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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.
101

Reconstruction of Past Climatic Variability: Final Technical Report

Fritts, Harold C., Blasing, T. J., DeWitt, E., Lofgren, G. R., McDougall, K. B., Shatz, D. J., Sherwood, J.A., Stevens, D. W., Winter, C. L., Wiseman, M. A. 01 March 1976 (has links)
Final Technical Report / Grant No. AFOSR 72-2406 / March 1, 1976 / Results are reported from the first three years of a five-year project to reconstruct past climatic fluctuations in the Northern Hemisphere from variations in the growth rings of trees. The most significant result is the growing international collaboration stimulated by this research effort. The second is the development of 127 high-quality tree-ring chronologies from North America and Europe. Other developments include the establishment of the International Tree-Ring Data Bank, evaluation of multivariate techniques for calibration and analysis, the selection of a revised data set for reconstructing North American climate, and several other technical achievements. These results now will be used to improve reconstructions of past climate and to expand them to eastern North America and Europe.
102

Emprego da fluorescencia de raios X por dispersao de energia no estudo da dinamica da vinhaca no solo

SIMABUCO, SILVANA M. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:37:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:30Z (GMT). No. of bitstreams: 1 02034.pdf: 6301635 bytes, checksum: 60b2f711d04c084336ad48884de17afa (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
103

Caracteriza??o geol?gica tridimensional e monitoramento de dunas no litoral oriental do Rio Grande do Norte

Ara?jo, Ver?nica Dantas de 19 May 2006 (has links)
Made available in DSpace on 2015-03-13T17:08:40Z (GMT). No. of bitstreams: 1 VeronicaDA.pdf: 5709097 bytes, checksum: 4074580aee5ec2b7d354ddab1d446e43 (MD5) Previous issue date: 2006-05-19 / This work presents geophysical and geological results obtained in a dunefield located in the east coast of Rio Grande do Norte State, with the aim to recognize the aeolian body depositional geometries to a future geologic modeling of the aeolian petroliferous reservoirs. The research, which was done in blowouts region situated at Nisia Floresta Municipally, included the characterization of external geometries with GPS and internal geometry analysis by GPR. Data was integrated in GoCAD software, where it was possible the three-dimensional characterization and interpretation of the studied deposits. The interpretation of GPR profiling allowed identifying: First-order bounding surfaces that separated the aeolian deposits of the Barreiras Formation rocks; Second-order bounding surfaces, which limit dune generations and Third-order bounding surfaces, a reactivation surface. This classification was based and adapted by the Brookfield (1977) and Kocurek (1996) propose. Four radarfacies was recognized: Radarfacies 1, progradational reflectors correlated to foresets of the dunes, Radarfacies 2, plain parallels reflectors related to sand sheets, Radarfacies 3, plain parallels reflectors associated to reworking of the blowout dune crest and Radarfacies 4, mounded reflectors associated to vegetated mound of sand or objects buried in subsurface. The GPR and GPS methods was also employed to the monitoring of dunefields susceptible to human activities in Buzios Beach, where the constructions along the blowout region and the tourism are changing the natural evolution of the deposits. This fact possibly to cause negative impacts to the coastal zone. Data obtained in Dunas Park, a unit environmental conservation, was compared with information of the Buzios Beach. There is a major tendency of erosion in Buzios, specifically in blowout corridor and blowout dune / Este trabalho apresenta os resultados geol?gicos e geof?sicos obtidos em um campo de dunas situados no litoral oriental do Rio Grande do Norte e teve como objetivo definir as geometrias deposicionais dos corpos e?licos para posterior aplica??o na modelagem geol?gica de campos produtores de ?leo e g?s de origem e?lica. A pesquisa foi realizada em uma regi?o de blowouts, situada no munic?pio de N?sia Floresta - RN, onde foi poss?vel definir a superf?cie externa com o uso do GPS geod?sico e a estrutura??o interna utilizando o GPR (Ground Penetrating Radar). Estes dados foram integrados no software de modelagem geol?gica Gocad, permitindo a visualiza??o tridimensional e interpreta??o dos dep?sitos estudados. O levantamento de perfis geof?sicos permitiu a investiga??o da geometria interna dos dep?sitos, nos quais foi poss?vel reconhecer superf?cies limitantes de 1? ordem (superf?cie deposicional que separa os dep?sitos e?licos de rochas da Forma??o Barreiras), 2? ordem (superf?cie que separa diferentes pulsos de sedimenta??o e?lica) e 3? ordem (superf?cies de reativa??o). A classifica??o destas superf?cies acima descritas foi baseada e modificada das propostas de Brookfield (1977) e Kocurek (1996). Foram ainda definidas quatro radarf?cies, com base na forma e termina??o dos refletores: Radarf?cies 1, representada por refletores progradantes, os quais se relacionam aos foresets das acumula??es e?licas; Radarf?cies 2, que ? constitu?da por refletores suscept?veis ? a??o antr?pica na praia de B?zios, onde constru??es ao longo da regi?o de blowouts e a pr?tica intensiva de turismo est?o modificando o desenvolvimento natural destas acumula??es e?licas, podendo gerar impactos ambientais negativos para a zona costeira. Dados obtidos numa ?rea situada no Parque das Dunas (unidade de conserva??o ambiental) foram utilizados para compara??o com as informa??es adquiridas em B?zios. H? uma tend?ncia maior de eros?o na ?rea de B?zios, notadamente no corredor do blowout e na duna de blowout
104

