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Sample records for na modelagem crustal

  1. Aplicabilidade da CIPE® fundamentada na teoria da modelagem e modelagem de papel

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    Manuela de Mendonça Figueirêdo Coelho

    2014-06-01

    Full Text Available Objetivou-se analisar a proposta de plano educativo organizado por meio do processo de enfermagem, utilizando a Classificação Internacional para a Prática de Enfermagem (CIPE®, fundamentada pela Teoria da Modelagem e Modelagem de Papel, a um grupo de mulheres em Maracanaú-CE, Brasil. Trata-se de um estudo de caso realizado em grupo educativo de mulheres. A abordagem qualitativa conduziu a produção dos dados guiados pelo Método Criativo e Sensível. Dois diagnósticos centrais emergiram das necessidades apresentadas pelo grupo: saúde comprometida e conhecimento adequado, assim como formulação de resultados e intervenções de enfermagem. O estudo aponta a possibilidade de aplicação do processo de enfermagem apoiado pela CIPE® e ações educativas baseadas na Teoria da Modelagem e Modelagem de Papel.

  2. Resina industrial de poliuretano modificada com terra diatomácea para ser empregada na modelagem odontológica

    OpenAIRE

    Gisseli Bertozzi de Avila

    2009-01-01

    Este estudo avaliou a resina de poliuretano de alto desempenho 6470 e endurecedor Dt 082 (Huntsman Advanced Materials Química Brasil Ltda., fornecido pela Maxepoxi, Santo Amaro, São Paulo, Brasil) carregada com 30 % diatomita para ser empregada na modelagem odontológica. O material foi manipulado na proporção de 1/8 entre resina e endurecedor, com acréscimo de acelerador de poliuretano na proporção de uma gota para cada 200gramas de resina. Foram obtidas amostras de resina pura, modificada co...

  3. Modelagem e propriedades termodinâmicas na secagem de morangos

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    Gabriel Henrique Horta de OLIVEIRA

    2015-12-01

    Full Text Available Resumo A secagem de produtos agrícolas é largamente utilizada no mundo para diminuir o teor de água do produto, dificultando o crescimento microbiano e a ocorrência de reações químicas e bioquímicas e possibilitando a armazenagem segura por períodos longos, além de reduzir o volume e a massa a ser transportada. O objetivo do presente trabalho foi avaliar e modelar a etapa de secagem de morangos (Fragaria L., bem como obter parâmetros termodinâmicos em três diferentes temperaturas (40 °C, 50 °C e 60 °C. Foram utilizados frutos obtidos na CEASA-DF, com teor de água inicial de 93,0% (b.u.. Os dados experimentais foram ajustados a seis modelos matemáticos usualmente utilizados para a representação da etapa de secagem. A energia de ativação para a secagem dos morangos, a entropia, a entalpia e a energia livre de Gibbs foram obtidas. O modelo Logaritmo foi o que melhor representou a secagem de frutos de morangueiro, apresentando valores de erro médio relativo entre 7,59% e 8,48%, desvio-padrão da estimativa entre 0,03 e 0,06 e coeficiente de determinação entre 99,93% e 99,95%. A entalpia do processo de secagem diminuiu com o aumento da temperatura de secagem, com valores de –481,21, –564,35 e –647,49 J mol–1 para as temperaturas 40, 50 e 60 °C, respectivamente. O mesmo comportamento ocorreu com a entropia, com valores -238,35, -238,61 e –238,86 J mol–1 K–1, para temperaturas 40, 50 e 60 °C, respectivamente. A energia livre de Gibbs aumentou com o aumento da temperatura, atingindo valores de 74.159,75, 76.544,54 e 78.931,90 J mol–1 para as temperaturas 40, 50 e 60 °C, respectivamente.

  4. MODELAGEM DE OCORRÊNCIA DE COORTES NA ESTRUTURA DIAMÉTRICA DA Araucaria angustifolia (Bertol.) Kuntze

    OpenAIRE

    Ebling,Ângelo Augusto; Netto, Sylvio Péllico

    2015-01-01

    Estudos referentes à estrutura diamétrica das florestas nativas são essenciais para o entendimento do desenvolvimento, fornecer parâmetros do crescimento e produção suficientes para gerar estimativas que subsidiem o manejo sustentado. No entanto, a modelagem matemática de funções probabilísticas, como as de densidade, tornam-se de difícil aplicação em distribuições multimodais. A espécie Araucaria angustifolia (Bertol.) Kuntze, de importância social, ambiental e econômica, apresenta padrão de...

  5. Modelagem da dispersão de coliformes termotolerantes e enterococos em duas enseadas na região costeira de Ubatuba (SP, Brasil

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    Silvana Simone Batista

    Full Text Available RESUMO Foram avaliados os efeitos de ações antrópicas sobre o sistema costeiro de Ubatuba (SP através de modelos que descrevem os mecanismos e as reações envolvidas na dispersão de indicadores microbiológicos (coliformes termotolerantes e enterococos na água do mar. A análise da qualidade das águas destinadas à recreação, além de ser uma ação importante em termos de saúde pública, também se justifica em vista da importância da atividade turística em Ubatuba, possuindo, ainda, grande relevância para o planejamento ambiental. Na modelagem, foram utilizados os módulos do sistema Delft3D. No módulo de qualidade da água, foram estudados os mecanismos de dispersão dos poluentes, a partir da associação de dados de poluição com os resultados do módulo hidrodinâmico, em duas enseadas em Ubatuba (SP: Flamengo e Palmas. Os resultados obtidos permitem afirmar que o sistema de correntes nas enseadas, determinado pela geomorfologia da região, não confere alta capacidade de diluição e dispersão de efluentes na área de estudo. Todavia, a circulação marinha e os processos envolvidos no decaimento das bactérias são suficientes para difundir e diminuir suas concentrações ao longo das enseadas. Concluiu-se que a modelagem ambiental reproduziu de maneira satisfatória os processos envolvidos no transporte e na difusão de indicadores microbiológicos, contribuindo com os estudos sobre os efeitos das atividades antrópicas no sistema costeiro de Ubatuba.

  6. Utilização do GeoGebra na resolução de problemas físicos: uma possibilidade para a Modelagem Matemática na Educação Básica

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    Tiago Vencato Martins

    2017-05-01

    Full Text Available Este artigo discute a abordagem da Lei de Resfriamento de Newton como possibilidade para a Modelagem Matemática na Educação Básica. Propomos que os alunos desenvolvam modelos que não estariam ao seu alcance, em função dos sofisticados conhecimentos matemáticos que exigem, valendo-se de recursos da Modelagem Matemática e auxiliados pelo software GeoGebra. Aliando o uso da tecnologia ao ensino da álgebra, baseando-nos em bibliografias que apoiam esta associação, apresentamos como sugestão uma atividade experimentada no primeiro ano do Ensino Médio onde abordamos o ensino de funções. Nela apontamos que a adoção de uma metodologia apoiada por recursos tecnológicos pode colaborar no desenvolvimento de habilidades inerentes ao pensamento matemático, tais como: estabelecer relações, fazer conjecturas, realizar aproximações, previsões e resolver problemas.

  7. Modelagem de processos de negócios na implementação de ERPs nacionais em PMEs Business processes modeling in the implementation of national ERPs within SMEs

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    Fernanda Pereira Carneiro da Silva; Néocles Alves Pereira

    2006-01-01

    Este artigo apresenta evidências encontradas em uma pesquisa que teve como objetivo investigar a contribuição do uso da Modelagem dos Processos dos Negócios (MPN) na implementação do Enterprise Resource Planning (ERP) em pequenas e médias empresas (PMEs). Foi observado, nos principais fornecedores nacionais deste sistema, o uso da MPN, verificando sua influência na integração dos processos internos dos negócios de seus clientes. Para esta investigação buscaram-se as informações nos fornecedor...

  8. Modelagem da Lagoa da Pampulha: uma ferramenta para avaliar o impacto da bacia hidrográfica na dinâmica do fitoplâncton

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    Talita Fernanda das Graças Silva

    2016-03-01

    Full Text Available RESUMO No processo de urbanização, o aumento na proporção de superfícies impermeabilizadas e as mudanças no uso do solo são responsáveis por maiores volumes e velocidades do escoamento superficial, refletindo em uma maior capacidade de arraste e em um maior aporte de nutrientes nos corpos d'água receptores. O objetivo deste trabalho foi implementar uma ferramenta matemática capaz de reproduzir o impacto de mudanças na bacia hidrográfica sobre a dinâmica do fitoplâncton em um lago urbano. Neste artigo são apresentados o desenvolvimento e os resultados de um modelo integrado constituído de um modelo hidrológico, para simular vazões escoadas em uma bacia hidrográfica, e de um modelo hidrodinâmico e ecológico, para simular a biomassa fitoplanctônica em um corpo d'água urbano. A Lagoa da Pampulha (Belo Horizonte, Minas Gerais, escolhida como estudo de caso, foi intensamente monitorada, assim como sua bacia de drenagem, entre outubro de 2011 e junho de 2013. Os dados obtidos foram utilizados para calibrar e validar ambos os modelos. Os resultados obtidos com o modelo hidrológico mostraram-se coerentes com as medidas realizadas em campo (o coeficiente de Nash variou entre 0,70 e 0,88. O modelo da lagoa representou corretamente a evolução da comunidade fitoplanctônica (erro médio absoluto normalizado: 0,25-0,42 e o coeficiente de Pearson: 0,82-0,89; p<0,0001. O monitoramento e a modelagem da lagoa mostraram que a proliferação de cianobactérias é bastante perturbada pelas desestratificações térmicas que ocorrem na lagoa em virtude de eventos meteorológicos. A ferramenta de simulação desenvolvida possui potencial para avaliar diferentes cenários de mudança das condições climáticas e das características da bacia, podendo auxiliar na gestão dos corpos d'água situados em meio urbano.

