico 3x/dia por 5 dias. Uma hora após cada desafio erosivo, um espécime irradiado e um não irradiado foram escovados usando uma escova elétrica e slurry de dentifrício. As variáveis de resposta foram as mesmas empregadas no primeiro experimento. ANOVA a dois critérios revelou que não houve interação significativa entre desafio erosivo-abrasivo e irradiação com laser de CO2 (p=0,614). A irradiação laser não influenciou no desgaste do esmalte (p=0,742). O desgaste do esmalte dos espécimes submetidos a erosão + abrasão não foi diferente daquele verificado quando a erosão foi realizada sozinha (p=0,626), independente do laser de CO2 ter sido aplicado ou não. Pode-se concluir que, em condições intraorais, a irradiação com laser de CO2 não controlou a progressão de lesões de erosão nem de lesões de erosivo-abrasivas no esmalte. / This study, composed of 2 in situ experiments, aimed to evaluate the effect of CO2 laser irradiation to control the progression of erosive lesions and, after, analyze the influence of abrasion on irradiated and eroded surfaces. At the first experiment, 56 slabs of bovine incisors (5x3x2.5mm) had its enamel surface divided in 4 areas: 1. Sound (reference area); 2. Initial erosion; 3. Treatment (irradiated or not with CO2 laser); 4. After in situ phase. The erosive challenge was performed with 1% citric acid (pH 2.3), during 5 minutes, 2x/day, for 2 days. The specimens were divided in 2 groups according to the surface treatment: CO2 laser irradiated (λ = 10.6 m; 0.5 W) and non-irradiated. After a 2-day-lead-in period, 14 volunteers wore an intraoral palatal device containing 2 specimens (irradiated and non-irradiated), in 2 intraoral phases of 5 days each. Following a crossover design, during the first phase, half of the volunteers immersed its device on 100mL of citric acid during 5 minutes, 3x/day, while the other half immersed on deionized water (control). Volunteers were crossed on the challenges on the second phase. The enamel wear was quantitatively determined by an optical profilometer and the morphology of enamel surface was qualitatively evaluated by scanning electron microscopy. Three-way ANOVA for repeated measures showed that there was no significant interaction between erosive challenge and CO2 laser irradiation (p=0.419). The erosive challenge significantly increased the enamel wear (p=0.001), regardless of irradiated or not with CO2 laser. There was no difference on the enamel wear of irradiated and non-irradiated specimens (p=0.513). At the second experiment, preparation and selection of bovine enamel specimens, induction of initial erosive lesion and treatments were performed as already described for the first experiment. After a 2-day-lead-in period, 12 volunteers wore and intraoral palatal device containing 2 irradiated and 2 non-irradiated specimens, at two intraoral phases of 5 days each. Following a split-mouth protocol, volunteers immersed the devices extra orally, during 5 minutes, in 1% citric acid, 3x/day for 5 days. One hour after each erosive challenge, one irradiated and one non-irradiated specimen were brushed with an electrical toothbrush and dentifrice slurry. The response variables were the same studied at the first experiment. Two-way ANOVA revealed that there was no significant interaction between erosive-abrasive challenge and CO2 laser irradiation (p=0.614). The laser irradiation did not influence on the enamel wear (p=0.742). The enamel wear presented by the specimens subjected to erosion + abrasion did not differ from that verified when the erosion was performed alone. It can be concluded that, in intraoral conditions, the CO2 laser irradiation did not controlled the progression of erosive lesions or erosive-abrasive lesions on enamel

O Laser de Alta potência, também denominado, Laser Cirúrgico, tem sido usado em procedimentos médicos, para coagulação e vaporização dos tecidos. O maior problema, hoje encontrado, pela medicina no uso deste Laser, especialmente o laser de CO2, é a destruição térmica, causada pelo acúmulo de energia, convertida em calor, nos tecidos adjacentes, por ele irradiado. Uma vez absorvida esta energia, o tecido acumulará mudanças, que ocorrerão, durante o processo de irradiação e resfriamento. Estas variações poderão ir desde: uma mudança física, química e alterando completamente, os mecanismos biológicos, antes efetuados, pelo tecido irradiado. Este estudo tem como objetivo, analisar tais mudanças, verificando as diferenças morfológicas e geométricas, bem como utilizar experimentação para reconhecer, as zonas limitantes, ao processo de ablação. Para isto, quatro partes iguais de uma mandíbula bovina, foram usadas. Sendo que, cada uma destas, recebeu uma potência, diferente de laser. A cada amostra, foi aplicada a potência escolhida, em cinco diferentes tempos, mantendo uma distância aproximada de 250mm, entre uma aplicação e outra, com uma distância focal de 6mm. Em primeiro, observou-se característica macroscópica da região de interação, utilizando-se de um modelo zonal, para análise. Através de uma análise, mais aprofundada, com o uso de microscopia eletrônica, pode-se notar as variações imprevistas, ocorridas pelo processo de acúmulo e condução térmicos, advindos da ablação. A região de interação foi delineada em zonas de variações, denominadas as mesmas, como: Z I, Z2, e Z3. Sendo que a Z1, é o diâmetro formado pelo ponto de penetração da luz no tecido, ora irradiado.