Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-25T21:35:38Z No. of bitstreams: 1 TallesNobregaSousa_DISSERT.pdf: 16640044 bytes, checksum: 69382eddd638c4ed030be4e794aaecaa (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-27T20:25:47Z (GMT) No. of bitstreams: 1 TallesNobregaSousa_DISSERT.pdf: 16640044 bytes, checksum: 69382eddd638c4ed030be4e794aaecaa (MD5) / Made available in DSpace on 2016-04-27T20:25:47Z (GMT). No. of bitstreams: 1 TallesNobregaSousa_DISSERT.pdf: 16640044 bytes, checksum: 69382eddd638c4ed030be4e794aaecaa (MD5) Previous issue date: 2015-05-29 / A constante busca da ind?stria de petr?leo pelo aumento de produ??o ? um baixo custo operacional faz necess?rio o desenvolvimento de tecnologias que una as duas necessidades. A Acidifica??o de matriz ? um m?todo de estimula??o frequentemente empregado para aumentar produ??o de um po?o de petr?leo com um custo menor se comparado a um fraturamento. O objetivo deste trabalho ? estudar a obten??o de nanoemuls?es ?cidas para aplica??o em acidifica??o de matriz. As nanoemuls?es s?o capazes de retardar rea??es, por diminuir a difus?o do ?cido no meio, possibilitando a acidifica??o em reservat?rios com baixa permeabilidade. Os reagentes utilizados para formar os sistemas nanoemulsionados foram UNT L90/OMS e RNX 110 como tensoativos, Sec-butanol como cotensoativo, Xileno e Querosene como fase ?leo e Solu??o de HCl como fase aquosa. As nanoemuls?es foram obtidas a partir da dilui??o de microemuls?es com ?gua ou solu??o de HCl. Foi realizado estudo das tens?es superficiais, estudo das cin?ticas de rea??o, avalia??o da inje??o em rocha carbon?tica e remo??o de borra asf?ltica. As nanoemuls?es apresentaram tens?o superficial menor que suas microemuls?es de origem. As nanoemuls?es tiveram ?xito em retardar a rea??o entre CaCO3 e HCl, onde o sistema mais eficiente ? composto por UNT L90/OMS, Secbutanol, Querosene e solu??o de HCl. As nanoemuls?es foram eficientes em formar wormholes em plugs de carbonato calcitico com baixa permeabilidade natural. As wormholes proporcionaram incremento de permeabilidade alcan?ando valores de at? 390 mD. O sistema ?cido apresentou bom resultado de remo??o de borra asf?ltica, mostrando o potencial das nanoemuls?es em remover esse tipo de dano. Conclui-se que os sistemas nanoemulsionados t?m grande potencial de aplica??o em acidifica??o de matriz.

Neste trabalho, construímos novas soluções com simetria esférica ou axial para as equações do campo gravitacional induzido num cenário brana do tipo Randall-Sundrum, onde uma 3-brana com constante cosmológica está imersa num espaço-tempo 5-dimensional conhecido como bulk. Para o caso esfericamente simétrico, com constante cosmológica negativa, obtivemos uma família de soluções numa brana assintoticamente anti-de Sitter, sendo que cada membro desta é diferenciado de outro por uma constante integração C, que fixada proveu-nos soluções de buracos negros ou buracos de minhocas. Com a mesma simetria, geometrias que descrevem buracos de minhoca foram encontradas numa brana assintoticamente de Sitter. Para o caso axialmente simétrico, métricas assintoticamente anti-de Sitter e de Sitter foram construídas no contexto citado. Propriedades óticas, como a rotação do vetor de polarização, foram estudadas, mostrando-nos algumas diferenças entre os mundos brana, tratados como uma teoria de gravitação modificada, e a relatividade geral. / In this work we have constructed new solutions, with axial or spherical symmetry, to the induced gravitational field equations within a Randall-Sundrum type brane world scenario, where a 3-brane with cosmological constant is embedded in a 5-dimensional space-time called bulk. For the spherical case with negative cosmological constant, we have found a family of solutions in an anti-de Sitter brane, where each member of the family is different from another when C is fixed. With a fixed C we have black holes or wormholes. In this same case, with spherical symmetry, we have obtained wormhole solutions in a de Sitter brane. In the same context, for the axially symmetric case, metrics asymptotically anti-de Sitter and de Sitter were built. Optics features, like rotation of polarization vector, have been studied. These features showed some differences between brane worlds, a theory of modified gravity, and the General Relativity.

