Made available in DSpace on 2015-05-14T12:59:32Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 730230 bytes, checksum: c9ea66b757014e0b2d6d2b07b2de3af1 (MD5) Previous issue date: 2012-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Acinetobacter species have gained importance in recent years due to their increased involvement in serious infections and antimicrobial resistance. Since multidrug resistant bacteria pose a challenge to the treatment of infections, it is necessary to find new substances with antimicrobial properties in combating these microorganisms. Thus, medicinal plants are studied, since they are used for treatment of various illnesses. Therefore, many studies on biological activity have been performed with essential oils obtained from medicinal plants, such as the essential oil from Citrus limon (EOCL), attempting to help overcome this problem. Thus the present study aimed to evaluate the effect of the essential oil of EOCL against multidrug resistant strains of Acinetobacter spp. Its chemical composition was determined by GC/MS and its antibacterial activity was assessed by determining their MIC and MBC by microplate bioassay, its Time kill too was determinated. Also was analyzed the effect of modulating action of conventional antibiotics by microplate bioassay. Among phytochemicals, Neral (29.4%) presented as the major essential component of EOCL. The oil caused growth inhibition in 16 (67%) of 24 strains tested, showing a MIC of 625 μg/ml and MBC of 1250 μg/mL. In a time kill study, the oil displayed a concentration-dependent antibacterial activity. Results of combining antibiotics and EOCL had shown us a synergistic and additive effect with EOCL /antibiotics combinations. The results of this study suggest that essential oil of C. limon may suppress the growth of Acinetobacter species and could be a source of metabolites with modified antibacterial activity. / Espécies do gênero Acinetobacter ganharam importância nos últimos anos devido ao seu envolvimento crescente em infecções graves e resistência antimicrobiana. Uma vez que bactérias resistentes a múltiplas drogas representam um desafio para o tratamento de infecções, é necessário encontrar novas substâncias com propriedades antimicrobianas no combate a estes microrganismos. Para tentar superar este panorama, várias pesquisas vêm sendo desenvolvidas em busca de novos produtos antibacterianos, dentre elas estão os estudos com os metabólitos de plantas, como o óleo essencial de Citrus limon (OECL). Assim, o presente estudo teve como objetivo avaliar o efeito do óleo essencial de Citrus limon contra cepas de Acinetobacter multidroga resistentes. Sua composição química foi determinada por CG/EM e sua atividade antibacteriana avaliada pela determinação de sua CIM e CBM pela técnica de microdiluição, sua cinética de morte microbiana também foi analisada. Verificou-se também seu efeito modulador da ação dos antibióticos convencionais por técnicas de microdiluição. Entre os fitoconstituintes, neral (29,4%) apresenta-se como o principal componente de OECL. O referido óleo inibiu o crescimento de 67% das 24 cepas ensaiadas, tendo sua CIM estabelecida em 625 μg/mL e a CBM em 1250 μg/mL Este óleo possui atividade antibacteriana dependente de sua concentração e do tempo de exposição no microrganismo e é um modulador da ação dos antibióticos convencionais. Os resultados deste estudo sugerem que o referido óleo pode suprimir o crescimento de espécies de Acinetobacter e poderia ser uma fonte de metabólitos com atividade modificadora antibacteriana.

Les sols non saturés jouent un rôle important dans de nombreux domaines. En Génie Civil (stabilité des talus, fondations superficielles), en Ingénierie de l'environnement (transport de polluants par les eaux souterraines, enfouissement de déchets radioactifs), en Ingénierie des Réservoirs (subsidence suite aux pompages dans les champs pétroliers ou dans les nappes aquifères), etc. L'objet de la thèse est l'étude du comportement hydromécanique des sols fin non saturés, tels les limons et les argiles. Les phénomènes typiques du comportement de ces sols sont d'abord présentés avant d'aborder l'étude de leurs lois constitutives. Divers modèles sont passés en revue et un modèle unifié original est développé. Ensuite, une vaste gamme d'essais de laboratoire est analysée. Ils portent sur des sols saturés, quasi saturés et non saturés et concernent quatre matériaux: l'argile de Kruibeke, le limon de Gembloux, l'argile de Boom et la bentonite d'Almeria. Cette partie de la recherche conduit à une critique détaillée des procédures classiques d'essais de laboratoires sur les sols supposés saturés. Elle fournit également une base de données importante pour la calibration de la loi constitutive unifiée développée plus haut. Enfin, des simulations numériques, réalisées en aveugle, d'expériences n'ayant pas servi à la calibration permettent de valider ce modèle.

