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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
311

The construction of optimal drape surfaces with constrained first and second derivatives

Fossati, Reiner Justin 31 January 2003 (has links)
The need to construct optimal drape surfaces arises in airborne geophysical surveys where it is necessary to fly a safe distance above the ground and within the performance limits of the aircraft used, but as close as possible to the surface. The problem is formulated as an LP with constraints at every point of a grid covering the area concerned, yielding a very large problem. The objective of the LP is to create as "good" a surface as possible. This formulation is new, as previous methods did not aim to minimise an objective function. If the desired surface has only slope limitations, the resulting drape surface must be constrained in the first derivative. Such a drape surface is readily constructed using the Lifting Algoritlun. It is shown that the Litling Algorithm is both exact and has great speed advantages. Some numerical results confinning exacmcss and speed are presented, as is the algorithm's analogy to a flow network method. An enhanced lifting method with a better order of complexity is also proposed and tested numerically. In most practical situations a drape surface is required which has both first and second derivatives constrained. If only a cut through such a surface is considered, the problem can be solved with relative ease by exploiting its nctwork~Jike structure. This method fonns the basis of one of the preferred heuristics developed later. It was not possible to generalise this method to a full two~dimensional drape surface. A commercially available LP package fares better in finding the optimal solution. Several heuristic methods were examined. first a general heuristic method based on a lifting approach was developed. This was followed by a method using repeated application of the method used for sections (the Alternating One-dimensional Dual Algorithm ["AODA"]). Three heuristics based on thimbles were also designed. Thimbles are caps whose first and second derivatives are acceptable and which are placed over local infeasibilities in the topography The work ends with a chapter comparing the efficiency of various heuristics and comparing the results obtained using a number of test datasets. It was fOLmd that heuristic methods provide acceptable drape surfaces and that the choice lies between speed and accuracy, with a previously designed smoothing method being the fastesl and the AODA the most accurate and quick enough. / Operations Research / D.Phil.
312

Some aspects of the dynamics of rotating, stratified and shear flows : astrophysical and geophysical applications / Quelques aspects de la dynamique d'un fluide stratifié en rotation et / ou cisaillé : applications astrophysiques et geophysiques

Facchini, Giulio 19 December 2017 (has links)
Ce travail de thèse cherche à caractériser, à l'aide d’expériences de laboratoire, le mouvement d'un fluide stratifié à la fois tournant et cisaillé. Dans ce contexte on a considéré trois problèmes qui sont issus des observations géophysiques et astrophysiques où ces écoulements sont très communs. En premier nous avons observé expérimentalement et modélisé l'évolution en temps d'un anticyclone en milieu stratifié tournant, dans le but de comprendre la longévité des meddies, des vortex qui se forment à la sortie de la Méditerranée et peuvent perdurer pendant des années. Nos anticyclones modèles montrent une relaxation visqueuse anormale en raison de l’interaction entre stratification et cisaillement. Nos résultats expérimentaux ont été confirmés à l'aide d'un modèle géostrophique et de simulations numériques qui montrent aussi le rôle majeur joué par les circulations secondaires. Dans un deuxième temps nous avons considéré la stabilité linéaire de l'écoulement de Couette Plan, un des plus simple des écoulement plans cisaillés. On montre que cet écoulement devient instable lorsque l'on ajoute de la stratification verticale. Nous remarquons aussi que la structure spatiale de l'instabilité ressemble à celle de certains jets océaniques que l'on observe près de l'équateur. Enfin nous avons caractérisé une instabilité non linéaire dite des zombie vortex qui a été récemment découverte et pourrait jouer un rôle fondamental dans la déstabilisation des disques d'accrétion, une étape fondamentale de la formation des planétaire. Nous avons construit le diagramme de stabilité de la ZVI dans l'espace de trois fréquences caractéristiques et quantifié la dissipation visqueuse. / The present PhD work comes with the scope of characterizing, analysing and modelling some laboratory flows in the simultaneous presence of rotation, stratification and shear. To this aim we address three specific questions inspired by geophysics and astrophysics where these three ambient features are commonly relevant. First we characterize and model the time evolution of a compact anticyclone in a rotating and stratified laboratory flow. We aim to understand the longevity of analogous vortices known as meddies which populate the Atlantic ocean at the exit of the Mediterranean sea. We observe that viscous relaxation happens in an unusual way because of the balance between rotation and stratification. The results are confirmed by a quasi-geostrophic model and numerical simulations which show the crucial role played by secondary circulations. Secondly we consider the linear stability of one of the simplest parallel shear flow, namely the plane Couette Flow, and show that it becomes unstable when adding a vertical stratification. Interestingly the unstable pattern reminds of deep oceanic jets observed close to the equator. The signature of this instability is observed in an ad-hoc experimental flow and interpreted with the support of direct numerical simulations. Finally we characterize the behaviour of a recently disclosed finite amplitude instability, namely the zombie vortex instability or ZVI. This instability appears when rotation, stratification and shear are of the same order and may may destabilize proto-planetary disks. We construct a stability diagram for ZVI in the space of the three ambient frequencies and analyse the effect of viscous dissipation.
313