  9. Usando splines cúbicas na modelagem matemática da evolução populacional de Pirapora/MG

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    José Sérgio Domingues

    2014-08-01

    Full Text Available O objetivo desse trabalho é obter um modelo matemático para a evolução populacional da cidade de Pirapora/MG, baseando-se apenas nos dados de censos e contagens populacionais do Instituto Brasileiro de Geografia e Estatística (IBGE. Para isso, é utilizada a interpolação por splines cúbicas, pois as técnicas de interpolação linear e polinomial, e também o modelo logístico, não se ajustam bem a essa população. Os dados analisados não são equidistantes, então, utiliza-se como amostra anos separados com passo h de 10 anos. Os valores descartados inicialmente e as estimativas populacionais para esse município, descritos pela Fundação João Pinheiro, serviram para validação do modelo construído, e para a estimativa das diferenças percentuais de previsão, que não ultrapassaram os 2,21%. Ao se considerar que o padrão de evolução populacional de 2000 a 2010 se manterá até 2020, estima-se as populações da cidade de 2011 a 2020, cuja diferença percentual média foi de apenas 0,49%. Conclui-se que o modelo se ajusta muito bem aos dados, e que estimativas populacionais em qualquer ano de 1970 e 2020 são confiáveis. Além disso, o modelo permite a visualização prática de uma aplicação dessa técnica na modelagem populacional, e, portanto, também pode ser utilizada para fins didáticos.Palavras-chave: Splines cúbicas. Interpolação. Modelagem matemática. Evolução populacional. Pirapora.Using cubic splines on mathematical modeling of the population evolution of Pirapora/MGThe main objective of this paper is to obtain a mathematical model for the evolution of the population in Pirapora/MG, based only on data from censuses and population counts from Brazilian Institute of Geography and Statistics (IBGE. For this, the cubic spline interpolation is used because the technique of linear and polynomial interpolation, and also the logistic model do not fit well with this population. The analyzed data are not equidistant

  10. 3D modeling of material flow and temperature in Friction Stir Welding Modelagem 3D do fluxo de material e da temperatura na soldagem "Friction Stir"

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    Diego Santiago

    2009-09-01

    Full Text Available The process of Friction Stir Welding (FSW is a welding method developed by the "The Welding Institute" (TWI of England in 1991. The welding equipment consists of a tool that rotates and progresses along the joint of two restrained sheets. The joint is produced by frictional heating which causes the softening of both components into a viscous-plastic condition and also by the resultant flow between the sheets to be joined. Numerical Modeling of the process can provide realistic prediction of the main variables of the process, reducing the number of experimental tests, thus accelerating the design processes while reducing costs and optimizing the involved technological variables. In this study the friction stir welding process is modeled using a general purpose finite element based program, reproducing the material thermal map and the corresponding mass flow. Numerical thermal results are compared against experimental thermographic maps and numerical material flow results are compared with material flow visualization techniques, with acceptable concordance.O processo denominado "Friction Stir Welding" (FSW é um método de soldagem desenvolvido pelo "The Welding Institute" (TWI na Inglaterra em 1991. O equipamento de soldagem consiste de uma ferramenta que gira e avança ao longo da interface entre duas chapas fixas. A junção é produzida pelo calor gerado por fricção o qual causa o amolecimento de ambos os componentes atingindo uma condição visco-plástica e também pelo escoamento resultante entre as laminas a ser unidas. A modelagem numérica do processo pode fornecer uma predição real das principais variáveis do processo, reduzindo o número de testes experimentais, acelerando, portanto os processos de projeto ao mesmo tempo em que reduz custos e permite a otimização das variáveis tecnológicas envolvidas. Neste trabalho, o processo de soldagem por fricção é modelado empregando um programa de propósito geral baseado no m

  11. Vadose zone measurement and modeling Mensurações e modelagem na zona não saturada

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    J. W. Hopmans

    1997-06-01

    Full Text Available The following treatise is a summary of some of the ongoing research activities in the soil physics program at the University of California in Davis. Each of the four listed areas win be presented at the Workshop on special topics on soil physics and crop modeling in Piracicaba at the University of Sao Paulo. We limited ourselves to a general overview of each area, but will present a more thorough discussion with examples at the Workshop.O presente texto é o resumo das atuais atividades do programa de física do solo na Universidade da Califórnia, em Davis. As quatro áreas aqui relacionadas serão apresentadas no "Workshop on special topics about soil physics and crop modeling and simulation" na Universidade de São Paulo, em Piracicaba. O texto se restringe a urna abordagem geral de cada área, porém discussões e exemplos mais detalhados serão apresentados no Workshop.

  12. Modelagem matemática na educação básica: uma experiência aplicada na Construção Civil

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    Pedro Elton Weber

    2015-05-01

    Full Text Available O artigo é resultado de um projeto de modelagem matemática, aplicado a crianças com dificuldades de aprendizagem do quarto e quinto anos do Ensino Fundamental, de uma escola da periferia do Município de Palmas, Paraná, Brasil. O projeto foi desenvolvido com o auxílio de alunos da Licenciatura em Matemática, constituindo-se em uma atividade integrante de sua formação profissional e tendo por objetivo contribuir para a melhoria da aprendizagem de matemática das crianças envolvidas. Foram construídas, sob a orientação dos professores e licenciandos, maquetes de casas planejadas pelos próprios alunos. Foram trabalhados diversos conceitos matemáticos, relacionados a operações básicas, frações, geometria, porcentagens, planejamentos financeiros, entre outros. Além da motivação observada, o trabalho contribuiu com o processo de ensino e aprendizagem dos alunos e proporcionou aos futuros docentes uma experiência significativa em sua formação.Mathematical modeling in basic education: an experience inspired in constructionAbstractThe paper is the result of a project for mathematical modeling applied to children with learning difficulties in the fourth and fifth years of Fundamental Education at a school on the periphery in the city of Palmas, PR. The project was developed with the help of mathematics undergraduates students, thus becoming an their professional training a activity and taking aim at contributing to improving the math learning of the children involved. They built houses maquettes designed by the students under the teachers and student teachers supervision. We worked many mathematical concepts related to basic operations, fractions, geometry, percentages, financial planning, among others. Besides the motivation observed, the work contributed to the teaching and learning formation of students and provided to prospective teachers a meaningful experience in their training.Keywords: maquettes construction, mathematical

  13. Modelagem e aplicações matemáticas na confecção do molde de vestuário: Um caso de estudo

    OpenAIRE

    Araújo, Aylla Gabriela Paiva de

    2016-01-01

    Esse estudo centraliza nossas preocupações referentes ao ensino-aprendizagem da Matemática no Curso Técnico de Modelagem de Vestuário. A pesquisa objetivou a responder uma sequência de três atividades que relacionam a Matemática com a construção de moldes de vestuários. Ocorreram 10 encontros no período de 11 de setembro a 21 de novembro de 2014, com duas turmas, no turno manhã e tarde. Uma das atividades desenvolvidas buscou suprir necessidades relacionadas aos planejamentos e andamento da d...

  14. Sobre a categorização dos signos na Semiótica Peirceana em atividades de Modelagem Matemática

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    Lourdes M.Werle de Almeida

    2011-07-01

    Full Text Available Neste trabalho buscamos uma aproximação entre Semiótica Peirceana, em particular, entre as categorizações fenomenológicas e os níveis de relações dos signos estabelecidos por Peirce e a Modelagem Matemática como alternativa pedagógica. A análise de uma atividade de Modelagemnos permite inferir que há ações que são ‘primeiras’, ações que são ‘segundas’ e ações que são ‘terceiras’ durante o desenvolvimento de uma atividade de Modelagem Matemática, em sintonia com as categorias Primeiridade, Secundidade e Terceiridade caracterizadas por Peirce. A análise dos níveis de relações (significação, objetivação,interpretação estabelecidos pelos signos e efetivados pelos alunos, implica em observar as relações ou generalizações conceituais emitidas por eles durante suas ações, possibilitando observar elementos indicativos do pensar refletido nas representações apresentadas para o fenômeno em estudo.

  15. PROPOSTA DE MODELAGEM CONCEITUAL PARA A ORGANIZAÇÃO DA INFORMAÇÃO NA BIBLIOTECA VIRTUAL EM SAÚDE PREVENÇÃO E CONTROLE DE CÂNCER

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    Kátia de Oliveira Simões

    2015-11-01

    Full Text Available O trabalho aborda a organização da informação na Biblioteca Virtual em Saúde Prevenção e Controle de Câncer, mediante estrutura adequada à sua especificidade, investiga os princípios teóricos e metodológicos para uma representação temática adequada ao ambiente da Prevenção e Controle de Câncer, por meio de análise da literatura em modelagem conceitual e das diretrizes de construção de sistemas de organização do conhecimento, em especial, os relacionados à elaboração de tesauros, focalizando histórico, definições, normas de elaboração e tipos de relacionamentos entre termos para subsidiar a construção da proposta metodológica que vai auxiliar a indexação e recuperação de informações na Biblioteca Virtual. A pesquisa terá como base a compreensão do domínio Prevenção e Controle do Câncer por meio de análise da Biblioteca Virtual visando levantar as etapas de sua construção, desenvolvimento, características e estrutura.

  16. Critérios de projeto e benefícios esperados da implantação de técnicas compensatórias em drenagem urbana para controle de escoamentos na fonte, com base em modelagem computacional aplicada a um estudo de caso na zona oeste do Rio de Janeiro

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    Anaí Floriano Vasconcelos

    Full Text Available RESUMO O processo de urbanização resulta em alterações no ciclo hidrológico prejudiciais à população. Para amenizar esses efeitos, as técnicas compensatórias em drenagem urbana visam à maior sustentabilidade hidrológica na expansão urbana. Nesse sentido, este artigo teve como objetivos avaliar, por meio de modelagem computacional, o efeito da adoção dessas técnicas na escala de lote e da bacia hidrográfica e avançar com diferentes possibilidades de concepção de projeto. A modelagem foi realizada para diversos cenários, considerando a implantação das técnicas de forma isolada e combinada. Os parâmetros utilizados na modelagem visaram verificar possibilidades extremas de aplicação, de modo a disponibilizar dados para balizamento de projetos reais. As chuvas avaliadas possuem variadas durações e intensidades, facilitando a extrapolação dos resultados deste trabalho para bacias hidrográficas de diferentes escalas. Os resultados das simulações indicam potenciais benefícios na drenagem urbana oriundos do uso dessas técnicas no lote, com mais efetividade para as menores chuvas de projeto. Esse foi o caso dos cenários que avaliaram os jardins rebaixados isoladamente ou combinados em série com um reservatório de lote e os cenários de pavimentos permeáveis na calçada que receberiam o escoamento superficial do lote adjacente. Também foi verificado que a combinação paralela de um reservatório de lote com as dimensões propostas pela legislação municipal e um jardim rebaixado em 0,07 m seria capaz de neutralizar, hidrologicamente, os impactos da ocupação do lote para todas as chuvas de projeto analisadas, entretanto o reservatório proposto pela legislação municipal, quando adotado isoladamente, quase não atuou na escala da bacia..