Lateral spread is a seismic hazard associated with soil liquefaction in which permanent deformations are developed within the soil profile due to cyclic mobility. Lateral spread has historically been one of the largest causes of earthquake-related damage to infrastructure. One of the infrastructure components most at risk from lateral spread is that of deep foundations. Because performance-based engineering is increasingly becoming adopted in earthquake engineering practice, it would be beneficial for engineers and researchers to have a performance-based methodology for computing pile performance during a lateral spread event. This study utilizes the probabilistic performance-based framework developed by the Pacific Earthquake Engineering Research Center to develop a methodology for computing probabilistic estimates of kinematic pile response. The methodology combines procedures familiar to most practicing engineers such as probabilistic seismic hazard analysis, empirical compution of lateral spread displacement, and kinematic pile response using p-y soil spring models (i.e. LPILE). The performance-based kinematic pile response model is applied to a series of lateral spread case histories from the earthquake that struck the Limon province of Costa Rica on April 22, 1991. The M7.6 earthquake killed 53 people, injured another 193 people, and disrupted an estimated 30-percent of the highway pavement and railways in the region due to fissures, scarps, and soil settlements resulting from liquefaction. Significant lateral spread was observed at bridge sites throughout the eastern part of Costa Rica near Limon, and the observed structural damage ranged from moderate to severe. This study identified five such bridges where damage due to lateral spread was observed following the earthquake. A geotechnical investigation is performed at each of these five bridges in an attempt to back-analyze the soil conditions leading to the liquefaction and lateral spread observed during the 1991 earthquake, and each of the five resulting case histories is developed and summarized. The results of this study should make a valuable contribution to the field of earthquake hazard reduction because they will introduce a procedure which will allow engineers and owners to objectively evaluate the performance of their deep foundation systems exposed to kinematic lateral spread loads corresponding to a given level of risk.

La pérennité des améliorations apportées par la chaux à un sol limoneux utilisé pour la construction d’ouvrages hydrauliques ou de remblais en zone inondable vis-à-vis des sollicitations hydriques auxquelles ces derniers peuvent être soumis (immersion, circulation d’eau) est encore débattue. Dans ce contexte, ce travail s’est attaché à simuler expérimentalement puis à décrire l’effet de ces sollicitations sur les propriétés géotechniques d’un sol limoneux compacté traité à la chaux (perméabilité, résistance mécanique). Il a été établi que le maintien des améliorations mécaniques est fortement lié à la perméabilité des sols : plus leur perméabilité est forte, plus les pertes de performances mécaniques sont rapides. Ces pertes de performances peuvent être attribuées à une dissolution partielle de la chaux non consommée mais aussi à la décalcification des produits cimentaires formés suite à l’ajout de chaux. L’ampleur de ces processus s’avère être une fonction de la perméabilité, une forte perméabilité les accélérant à l’inverse d’une faible perméabilité. Enfin, une étude a été conduite sur l’effet des conditions initiales sur la microstructure et la perméabilité des sols traités à la chaux afin de déterminer les états initiaux à privilégier en terme de durabilité. Il a été montré que l’ajout d’un faible dosage en chaux et qu’un compactage à une faible énergie pouvait induire, au contraire d’un fort dosage et d’un compactage du côté humide, de fortes perméabilités. Ainsi, un fort dosage en chaux et un compactage du côté humide pourraient permettre de maintenir dans le temps les améliorations apportées par la chaux aux sols limoneux exposés à des sollicitations hydriques.

Made available in DSpace on 2014-12-17T14:20:04Z (GMT). No. of bitstreams: 1 JoseGledsonNM_DISSERT.pdf: 5793403 bytes, checksum: 8c351455b3aa026e15d39791d88cdf58 (MD5) Previous issue date: 2011-08-02 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The study analyzed regarding cultural policies developed in the city of North-EC Limoeiro by the Municipal Culture and Tourism (Semuc) in the period between the years 2005 and 2010. Period that marks the resumption of the figure of the State Ministry of Culture (MinC) as a major factor in formulating and implementing public policies in the area of culture in the country, especially with the creation of the National Culture System (CNS) and the preparation of National Culture Plan (NCP). The work was through research documents (laws) about what had legislated on culture in the city, the reports of consultation activities undertaken by Semuc and interviews with former managers, a former - employee and the Secretary of that folder. Thus, given the contemporary context where the culture is replaced by increasing visibility, the analysis undertaken on policies developed by cultural Semuc revealed the most diverse forms of action: investment in events (capture and promotion), the institution permanent cultural policies, cultural background, the appreciation of local culture, and specific actions / O referente trabalho analisou as pol?ticas culturais desenvolvidas na cidade de Limoeiro do Norte-CE pela Secretaria Municipal