Multiphase Fluid Flow through Porous Media: Conductivity and Geomechanics

January 2016 (has links)
abstract: The understanding of multiphase fluid flow in porous media is of great importance in many fields such as enhanced oil recovery, hydrology, CO2 sequestration, contaminants cleanup, and natural gas production from hydrate bearing sediments. In this study, first, the water retention curve (WRC) and relative permeability in hydrate bearing sediments are explored to obtain fitting parameters for semi-empirical equations. Second, immiscible fluid invasion into porous media is investigated to identify fluid displacement pattern and displacement efficiency that are affected by pore size distribution and connectivity. Finally, fluid flow through granular media is studied to obtain fluid-particle interaction. This study utilizes the combined techniques of discrete element method simulation, micro-focus X-ray computed tomography (CT), pore-network model simulation algorithms for gas invasion, gas expansion, and relative permeability calculation, transparent micromodels, and water retention curve measurement equipment modified for hydrate-bearing sediments. In addition, a photoelastic disk set-up is fabricated and the image processing technique to correlate the force chain to the applied contact forces is developed. The results show that the gas entry pressure and the capillary pressure increase with increasing hydrate saturation. Fitting parameters are suggested for different hydrate saturation conditions and morphologies. And, a new model for immiscible fluid invasion and displacement is suggested in which the boundaries of displacement patterns depend on the pore size distribution and connectivity. Finally, the fluid-particle interaction study shows that the fluid flow increases the contact forces between photoelastic disks in parallel direction with the fluid flow. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016
314

Effective-diffusion for general nonautonomous systems

January 2018 (has links)
abstract: The tools developed for the use of investigating dynamical systems have provided critical understanding to a wide range of physical phenomena. Here these tools are used to gain further insight into scalar transport, and how it is affected by mixing. The aim of this research is to investigate the efficiency of several different partitioning methods which demarcate flow fields into dynamically distinct regions, and the correlation of finite-time statistics from the advection-diffusion equation to these regions. For autonomous systems, invariant manifold theory can be used to separate the system into dynamically distinct regions. Despite there being no equivalent method for nonautonomous systems, a similar analysis can be done. Systems with general time dependencies must resort to using finite-time transport barriers for partitioning; these barriers are the edges of Lagrangian coherent structures (LCS), the analog to the stable and unstable manifolds of invariant manifold theory. Using the coherent structures of a flow to analyze the statistics of trapping, flight, and residence times, the signature of anomalous diffusion are obtained. This research also investigates the use of linear models for approximating the elements of the covariance matrix of nonlinear flows, and then applying the covariance matrix approximation over coherent regions. The first and second-order moments can be used to fully describe an ensemble evolution in linear systems, however there is no direct method for nonlinear systems. The problem is only compounded by the fact that the moments for nonlinear flows typically don't have analytic representations, therefore direct numerical simulations would be needed to obtain the moments throughout the domain. To circumvent these many computations, the nonlinear system is approximated as many linear systems for which analytic expressions for the moments exist. The parameters introduced in the linear models are obtained locally from the nonlinear deformation tensor. / Dissertation/Thesis / Doctoral Dissertation Applied Mathematics 2018
315

Modelo geológico 3D de reservatório carbonático albiano no sudoeste da Bacia de Campos (RJ) / 3D geological model of albian carbonate reservoir in the southwest of Campos Basin (RJ)