[en] FAULT MESHING GENERATION IN SEISMIC DATA BY COMPETITIVE LEARNING / [pt] GERAÇÃO DE MALHAS DE FALHAS EM DADOS SÍSMICOS POR APRENDIZADO COMPETITIVO

MARCOS DE CARVALHO MACHADO 10 July 2008 (has links)
[pt] O mapeamento manual de falhas em dados sísmicos tridimensionais é uma tarefa que consome muito tempo do intérprete. Uma grande quantidade de atributos sísmicos tem sido proposta para realçar medidas de descontinuidades associadas com as falhas. Entretanto, as falhas vistas através desses atributos aparecem mais como tendências do que como superfícies contínuas bem definidas, o que torna difícil a automatização da construção de modelos de falhas. Esta tese explora técnicas de Aprendizado Competitivo aplicadas aos problemas de extração e visualização de falhas em dados sísmicos. A estratégia proposta parte de um atributo de falha previamente calculado e consiste de três etapas. Na primeira, os dados tridimensionais uniformemente amostrados do atributo de falha são convertidos em um grafo com uso do algoritmo de aprendizado competitivo Growing Neural Gas. Na segunda etapa, o grafo sofre um processo de segmentação de forma a extrair um conjunto de subgrafos, cada um compatível com uma superfície de falha. Na terceira etapa, é utilizado o algoritmo Malhas Neurais Abertas para construir uma malha triangular para cada uma das superfícies identificadas. Malhas Neurais Abertas é um algoritmo de Aprendizado Competitivo que é proposto nesta tese, o qual constrói uma malha a partir de uma função de probabilidades com topologia de uma superfície aberta sem buracos. Exemplos com dados bidimensionais e tridimensionais, sintéticos e reais, são apresentados. Outra aplicação de Aprendizado Competitivo introduzida nesta tese é a geração de malhas geológicas, isto é, malhas que podem ser utilizadas na simulação do comportamento de fluidos em subsuperfície. / [en] Manual fault mapping from 3D seismic data is a time-consuming task. A plethora of seismic attributes has been proposed to enhance the discontinuity measures associated with faults. However, faults viewed through these attributes appear more like trends than well-defined, continuous surfaces, posing obstacles to the automation of the fault modeling process. This thesis explores the use of Competitive Learning techniques in fault extraction and visualization. The proposed strategy starts with a pre-computed fault attribute and consists of three steps. In the first, the uniformly sampled 3D fault attribute data are converted into a graph using Growing Neural Gas, a Competitive Learning algorithm. In the second step, the graph is submitted to a segmentation process in order to extract a set of subgraphs, each one compatible with a fault surface. In the third step, the Open Neural Meshes algorithm is used to build a triangulated mesh for each previously identified surface. Open Neural Meshes is a Competitive Learning algorithm proposed in this thesis, which builds a mesh from a probability function with no-hole open surface topology. Examples with 2D and 3D, synthetic and real data are presented. Another Competitive Learning application introduced in this thesis is the generation of geologic meshes. These meshes can be used to simulate fluid flows in subsurface reservoirs.
105