(Cratera). Z2 é o diâmetro envolvendo, a primeira camada de alteração do tecido irradiado, circundante a cratera. Z3, determina todo o diâmetro das alterações, por nós verificadas nas microfotografias. A partir deste ponto, usamos as amostras irradiadas, para calcular a quantidade de material removido, pela ablação. Através de um corte histológico, parafinado, analisamos todas profundidades, dos orifícios de entrada, formadas pela interação, por nós estudadas. Para cada lâmina, foi feita uma medida, da profundidade, formada pela entrada do raio, e pela material removido pela ablação. Tendo-se as medidas dos orifícios das crateras, as profundidades das mesmas, calculamos, aproximadamente, o material removido pela ablação. Considerando para isto, que os orifícios de penetrações, sendo, todos eles, de formatos de circunferências e as profundidades, em formatos Gaussianos. Obtendo, portanto, um formato conforme, para cada cratera. . Obtivemos, a partir do calculo matemático, o volume de massa de material retirado por ablação / The high power lasers are being widely used in surgical procedures, where there are vaporization and coagulation of the soft tissues. For hard tissues, such as, bones and teeth, pulsed lasers are stranded out because they may cause less thermal damage, as an example, the CO2 laser. Termal effects on tissue are recognized as being an accumulation of changes that occur during the entire period of irradiation and ensuing cooling (Mc KENZIE 1990). Located heating is affected by termal conductivity and convection by blood flow. Upon heating tissue experiences an alteration in a variety of physical, chemical and biological mechanism at the scale of chemical, organelle cell and tissue. Changes in tissue geometry and local microcirculation, could be affected. The purpose of these studies was to verify the physical and chemical variation and also reactions during the process of light exposure in the bone parts, especially the laser beam ablation patters. The generation of craters and other abnormal superficial termal damage, and craters that\'s show irregular wall contours. The relation and interaction between medicai CO2 laser beam and animal, human, and other biological tissues. For this experiment, a cattle\' s jaw, of four years old, were chosen for these experimental. Procedure to be described in this paper Those jaws were cut in four different pieces, in an effort, those parts were kept in the same shape and size, so no different variation of depth or length, would make it improper for the studies about to be made. Numbers were put in each different piece, showing in each sample, the time and the potency that were applied in that part. All samples were under favorable conditions (with long pulses and without water spray). Since classical pathology techniques for characterizing thermal damage to tissue are based on the microscopic examination of prepared tissue specimens for evidence of coagulation necrosis (nuclear psychoses, disintegration of organelles, hyalinization of collagen, loss of birefringence in muscle tissue, carbonization, etc.) Once the experimental appliance were done, a different colored circle were clear and optical visible around each bole, In a suggestion of that changes have happened in the material, used indeed. For almost, all the averages of the holes, in the electronic microscope, could be seeing the presence of minimal layer of superficial carbonization in the remaining bone. Therefore, the bone that received irradiation caused by CO2 laser, in a agreement with the proposal methodology, showed a variation of the tissue, that changed as the exposure changed the TIME/POWER. For each different pulse, the samples were analyzed. The tissues response to extreme temperature change in this zone usually consists of immediate coagulation necrosis, coagulation of vessels and macroscopic destruction of the tissue. An intermediary volume Between the necrosis core and the reversibly affected region is referred to as the Marginal Zone\". Therefore in this task, we called each analyzed zone as Z1 for the crater\'s diameter and Z2 for following areas, and finally, Z3 for the total diameter of the affected tissue. . All the measured zones, contains the shift from perfusion increases to coagulation, and the transition from structurally intact cells to dead cells. The most interest, issue that this study, may bring up, is for the clinical for the future\'s procedures because it contains the boundaries between the reversible and the irreversible tissue changes. Very few studies describe the presence and the address the consequences of the ablative aberrations, which can frequently and randomly happen during laser surgery. The knowledge of the different boundaries, of the affected areas, could predict severe impacts on the quality of the final surgical outcome, specially, when precision surgery techniques are required. The results of this discussed experiment shows how important it is to constantly and carefully observe, both the irradiated tissue\'s structure and the beam\'s broadening at the surface during the ablation.