Nascimento, Luana Fernandes do [UNESP] 21 October 2016 (has links)
Submitted by Luana Fernandes do Nascimento (luanaf_n@yahoo.com.br) on 2016-12-14T18:53:09Z No. of bitstreams: 1 Luana_Unesp_Mestrado_Final.pdf: 15010826 bytes, checksum: d648b060d92f0de0538ad7924f8a3ce0 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-12-19T17:24:32Z (GMT) No. of bitstreams: 1 nacimento_lf_me_rcla.pdf: 15010826 bytes, checksum: d648b060d92f0de0538ad7924f8a3ce0 (MD5) / Made available in DSpace on 2016-12-19T17:24:32Z (GMT). No. of bitstreams: 1 nacimento_lf_me_rcla.pdf: 15010826 bytes, checksum: d648b060d92f0de0538ad7924f8a3ce0 (MD5) Previous issue date: 2016-10-21 / Outra / A área de estudo corresponde a um campo produtor de hidrocarbonetos situado no sudoeste da Bacia de Campos a 80 km da costa. Esta região produz hidrocarbonetos de diversos níveis estratigráficos, entre eles, os carbonatos do Albiano, foco deste estudo. O alto interesse econômico dos carbonatos no setor petrolífero mundial e a complexidade da sua análise nos dados geofísicos, justifica a importância desta pesquisa na definição de um método que auxilie na caracterização da distribuição regional da propriedade da rocha reservatório, neste caso, a porosidade. Neste contexto, este trabalho objetiva a determinação da heterogeneidade lateral e vertical das propriedades das rochas reservatórios, por meio da construção de um modelo geológico 3D de porosidade dos dois principais reservatórios identificados na Formação Quissamã (Grupo Macaé). Com esta finalidade, o método incluiu seis etapas principais: análise dos perfis geofísicos e correlação de poços, interpretação sísmica, conversão tempo x profundidade, análise de atributos sísmicos, análise geoestatística e modelagem geológica por meio da aplicação de Simulação Sequencial Gaussiana. Como níveis de referência, foram interpretados os intervalos estratigráficos correspondentes à Formação Outeiro e, na Formação Quissamã, os níveis Q1 e reservatórios R1 e R2 (principais produtores do campo). Estes níveis foram definidos com base na mudança do padrão geométrico dos perfis geofísicos de raio gama (RG), densidade (RHOB) e porosidade (Nphi). Os intervalos estudados estão distribuídos em um alto estrutural com eixo principal de direção NW-SE delimitado por falhas e pela própria geometria do banco carbonático. Na porção central do campo, este alto estrutural apresenta valores altos de porosidade (>21%), e se destacou no mapa de resistividade como portador de hidrocarbonetos nos reservatórios R1 e R2. Estas fácies carbonáticas variam para norte e nordeste da área com valores de porosidade mais baixos (<18%), representando a diminuição da qualidade dos reservatórios para estas regiões; esta observação, aliada à influência das falhas a sudoeste e nordeste do banco, permitiu classificar a trapa destes reservatórios como estrutural-estratigráfica. O sistema de falhas predominante na área de estudo corresponde ao NW-SE, que originou estruturas do tipo rollovers e horsts com potencial reservatório. Estas falhas abateram os blocos a sudeste e sul, que foram realçados nos mapas de atributos sísmicos como portadores de alta porosidade, comprovados por gráficos de correlação com coeficiente R2>0,65. Esta análise foi utilizada para determinar o modelo geológico 3D de porosidade, gerado por Simulação Sequencial Gaussiana. O resultado consistiu em uma representação coerente, com maior grau de certeza no alto estrutural central, que possui maior quantidade de dados de poços. Apesar das áreas a sudoeste e sul não apresentarem dados de poços, o método de Simulação Sequencial Gaussiana extrapolou altos valores de porosidade em 23% das 30 realizações geradas. / The study area is an ancient field and hydrocarbon producer, located in the southwest of the Campos Basin, in a water depth of approximately 100 m and 80 km distant from the coast. This region produces hydrocarbon from multiple stratigraphic layers, among them, there are the Albian carbonates, the focus of this research. The high economic interest in carbonates plays by the global oil industry and the complexity of their analysis in geophysical data, justifies the importance of this research to define a method, which determine the regional distribution of the property of the reservoir rock, in this case, the porosity. In this context, this study aims to determine the lateral and vertical heterogeneity of the properties of the reservoir rocks through the construction of a 3D geologic model of porosity from two main reservoirs in Quissamã formation (Macae Group). For this purpose, the method includes six major steps: analysis of well log and correlation of wells, seismic interpretation, conversion time vs. depth, analysis of seismic attributes, geostatistical analysis and geological modeling through the application of Gaussian simulation. The stratigraphic intervals such as Outeiro Formation and Quissamã Formation, which include level Q1, R1 and R2 reservoirs (main producers of the field) were interpreted as reference levels. These intervals were defined based on the change of the geometric standard of the geophysical profiles, as gamma ray (GR), density (RHOB) and porosity (Nphi). These levels are distributed in a carbonate bank with main axis in NW-SE direction, delimited by faults and its geometry. It was observed a structural high in the central portion of the field presenting high porosity values (> 21 %) that was highlighted in the resistivity maps as filled by oil in the reservoirs R1 and R2. These carbonate facies vary to the north and northeast of the area with lower values representing the decline in the quality of the reservoirs for these regions; this observation combined with the influence of the faults , in the southwest and northeast of the bank, allowed to classify the trap of these reservoirs as structural-stratigraphic. The predominant fault system in the study area corresponds to the NW-SE, which formed structures like rollovers and horsts with potential of being reservoir. These faults shot down the block to the southwest and south, which were highlighted in the maps of seismic attributes as having high porosity, supported by cross plots with correlation coefficient of R2> 0.65. This analysis was used to determine the 3D geologic model of porosity, generated by Gaussian simulation, most appropriate to the context of the geological area. The result was a coherent representation with greater certainty in the central structural high that presents a higher amount of well data. Despite the southwest and south areas do not present well data, the method was efficient in interpolate high values of porosity in 23% of 30 generated realizations. / PRH 05: 6000.0082154.13.4
316