  17. Estudo do Fenômeno da Ilha de Calor na Cidade de Manaus/AM: Um Estudo a Partir de Dados de Sensoriamento Remoto, Modelagem e Estações Meteorológicas

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    Polari Batista Corrêa

    2016-06-01

    Full Text Available Resumo O fenômeno da ilha de calor (IC na cidade de Manaus foi estudado usando dados de modelagem do clima urbano com o modelo Weather Research and Forecasting (WRF e dados de estações meteorológicas. Foram usados os dados de temperatura da superfície (TS obtidos pelo sensor MODIS do satélite ambiental Aqua, produto MYD11A2 na resolução horizontal de 1 km por um 1 km para o período de 2002 a 2012 na cidade de Manaus para avaliar o processo de urbanização. Foi realizado um estudo de caso com as simulações de TS e de temperatura do ar (TA nos meses de agosto e setembro de 2009 que foram comparadas, respectivamente, com os dados de satélite e de estações meteorológicas. Identificou-se a distribuição espacial da TS na cidade, e as diferenças de TS entre a área urbana e a de floresta e entre a área urbana e de rios foram quantificadas. As diferenças de TS ao longo das faixas de longitude de 60,03° O a 59,97° O e de latitude de 3,09° S a −3,03° S foram analisadas com os dados do modelo WRF e do sensor MODIS. A intensidade da IC estimada com os dados de TA do modelo e de estações meteorológicas foram, em média, respectivamente de 1,87 °C e de 1,80 °C, consistentes com resultados anteriores. Portanto, a TA simulada pode ser usada para fins de estimar a intensidade da IC em Manaus.

  18. Modelagem da Distribuição da Saturação de Água do Solo em Terrenos Complexos Baseada na Teoria de Similaridade – Proposição de Abordagem Lagrangiana

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    Hugo Abi Karam

    2014-07-01

    Full Text Available Neste trabalho propõe-se uma modelagem lagrangiana da distribuição de saturação de água do solo de terrenos complexos baseada na teoria de similaridade, com destaque para aspectos hidrometeorológicos. A distribuição da água precipitada no terreno é obtida como uma consequência da conservação de massa do escoamento, considerada a similaridade hidrológica ao longo de faixas de drenagem, sob diferentes condições de inclinação topográfica, captação e infiltração. A aplicação desse tipo de modelo de distribuição hidrológica permite uma otimização computacional, tanto na estimativa do deficit de saturação do solo quanto na distribuição da profundidade do lençol freático. A aplicabilidade da proposição lagrangiana é exemplificada para um morro suave e também para discutir qualitativamente a hidrologia da Baixada Fluminense encontrada ao norte da Região Metropolitana do Rio de Janeiro (RMRJ, RJ, Brasil. Mostra-se que uma resolução espacial inferior a 90 m deve ser empregada para considerar os detalhes do problema. Os resultados destacaram o papel da topografia complexa, incluindo a hidrologia de planícies fluviais e as modificações antrópicas da superfície (na forma de canais de escoamento urbano e urbanização para a compreensão da hidrometeorologia da RMRJ.

  19. Modelagem hierárquica Bayesiana na avaliação de curvas de crescimento de suínos genotipados para o gene halotano

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    Leandro Roberto de Macedo

    2014-10-01

    Full Text Available Para avaliar a influência do gene halotano sobre a curva de crescimento de suínos, bem como sua interação com o sexo do animal, foi proposta uma modelagem hierárquica Bayesiana. Nesta abordagem, os parâmetros dos modelos não-lineares de crescimento (Logístico, Gompertz e von Bertalanffy foram estimados conjuntamente com os efeitos de sexo e genótipos do gene halotano. Foram utilizados 344 animais F2(Comercial x Piau pesados ao nascer, aos 21, 42, 63, 77, 105 e 150 dias. O modelo Logístico foi aquele que apresentou melhor qualidade de ajuste por apresentar menor DIC (Deviance Information Criterion que os demais. As amostras das distribuições marginais a posteriori para as diferenças entre as estimativas dos parâmetros do modelo Logístico indicaram que o peso dos machos à idade adulta com genótipo heterozigoto (HalNn foi superior ao dos homozigotos (HalNN. A título de comparação, também foi considerada a abordagem frequentista tradicional, baseada em dois passos distintos, a qual, por apresentar um menor poder de discernimento estatístico, não mostrou diferenças significativas

  20. Modelagem de processos de negócios na implementação de ERPs nacionais em PMEs Business processes modeling in the implementation of national ERPs within SMEs

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    Fernanda Pereira Carneiro da Silva

    2006-08-01

    Full Text Available Este artigo apresenta evidências encontradas em uma pesquisa que teve como objetivo investigar a contribuição do uso da Modelagem dos Processos dos Negócios (MPN na implementação do Enterprise Resource Planning (ERP em pequenas e médias empresas (PMEs. Foi observado, nos principais fornecedores nacionais deste sistema, o uso da MPN, verificando sua influência na integração dos processos internos dos negócios de seus clientes. Para esta investigação buscaram-se as informações nos fornecedores nacionais de sistema ERP e seus clientes, mediante questionários específicos. Esta pesquisa possibilitou obter informações reais das principais características de implementação nas PMEs, destacando-se como a MPN contribui efetivamente na implementação para otimizar a integração dos processos internos dos negócios.This article presents evidences found in a research whose objective was to investigate the contribution of using business processes modeling (BPM in the implementation of Enterprise Resource Planning (ERP in small and middle companies (SMEs. The use of the BPM and assessment of its influence for the integration of the internal business processes of their customers, was also observed in the main national ERP system suppliers. To carry out this research, information was obtained by means of specific questionnaires answered by the national ERP system suppliers and their customers. This research allowed to obtain actual data about the main implementation characteristics within the SMEs, showing how the BPM effectively contributes for the implementation and better integration of the internal business processes.

  1. Modelagem de misturas na fabricação de compósitos polímero-fibra, utilizando polietileno e serragem de Pinus sp.

    Directory of Open Access Journals (Sweden)

    Éverton Hillig

    2010-08-01

    Full Text Available Neste trabalho, foi estudado o efeito da composição de diferentes misturas de polietileno de alta densidade (HDPE virgem, HDPE reciclado e serragem de Pinus sp., nas propriedades físico-mecânicas de placas confeccionadas pelo processo de compressão. As misturas foram homogeneizadas em um misturador tipo Drais, sem controle de temperatura e moldadas por compressão em prensa hidráulica a 150oC. Partindo das placas, foram confeccionados corpos-de-prova para ensaios de tração, flexão, impacto e dureza, segundo normas ASTM, e também foram determinadas as densidades médias das placas. A modelagem estatística foi realizada segundo o planejamento centróide simplex, utilizando sete misturas dos três componentes e três repetições de cada mistura. Os resultados mostraram que a resistência à tração, a resistência à flexão, a dureza e a densidade das placas, são explicadas pelo modelo linear, enquanto a resistência ao impacto é explicada pelo modelo quadrático. Não houve diferença significativa nas propriedades físico-mecânicas dos compósitos confeccionados com HDPE virgem, daqueles confeccionados com HDPE reciclado, exceto para resistência ao impacto, no qual o HDPE virgem apresentou maiores valores.

  2. MODELAGEM DE MISTURAS NA FABRICAÇÃO DE COMPÓSITOS POLÍMERO-FIBRA, UTILIZANDO POLIETILENO E SERRAGEM DE Pinus sp.

    Directory of Open Access Journals (Sweden)

    Karla Pocai

    2006-07-01

    Full Text Available Neste trabalho, foi estudado o efeito da composição de diferentes misturas de polietileno de alta densidade (HDPE virgem, HDPE reciclado e serragem de Pinus sp., nas propriedades físico-mecânicas de placas confeccionadas pelo processo de compressão. As misturas foram homogeneizadas em um misturador tipo Drais, sem controle de temperatura e moldadas por compressão em prensa hidráulica a 150oC. Partindo das placas, foram confeccionados corpos-de-prova para ensaios de tração, flexão, impacto e dureza, segundo normas ASTM, e também foram determinadas as densidades médias das placas. A modelagem estatística foi realizada segundo o planejamento centróide simplex, utilizando sete misturas dos três componentes e três repetições de cada mistura. Os resultados mostraram que a resistência à tração, a resistência à flexão, a dureza e a densidade das placas, são explicadas pelo modelo linear, enquanto a resistência ao impacto é explicada pelo modelo quadrático. Não houve diferença significativa nas propriedades físico-mecânicas dos compósitos confeccionados com HDPE virgem, daqueles confeccionados com HDPE reciclado, exceto para resistência ao impacto, no qual o HDPE virgem apresentou maiores valores.

  3. Modelagem hidrológica na bacia hidrográfica do Rio Aiuruoca, MG Hydrologic modeling in the Aiuruoca river basin, Minas Gerais State

    Directory of Open Access Journals (Sweden)

    Marcelo R. Viola

    2009-10-01

    Full Text Available A simulação do comportamento hidrológico de bacias hidrográficas consiste em uma das principais ferramentas na gestão dos recursos hídricos, devido à possibilidade de predição do regime fluvial. A bacia em estudo está localizada na região Alto Rio Grande, Sul de Minas Gerais, com área de drenagem de 2.094 km², constituindo uma das bacias fundamentais de drenagem para o reservatório da Usina Hidrelétrica de Camargos (UHE - Camargos/CEMIG. Neste contexto se objetivou desenvolver e aplicar um modelo hidrológico semi-conceitual, na forma semi-distribuída, para simular o comportamento hidrológico da bacia do Rio Aiuruoca, com apoio dos SIGs e sensoriamento remoto, disponibilizando uma ferramenta útil para o gerenciamento e planejamento dos recursos hídricos na região. Os resultados do coeficiente estatístico de Nash-Sutcliffe (CNS foram de 0,87 e 0,92 para as etapas de calibração e verificação, respectivamente, o que, de acordo com a classificação proposta para modelos hidrológicos de simulação, permite qualificá-lo para simulação do comportamento hidrológico na bacia hidrográfica do Rio Aiuruoca.The hydrological simulation of watersheds is one of the most important tools for water resources management due to the possibility of flow regime prediction. The Aiuruoca river basin is located in the Alto Rio Grande Basin, southern Minas Gerais State, with 2,094 km² of drainage area, and is very important drainage basin into the Camargos Hydropower Plant Reservoir (UHE - Camargos/CEMIG. In this context, this work had the objective of developing and applying a semi-conceptual hydrologic model, in semi-distributed approach, for hydrologic simulation in the Aiuruoca river basin, based on GIS and Remote Sensing tools, thus creating an important tool for management and planning of water resources in the region. The Nash-Sutcliffe coefficients (CNS, respectively, for calibration and validation periods, were 0.87 and 0

  4. Contribuições de modelagem de equações estruturais na análise de dados em modelos comportamentais de destino turístico

    OpenAIRE

    2014-01-01

    A fragilidade brasileira quanto à competitividade turística é um fato observável nos dados da Organização Mundial do Turismo. O Brasil caiu em 2011, da 45ª para a 52ª posição, apesar de liderar no atributo recursos naturais e estar colocado na 23° em recursos culturais. Assim, grandes interesses e esforços têm sido direcionados para o estudo da competitividade dos produtos e destinos turísticos. O destino turístico é caracterizado por um conjunto complexo e articulado de fatores tangíveis e i...