Psidium guajava é uma espécie tropical, frutífera, de grande importância na fruticultura brasileira e é usada em diversas partes do mundo para o tratamento de doenças que acometem a humanidade. Além de sua importância alimentícia e medicinal, P. guajava também se mostrou boa bioindicadora de poluentes atmosféricos como ozônio e SO2 , pois apresenta respostas características e dose-dependentes das concentrações desses poluentes. Mostrou-se, dessa forma, uma espécie interessante para o estudo de respostas de espécies tropicais a elevadas concentrações de CO2 atmosférico. A fim de avaliar se o elevado CO2 seria uma situação estressante para essa espécie, foi realizada uma fumigação de 130 mudas de P. guajava cv. Pedro Sato em quatro câmaras de topo aberto: duas com ar ambiente ((∼390 ppm) e duas com atmosfera enriquecida com CO2 (∼720 ppm). Foram realizadas coletas quinzenais, retirando-se cinco indivíduos de cada câmara, aleatoriamente, que foram separados em raiz, caule e folhas e imediatamente congelados com nitrogênio líquido. Foram analisados componentes relacionados a sinalização e inativação de espécies reativas de oxigênio em folhas: os teores de poliaminas solúveis, ácido ascórbico e glutationa, além de fenóis, flavonoides, proantocianidinas e taninos totais. Além disso, os extratos metanólicos de folhas foram submetidos à CLAE para análises quali e quantitativas dos principais flavonoides. Parâmetros relacionados ao desenvolvimento da planta também foram analisados, como incremento em altura, massa seca, fração de massa, acúmulo de carbono, açúcares solúveis e amido. As análises de poliaminas, ácido ascórbico, glutationa, e compostos fenólicos de folhas não revelaram alterações significativas entre os tratamentos, exceto para a análise de taninos totais onde foi observado um aumento significativo dessas substâncias nas plantas mantidas a elevado CO2 e após 90 dias de fumigação. A análise por CLAE revelou que a maioria dos flavonoides dessa espécie é derivada de quercetina. Com relação aos parâmetros de crescimento, P. guajava não apresentou diferenças significativas de incremento em altura e massa seca, mas apresentaram acúmulo de amido nas folhas. Analises multivariadas foram utilizadas para integrar as 46 variáveis analisadas. Neste estudo viu-se que a situação de elevado CO2 em mudas de P. guajava é favorável, visto que ocorre acúmulo de amido, substâncias anti-herbivóricas (taninos) e, aparentemente, não há alteração no balanço redox. Contudo, é de extrema importância estudos que avaliem alterações concomitantes de parâmetros ambientais, como aumento de temperatura, disponibilidade de água, ozônio e elevado CO2 . A goiabeira apresenta grande importância econômica relacionada à produção e qualidade de seus frutos, dessa forma são necessários estudos que avaliem o efeito do aumento do CO2 na quantidade e qualidade de frutos produzidos por esta espécie. Por ser uma espécie de crescimento lento, períodos de exposição mais longos são aconselháveis para uma melhor analise da susceptibilidade dessa espécie ao elevado CO2 / Psidium guajava is a tropical fruit species of great importance in Brazilian economy; it is also used in several parts of the world as medicinal. Besides its importance as medicinal and nutritional species, P. guajava has also showed to be a good bioindicator of air pollutants, such as ozone and SO2 . It presents characteristic responses, dose-dependent of the concentrations of these pollutants. Therefore, this species seems to be interesting to study the responses of a tropical species to high concentrations of atmospheric CO2 . In order to assess whether the high CO2 would be a stressful situation for this species, we performed a fumigation experiment using 130 seedlings of P. guajava cv. Pedro Sato in four open-top chambers: two with ambient air (∼ 390 ppm CO2 ) and two with elevated CO2 (∼ 720 ppm). Biweekly, five individuals of each chamber were randomly collected, separated into root, stem and leaves and immediately frozen with liquid nitrogen. Were analyzed parameters related to signaling and inactivation of reactive oxygen species in leaves: levels of soluble polyamines, ascorbate and glutathione, as well as contents of phenols, flavonoids, tannins and proanthocyanidins. Furthermore, the methanol extracts were subjected to HPLC for quantitative and qualitative analysis of the major flavonoids. Parameters related to the development of the plant were also analyzed, as height increment, dry mass, mass fraction, carbon accumulation, soluble sugars and starch accumulation. The analysis of polyamines, ascorbate, glutathione and phenolic compounds of leaves, showed no significant changes when comparing treatments, except for the analysis of tannins which was observed a significant increase of these substances in plants at high CO2 after 90 days of fumigation. HPLC analysis revealed that most of flavonoid composition is quercetin derivatives. The growth parameters showed