Identificação de areias siliciclásticas para a recuperação de praias em erosão através de métodos geofísicos acústicos / Sand search for beach nourisment by acoustic geophysical methods

Nãnashaira Medeiros Siqueira 30 July 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Devido a sua grande extensão latitudinal, a costa brasileira é influenciada por diferentes regimes climáticos e oceanográficos. Adicionalmente, a distribuição da população brasileira é caracterizada por uma alta concentração nas capitais litorâneas. Todos esses fatores levam à construção de inúmeras estruturas de engenharia que podem de alguma forma impactar o transporte de sedimento e consequentemente o balanço sedimentar de algumas praias. Uma das formas mais eficientes de recuperar esse balanço sedimentar é a alimentação artificial de praias, com sedimentos provenientes da plataforma continental com características semelhantes. Os métodos geofísicos acústicos permitem mapear de forma eficiente o fundo e o subfundo marinho para a busca de áreas fontes para a lavra de forma eficiente. O objetivo deste estudo é a identificação de padrões geoacústicos a partir de analises quantitativas e qualitativas, para a caracterização de áreas fontes de areias siliciclásticas compatíveis com sedimentos de praias em erosão na cidade do Rio de Janeiro. O mapeamento foi realizado na plataforma continental interna do Rio de Janeiro, em área adjacente à praia de Itaipuaçu (Maricá, RJ). As análises evidenciaram depósitos, localizados entre 19 e 30 metros, de areias com granulometria, textura e selecionamento em condições ideias para a recomposição de praias do Rio de Janeiro. / The Brazilian coast is afected by different oceanographic characteristics, mainly due to its large latitudinal extention. Additionally, the distribution of the Brazilian population is characterized by a high concentration in the coastal capital. These facts generate a large number of coastal engineering structures that may impact the sediment transport and consequently the sediment balance in some beaches. All these factors impact some sand beaches and the best choice for its mitigation and recovering is the beach nourishment - with sediments from the continental shelf with similar characteristics. However to find a good place for dredging in the shelf, we need to use geophysical methods that allow to map the bottom and sub bottom environments more efficiently. The objective of this study is the identification of geoacoustics patterns, following qualitative and quantitative analyzes, for characterizing source areas of siliciclastic sands in ideal conditions for recovering eroded beaches in Rio de Janeiro. The mapping was done in the shelf in front of Itaipuaçu beach (Maricá, RJ). The quantitative results showed well sorted median sand placers seaward of the closure depth, located between 19 and 30 meters, ideal for Rios beaches recovering.
317