  5. Modelagem multicritério para seleção de intervalos de manutenção preventiva baseada na teoria da utilidade multiatributo

    Directory of Open Access Journals (Sweden)

    Adiel Teixeira de Almeida

    2005-04-01

    Full Text Available O problema de seleção de intervalos ou periodicidade para manutenção preventiva foi analisado através de um modelo de decisão multicritério. Este modelo de decisão apóia decisores na escolha da melhor combinação das conseqüências custo e confiabilidade, analisando um contexto de sistema de produção de serviços. O modelo de decisão é baseado na Teoria da Utilidade Multiatributo (MAUT. O artigo apresenta os principais aspectos teóricos e os elementos básicos utilizados para construção do modelo. Uma aplicação numérica é apresentada para ilustrar o uso do modelo de decisão.The problem of interval selection for preventive maintenance has been analysed through a multicriteria decision model. This decision model supports decision makers in choosing the best combination of consequences cost and reliability, analysing a context of service production systems. The decision model is based on the multiattribute utility theory (MAUT. The paper presents the main theoretical and practical aspects related to model building. A numerical application is presented in order to illustrate the use of the decision model.

  6. Análise e modelagem da evolução temporal da posse de autos na Região Metropolitana de São Paulo

    Directory of Open Access Journals (Sweden)

    Letícia Marconcim Pfeiffer

    2009-10-01

    Full Text Available

    O objetivo deste trabalho é estudar o comportamento da posse de autos familiar na Região Metropolitana de São Paulo, buscando analisar a evolução ocorrida entre 1987 e 1997. Foi utilizado um modelo logit multinomial que considera variáveis sociodemográficas e econômicas que influenciam o comportamento das famílias: tamanho da família, número de trabalhadores, número de estudantes, presença ou não de crianças, sexo do chefe, idade do chefe e a renda familiar. Os resultados apontaram mudanças de comportamento ao longo do tempo com relação às variáveis envolvidas, verificando-se uma redução da importância dessas características familiares para explicar a posse de autos, destacando-se o efeito decrescente da renda ao longo do tempo. Esses resultados sugerem que vem crescendo a importância de outros fatores na decisão de posse de auto das famílias, provavelmente relacionados com o mercado de veículos e com políticas urbanas e de transportes.

  7. Modelagem de um reator integral aplicado na reação de reforma a vapor de metano = Modeling of integral reactor applied methane steam reforming

    Directory of Open Access Journals (Sweden)

    Giane Gonçalves

    2007-07-01

    Full Text Available Freqüentemente, a validação de modelos matemáticos aplicados a reatores industriais esbarra na dificuldade de obtenção de medidas experimentais confiáveis. Uma maneira de contornar esta limitação corresponde à implantação de uma unidade em escala de bancada devidamente instrumentada, na qual são obtidos dados experimentais emcondições controladas. Neste contexto, foram efetuados ensaios em um reator integral de reforma a vapor de metano em escala de bancada, em diversas condições experimentais. As medidas de temperatura no leito foram efetuadas por meio de um termopar multiponto em seis posições axiais distintas, enquanto a composição do efluente do reator foi determinada por cromatografia gasosa. Estes dados experimentais foram comparados com as previsões de um modelo pseudo-homogêneo, unidimensional e dinâmico. Os resultados indicam que o modelo é adequado, sendo que tanto a atividade catalítica como a conversão são sensíveis à temperatura operacional, enquanto a temperatura do leito é praticamente insensível à vazão nas condições experimentais exploradas.Frequently, the validation of applied mathematical models of industrial reactors dash into the difficulty of obtaining reliable experimental data. A way to overcome this limitation is the proper use and operation or a in bench scale, experimental setup from whichexperimental data can be obtained in controlled conditions. In this context, experiments were carried out in an integral reactor of steam reform, in different experimental conditions. Thermocouples were placed along the catalyst bed to allow for temperature monitoring in six equally spaced and distinct positions of the reactor, the composition of the effluent of the reactor was determined by gas chromatography. These experimental data were compared with the theoretical results of a pseudo-homogeneous one-dimensional,dynamic mathematical model. The results indicate that the model can successfully

  8. Crustal evolution of South American Platform based on Sm-Nd isotope geochemistry; Evolucao crustal da plataforma sul americana com base na geoquimica isotopica Sm-Nd

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Kei

    1998-07-01

    Sm-Nd isotopic systematics is relevant to the topics of origin and evolution the of continental crust, where model ages refer to the time when crustal material was differentiated from the upper mantle. Alternative interpretations are due to a lack of adequate information on crustal processes and the variable composition of the mantle sources. The Sm-Nd methods are presented, and applied on rock materials from the South American Platform. The main conclusions indicate juvenile accretion with higher growth rates (peaks), around 3.7-3.5 Ga ({approx} 0.5% in volume), 3.1 - 2.9 Ga ({approx}16%), 2.7 - 2.6 ({approx} 9%), 2.2 - 1.9 (35%) and 1.3-1.0 (7%). The continental growth curve indicates that about 35 % of the crust was formed by 2.5 Ga, 88% by 1.8 Ga and 99% by 1.0 Ga, and the remaining {approx} 1 % was added in the Phanerozoic. Rapid crustal growth occurred between 2.2 and 1.9 Ga. The main period of continental crust formation occurred during the Paleoproterozoic, corresponding to 54 % in volume. Sm-Nd model ages, when compared with the crystallisation ages of granitoid rocks, furnish a rough estimate of juvenile vs. reworked material. Within the South American Platform about 45% of juvenile continental crust is still preserved within tectonic provinces of different ages. The remainder represents continental crust reworked in younger tectono-thermal events. In particular crustal reworking was predominating over juvenile accretion during Meso-Neoproterozoic. The Transbrasiliano Lineament is a megasuture, active in the Neoproterozoic, which separates a large northwestern mass, including the Amazonian and Sao Luis Cratons, from a southeastern mass, formed by a collage of cratonic fragments, of which the Sao Francisco and Rio de La Plata are the largest. The crustal evolutions of these two large continental masses are considered individually, and can be resumed following form: I - Old Archean rocks (>3.4 Ga) are found only within the south-eastern part (Gaviao Block

  9. Modelagem computacional dos defeitos substitucionais na hidroxiapatita

    OpenAIRE

    Santos, Ricardo Daniel Soares

    2014-01-01

    Os compostos formados a base de fosfatos de cálcio têm sido muito utilizados em diferentes aplicações biomédicas devido a sua excelente capacidade de ser considerado como um material que apresenta importantes propriedades de bioatividade, biocompatibilidade e biofuncionalidade com os mais diversos tipos de tecidos. Dentre tipos de fosfatos, a Hidroxiapatita HAP, composto cuja fórmula [Ca10(PO4)6(OH)2] é um dos principais biomateriais cerâmicos utilizados como um material que apresenta a cap...

  10. Uma interpretação semiótica de atividades de modelagem matemática : implicações para a atribuição de significado

    OpenAIRE

    Karina Alessandra Pessôa da Silva

    2013-01-01

    Esta pesquisa teve como objetivo investigar “Como emergem os signos interpretantes nas diferentes fases do desenvolvimento de uma atividade de Modelagem Matemática?”. Para tanto, nos pautamos em pressupostos teóricos da Modelagem Matemática na perspectiva da Educação Matemática e da Semiótica Peirceana no que se refere à atribuição de significado para o objeto em estudo. Por meio da tríade peirceana signo-objeto-interpretante fazemos uma interpretação semiótica de atividades de modelagem com ...

  11. Modelagem da laringe: da biologia ao computador

    Directory of Open Access Journals (Sweden)

    Marcelo de Oliveira Rosa

    2016-01-01

    Full Text Available Neste trabalho apresentamos uma descrição daanatomia e fisiologia da laringe, enfatizando os aspectos relevantes à fonação. A partir destes aspectos, a modelagem da laringe é apresentada. O principal objetivo de modelara laringe é representar de uma maneira simples esse órgãoatravés de equações matemáticos intimamente relacionadoscom características fisiológicas. Equações aerodinâmicase viscoelásticas são simplificadas de acordo com as pesquisas,sempre buscando simplicidade e aplicabilidade computacional. Assim, pesquisadores podem compreender melhor a laringe e a fala humana em termos dos efeitos linguísticos, cirúrgicos e computacionais produzidos pelamovimentação desse órgão. Palavras-chave: Laringe, modelagem, sinal glotal,produção da fala.