[en] APPROXIMATORS OF OIL RESERVOIR SIMULATORS BY GENETIC PROGRAMMING AND APPLICATION IN PRODUCTION OPTIMIZATION ALTERNATIVES / [pt] APROXIMADORES DE SIMULADORES DE RESERVATÓRIO DE PETRÓLEO POR PROGRAMAÇÃO GENÉTICA E APLICAÇÃO NA OTIMIZAÇÃO DE ALTERNATIVAS DE PRODUÇÃO

GUILHERME CESARIO STRACHAN 22 June 2015 (has links)
[pt] A definição da estratégia de produção de petróleo é uma tarefa muito importante que consiste em um processo bastante complexo devido à grande quantidade de variáveis envolvidas. Estas variáveis estão relacionadas com características geológicas, fatores econômicos e decisões como alocação de poços, número de poços produtores e injetores, condições operacionais e cronograma de abertura de poços. No contexto da otimização da produção de petróleo, o objetivo é encontrar a melhor configuração de poços que contribua para maximizar, na maioria dos casos, o valor presente líquido (VPL). Esse valor é calculado, principalmente, a partir do óleo, gás e água produzidos do campo, que são encontrados através do uso do simulador de reservatórios. Porém, vários parâmetros e variáveis devem ser prefixados e inseridos no sistema de simulação para que esses valores de produção sejam previstos. Esse processo geralmente exige um alto custo computacional para modelar as transferências de fluidos dentro do reservatório simulado. Assim, o uso de simuladores pode ser substituído por aproximadores. Neste estudo, eles são desenvolvidos através da Programação Genética Linear com Inspiração Quântica, uma técnica da Computação Evolucionária. Esses aproximadores serão utilizados para substituir a simulação do reservatório no processo de otimização da localização e tipo de poços a serem perfurados em um campo petrolífero. Para a construção dos proxies de reservatório, as amostras, originadas utilizando a técnica do Hipercubo Latino, foram simuladas para a criação da base de dados. O modelo para criação de aproximadores foi testado em um reservatório sintético. Dois tipos de otimização foram realizados para a validação do modelo. A primeira foi a otimização determinística e a segunda uma otimização sob incerteza considerando três diferentes cenários geológicos, um caso onde o número de simulações é extremamente alto. Os resultados encontrados apontam que o modelo para a criação de proxies consegue bom desempenho na substituição dos simuladores devido aos baixos erros encontrados e na considerável redução do custo computacional. / [en] The purpose of oil production strategy in the context of production optimization is to find the best configuration of wells that contributes to maximizing the Net Present Value. This value is calculated mainly from the amount of oil, gas, and water recovered from the field, which can be obtained by running the reservoir simulator. However, many parameters and variables must be prefixed and inserted into the simulation system in order to generate these production values. This process involves a high computational cost for modeling the transfer of fluids within the simulated reservoir. Thus, the use of simulators may be substituted by approximators. In this thesis, we aim to develop these approximators using Quantum-Inspired Linear Genetic Programming, a technique of Evolutionary Computation. These approximators were used to replace the reservoir simulation in the process of optimizing the location and type of wells to be drilled in a field. For the reservoir proxies construction, samples obtained from the technique of Latin Hypercube were simulated to create the database. The model for creating approximators was tested on a synthetic reservoir. Two types of optimization were performed to validate the model. The first was a deterministic optimization and the second an optimization under uncertainty considering three different geological settings, a situation in which the number of simulations becomes extremely high. Our results indicated that the model for the creation of proxies achieves a satisfactory performance in the replacement of simulators due to low levels of errors and a considerable reduction of the computational cost.
106

Emprego da fluorescencia de raios X por dispersao de energia no estudo da dinamica da vinhaca no solo