no significant differences in height increment and dry mass, but the leaves showed accumulation of starch after CO2 fumigation. Multivariate analyzes were used to integrate the 46 variables analyzed. In this study it was seen that the elevated CO2 seem to be favorable to seedlings of P. guajava, once there is an accumulation of starch, antiherbivore substances (tannins) and, apparently, there was no change in the redox balance. However, it is extremely important to perform studies that evaluate concomitant changes in environmental conditions, such as increased temperature, availability of water, ozone and elevated CO2 . Guava has great economic importance in Brazil, fact related to the production and quality of its fruits, so more studies are needed to assess the effect of increased CO2 in the quantity and quality of fruits produced by this species. As a slow-growing species, longer exposure periods are recommended to better analyze the susceptibility of this species to elevated CO2

Znalost o prostorovém rozložení, koncentraci a zdrojích CO2 v atmosféře je klíčová k pochopení přírodního cyklu oxidu uhličitého, k předpovědi vývoje a vlivu CO2 na klimatické změny. Tato práce se zabývá problematikou optického dálkového snímání za použití LIDAR (Light Detection and Ranging) systému. Obsahuje potřebné teoretické znalosti o LIDAR systému, použití a principy. Z mnoha aplikací využívající LIDAR je v této práci nastíněno provedení a měření pomocí DIAL (Differential Absorption LIDAR) systému určeného k určení koncentrace CO2 v atmosféře, tak i využití dalších aktivních či pasivních způsobů snímání CO2.

Le couplage d’un traitement électrochimique avec un procédé biologique est une alternative prometteuse pour la dégradation de composés organo-halogénés biorécalcitrants dans l’environnement. Les procédés d’électroréduction, connus pour couper sélectivement la liaison carbone-halogène, ont été mis en oeuvre afin de réduire la toxicité des molécules cibles et augmenter leur biodégradabilité avant une minéralisation totale des polluants par un traitement biologique. Pour améliorer le rendement de déchloration, la cathode préalablement nickelée a été modifiée par des nanoparticules d’argent car l’argent est considéré comme l’un des meilleurs catalyseurs pour couper sélectivement la liaison carbonehalogène. Le feutre de graphite a été choisi comme support d’électrode pour sa grande surface spécifique. Le principal produit de déchloration de l’alachlor s’est révélé être biorécalcitrant. Pour surmonter ce problème, un traitement par procédé électro-Fenton a été mis en oeuvre pour dégrader les polluants cibles. Une amélioration significative de la biodégradabilité de la solution d’alachlor a pu être observée après le traitement électro- Fenton, et qui est renforcée quand l’atome de chlore a été préalablement éliminé de la structure de l’alachlor par électroréduction. Le bismuth a été également utilisé comme support d’électrode du fait de sa grande surtension visà- vis de la réduction de l’eau. Une grande sélectivité a pu être obtenue sur cathode de bismuth lors de la réduction d’herbicides du type chloracétamide. La réduction électrochimique du dioxyde de carbone a également été réalisée sur électrode de bismuth modifiée par des nanoparticules d’argent comme autre application de cette nouvelle électrode. / Electrochemical process coupling with a biological treatment is a promising alternative for the degradation of biorecalcitrant organo-halogenated compounds in the environment. The electroreduction treatment, known to cut selectively carbon-halogen bonds, was first implemented to decrease the toxicity of the target molecules and increase their biodegradability before a complete mineralization of the pollutants by a biological treatment. To improve the dechlorination efficiency, the cathode was modified by silver nanoparticles after a previous nickelisation, since silver is considered as one of the best electrocatalysts to selectively cleave the carbonhalogen bond. The graphite felt was chosen as the electrode support due to its high specific surface area. For alachlor herbicide, deschloroalachlor, the main by-product after dechlorination, was still biorecalcitrant. To overcome this issue, electro-Fenton treatment, in which hydroxyl radicals were generated to degrade the target pollutants, was implemented. Significant improvement of biodegradability of the alachlor solution was observed after electro-Fenton treatment, which was further improved when the chlorine atom was beforehand removed from the alachlor structure by the electroreduction process. Bismuth was also used as electrode support due to its high overpotential for hydrogen evolution. A high selectivity of chloroacetamide herbicides reduction was observed on the bismuth based cathode. As an extended application of the bismuth based cathode, the electrochemical reduction of carbon dioxide was performed on Bi electrode modified by silver nanoparticles.