Sistematização do processamento de dados gravimétricos aplicados a determinação do modelo geoidal / AVL system development with intelligent position update rules that enhance tracks representations

Amarante, Rogério Rodrigues, 1972- 11 September 2012 (has links)
Orientador: Jorge Luiz Alves Trabanco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-21T16:53:48Z (GMT). No. of bitstreams: 1 Amarante_RogerioRodrigues_D.pdf: 8479306 bytes, checksum: c6760b22f8c1f110ad1b61e48c59508b (MD5) Previous issue date: 2012 / Resumo: Com o uso de métodos adequados, receptores GNSS podem determinar coordenadas com acurácia suficiente para aplicação em projetos de engenharia. Porém a altitude elipsoidal obtida não utiliza o mesmo sistema de referência da engenharia de transportes. A altitude elipsoidal pode ser transformada em ortométrica com a utilização de modelos geoidais que são gerados a partir de dados gravimétricos. Neste trabalho são apresentados alguns conceitos introdutórios sobre a geração de modelo geoidais. Em seguida mostra o desenvolvimento de uma nova sistematização do tratamento de dados gravimétricos com objetivo de facilitar a detecção de erros, aumentar a produtividade e melhorar a organização de resultados obtidos. Dentro deste desenvolvimento, são revisadas as teorias utilizadas para transformar medições feitas com gravímetros diferenciais em aceleração da gravidade. Apresenta também técnicas de ajustamento de observações com intuito tratar erros aleatórios. A nova abordagem sugerida foi utilizada para o desenvolvimento de um software objetivando validar as idéias propostas, permitir a comparação com outras soluções existentes e também servir como uma contribuição tecnológica. Dados gravimétricos reais foram testados dentro da abordagem proposta tendo sido observados mais organização, ganho de produtividade e principalmente a detecção de erros grosseiros e aleatórios. Com a revisão do cálculo da correção da maré, percebeu-se que programas e equipamentos atualmente em uso não possuem configuração do fator gravimétrico, fato que pode influenciar em até 0; 007mGals no processamento das observações / Abstract: With the use of appropriate methods, GNSS receivers can determine coordinates with sufficient accuracy for use in projects. The ellipsoidal height obtained, however, does not use the same reference system as the one used in transportation engineering. The ellipsoidal height can be transformed to orthometric height using geoid models that are generated from gravimetric data. In this work some introductory concepts on the generation of geoid model are presented. Then it shows the development of a new approach in systematization of gravimetric data processing aiming to facilitate the detection of errors, increase productivity and improve the organization of the results obtained in the gravimetric surveys. Within this development, the theories used to convert measurements of the differences in gravity acceleration are revised. It also features adjustment techniques of observations in order to deal with random errors. The new suggested approach was used to develop software in order to validate the proposed ideas, allow comparison with other existing solutions, and also serves as a technological contribution. Gravimetric data were tested within the suggested approach. It was observed better organization, productivity gains and mainly detection of gross errors and random. With the review of the tide correction calculation, it was realized that programs and equipments now widely used have no gravimetric factor setting, a fact that can influence up to 0; 007mGals in processing the readings / Doutorado / Transportes / Doutor em Engenharia Civil
318