SIMABUCO, SILVANA M. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:37:26Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:30Z (GMT). No. of bitstreams: 1 02034.pdf: 6301635 bytes, checksum: 60b2f711d04c084336ad48884de17afa (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
107

Avaliação do potencial de geração de metano e dióxido de carbono biogênicos em Folhelhos do Sudeste Brasileiro / not available

Dailson José Bertassoli Junior 16 March 2016 (has links)
não-convencionais de metano biogênico em folhelhos podem representar importante recurso energético e contribuir significativamente para emissões de gases do efeito estufa. Com o intuito de avançar na compreensão dos controles na geração de metano (CH4) e dióxido de carbono (CO2) em folhelhos ricos em matéria orgânica, o presente estudo avaliou o potencial de geração e a estrutura de poros de folhelhos das bacias sedimentares do Paraná e Taubaté, localizadas na região sudeste do Brasil. As formações Ponta Grossa (Devoniano, Bacia do Paraná), Irati (Permiano, Bacia do Paraná) e Tremembé (Paleógeno, Bacia de Taubaté) foram analisadas de modo a obter-se taxas de produção biogênica de CH4 e CO2 sob diferentes condições. Para tanto, foram efetuadas incubações de 24 amostras de folhelho em laboratório, sob meios seco, aquoso e com adição de ácido ácetico, durante períodos de até 1 ano. Também foram realizadas análises para a determinação do teor de carbono orgânico e testes de adsorção para caracterização de poros e superfície específica das amostras de folhelho com o intuito de compreender o papel destas variantes na geração de gases biogênicos. As taxas de produção de gás biogênico em amostras incubadas a seco atingiram valores de até 3,17 ml/t.d (CH4) e 2,45x10³ ml/t.d (CO2) durante os primeiros 30 dias. Amostras incubadas com adição de água demonstraram aumento de 54% na produção de CH4 e 151% na produção de CO2. A adição de ácido acético no sistema foi responsável pelo reínicio ou aumento da produção de CH4 e CO2 na maioria dos casos avaliados. A Formação Irati apresentou o maior potencial para produção de metano biogênico entre as unidades estratigráficas estudadas, fator que pode estar ligado à biodegradação de petróleo pesado presente nos poros. O volume total de poros e a superfície específica de amostras aparenta não afetar a produção biogênica. Entretanto, a umidade e disponibilidade de substrato exercem controle predominante no potencial de geração de CH4 e CO2 biogênicos em folhelhos ricos em matéria orgânica. / Unconventional biogenic shale gas systems may represent an important energy resource and significantly contribute to geological greenhouse gases emissions. In order to better understand the controls on biogenic methane (CH4) and carbon dioxide (CO2) generation in organic-rich shales, the present study evaluated the generation potential and the pore structure of shales from Taubaté and Paraná basins, located in southeastern Brazil. The Ponta Grossa (Devonian, Paraná basin), Irati (Permian, Paraná basin) and Tremembé Formations were analyzed in order to quantify production rates of biogenic CH4 and CO2 under distinct experimental conditions. Twenty four shale samples were used for batch incubations under dry, wet and acetic acid solution conditions during time periods reaching up to 1 year. The organic carbon content and nitrogen adsorption analysis for determining specific surface area and porosity were also performed to evaluate their role on biogenic gas generation.The biogenic gas production rates in samples under dry conditions reached up to 3.17 ml/t.d (CH4) and 2.45x10³ ml/t.d (CO2) during the first 30 days of incubation. Samples under wet conditions demonstrated production rates 54% higher for CH4 and 151% higher for CO2 in comparison with dry tests. Acetic acid addition restarted or increased CH4 and CO2 production in most cases. The Irati Formation showed the highest potential for biogenic methane production, which could be linked to the biodegradation of heavy liquid hydrocarbons occurring in this unit. Total pore volume and specific surface does not appear to significantly affect the biogenic production of CH4 and CO2. However, water content and substrate availability would exert predominant control over the biogenic gas generation within organic rich shales.
108

Study of Production Drifts Stability and Assessment of Reinforcement Requirements at LKAB Konsuln Test-Mine Levels 436 and 486 Using Geologic Structures Data, and Modelling Software – Dips and Unwedge:  a Part of dp1 Project (Mine Layout and Technology) of the Sustainable Underground Mining (Sum) Project