Le captage et stockage du CO2 (CSC) dans les formations géologiques profondes est une solution pour réduire les effets indésirables du CO2 atmosphérique. Les formations géologiques étant des milieux hétérogènes, contiennent souvent des réseaux de fissures. La ténacité (KC) est un paramètre de la roche associé à la capacité du matériau à résister la propagation d'une fissure. La propagation d'une fissure peut dériver du changement de l'état de contrainte ou du changement de la ténacité dû à la dégradation de la roche. La connaissance de la ténacité et son évolution due aux effets chimiques est donc importante pour la modélisation de la propagation des fissures dans le contexte de stockage géologique du CO2.Un objectif de ce travail est l'évaluation de la dégradation par le CO2 sur la ténacité d'une roche réservoir. Un calcaire (Pierre de Lens) est choisi pour être étudié dans son état sain et dégradé. La dégradation est réalisée dans un autoclave : les échantillons sont placés dans une solution aqueuse saturée en CO2, sous les conditions de réservoir (60°C et 15 MPa).Plusieurs configurations ont été choisies pour les essais mécaniques en mode I et en mode II. Certains essais ont été réalisés en utilisant une technique de corrélation d'images (DIC). Ce dispositif permet d'évaluer la ténacité à partir de l'évolution des champs de déplacements. Les résultats expérimentaux montrent que les valeurs de ténacité en mode I sont tout à fait concordantes entre les différents types d'essai. La technique de corrélation d'image met en évidence que la ténacité en mode II ne peut pas être évaluée dans les essais de chargement non confiné. Pour la procédure de dégradation, on peut constater par des analyses complémentaires que la porosité de la roche change peu (0,4 %). La ténacité de la roche n'est pas sensiblement affectée passant de 0,62 à 0,58 MPa.m0,5. On a également étudiée l'effet de la présence de l'eau par des essais de fracturation avec des échantillons saturés. Celle-ci a une influence plus significative avec une réduction d'environ 17% de la ténacité relatif aux échantillons secs. En ce qui concerne l'analyse en mode II (PTST), des essais ont été réalisés sous différentes pressions de confinement (5 - 15 MPa). On peut constater que cet essai permet une bonne évaluation en mode II (de l'ordre de 3 MPa.m0,5). Cependant, le mode I est encore présent pour les pressions de 5 et 10 MPa, et n'est pas toujours inexistant pour une pression de 15 MPa. On a montré, là encore, que l'influence de CO2 est faible avec une ténacité en mode II passant de 2,96 à 2,77 MPa.m0,5. L'influence de la dégradation de la roche par le CO2 sur la propagation de fissures a été étudiée à l'aide d'une modélisation numérique en utilisant le modèle ENDO-HETEROGENE, intégré dans le code de calcul Code-Aster®. Ce modèle est basé sur l'amorçage et la propagation des fissures dans un milieu hétérogène dont la variabilité des paramètres du matériau suit le modèle probabiliste de Weibull à 2 paramètres (m et σ0). On a exploré la possibilité que la dégradation chimique influence l'hétérogénéité de la microstructure. La modélisation montre que le paramètre m influence le nombre et la dimension des fissures, cependant, la taille maximale de la fissure ne varie pas avec m. Pour remettre ces résultats expérimentaux en contexte, les paramètres de Weibull sont évalués pour la roche saine et dégradée. On observe que m varie de 8,55 à 8,52 et σ0 de 2,8 et 2,2 MPa. Selon la simulation numérique cette variation n'est pas suffisante pour changer le réseau des fissures créées après un chargement dans une couche géologique. Ces résultats montrent que dans le cas d'un réservoir calcaire l'injection de CO2 n'influe pas significativement ni le paramètre ténacité, ni dans les paramètres probabilistes de la fracturation. Ces résultats correspondent à une période de 10 ans dans une zone du réservoir loin du puits d'injection / The capture and the storage of CO2 (CSC) on the underground geological formations is a solution for the CO2 undesirable effects reduction. The geological formations being composed by heterogenic material have a crack network. The fracture toughness (KC) is a rock parameter connected with the capacity of a material to resist crack propagation. The propagation of a crack can be due to the changing of