  12. Socioeconomic status, birth weight, maternal smoking during pregnancy and adiposity in early adult life: an analysis using structural equation modeling Situação sócio-econômica, peso ao nascer, tabagismo na gravidez e adiposidade na vida adulta jovem: uma análise utilizando-se modelagem com equações estruturais

    Directory of Open Access Journals (Sweden)

    Antônio Augusto Moura da Silva

    2010-01-01

    Full Text Available We describe here an example of structural equation modeling in epidemiology. The association between birth weight and adiposity in early adult life, adjusted for the number of cigarettes smoked during pregnancy and socioeconomic status at birth, was evaluated. Data involving 2,063 adults from the 1978/1979 Ribeirão Preto cohort study were used. Adiposity was measured by body mass index (BMI, waist circumference (WC and the sum of triceps and subscapular skinfolds (STSS. Models were submitted to maximum likelihood estimation, separately for men and women. Birth weight had a small and significant effect on adiposity in men (standardized coefficient, SC = 0.08 and women (SC = 0.09. Smoking during pregnancy did not influence adiposity in men (SC = 0.004, but its effect was marginally significant in women (SC = 0.07; P = 0.056. Socioeconomic status at birth had a small and positive effect on adiposity in men (SC = 0.08 and a moderate and negative effect in women (SC = -0.16. In this young adult population, BMI, WC and STSS used alone or in combination were valid estimators of body adiposity.O objetivo desse artigo é apresentar um exemplo da modelagem com equações estruturais. Foi avaliada associação entre peso ao nascer e adiposidade na vida adulta jovem, ajustando-se para número de cigarros fumados na gravidez e situação sócio-econômica ao nascimento. Dados de 2.063 adultos da coorte de Ribeirão Preto, São Paulo, Brasil, de 1978/1979 foram utilizados. A adiposidade foi medida pelo índice de massa corporal (IMC, circunferência da cintura, e somatório das pregas cutâneas subescapular e a tricipital. Os modelos foram estimados por máxima verossimilhança, separadamente para homens e mulheres. O peso ao nascer teve efeito pequeno e significante na adiposidade em homens (CP - coeficiente padronizado = 0,08 e mulheres (CP = 0,09. Tabagismo materno durante a gravidez não influenciou a adiposidade em homens (CP = 0,004, mas em mulheres a

  13. Modelagem Computacional para Produção e Pesquisa em Avicultura

    Directory of Open Access Journals (Sweden)

    Rondón EOO

    2002-01-01

    Full Text Available A modelagem computacional foi apresentada como uma ferramenta na tomada de decisões para solucionar problemas complexos e cotidianos na produção e pesquisa em avicultura. Aspectos teóricos relacionados à construção e implementação dos diferentes tipos de modelos matemáticos utilizados em avicultura foram descritos de maneira elementar, tentando deixar o artigo acessível às pessoas que não necessariamente possuem um forte conhecimento de estatística experimental. Uma ênfase especial foi dada à discussão das vantagens da modelagem para resolver o problema complexo de determinar exigências nutricionais das aves em diferentes condições. Uma revisão cronológica das publicações relacionadas aos pacotes computacionais desenvolvidos para auxiliar na formulação de estratégias nutricionais em aves mostrou que eles estão baseados na modelagem do crescimento associada aos modelos de estimação de exigências e de custo mínimo de rações. A evolução e sofisticação desses programas têm acompanhado os rápidos avanços computacionais. Contudo, a eficiência de uma simulação depende dos conhecimentos sobre situações reais. Esses conhecimentos são gerados pelas pesquisas tradicionais e muitas vezes é de fundamental importância a conexão de informações provenientes de diferentes disciplinas, direta ou indiretamente, relacionadas à avicultura.

  14. Modelagem dos efeitos do vento na uniformidade da irrigação por aspersão: aspersores de tamanho médio Modeling of wind effects on water application uniformity of sprinkler irrigation: medium-sized sprinklers

    Directory of Open Access Journals (Sweden)

    Lessandro C Faria

    2012-02-01

    Full Text Available O vento afeta a distribuição de água aplicada por aspersores, podendo tornar um determinado sistema de irrigação ineficiente. Nestas condições, a modelagem pode facilitar as avaliações de sistemas convencionais de aspersão, antes mesmo de sua implantação no campo. Neste estudo foi avaliada a aplicabilidade do modelo semiempírico de Richards & Weatherhead para aspersores de tamanho médio, modelos Agropolo/NY e Naan/5024, em diferentes condições de vento. Os valores do Coeficiente de Uniformidade de Christiansen (CUC, obtidos com dados de ensaios de campo e em simulações computacionais, foram comparados por meio de diversos índices resultando em valores de R²=0,88, desvio absoluto médio (DAM = 4,75% e índice de desempenho (c = 0,91, para aspersores operando isoladamente, para linhas laterais de aspersores, valores de R²= 0,78, DAM = 4,1% e c = 0,76. Demonstrou-se, assim, a aplicabilidade do modelo de Richards & Weatherhead frente à predição da uniformidade de aplicação de água de sistemas convencionais de irrigação operando com aspersores de tamanho médio em condições de vento, o que reduz o esforço e o tempo requerido em trabalhos de campo.The wind has influence on sprinkler water distribution and it can make a given irrigation system inefficient. Under this circumstance, the use of mathematical models can ease evaluations of conventional sprinkler irrigation systems, even before they are set up in the field. The aim of this study was to evaluate the applicability of the Richards & Weatherhead semi-empirical model using medium-sized sprinklers (Agropolo/NY and Naan/5024 under windy conditions. The Christiansen coefficient of uniformity (CUC values, based on in-field sprinkler tests, were compared to simulated values, resulting in the following indices: (i for individual solid set sprinkler system R²= 0.88, average absolute deviation (AAD = 4.75%, and performance index (c = 0.91; (ii for block sprinkler system

  15. O Tratamento de questões ambientais através da modelagem matemática: um trabalho com alunos do ensino fundamental e médio

    OpenAIRE

    Ferreira, Denise Helena Lombardo [UNESP

    2003-01-01

    Esta pesquisa tem como objetivo buscar compreender como ocorre a participação dos alunos, e quais elementos sociais e pedagógicos tornam-se presentes ao se abordar questões ambientais, na perspectiva do ensino-aprendizagem da Modelagem Matemática. A pesquisa foi desenvolvida numa abordagem qualitativa com alunos do Ensino Fundamental e Médio, ambas escolas públicas do município de Rio Claro, SP. A ação pedagógica, desenvolvida na perspectiva de Modelagem Matemática, envolveu os temas Água, Li...

  16. Modelagem do equilibrio de fases em misturas de dioxido de carbono supercritico e compostos presentes em produtos naturais

    OpenAIRE

    Pedro Felipe Arce-Castillo

    2002-01-01

    Resumo: A modelagem e simulação de processos de extração supercrítica requer uma boa predição das condições do equilíbrio entre fases, condições que determinam a maior concentração do líquido ou sólido (soluto) a ser extraído pelo fluido supercrítico (solvente). O problema principal na modelagem dos sistemas que se encontram em processos de extração supercrítica é a grande diferença de tamanho (peso molecular) entre as substâncias envolvidas (soluto e fluido supercrítico) e a baixa concentraç...

  17. Projeto Canteiros e PIBID: articulação com a modelagem matemática

    Directory of Open Access Journals (Sweden)

    Anderson Maciel Souza

    2012-12-01

    Full Text Available O presente trabalho foi realizado sobre a investigação da importância que os projetos de extensão universitária, em questão PIBID e Canteiros, apresentam juntamente com a Modelagem Matemática na solução de problemas e também para formação de conceitos matemáticos voltados para a Educação Matemática, mostrando como são propostas e também como estão sendo realizadas as atividades que esses dois projetos desenvolvem. Além disso mostrar a importância que que os programas e projetos extensionistas trazem para as universidades quando desenvolvem um trabalho voltado para o meio social, fazendo com que o papel da universidade vá além de formar profissionais, mas também contribuir para solucionar problemas que atingem a sociedade por meio de ações coletivas de aspecto social realizadas pela comunidade acadêmica que possibilitam ao acadêmico uma forma de proporcionar práticas associadas a seus estudos. Contudo, em particular apresentar as situações em que essas atividades permitem com que a matemática seja trabalhada através da modelagem matemática em um caráter científico e educacional.Palavras-chave: modelagem matemática; projetos de extensão; educação matemática.

  18. Efeitos de modelagem do comportamento verbal e de instruções sobre o comportamento de encaixar peças

    Directory of Open Access Journals (Sweden)

    Maria Regina Cavalcante

    Full Text Available Pesquisas têm demonstrado diferenças nos efeitos dos comportamentos verbais modelado e instruído sobre o comportamento verbal e não-verbal. Este estudo investigou efeitos da modelagem do comportamento verbal e das instruções sobre o comportamento verbal (falar sobre encaixar peças e o não-verbal (encaixar peças azuis e vermelhas, grandes e pequenas e quadradas e circulares de 10 crianças, entre 8 e 9 anos de idade. A coleta de dados foi realizada em duas condições com cinco participantes. Condição 1: modelagem do comportamento verbal. Condição 2: apresentação de instruções para o comportamento não-verbal. Quando ocorreu a modelagem do comportamento verbal foram observadas mudanças correspondentes no comportamento não-verbal. As instruções produziram imediata adesão do comportamento não-verbal e, na seqüência, o desempenho foi alterado. Esses dados reafirmam a importância de ampliar o conhecimento dos efeitos da modelagem do comportamento verbal e das instruções sobre o comportamento de crianças em jogos como o utilizado nesta pesquisa.

  19. Modelagem de um reator integral aplicado na reação de reforma a vapor de metano - DOI: 10.4025/actascitechnol.v29i2.705

    Directory of Open Access Journals (Sweden)

    Giane Gonçalves Lenzi

    2008-02-01

    Full Text Available Freqüentemente, a validação de modelos matemáticos aplicados a reatores industriais esbarra na dificuldade de obtenção de medidas experimentais confiáveis. Uma maneira de contornar esta limitação corresponde à implantação de uma unidade em escala de bancada devidamente instrumentada, na qual são obtidos dados experimentais em condições controladas. Neste contexto, foram efetuados ensaios em um reator integral de reforma a vapor de metano em escala de bancada, em diversas condições experimentais. As medidas de temperatura no leito foram efetuadas por meio de um termopar multiponto em seis posições axiais distintas, enquanto a composição do efluente do reator foi determinada por cromatografia gasosa. Estes dados experimentais foram comparados com as previsões de um modelo pseudo-homogêneo, unidimensional e dinâmico. Os resultados indicam que o modelo é adequado, sendo que tanto a atividade catalítica como a conversão são sensíveis à temperatura operacional, enquanto a temperatura do leito é praticamente insensível à vazão nas condições experimentais exploradas.

  20. Imputação de dados pluviométricos e sua aplicação na modelagem de eventos extremos de seca agrícola

    OpenAIRE

    Gláucia Tatiana Ferrari

    2011-01-01

    Este trabalho relata o procedimento utilizado na obtenção de um banco de dados contínuo de precipitação diária de estações meteorológicas localizadas no Estado do Paraná. O banco de dados é composto por 484 séries históricas com dados entre janeiro de 1975 a dezembro de 2009. Para preencher os dados faltantes do banco de dados foram testados três métodos de imputação: o vizinho mais próximo, distância inversa ponderada e regressão linear. A raiz do erro quadrático médio (REQM) foi utilizada p...

  1. Influência da função distribuição de quebra na modelagem e simulação do circuito de moagem de Carajás: parte 2 - simulação

    OpenAIRE

    Foggiatto,Bianca; Delboni Júnior,Homero

    2010-01-01

    Empregando-se o método descrito na Parte 1 desse artigo, foram realizadas caracterizações quanto à fragmentação dos principais tipos de minério de Carajás, provenientes das frentes de lavra das minas N4 e N5. A partir das características de tais minérios, foi empregado o modelo calibrado, para analisar, através de simulações, o desempenho do circuito de moagem de Carajás. Como resultado, foi possível verificar as variações de distribuição granulométrica do produto da moagem e do overflow dos ...