Olufe, Oludare Joseph January 2021 (has links)
Study of Production Drifts Stability and Assessment of Reinforcement Requirements at LKAB Konsuln Test-Mine Levels 436 and 486 Using Geologic Structures Data, and Modelling Software - Dips and Unwedge:  a Part of dp1 Project (Mine Layout and Technology) of the Sustainable Underground Mining (Sum) Project Oludare Joseph Olufe Global population has been on exponential increase over the past half century. The population explosion is driving massive urbanization and infrastructure developments across the globe, which result in huge demand for metals, especially steel. The trend is forecasted to continue to rise steeply in for the next two decades. This is putting enormous strain on metals mining, especially because new surface economic deposits are rare to come by. Therefore, mining is steadily going deeper in many of the mining destinations across the world.     Mining at great depths present unique challenges, particularly regarding stability of excavations at depths. Rock falls, rock burst, excavation collapse are common occurrences associated with deep mining. In regions with high seismicity potentials the frequency and consequences could be very high. Over the past decade ground instability has become a significant challenge confronting mining at LKAB deep mines. There had been incidents that resulted in long term closure of sections of the mines, with resultant adverse economic impacts. More undesirable is loss of live of personnel.     The study was conducted at the Konsuln test mine levels 436 and 486, aimed to investigate the impacts of geologic structures on excavations instability at depths, at the Kiruna iron ore mines, on one hand.  And on the other hand, evaluate the influence of geologic structures on ground reinforcements at the mine. Structural data were collected and analysed using Dips program to define orientation of major structures. The results were used for wedge analysis and excavations stability modelling using Unwedge program. Important rock mechanical parameters were defined based on data provided, and others based on literatures. A design factor of safety of 1.5 was used.     Results from the study established that structures have significant impact on excavations instability at the Konsuln mine. 100% of the production drifts studied has minimum of four wedges formed in its perimeters. Out of this approximately 37% has factor of safety lower than 1.5. Evaluation of reinforcements (shotcrete and rock bolts) implemented in the mine found that approximately 15% of the total wedges formed in the production drifts has factor of safety less that 1.5 after both shotcrete and rock bolt reinforcements had been implement. Also, approximately 5% of the total wedges has apex height longer the rock bolt length.     It was therefore concluded that structurally induced instability is a major contributor to excavations instability at the Kiruna mine. The study approach presented a new methodology to understand and provide robust solution to ground instability problem at the mine.
109

Geologic Map of Tennessee (East Sheet) - 1966

Tennessee Department of Conservation 01 January 1966 (has links)
Geologic map of Tennessee published in 1966 by the Tennessee Department of Conservation, Division of Geology. William D. Hardeman supervised and directed this geologic mapping and the compilation, preparation, and editing of this map. The source material for the map includes all recent (as of 1966) detailed published geologic maps and much recent unpublished geologic mapping that was begun and completed by the Division of Geology for the specific purpose of making this map of uniform accuracy through the state. The scale is 1:250,000 with the lower half including a detailed explanation including symbols/colors for rock types, mountain formations, and other geologic features. The sources of geologic information is also included. Physical copy resides in the Government Information, Law and Maps Department of East Tennessee State University’s Sherrod Library. / https://dc.etsu.edu/rare-maps/1016/thumbnail.jpg
110

Geologic Hazards Map of Tennessee (1977)

Tennessee Department of Conservation 01 January 1977 (has links)
Geologic hazards map of Tennessee published in 1977 by the Tennessee Department of Conservation, Division of Geology. Compiled by Robert A. Miller, assisted by Preston D. Sitterly. The preparation of this report was financed in part through a comprehensive planning grant form the Department of Housing and Urban Development. The lower half includes an explanation of various geographic hazards and how to identify those areas on the map. A list of selected references is also included. Physical copy resides in the Government Information, Law and Maps Department of East Tennessee State University’s Sherrod Library. / https://dc.etsu.edu/rare-maps/1018/thumbnail.jpg

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