Nesta dissertação são explorados efeitos clássicos e semi-clássicos em espaços-tempos quase-extremos. Na classe de geometrias tratadas aqui, uma região estática entre dois horizontes é considerada, de forma que estes horizontes estão muito próximos e as suas gravidades superficiais são muito pequenas. Este limite quase-extremo surge em vários contextos de interesse, envolvendo buracos negros assintoticamente de Sitter, buracos de minhoca e buracos negros em universos com seção espacial compacta. No trabalho desenvolvido, buracos de minhoca ligando duas regiões com horizontes cosmológicos são estudados em detalhes. Uma vez caracterizada, algumas das propriedades clássicas destas estruturas e efeitos semi-clássicos são explorados. O tratamento quântico proposto leva naturalmente a uma caracterização termodinâmica associada aos horizontes atrapantes presentes na geometria. Consideramos especificamente propriedades térmicas associadas a um campo escalar nos espaços-tempos de interesse. Uma revisão do formalismo de Hayward é feito, com a sua adaptação para espaços-tempos importantes. Buracos de minhoca no regime quase-extremo são discutidos em detalhes. / In this dissertation, classical and semi-classical effects in quasi-extreme spacetimes are explored. In the class of geometries treated here, a static region between two horizons is considered, in such a way that these horizons are very close and their surface gravities are very small. This quasi-extreme limit appears in several contexts of interest, such as asymptotically de Sitter black holes, wormholes and black holes in universes with compact spatial section. In the developed work, wormholes connecting two regions bounded by cosmological horizons are studied in detail. Once some of the classical properties of these structures are characterized, semi-classical effects are explored. The proposed quantum treatment naturally leads to a thermodynamic characterization associated to the trapping horizons present in the geometry. We specifically consider thermal properties associated to a scalar field in the spacetimes of interest. A review of Hayward\'s formalism is presented, with a proper adaptation to important space-times. Wormholes in the near extreme regime are discussed in detail.

Wormholes Project son pantallas gigantes instaladas en las redes de metro de distintas ciudades del mundo a través de las cuales las personas de distintos países podrán interactuar de modo audiovisual y en tiempo real. Su objetivo es hacer reexionar a la gente común y corriente (aquella que jamás viajará a Medio Oriente, Japón o Filipinas) sobre la existencia omitida del resto de personas que habita en el mundo, al permitir que accedan a ellos sensorial y socialmente, y de paso provocar que cuestione su rol frente a esta nueva realidad revelada. El presente trabajo busca justificar teóricamente, diseñar y registrar el primer intento fallido por implementar el prototipo entre Santiago de Chile y Tokio. La justificación teórica se vale de la obra de pensadores clásicos y contemporáneos, y de un par de estudios chilenos sobre cultura y raza respectivamente. En el diseño e intento de implementación participan instituciones chilenas importantes entre las que destacan la Universidad de Chile, Comisión Bicentenario y Metro. Wormholes busca aportar a un posicionamiento internacional protagónico de Chile en innovación, tecnología y democracia, y aportar a la consolidación de la imagen del Departamento de Ingeniería Industrial, de la Escuela de Ingeniería y de la Universidad de Chile, como principales focos generadores de iniciativas poderosas, innovadoras, protagónicas y democráticas en Chile. Este trabajo es la argumentación final previa al segundo intento de implementación del prototipo, a realizarse durante el año 2010.