  2. Uma modelagem de sequestro e armazenamento de dióxido de carbono atmosférico

    OpenAIRE

    Ferrufino, Gretta Larisa Aurora Arce [UNESP

    2008-01-01

    O dióxido de carbono (CO2) é um importante gás de efeito estufa. No entanto, um aumento gradual ameaça substancialmente o clima. Um dos principais desafios do planejamento ambiental é identificar um modelo que vincule todos os fatores do ciclo de carbono, ou seja, oceano – ecossistema terrestre – emissão antropogênica – atmosfera. Princípios básicos de Termodinâmica podem ser aplicados em uma modelagem estatística com bases em séries históricas para obter concentrações de CO2 na atmosfera, po...

  3. Uma modelagem de sequestro e armazenamento de dióxido de carbono atmosférico

    OpenAIRE

    Ferrufino, Gretta Larisa Aurora Arce [UNESP

    2008-01-01

    O dióxido de carbono (CO2) é um importante gás de efeito estufa. No entanto, um aumento gradual ameaça substancialmente o clima. Um dos principais desafios do planejamento ambiental é identificar um modelo que vincule todos os fatores do ciclo de carbono, ou seja, oceano – ecossistema terrestre – emissão antropogênica – atmosfera. Princípios básicos de Termodinâmica podem ser aplicados em uma modelagem estatística com bases em séries históricas para obter concentrações de CO2 na atmosfera, po...

  4. Modelagem termodinâmica de equilíbrio de fases de sistemas CO2 + alcoois

    OpenAIRE

    Pereira, Larissa Maria

    2013-01-01

    Resumo: Este trabalho tem como objetivo principal a modelagem termodinâmica de equilíbrio de fases dos sistemas associativos CO2(1) + metanol/etanol/pentanol/hexanol(2) com as equações de estado cúbicas de Peng-Robinson com regra de mistura quadrática de van der Waals (PR-vdW2), Peng-Robinson com regra de mistura de Wong-Sandler (PRWS) e Soave-Redlich-Kwong Preditivo (PSRK). Para o cálculo do equilíbrio de fases dos sistemas de interesse foi desenvolvido um algoritmo estocástico baseado na te...

  5. MODELAGEM SISTÊMICA DE PROJETOS DE AEC EM UML

    Directory of Open Access Journals (Sweden)

    Rita Cristina Ferreira

    2007-11-01

    Full Text Available O uso intensivo de Sistemas de Informação é uma possível solução para a integração das atividades de projeto em AEC, permitindo que decisões sejam tomadas ainda na fase de projeto e, conseqüentemente, evitando-se retrabalhos em obra. Neste sentido, esforços têm sido realizados para padronizar conceitos e terminologias de AEC, permitindo a troca e armazenagem de informações, como a norma ISO 12006-2 e os padrões estabelecidos pelo IFC. Ambas são baseadas na linguagem EXPRESS, assim como é o padrão industrial STEP. Entretanto, as representações de informação usadas na indústria de produtos não são as mais adequadas para a Engenharia de Software, responsável pelo desenvolvimento de Sistemas de Informação, onde as representações semânticas envolvem não somente a representação estrutural da informação, mas também a representação comportamental. Este artigo contribui com uma visão de implementação em UML da informação de um projeto de AEC e tornam explícitas, sob a ótica do desenvolvimento de software, as relações semânticas existentes. Os resultados desta pesquisa foram obtidos através da realização de um estudo de caso de projeto de produção em CAD 3D dos subsistemas alvenaria e revestimento para um edifício residencial. A partir das observações do estudo de caso foi feita a modelagem em UML dos objetos pertinentes. O principal resultado obtido foi a representação explícita das interfaces entre objetos AEC.

  6. INTEROPERABILIDADE DE FERRAMENTAS DE MODELAGEM PARAMÉTRICA EM PROJETOS INDUSTRIAIS

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    Ezequiel Rosa Dias

    2015-11-01

    Full Text Available Este trabalho resulta de uma pesquisa de mestrado que investigou a troca de dados entre diferentes ferramentas BIM utilizadas por um grupo de empresas de Belo Horizonte na elaboração de projetos industriais. As principais fontes da pesquisa exploratória foram entrevistas não estruturadas e análises de documentações. Verificou-se que as empresas utilizam a modelagem 3D principalmente para visualização e verificação de interferências construtivas. As mesmas se encontram focadas na resolução de problemas de interoperabilidade em função da utilização simultânea de ferramentas BIM e de modelagem paramétrica industrial, mescla que pode induzir o uso de novas tecnologias pelo setor AEC à medida que projetos mais complexos são desenvolvidos pelo setor. A interoperabilidade entre os softwares utilizados ocorre preferencialmente por links diretos e padrões proprietários, em virtude de inexistência de definições normativas, fato que requer iniciativas de harmonizações entre padrões como IFC, CIS/2 e ISO-15926. Este estudo mostra que as disciplinas de projeto compõem um modelo digital 3D integrado. Contudo, o modelo integrado não dispõe de características paramétricas suficientes para o emprego de simulações do empreendimento como um todo. Para a gestão da modelagem, as empresas adotam uma ferramenta própria para criação de objetos paramétricos, tradução de modelos entre ferramentas não interoperáveis e gestão de listas de materiais. A pesquisa possibilitou a compilação do fluxo da troca de dados entre softwares, com a discriminação das linguagens utilizadas, das fases de projetos e das equipes envolvidas.

  7. Validação Interna de Base de Conhecimentos utilizando Modelagem Matemática Bayesiana x Conexionista

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    Lucimar Fossatti de Carvalho

    2009-09-01

    Full Text Available Neste artigo, investigamos o aprendizado de máquina baseado na modelagem matemática envolvendo modelos bayesianos x conexionistas, aplicado no auxílio ao diagnóstico de eventos epilépticos (EEs e eventos não epilépticos (ENEs. Para esta finalidade alguns algoritmos de aprendizado de máquina foram comparados incluindo o aprendizado conexionista através das regras Delta Generalizada, Hebb, Oja, juntamente com o aprendizado em redes bayesianas. Foram considerados para este estudo 122 pacientes os quais apresentavam sintomas relacionados com EEs e ENEs. Os resultados empíricos desta pesquisa indicam que: (1 ambas as abordagens bayesianas e conexionistas são bastante similares, mostrando que os resultados são coerentes, mesmo utilizando heurísticas distintas; (2 o índice de acertos de casos positivos (EEs, por meio da modelagem bayesiana pode estar relacionado com a facilidade de implementação das probabilidades condicionais. Concluiu-se, portanto, que os modelos investigados fornecem informações importantes para o desenvolvimento de novas pesquisas tanto na área bayesiana como na área conexionista.

  8. A Utilização da Modelagem Computacional Semiquantitativa no Estudo do Sistema Mola-Massa

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    Camiletti Giuseppi

    2002-01-01

    Full Text Available O artigo apresenta resultados da investigação sobre a integração de ambientes de modelagem computacional ao aprendizado exploratório de Física. Os resultados aqui apresentados são relativos ao estudo da interação e desempenho de alunos de ensino superior durante a utilização do ambiente de modelagem computacional semiquantitativo WLinkIt em uma atividade de conteúdo específico em Física: o sistema mola-massa. Os resultados mostram que os estudantes apresentaram habilidades para desenvolver um modelo sobre a situação proposta e relacionar o comportamento apresentado pelo modelo com o esperado por eles, alterar o modelo e explicar o comportamento apresentado pelas variáveis. Os resultados mostram também que as dificuldades apresentadas foram relacionadas à delimitação do sistema a ser estudado, ao entendimento da influência de uma variável sobre a outra, ao entendimento de quem é o agente causal do sistema, ao entendimento da função de uma ligação entre duas variáveis e ao entendimento dos conceitos envolvidos. Assim, o mapeamento desses aspectos é fundamental para o delineamento de pesquisas futuras no sentido de promover, na prática, a integração de Ambientes de Modelagem Computacional Semiquantitativos na sala de aula, mais especificamente para o estudo de tópicos de Física.

  9. Modelagem do vento e da fotosfera de AG Carinae

    Science.gov (United States)

    Groh, J. H.; Damineli, A.

    2003-08-01

    A trajetória evolutiva das estrelas de alta massa depende fortemente de suas taxas de perda de massa. Apesar do rápido progresso no estudo destas estrelas, a taxa de perda de massa e outros parâmetros físicos básicos, como a temperatura superficial e a velocidade terminal do vento ainda não estão bem determinados. Isto ocorre devido à presença de ventos irregulares, rápidos e fortes ao redor destas estrelas, tornando a interpretação dos seus espectros uma tarefa difícil. Assim, a modelagem do vento e da fotosfera dessas estrelas está sendo cada vez mais usada para obter tais parâmetros a partir dos espectros. O aumento da taxa de perda de massa durante a fase LBV (Variáveis Luminosas Azuis), comparado com outros tipos de estrelas, tem sido atribuído a instabilidades do tipo S Doradus. Dispomos de uma base de dados espectroscópicos cobrindo 22 anos de observações de AG Carinae, incluindo um ciclo S Doradus completo, com espectros CCD em alta resolução na faixa óptica e infravermelha. Utilizamos o programa desenvolvido por Schmutz (1997) para uma análise preliminar desse ciclo, obtendo a taxa de perda de massa a partir da linha do Ha. Não existe uma correlação clara da taxa de perda de massa com mudanças da temperatura efetiva, do raio da estrela e do fluxo na banda V. A estrela atingiu seu mínimo fotométrico (raio mínimo) em 1990 e o máximo fotométrico (raio máximo) em 1995, enquanto que o fluxo máximo da linha do Ha ocorreu em 1996. Além disso a taxa de perda de massa não segue esse ciclo, contrariamente às idéias correntes. Para fazer um modelo mais realista estamos usando o programa CMFGEN (Hillier & Miller), que trata a fotosfera e o vento estelar de forma consistente, considerando a radiação fora do equilíbrio termodinâmico (NLTE) e com blanketting total de linhas. Simulamos o espectro de AG Carinae em duas épocas extremas do ciclo S Dor para testar os resultados obtidos com o modelo mais simplificado.