the stress or to the rock degradation. The evaluation of the fracture toughness and its evolution due to the chemical effects is then important to the modelling of the crack propagations on the CO2 storage context. One objective of this work is the experimental evaluation of the CO2 degradation on the fracture toughness. For the experimental program a preliminary study was made to the choice of the rock and the test to be performed. In this way, a limestone (Pierre de Lens) was chosen to be studied in an intact and degraded state. The degradation takes place in an autoclave, where the samples are put at CO2-saturated water in reservoir conditions (60 °C and 15 MPa).Several experimental tests are chosen for the evaluation of the fracture toughness in modes I and II. Some examples are the Central crack Brazilian disc (CCBD) for the mode I and the Punch through shear test (PTST) for the mode II. Some tests where performed using an image correlation technique (DIC). This set-up allows the fracture toughness evaluation by the displacement field evolution. The experimental results shows the fracture toughness values obtained by the different configurations are in good agreement. After the DIC technique analysis we can point the fracture toughness in mode II can not be evaluated in a non confined test. For the degradation process, the complementary analysis in the mercury porosimeter shows the rock porosity changing is low (0.4 %). At the SEM, the degradation can be observed by a homogenization of the sample. For the fracture toughness it value passes from 0.62 to 0.58 MPa.m0.5. We also have studied the effect of water performing tests in a saturated environment. The influence is more significant with a reduction on 17 % in the fracture toughness. The CO2 presence in the fluid does not affect this value. Concerning the mode II evaluation by the PTST test, the samples were submitted to different confining pressures (5, 10 and 15 MPa). We can observe a good evaluation of the fracture toughness in mode II (around 3 MPa.m0.5). Nevertheless, the mode II is still present for the pressures 5 and 10 MPa, and it is not inexistent for a 15 MPa pressure. Still in this case the influence of CO2 is low with values passing from 2.96 to 2.77 MPa.m0.5.The influence if the rock degradation by the CO2 presence on the crack propagation were studied by the help of a numerical model ENDO-HETEROGENE, that is present in the Code-Aster® calculation code. This model is base on the initiation and propagation of cracks in a heterogenic environmental where the parameter variability follows the 2 parameters Weibull probabilistic model (m and σ0). We exploited the possibility of the chemical degradation influence on the microstructure heterogeneity that is represented by the parameter m. The model shows that the changing of m influence on the crack number and dimensions by the maximum size of the crack didn't change. Putting this result in context, the Weibull parameters were evaluated for the intact and degraded rock. We observed that m changes from 8.55 to 8.52 and σ0 from 2.8 to 2.2 MPa. The numerical simulations show this variation is not enough to change the crack network that is formed after a load in a geological layer. The general results show that for a limestone reservoir the CO2 injection affect significantly neither the fracture toughness nor the probabilistic parameters. These results correspond to a 10 years period for a zone far from the injection point

Carbon dioxide (CO2) has long been regarded as the major greenhouse gas, which leads to numerous negative effects on global environment. The capture and separation of CO2 by selective adsorption using porous materials proves to be an effective way to reduce the emission of CO2 to atmosphere. Porous organic polymers (POPs) are promising candidates for this application due to their readily tunable textual properties and surface functionalities. The objective of this thesis work is to develop new POPs with high CO2 adsorption capacities and CO2/N2 selectivities for post-combustion effluent (e.g. flue gas) treatment. We will also exploit the correlation between the CO2 capture performance of POPs and their textual properties/functionalities. Chapters Two focuses on the study of a group of porous phenolic-aldehyde polymers (PPAPs) synthesized