This study has investigated navigation strategies and spatial memory in Euclidean versus non-Euclidean environments. It also had a focus on mental maps, homing abilities and past video game experiences. Two test groups traversed mazes with identical layouts, but in which the non-Euclidean version incorporated wormholes that teleported participants in an, to the participant, unobvious manner. Data such as distances, time taken, and individual routes was collected. A thematic survey regarding strategies and tests for deeming what kind of mental map the participants used were also employed. Shapiro-Wilk tests, QQ-plots, PCA, Boxplots, T-tests, Heatmaps and Mann-Whitney U tests were used depending on the suitable data. Results showed that there were no significant differences between the two test groups in terms of quantifiable data and overall strategies used, while still there were signs of better performance for both groups in some certain respects. At the look on the groups as a whole, the participants that were deemed to use cognitive topological graphs, rather than cognitive Euclidean maps, were more successful in achieving the objectives. The results imply that areas like game design can be pushed further when it comes to using abstract or non-conventional spaces created by wormholes, without having a negative effect on the players navigational abilities. The results are also consistent with prior research in the field of psychology that refers to people using both maps and graphs as a cognitive representation of space.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-11T22:42:30Z No. of bitstreams: 1 PedroTupaPandavaAum_TESE.pdf: 7374843 bytes, checksum: da0bd8befae6b9c55d40316b4a0ba58d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-10-17T23:38:00Z (GMT) No. of bitstreams: 1 PedroTupaPandavaAum_TESE.pdf: 7374843 bytes, checksum: da0bd8befae6b9c55d40316b4a0ba58d (MD5) / Made available in DSpace on 2016-10-17T23:38:00Z (GMT). No. of bitstreams: 1 PedroTupaPandavaAum_TESE.pdf: 7374843 bytes, checksum: da0bd8befae6b9c55d40316b4a0ba58d (MD5) Previous issue date: 2016-03-22 / Um dos desafios na acidifica??o de po?os em forma??es carbon?ticas ? o controle da rea??o de dissolu??o do carbonato de c?lcio. Devido a elevada taxa de rea??o entre o ?cido clor?drico (HCl) e a forma??o, o HCl ? todo consumido na regi?o da forma??o pr?xima ao po?o de maneira que as zonas mais profundas n?o s?o alcan?adas e as regi?es de dano podem n?o ser ultrapassadas. Diversos sistemas foram desenvolvidos para retardar a rea??o de dissolu??o, incluindo a utiliza??o de ?cidos org?nicos, sistemas viscosos e emulsionados. Contudo, poucos estudos reportam a utiliza??o de sistemas microemulsionados como sistemas retardados. Neste trabalho foram estudados sistemas microemulsionados ?cidos do tipo ?leo em ?gua para aplica??o em acidifica??o de carbonatos e limpeza de po?o. O trabalho foi dividido em duas etapas principais, sendo elas: a obten??o e caracteriza??o dos sistemas; e a avalia??o da efici?ncia realizando experimentos de inje??o em plugues de rocha carbon?tica. Para formula??o dos sistemas microemulsionados, dois ?cidos foram utilizados: o ?cido clor?drico (HCl); e o ?cido etilenodiamino tetra-ac?tico (EDTA). O tensoativo utilizado foi o ALK L90 (n?o i?nico), o sec-butanol como co-tensoativo e o xileno como componente org?nico. Foram obtidos sistemas microemulsionados ?cidos com HCl e com EDTA. Os resultados mostraram que a adi??o de ?cidos em determinadas condi??es promove a transi??o de fases dos sistemas de microemuls?o. Os ensaios de inje??o mostraram que os sistemas microemulsionados ?cidos propostos foram eficientes em estimular os plugues de forma??o carbon?tica, alcan?ando incrementos na permeabilidade entre 10-30%, sem apresentar dissolu??o na face e formando wormholes. / One of the challenges in acidification of wells in carbonate formations is controlling the dissolution reaction of calcium carbonate. Due to the high rate of reaction between hydrochloric acid (HCl) and the rock formation, the HCl is all consumed close to the wellbore region. In this way, the deeper areas are not reached and the damage regions may not be exceeded. Several systems have been developed to retard the dissolution reaction, including the use of organic acids, viscous emulsion systems, and the use of chelating agents. However, few studies have reported the use of microemulsion systems as retarded acid systems. In this work, oil in water acid microemulsions are studied for use in carbonate acidizing. The work was divided into two main stages. The first stage was the obtaining and the characterizing of the systems and the second one was the efficiency evaluation by performing injection experiments in carbonate cores. Two microemulsion systems were obtained, one using the hydrochloric acid (HCl) and the second using the ethylenediaminetetraacetic acid (EDTA), a chelating agent. The surfactant used was the ALK-L90 (non-ionic), sec-butanol was used as a co-surfactant, and xylene as the organic component. The results showed that the addition of the HCl or chelating agent promotes the transition of the phase of microemulsion system. Wettability studies showed that the microemulsion systems obtained have a greater power of interaction with the carbonate than the aqueous solutions and also the microemulsion systems without addition of HCl or EDTA. The coreflood experiments showed that the microemulsion systems obtained were effective in stimulating the carbonate cores, achieving increases in permeability up to 86% without showing core face dissolution. The HCl and EDTA corrosiveness in microemulsion media was 80% less than in the aqueous solution. The microemulsion systems obtained can be a promising candidate to use as alternative fluids to carbonate stimulation.