  10. Aplicação dos conceitos de modelagem e de redes de Petri na análise do processo produtivo da indústria sucroalcooleira Application of modeling and Petri net concepts in the productive process of the sugarcane industry

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    Mamoru Carlos Yamada

    2002-06-01

    Full Text Available A modelagem, como meio de análise de processos do agronegócio, bem como de cadeias produtivas, atende à demanda por métodos apropriados. O presente trabalho objetivou avaliar a aderência dos conceitos de modelagem e de rede de Petri aplicados ao complexo agroindustrial da cana-de-açúcar. Utilizou-se uma empresa real para a aquisição das informações. Os modelos das cadeias de atividades foram validados com o uso da rede de Petri, por meio de um método de análise em que são simulados todos os caminhos possíveis e os estados que o sistema modelado pode atingir. O estudo resultou em 14 conjuntos de etapas de produção, englobando todas as operações unitárias das cadeias produtivas do açúcar e do álcool, desde o plantio da cana até o armazenamento do açúcar e do álcool.The modeling, as a tool of analysis of agribusiness processes as well as of productive chains, supplies the demand for appropriated methodological tools. The present work aimed to evaluate the adherence of modeling and Petri net concepts applied to the sugarcane agroindustrial complex. A real company was used for the acquisition of the information. Models of the chains of activities were validated with the Petri net tool, through an analysis method where all possible paths and all states that the modeled system can reach are simulated. The study resulted in 14 groups of production stages, including all unitary operations of the sugar and alcohol productive chains, from the planting of the cane to the storage of the sugar and alcohol.

  11. Modelagem e Simulação no Âmbito da Hidrologia

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    Vassiliki Terezinha Galvão Boulomytis

    2011-04-01

    Full Text Available A modelagem hidrológica pode ser considerada como um conjunto de ferramentas destinadas ao cálculo e à representação de dados que possibilita a previsão de eventos, a realização de projetos, o gerenciamento dos recursos hídricos, além de outros tipos de aplicação. No entanto, devido à variabilidade na ocorrência dos processos hidrológicos, escassez e dificuldade na obtenção de dados levantados em campo, os modelos conceituais vêm sendo combinados com os físicos e empíricos, utilizando-se de novas técnicas, entre elas, o sensoriamento remoto e o geoprocessamento para a coleta, processamento, análise e geração de resultados. Neste trabalho será apresentada a base conceitual e a importância do conhecimento do tipo de ferramenta que se deseja utilizar para a implementação ou uso de um modelo hidrológico, para que deste modo seja possível verificar a possibilidade do mesmo ser de fato desenvolvido.

  12. Modelagem Integrada do Problema de Programação de Tripulantes de Aeronaves

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    Wagner de Paula Gomes

    2011-09-01

    Full Text Available

    Este artigo trata o Problema de Programação de Tripulantes (PPT, de importância fundamental no planejamento operacional das empresas aéreas. O PPT é normalmente dividido na literatura em dois subproblemas, formulados e resolvidos sequencialmente: Problema de Determinação das Viagens (PDV e Problema de Atribuição de Escalas (PAE. Esta decomposição justifica-se pela sua natureza combinatória, porém deixa de proporcionar um tratamento global ao PPT, em termos de custo e qualidade da solução final. Portanto, o estado da arte envolve a solução integrada do PPT, em que ambos os subproblemas são resolvidos simultaneamente. O problema, no entanto, é NP-Difícil. Esta pesquisa apresenta uma metodologia para modelagem integrada do PPT, através de um Algoritmo Genético Híbrido (AGH associado a um procedimento de busca em profundidade, levando em conta as particularidades da legislação brasileira. A metodologia foi testada, com sucesso, para a solução de instâncias baseadas na malha real de uma empresa aérea brasileira.

  13. Sistema de secagem solar para frutos tropicais e modelagem da secagem de banana em um secador de coluna estática

    OpenAIRE

    Costa, Antonio Raimundo da Silva

    2008-01-01

    Neste trabalho foi projetado, construído e testado um secador elétrico-solar composto por um coletor solar, uma câmara de secagem, um exaustor eólico e um ventilador para promover a convecção forçada do ar quente. Também foram realizados experimentos de secagem de banana em um secador de coluna estática, para modelar a secagem e obter parâmetros que podem ser usados, como uma primeira aproximação, na modelagem de um secador elétrico-solar, dependendo da simil...

  14. Automatização do traçado dos moldes básicos femininos por meio de software de modelagem paramétrica

    OpenAIRE

    Thays Neves Costa

    2016-01-01

    Esta pesquisa tem por objetivo automatizar a personalização do traçado do processo de construção dos moldes básicos do vestuário feminino, através da utilização de software paramétrico, mais precisamente o Grasshopper. Para a construção do trabalho, foram investigados alguns conceitos que fundamentaram esta pesquisa. São eles: antropometria e seus conceitos aplicados ao vestuário; tabela de medidas e como ela é empregada no desenvolvimento do produto sob medida; a modelagem inserida na sequên...

  15. Etnomatemática e modelagem matemática: Um estudo comparativo com os processos de criação de alegorias de carnaval

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    Zulma Elizabete de Freitas Madruga

    2014-04-01

    Full Text Available Neste artigo apresenta-se uma pesquisa cujos dados empíricos advieram de um criador de alegorias de carnaval – carnavalesco. Objetivou-se fazer uma análise comparativa entre o processo de criação de alegorias, modelagem matemática e etnomatemática. Modelagem Matemática é a arte na elaboração de um modelo; e etnomatemática é a arte de conhecer, explicar e entender os diversos fazeres e saberes das pessoas em seus contextos culturais. Os procedimentos metodológicos foram divididos em duas etapas: apreensão empírica e significação dos dados a luz da teoria. A apreensão, etnografia do lugar e da pessoa que cria as alegorias para um desfile de carnaval. Os dados foram coletados por meio de observações in loco, documentos, relatos gravados, fotos, vídeos e entrevista concedida pelo carnavalesco. A Significação implicou na organização, classificação e a análise desses dados comparando o processo de criação de alegorias pelo carnavalesco aos procedimentos de modelagem e ao programa etnomatemática. O resultado mostrou que o carnavalesco cria modelos de alegorias em sua mente, advindas de percepções e apreensões do entorno, que a partir da compreensão e do entendimento, transpassa em um modelo externo - conjunto de submodelos representados em desenhos, propostas e esquemas que uma vez produzidos ilustrarão o desfile de carnaval. A análise dos processos envolvidos na criação de alegorias do carnavalesco sugere que as pessoas que criam alguma coisa nas mais diversas áreas do conhecimento perpassam as mesmas etapas prescritas na modelagem sob uma perspectiva etnomatemática: a partir de uma situação-problema que espera compreender para então propor solução ou melhoria, busca perceber e apreender os dados de fontes diversas, compreender e explicar formulando um modelo, e significar e explicitar resolvendo e validando o modelo, gerando novos conhecimentos frente a novas necessidades impostas pelo meio, seja econ

  16. Gênero, volte para o armário! Discurso religioso, gênero e modelagem de comportamento

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    Rodrigo Pedro Casteleira

    2017-02-01

    Full Text Available A proposta do presente artigo é a de discutir as questões sobre o conceito de gênero, que envolveram as discussões sobre o Plano Municipal de Educação (PME, aliado com os conceitos sobre modelagem de comportamento e educação sob uma estrutura skinneriana. Além disso, o discurso religioso veiculado pelo Conselho Nacional de Bispos do Brasil (CNBB parece tentar modelar o comportamento, a fim de que as pessoas rejeitem a própria palavra ‘gênero’ nos documentos, ignorando as bases legais na educação. Os resultados teóricos revelam em que medida os argumentos religiosos tentam controlar ou alterar as contingências humanas, entre elas a educacional, com o uso do reforço verbal condicionando-o à ideia de possibilidade de céu ou inferno.

  17. Aplicação da modelagem por redes de Petri para avaliação ocupacional de trabalhadores

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    Jonas Lied

    2009-07-01

    Full Text Available Este trabalho introduz a modelagem por Redes de Petri Coloridas (RPC como ferramenta para avaliação dos riscos ocupacionais de trabalhadores em uma linha de manufatura. O uso da ferramenta consiste em modelar a linha de manufatura por Redes de Petri Coloridas, simular o modelo em computador, informando a situação inicial do processo.  A partir deste ponto, com os resultados obtidos da simulação avaliar a carga de trabalho individual dos trabalhadores, permitindo verificar quais as tarefas desenvolvidas devem ser estudadas para diminuição dos riscos ocupacionais envolvidos. Foi possível verificar que alguns trabalhadores estão sobrecarregados e outros folgados na linha de montagem estudada.

  18. Utilização da função pearson tipo V, Weibull e hiperbólica para modelagem da distribuição de diâmetros

    OpenAIRE

    Daniel Henrique Breda Binoti; Mayra Luiza Marques da Silva Binoti; Helio Garcia Leite

    2013-01-01

    Objetivou-se neste estudo avaliar a eficiência da função log-Pearson tipo V para a descrição da estrutura diamétrica de povoamentos equiâneos de eucaliptos, bem como propor um modelo de distribuição diamétrica utilizando essa função. A modelagem realizada pela função log-Pearson tipo V foi comparada com a modelagem realizada com a função Weibull e hiperbólica. Para isso utilizou-se dados de parcelas permanentes de eucalipto, localizadas na região centro oeste do estado de Minas Gerais. A funç...

  19. ANÁLISE DA FUNÇÃO LOG-LOGÍSTICA PARA MODELAGEM DA DISTRIBUIÇÃO DE DIÂMETROS1

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    Daniel Henrique Breda Binoti

    2015-10-01

    Full Text Available RESUMO Objetivou-se neste estudo avaliar a eficiência da função log-logística com dois e três parâmetros, γ = dapmin e truncada à direita para a descrição da estrutura diamétrica de povoamentos equiâneos, bem como ajustar um modelo de distribuição diamétrica utilizando as funções. A modelagem realizada pela função log-logística foi comparada com a modelagem realizada com a função Weibull. Para isso, utilizaram-se dados de parcelas permanentes de clones de Eucalyptus, mensuradas em seis ocasiões. A aderência das funções aos dados foi comprovada pela aplicação do teste de Kolmogorov-Smirnov (K-S. Os valores médios da estatística do teste K-S foram 0,0901; 0,0997; 0,1297; e 0,0616 para a função com 2P, 3P, α = dapmin e truncada à direita, respectivamente. Para a função Weibull, obteve-se a média de 0,0638 para a estatística do teste K-S. A função log-logística de dois parâmetros pode ser utilizada na modelagem da estrutura diamétrica de povoamentos de eucalipto.