da Cultura e do Turismo (SEMUC) no per?odo compreendido entre os anos de 2005 e 2010. Per?odo que demarca a retomada do Estado na figura do Minist?rio da Cultura (MinC) enquanto um dos principais respons?veis por formular e executar as pol?ticas p?blicas na ?rea da cultura no pa?s, especialmente com a cria??o do Sistema Nacional de Cultura (SNC) e a elabora??o do Plano Nacional de Cultura (PNC).O trabalho se constituiu atrav?s de pesquisa documental (Leis) acerca do que se tinha legislado no munic?pio sobre cultura, de consultas aos relat?rios das atividades desenvolvidas pela SEMUC e de entrevistas realizadas com ex- gestores, um ex- funcion?rio e o secret?rio da referida pasta. Desta forma, diante do contexto contempor?neo onde a cultura passa a ter cada vez mais visibilidade, a an?lise empreendida acerca das pol?ticas culturais desenvolvidas pela SEMUC, revelou as mais diversas formas de a??o: o investimento em eventos (capta??o e promo??o); a institui??o de pol?ticas culturais permanentes; a forma??o cultural, a valoriza??o da cultura local, al?m de a??es pontuais

Cette recherche concerne l'étude expérimentale et l'analyse théorique de la consolidation des sols fins saturés sous chargement cyclique. La synthèse des travaux antérieurs a révélé que les cycles ont pour effet de retarder la consolidation et que les courbes de consolidation en tassement et en contrainte effective tendent vers un état d'équilibre sous chargement cyclique ; mais les modèles théoriques ne permettent pas d'approcher les résultats expérimentaux. Après cette synthèse, le premier objet de notre travail a consisté à améliorer la modélisation théorique de la consolidation en tenant compte de l'irréversibilité du comportement du sol dans le domaine surconsolidé. Cette modélisation a permis de mieux approcher les résultats expérimentaux obtenus au CERMES par A. BERNARDET. Après avoir analysé les résultats obtenus sur le limon (sol peu plastique), nous avons entrepris 1'étude expérimentale à l'oedomètre d'une kaolinite (argile plastique). Il s'est avéré que les cycles retardent considérablement la consolidation ; mais contrairement au résultat obtenu sur le limon, il a été observé que la courbe de consolidation en tassement ne présente pas d'état d'équilibre sous chargement cyclique. L'analyse théorique de la kaolinite a conduit qualitativement au même résultat ; mais le modèle adopté pour le comportement du sol dans le domaine surconsolidé ne nous a pas permis d'approcher les résultats expérimentaux. Cette analyse nous a en plus révélé que, contrairement au tassement, la courbe de consolidation en contrainte effective présente un état d'équilibre sous chargement cyclique. Les résultats expérimentaux avec mesure de surpressions interstitielles à la cellule de Rowe et au triaxial nous ont permis de confirmer qualitativement ces résultats. Il apparaît donc que, lorsque le sol est plastique, il y a une accumulation de tassements sous chargement cyclique sans dissipation de surpressions interstitielles.

The overall objective is to improve the one-dimensional numerical prediction of the fine and non-cohesive bed material load in alluvial rivers, especially during high intensity episodes during which sediment beds are strongly remobilized. For this reason, we attempt to reduce the major inaccuracy sources coming from the alluvial resistance and bed material load relations needed to close the mathematical system. Through a shared parameter called the control factor m, the interactions occurring in alluvial rivers are incorporated more deeply into the mathematical model and more particularly into the closure laws: bed material load (SVRD, Suction-Vortex Resuspension Dynamics) and the energy slope (Verbanck et al. 2007). The control factor m is assumedly related to the Rossiter resonance modes of the separated flow downstream the bed form crest. <p><p>To further improve the representation of the flow-sediment-morphology interactions, a fully coupled model approach has been naturally chosen. In this work the terminology fully coupled means that the three equations forming the system are solved synchronously and that the terms often neglected by more traditional decoupled models are kept. <p><p>The feasibility of the new closure methodology has been drawn up by reproducing numerically the silt-flushing experiment conducted by the Yellow River Conservancy Commission (Y.R.C.C.) in the Lower Yellow River (LYR) in Northern China. The objective of the silt flushing experiment is to reverse the aggradation trend of the Lower Yellow River which, in the last decades, has become a perched river. The numerical simulation specifically reproduces the silt-flush effects in a reach of LYR located in the meandering part of the river. This reach (around 100 km) is delimited by Aishan and Luokou hydrometric stations.<p><p>Since the SVRD formulation has been developed from flume observations, the law has first been confronted to river datasets. The confrontation has revealed that the SVRD law becomes less suitable for fine sediment fluxes (ratio of water depth over median particle size > 5000). Therefore, a modified equation SVRD-2 has been built to enlarge the validity range.