abstract: Two ideas that extends on the theory of General Relativity are introduced and then the phenomenology they can offer is explored. The first idea shows how certain types of $f(R)$ gravity allows for traversable wormholes among its vacuum solutions. This is surprising to find in such simple setting as these type of solutions usually requires fairly complex constructions to satisfy the equations of motion of a gravitational theory. The second idea is the matter bounce description of the early universe where a fairly unique feature of the model is identified. Consequences of this feature could allow the paradigm to distinguish itself from other alternative descriptions, such as inflation, through late time observations. An explicit example of this claim is worked out by studying a model involving an interaction in the dark sector. Results of a more astrophysical nature, where a careful analysis of the morphology of blazar halos is performed, are also presented in the Appendix. The analysis determined that the $Q$-statistic is an appropriate tool to probe the properties of the intergalactic magnetic fields responsible for the halos formation. / Dissertation/Thesis / Doctoral Dissertation Physics 2017

Quadratic curvature terms are commonly introduced in the action as first-order corrections of General Relativity, and, in this thesis, we investigated their impact on the most simple isolated objects, that are the static and spherically symmetric ones. Most of the work has been done in the context of Stelle's theory of gravity, in which the most general quadratic contractions of curvature tensors are added to the action of General Relativity without a cosmological constant. We studied this theory's possible static, spherically symmetric and asymptotically flat solutions with both analytical approximations and numerical methods. We found black holes with Schwarzschild and non-Schwarzschild nature, naked singularities which can have either an attractive or repulsive gravitational potential in the origin, non-symmetric wormholes which connects an asymptotically flat spacetime with an asymptotically singular one, and non-vacuum solutions modeled by perfect fluids with different equations of state. We described the general geometrical properties of these solutions and linked these short-scale behaviors to the values of the parameters which characterize the gravitational field at large distances. We studied linear perturbations of these solutions, finding that most are unstable, and presented a first attempt to picture the parameter space of stable solutions. We also studied the Thermodynamics of black holes and described their evaporation process: we found that either evaporation leads black holes to unstable configurations, or the predictions of quadratic gravity are unphysical. We also considered the possibility of generalizing Stelle's theory by removing the dependence from the only mass-scale present by including a new dynamical scalar field, making the theory scale invariant. Having a more complex theory, we did not investigate exotic solutions but limited ourselves to the impact of the new additional degrees of freedom on known analytical solutions. It was already known that in a cosmological setting this theory admits a transition between two de Sitter configurations; we analyzed the same problem in the context of static and spherically symmetric solutions and found a transition between two Schwarzschild-de Sitter configurations. In order to do that, we studied both linear perturbations and the semiclassical approximation of the path integral formulation of Euclidean quantum gravity. At last, we tried to extract some phenomenological signatures of the exotic solutions. In particular, we investigated the shadow of an object on background free-falling light, and a possible way of determining the behavior close to the origin using mass measurements that rely on different physical processes. We show that, whenever these measurements are applied to the case of compact stars, in principle it could be possible to distinguish solutions where different equations of state describe the fluid.