by a catalyst-free method, the CO2 capture capacities of these PPAPs exceed 2.0 mmol/g at 298 K and 1 bar, while keeping CO2/N2 selectivity of more than 30 at the same time. Chapter Three reports the gas adsorption results of different hyper-cross-linked polymers (HCPs), which indicate that heterocyclo aromatic monomers can greatly enhance polymers’ CO2/N2 selectivities, and the N-H bond is proved to the active CO2 adsorption center in the N-contained (e.g. pyrrole) HCPs, which possess the highest selectivities of more than 40 at 273 K when compared with other HCPs. Chapter Four emphasizes on the chemical modification of a new designed polymer of intrinsic microporosity (PIM) with high CO2/N2 selectivity (50 at 273 K), whose experimental repeatability and chemical stability prove excellent. In Chapter Five, we demonstrate an improvement of both CO2 capture capacity and CO2/N2 selectivity by doping alkali metal ions into azo-polymers, which leads a promising method to the design of new porous organic polymers.

L’utilisation des ressources fossiles a permis l’industrialisation de notre société, cependant, après 200 ans de consommation effrénée, notre dépendance nous oblige à faire face à plusieurs défis. 1) Capter et stocker/valoriser le CO2 pour limiter le relargage massif de CO2 dans l’atmosphère 2) Trouver une nouvelle source de carbone pour la synthèse de produits chimiques afin de réduire la pression mise sur les réserves de ressources fossiles 3) Développer des nouveaux moyens de stockage de l’énergie pour pouvoir se reposer sur les énergies renouvelables intermittentes. Le CO2 étant une source de carbone abondante et peu chère il peut être utilisé comme brique moléculaire pour la synthèse de produits chimiques et être ainsi valorisé. De plus il peut également être utilisé notamment via le coupleCO2/MeOH pour le stockage de l’énergie. Cependant peu de procédés utilisant le CO2 sont actuellement déployés à l’échelle industrielle car la barrière cinétique associée à la réduction du CO2 entraîne de faibles rendements faradiques et les produits accessibles directement à partir de celui-ci sont peu nombreux.En s’inspirant de la Nature nous avons voulu, au cours de cette thèse, développer des réactions à partir de molécules facilement et directement accessibles à partir du CO2 afin de s’affranchir des limitations liés à ce dernier. Nous avons donc développé plusieurs réactions catalytiques à partir de l’acide formique et du monoxyde de carbone qui sont les principaux dérivés du CO2. Nous avons notamment étudié la réduction du CO2 en méthanol en utilisant l’acide formique comme réducteur et nous avons appliqué cette réactivité pour la méthylation des amines. Enfin nous avons également utilisé le CO comme relais pour la synthèse de liaison C–C à partir du CO2. Cette stratégie a été prouvée pour la synthèse d’alkylamines avec de longues chaînes alkyl à partir de CO et d’un réducteur. / Fossil resources have been extensively used for the past 200 years allowing a fast paced industrializationin our society. However we are facing today several challenges to preserve our way of life 1) CO2 shouldbe captured and stored/used to avoid large quantity of CO2 to be released in the atmosphere 2) Bypassthe use of fossil resource by using another source of carbon for the synthesis of chemicals 3) Developefficient energy storage technologies to rely more on renewable intermittent energy sources. As CO2 is acheap widely available resource, this waste could be used as well as a source of carbon for the synthesisof value added chemicals but also as a way to store energy in the tandem CO2/MeOH. However as it isan inert gas few processes using CO2 have been industrialized so far.Inspired by Nature’s way to use CO2 we decided to design new reactions from carbon monoxide andformic acid, two derivatives easily available from CO2 that could enable us to overcome the limitationwe faced with CO2. We therefore studied the transformation of CO2 to methanol using formic acid as anintermediate and a reductant and we subsequently used this reaction to perform the methylation ofaromatic amines using formic acid. Finally we developed a new reaction of amines homologation withcarbon monoxide allowing the formation of several C–C bonds.

No description available.

No description available.