InterSis : uma interface grafica para modelamento sismico

Calle Ochoa, Andres Eduardo 10 September 2003 (has links)
Orientadores: Martin Tygel, Rodrigo de Souza Portugal / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-03T20:40:40Z (GMT). No. of bitstreams: 1 CalleOchoa_AndresEduardo_M.pdf: 5418722 bytes, checksum: d570c726fc5841a6556ad52fca983209 (MD5) Previous issue date: 2003 / Resumo: o modelamento desempenha importante papel nos estudos de processamento e inversão de dados sísmicos. Muitos problemas complicados podem ser melhor atacados e entendidos quando os fenômenos de propagação de ondas envolvidos podem ser modelados, pelo menos em modelos geológicos mais simples. Tendo em vista ser o modelamento sísmico uma área de vasta aplicação e interesse, um grande número de pacotes computacionais existem capazes de oferecer sofisti-cadas capacitações para propósitos de modelagem. Esses pacotes são sujeitos entretanto, a severas limitações em sua utilização, não só devido aos seus altos custos, quanto também à inacessibi-lidade de seus códigos fonte. Por outro lado, as alternativas que existem, na forma de pacotes de uso livre, não representam substituição satisfatória. Isto porque os pacotes de modelamento disponíveis, geralmente desenvolvidos em ambientes científico-acadêmicos, não são suficiente-mente amigáveis e flexíveis, por exemplo na especificação de parâmetros de entrada, disposição gráfica de resultados, etc. o objetivo desta dissertação é investigar os principais problemas associados à construção de uma interface gráfica capaz de suportar uma variedade de programas de modelamento existentes e disponíveis como programas livres. Como resultado dessas investigações, é apresentada neste tra-balho a interface gráfica chamada InterSis. A interface InterSis foi construída de modo a aceitar, de forma simples e unificada, programas de modelamento destinados à propagação de ondas em meios 2D e 2.5D.InterSis foi desenvolvida utilizando os pacotes de domínio público GTK + (Graphical Tool/dt) e SU (Seismic Una). No seu presente estágio, InterSis é capaz de atuar como efetiva plataforma para os programas: (a) Seis88, um programa bem estabelecido de traçado de raios em mode-los elásticos e isotrópicos, desenvolvido por V. Cerveny e I. Psencík e (b) fd2d um programa de diferenças finitas para a equação de onda acústica, desenvolvido por 1. Costa. Como uma pro-priedade de particular interesse, InterSis utiliza a informação fomecida pelo programa Seis88 para computar os parâmetros do chamado método CRS (do Inglês Common-Reflection-Suiface). Desta forma, a interface proposta pode ser de valia nos estudos de imageamento e inversão que utilizam o método CRS. Vale notar que, devido à sua estrutura de caráter geral, InterSis pode ser bem adaptada a outros programas de modelamento / Abstract: Modelling plays an important role in seismie data processing and inversion. Several compli-cated problems can be better addressed and understood, when the wave propagation involved ean be modelled, at least in simple versions ofthe geological model. As a wide topie of application and interest, a number of commercial softwares exist that offer sophisticated capabilities for modelling purposes. These packages are subjected to a number of limitations on their use, not only of costs, but also because their source codes are not accessible. On the other hand, the few ahematives existo in the form of open packages do not represent an easy replacement. The available modelling codes, mainly developed within academie-scientific environments, are not friendly and flexible enough, e.g., in the specification of input parameters and display of resu1ts. The aim of this work is to investigate the main problems connected with the construction of a graphica1 interface that would be an useful support to a number of modelling programs available as open codes. As a result of the investigations, a graphical interface, ca1led InterSis, has been developed. InterSis ean accept and handle, in a simple and unified way,softwares that involves seismic modelling in 2D and 2.5D media. InterSis was developed using the public-domain softwares GTK + (Graphica/ Too/kit) and SU (Seismic Unix). In its present stage, it is able to be an effective platform for the following programs : (a) Seis88, a well-established ray-tracing program developed by v. Cerveny and I. PsenãK and (b) fd2d a finite-difference program for the acoustie wave equation developed by J. Costa. As a particular feature, InterSis uses the information provided by Seis88 to compute the parameters ofthe COmnJOlI-Rejlectioll-Surface (CRS) method. In this way, the proposed intedàce ean be useful to imaging and inversion studies based on the CRS method. It is to be noted that, due to its general s1ructure, InterSis can be well adapted to other modelling programs / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo
319

Study of canopy variability and irrigable potential of rehabilitated and virgin mine lands by means of remote sensing and spatial analysis

Narciso, Giovanni 01 August 2005 (has links)
Please read the abstract in the section 00front of this document / Dissertation (MSc (Agronomy))--University of Pretoria, 2006. / Plant Production and Soil Science / unrestricted
320

Aplicação de métodos geofísicos aplicados em pontos selecionados do Estuário do Rio Itanhaém / Application of the geophysical metods in selected places along Itanhaém River Estuary