<p><p>The suitability of the SVRD-2 equation to predict fine sediment fluxes has been tested on data available from several hydrometric stations located in the meandering reach of the LYR: historical observations and measures collected during the flushes. The SVRD-2 has also been compared with relations specifically calibrated for this configuration. The comparison has pointed out that the performance of the two formulas is similar, which is encouraging for the SVRD-2 approach as it has not been calibrated on those data. <p><p>The closed equation system has been written on its quasi-linear form and is solved by a Finite Volume Method combined with a linearized Riemann algorithm. The numerical model has been checked up on two test cases: deposition upstream of a dam and the aggradation experiment conducted by Soni 1975. <p><p>As it is not yet possible to predict dynamically the value of the control factor m, a possible solution would be to extract its value from the measured data at the inlet cross section. Unfortunately, the necessary data are not measured locally. Moreover, a uniform value of the control factor m may not suffice to reproduce the flow along the whole reach. Therefore, it has been proposed to work temporarily in the reverse way. <p><p>From the comparison between the numerical results and the experimental data, a time evolution of the control factor m has effectively been extracted and it has been shown that it varies along the reach. At Aishan, the evolution of the control factor m corresponds to the evolution expected from the data analysis previously conducted on other data sets: the value of the control factor m decreases during the flush as it tries to reach the optimal value m=1. The time evolution at Luokou behaves differently to the one at Aishan, but remains in agreement with m evolution patterns observed historically for the river section flowing round Jinan City walls. For Luokou, the highlighted differences may come from three dimensional effects coming from the meander bend upstream the station.<p><p>Generally, the results obtained for the hydraulics, the sediment transport and bed adaptation are encouraging but still need improvements and additional feeding from the experimental data. The results for the concentration and therefore the bed elevation are very sensitive to the value of the control factor m as it influences most of the terms of the bed material load equation (SVRD-2). <p><p>The major remaining difficulties are, firstly, to deal with the rapid transients for which the model is less suitable and, secondly, to improve the prediction of the value of control factor m. Before paying more attention into the transients, enhancements concerning the flow along the reach (initial condition and discharge rates during the first days of the flush) must be conducted in priority. Indeed as the prediction of the bed or the cross section evolutions depend directly on the quality of the prediction of the sediment concentration and the hydraulics, one should first improve these aspects. To perform this study, more information about the water levels or sediment concentrations is necessary at some intermediate stations. One solution is to lengthen the studied reach, upstream to Sunkou and downstream to Lijin, totaling a river length of 456 Km.<p><p>A more entire signal of the energy slopes and the associated bed configurations at different stations would enlighten how the control factor m evolves along the reach during the silt-flush events. <p><p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Le clouage est une technique de renforcement des sols en place par des inclusions passives. Dans la première partie de ce rapport, on présente les résultats expérimentaux et théoriques d'une recherche approfondie sur le mécanisme d'interaction sol-renforcement rigide et la mobilisation de la résistance au cisaillement du sol lors du cisaillement direct de la masse du sol cloué. La méthode des éléments finis a été utilisée pour la simulation numérique des essais de cisaillement direct effectués au CERMES en 1980-1981 sur des éprouvettes de grandes dimensions (40 x 60 x 40 cm) de limon argileux renforcé par des inclusions perpendiculaires à la surface de cisaillement. Cette étude a permis de mettre en évidence la mobilisation d'une cohésion apparente et une diminution de l'angle de frottement interne de la masse du sol renforcé et d'étudier l'effet de certains paramètres (contrainte normale appliquée ; rigidité et nombre de renforcements) sur l’effet des inclusions, le comportement de la masse du sol renforcé et la mobilisation de sa résistance globale au cisaillement. La deuxième partie de ce rapport présente une analyse du comportement des ouvrages de soutènement en sol renforcé. On étudie, d'une part, les remblais en Terre Armée, et d'autre part, les soutènements in-situ par clouage. Si la technique de la Terre Armée a fait l'objet de plusieurs recherches et observations sur ouvrages en vraie grandeur, peu d'expérimentations ont été effectuées jusqu'à présent sur des soutènements par clouage. Ces quelques expérimentations montrent une certaine analogie entre le comportement de ces deux types d'ouvrages. Cependant, il existe des différences fondamentales qui concernent en particulier : - Les modes de constructions, - La rigidité des renforcements, - L'inclinaison des renforcements, - La technique de mise en place des renforcements, - La nature du sol. Notre travail a essentiellement pour objectif d'étudier l'influence de ces paramètres sur le comportement global de l'ouvrage sur les efforts mobilisés dans les inclusions ainsi que sur le déplacement de la paroi. On a utilisé une simulation numérique à l'aide d'un programme de calcul en éléments finis, permettant une modélisation phase par phase de ces deux techniques. Pour vérifier cette modélisation on compare les résultats de calculs, d'une part, avec les mesures sur ouvrages réels, et d'autre part, avec observations sur modèles réduits.