Vinhas, Maria Cecilia Sodero, 1968- 27 August 2018 (has links)
Orientador: Sueli Yoshinaga Pereira, Rodrigo de Souza Portugal / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-27T02:27:34Z (GMT). No. of bitstreams: 1 Vinhas_MariaCeciliaSodero_D.pdf: 6306176 bytes, checksum: 930cddf48712d9d8f841ea47190c1beb (MD5) Previous issue date: 2014 / Resumo: Essa pesquisa objetivou a aplicação e o entendimento da relação de três métodos geofísicos: eletrorresistividade, sísmica de refração e sismoelétrica; em pontos selecionados no Estuário do Rio Itanhaém e se eles podem ser validados pelas informações geológicas e hidrogeológicas da região. Os levantamentos foram realizados em duas etapas. A primeira etapa foi o de reconhecimento de campo, realizado no período de 21 a 26 de setembro/2009 que é considerado um período menos chuvoso. Os pontos escolhidos foram denominados de Ponto Praia, Ponto Chácara, Ponto Lixão e Ponto Country Club. A segunda etapa consistiu na coleta de dados propriamente dita nos pontos Chácara, Lixão e Country Club; o ponto Praia foi excluído por estar próximo às grandes torres de transmissão de energia, fazendo com que houvesse interferência nos dados. No ponto Lixão foi verificada a existência de gás metano, na superfície, através das bolhas de ar nas poças de água, no Ponto Country se localizava próximo a dois brejos e um pequeno córrego, e por fim o Ponto Chácara se localizava próximo ao Rio Branco, onde foi possível perceber a influência do aquífero livre na coleta dos dados. O período da segunda etapa dos levantamentos de dados ocorreu entre setembro de 2010 e agosto de 2011. Os levantamentos resultaram em um perfil vertical central, dos pontos selecionados, onde foram encontrados os seguintes materiais: areia, sedimentos arenosos, areia argilosa, argila seca, dois tipos de aquífero (de água doce e de água salobra), além de solos saturados e não saturados, e lixo. Em alguns levantamentos atingiram a rocha sã. Os levantamentos eletrorresistivos foram os que tiveram melhor resultado, os levantamentos de sísmica obtiveram uma camada apenas em quase todos os levantamentos, sendo que em um deles, o segundo campo do Ponto Country Club, se obteve mais de uma camada de material. Os levantamentos sismoelétricos não tiveram seus tratamentos finalizados, pois se percebeu que era necessária a utilização pré-amplificador; sua ausência no levantamento no campo, aliado a presença de linhas elétricas nos locais do levantamento, prejudicou nos resultados dos dados coletados, fato indicado pela presença das linhas harmônicas nos dados, e consequentemente não ter finalizado o algoritmo de tratamento desses dados / Abstract: This research intended the application and understanding about connexion among three geophysical methods: eletrical resistivity, refraction seismic and eletrical seismic; in selected places along Itanhaem River Estuary and if they can be accepted by geological and hydrogeological information of the region. The survey was accomplished in two phases. The first one was to recognize field of study, which was realized from 21st to 26th of September 2009, that is considered a less rainy season. The chosen sites were: Praia Point, Chácara Point, Lixão Point and Country Club Point. The second phase was the data collection, at these chosen sites, Chácara, Lixão and Country Club; The Praia Point was excluded because it was very near of large power transmission towers and it was causing interference in the collected information, at the Lixão Point was verified existence of methane, on the surface, through the air bubbles in puddles, in the case of Country Club Point was located near two swamps and a small stream, the Ranch Point was located near the river called Branco, and it was possible to realized the free influence of this aquifer in data collection. The second phase period of data collection, occurred between September 2010 and August 2011. The surveys resulted in a central vertical shape of the selected sites, where the following materials were found sand, sandy sediments, clayey sand, dry clay, two types of groundwater (freshwater and brackish water), and saturated and unsaturated soils and waste. In some surveys reached the bedrock. The electrical resistivity surveys were those who obtained better results, the seismic surveys obtained only a layer in almost all surveys, and in one of them, the second Country Club Point, got more than one layer of material. The electrical seismic surveys were not their treatments finalized, because it was realized the need to use a preamplifier; its absence in the field survey, combined with the presence of power lines in the survey sites, affected the collected data results, condition indicated by the presence of harmonic lines in the data, and consequently have not finalized these data processing algorithm / Doutorado / Geologia e Recursos Naturais / Doutora em Ciências

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