  20. Modelagem de um sistema de informação para rastreabilidade na indústria do vinho baseado em uma arquitetura orientada a serviços Modeling of an information system for wine traceability based on a service oriented architecture

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    Osvaldo Gogliano Sobrinho

    2010-02-01

    Full Text Available Apresenta-se neste trabalho pesquisa científica que levou à modelagem de um sistema de informação para o registro de dados de rastreabilidade destinado à indústria do vinho, segundo os conceitos de uma arquitetura computacional orientada a serviços (service oriented architecture, SOA. Desde 2005, a manutenção de tais registros é obrigatória para todos os produtores que pretendem exportar para países da União Europeia. Ademais, os consumidores finais, inclusive brasileiros, preocupados com a segurança alimentar, apresentam demanda crescente por informações. Buscou-se uma solução que contemple a indústria coletivamente, por meio de consórcios ou associações de produtores, diluindo custos e compartilhando benefícios. A partir do levantamento bibliográfico realizado e de contatos com pesquisadores e representantes do setor produtivo vinícola brasileiro, em Bento Gonçalves -RS, pesquisaram-se tópicos de tecnologia da informação ligados ao tema, além de detalhes sobre o processo produtivo do vinho. A partir de um modelo do processo produtivo do vinho sugerido pelos autores, empregou-se a Unified Modeling Language (UML, para a modelagem do sistema, que utiliza a tecnologia de web services para o tráfego de dados. Com um protótipo funcional, constataram-se a viabilidade do modelo e a possibilidade de sua utilização em outros domínios.The purpose is to present a scientific research that led to the modeling of an information system which aimed at the maintenance of traceability data in the Brazilian wine industry, according to the principles of a service-oriented architecture (SOA. Since 2005, traceability data maintenance is an obligation for all producers that intend to export to any European Union country. Also, final customers, including the Brazilian ones, have been asking for information about food products. A solution that collectively contemplated the industry was sought in order to permit that producer

  1. Modelagem numérica de ressacas na plataforma sudeste do Brasil a partir de cartas sinóticas de pressão atmosférica na superfície Numerical modeling of storm surges in the brazilian southeastern shelf using synopitc charts of atmospheric pressure at the surface

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    Ricardo de Camargo

    1994-12-01

    Full Text Available Um modelo numérico tri-dimensional, linear, barotrópico e de meso-escala, é usado para a plataforma sudeste brasileira, de maneira a representar a composição das principais componentes astronômicas de maré, sobrepostas a efeitos meteorológicos extremos, para períodos específicos de interesse. No entanto, como dados meteorológicos relativos a esta área são muito escassos e esparsos, foi utilizada uma metodologia de fornecimento de condições meteorológicas para o modelo de circulação oceânica, baseada somente em cartas sinóticas de pressão atmosférica na superfície. O campo de pressão foi bem representado, mas as intensidades calculadas para os ventos foram bem maiores do que as observadas na costa. Os resultados do modelo indicam que é possível associar o centro de alta pressão do Atlântico Sul e as correspondentes elevações de superfície paralelas à linha da costa a um sistema geostrófico de circulação oceânica. Por outro lado, a passagem de frentes frias na área induz sistemas transientes que modificam o padrão geostrófico, também mudando a configuração das isolinhas de elevação de superfície.A three-dimensional, linear, barotropic and meso-scale numerical model is used for the southeastern Brazilian shelf, in order to represent the composition of the main astronomical tidal constituents, superimposed to extreme meteorological effects, for specific periods of interest. However, meteorological data relative to this area are very few and sparse, so that a methodology to provide meteorological conditions to the oceanic circulation model was used, based only on atmospheric pressure charts at the surface. The pressure field was well represented, while the calculated wind speeds were much larger than the observed winds at the coast. The model results indicate that it is possible to associate the predominant high pressure center in the South Atlantic and the correspondent surface elevations parallel to the

  2. Semiótica e as ações cognitivas dos alunos em atividades de modelagem matemática: um olhar sobre os modos de inferência

    Directory of Open Access Journals (Sweden)

    Lourdes Maria Werle de Almeida

    2012-01-01

    Full Text Available Neste trabalho apresentamos algumas reflexões, à luz da semiótica peirceana, sobre a possibilidade de se introduzirem, na sala de aula, atividades que sinalizem potencial para se desenvolverem diferentes tipos de raciocínio e diferentes ações cognitivas nos estudantes. Iniciamos o trabalho com pressupostos teóricos da semiótica no que diz respeito aos modos de inferência abdução, dedução e indução e à Modelagem Matemática como alternativa pedagógica. Com o objetivo de investigar as relações entre as ações cognitivas evidenciadas em atividades de modelagem e os modos de inferência, analisamos uma atividade de modelagem desenvolvida por alunos de um curso de licenciatura em matemática. A partir dessa análise, concluímos que os modos de inferência ativados nessa atividade estão associados às ações cognitivas dos alunos durante as transições entre as diferentes etapas do desenvolvimento da atividade.

  3. Ensino de Geometria Espacial métrica: uma experiência com modelagem

    Directory of Open Access Journals (Sweden)

    Andrea Cardoso

    2012-12-01

    Full Text Available O estudo de geometria permite o desenvolvimento de habilidades e conhecimentos em relação a fatos e questões do cotidiano. Entretanto, os resultados em exames oficiais apontam uma grande defasagem no ensino e aprendizagem, principalmente em geometria espacial. Esta pesquisa está inserida no contexto do ensino e aprendizagem da geometria espacial na educação básica, em particular, à métrica dos sólidos geométricos. O objetivo do trabalho é apresentar uma sequência didática utilizando a modelagem matemática como alternativa metodológica, tendo em vista seu potencial para quebrar a dicotomia existente entre a matemática escolar e a matemática presente nas mais variadas situações do cotidiano. A sequência foi desenvolvida em duas escolas públicas junto a estudantes do ensino médio. Para validar a sequência proposta, a pesquisa foi fundamentada nos princípios da engenharia didática e a análise foi realizada utilizando-se registros em diário de campo, registros das atividades desenvolvidas pelos estudantes e aplicação de questionários e testes diagnósticos. Os resultados obtidos levaram a concluir que houve um avanço por parte dos estudantes na apreensão de conceitos de geometria plana e espacial.

  4. Modelagem, simulação e controle de robos flexiveis

    OpenAIRE

    Sergio Adriani David

    1996-01-01

    Resumo: Este estudo tem como objetivo principal a modelagem dinâmica de manipuladores flexíveis, e um estudo comparativo com robôs rígidos, tomando-se possível uma simulação deste modelo e o desenvolvimento de controladores eficientes. Neste trabalho desenvolve-se a modelagem dinâmica para um sistema que possui dois links flexíveis e duas juntas rotacionais, e para efeito de comparação trabalha-se também com uma estrutura rígida nas mesmas condições. A modelagem do sistema flexível exige o de...

  5. ESTUDO PROSPECTIVO RELATIVO À MODELAGEM DE CREDIT SCORE

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    Fillipe Silva Marinho Mota

    2016-03-01

    Full Text Available Empresas do ramo financeiro possuem uma grande necessidade de uma gestão financeira que permita resguardar a empresa quanto a perdas que possam ser evitadas. Para que essa gestão seja eficiente, deve-se adotar uma análise que leve em consideração critérios que permitam um amplo conhecimento do tomador de crédito. Porém, o processo de tomada de decisão sobre uma avaliação de risco de crédito é frequentemente de uma complexidade muito grande para o julgamento humano, devido à enorme gama de variáveis envolvidas no processo, o que dificulta a análise dos fatores atrelados e suas respectivas inter-relações. Esse artigo tem como finalidade realizar o levantamento de depósitos de patentes a respeito de modelagem de credit score utilizando sistemas computacionais.

  6. MODELAGEM FUZZY EM PARÂMETROS DE BEM-ESTAR HUMANO

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    Leonardo Schiassi

    2013-11-01

    Full Text Available Diante das preocupações com o ambiente de trabalho e consequentemente  com o bem-estar dos trabalhadores, objetivou-se com o presente trabalho avaliar a utilização da modelagem matemática fuzzy, na avaliação da salubridade de trabalhadores agrícolas, relacionada ao ambiente térmico e acústico. Para tanto, foram consideradas como variáveis de entrada  do sistema,  o índice de bulbo úmido e termômetro de globo (IBUTG, °C e o nível de ruído (dB(A,  tendo como variável de saída o índice de bem-estar humano (IBEH. O método de inferência utilizado foi o de Mandani e na defuzificação, utilizou-se o método do centro de gravidade. Foram utilizadas 25 regras para representar estes dados, sendo que para cada regra foi atribuído peso igual a 1. Os resultados indicam que o modelo matemático teve uma metodologia satisfatória, podendo auxiliar na tomada de decisões e análises cotidianas.Palavra-chave: salubridade, ambiente de trabalho, sistemas inteligentes.FUZZY MODELING IN HUMAN WELL-BEINGPARAMETERS ABSTRACTGiven the concerns about the work environment and consequently the well-being of workers, this study aimed to evaluate the use of fuzzy mathematical modeling in assessing of the farm workers health, related to thermal and acoustic environment. So, were considered as input variables of the system, the wet bulb globe temperature index (WBGT, °C and noise level (dB (A, and the output variable was the human well-being index (HWBI. The inference method used was the Mandani and in the defuzzification, we used the center of gravity method. Twenty five rules have been used to represent these data, and for each rule were assigned a weight equal 1. The results indicate that the mathematical model has a satisfactory methodology to assist in the making decision and daily analysis.Keywords: salubrity, work environment, intelligent systems. DOI: http://dx.doi.org/10.14583/2318-7670.v01n01a02

  7. Modelagem computacional de efeitos de distorções não lineares para guitarra elétrica

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    Thomaz Chaves A. Oliveira

    2013-11-01

    Full Text Available Este trabalho tem como objetivo revisar e simular alguns dos métodos de emulação computacional de efeitos de distorção de guitarras elétricas e de amplificadores valvulados que tem caracterizado os timbres deste instrumento nos últimos 50 anos. Recentemente, através da disseminação do processa- mento digital de sinais, estas distorções têm sido reproduzidas através de softwares embarcados ou na forma de pluggins em softwares de estúdio. Para a simulação de distorções, duas abordagens são basicamente utilizadas: caixa preta e caixa branca. Na primeira, waveshapers estáticos simplificam o sistema através de equações não-lineares que aproximam o comportamento do aparelho. Algumas das equações presentes na literatura são simuladas neste trabalho, com as respectivas respostas dos sistemas não-lineares no tempo e na frequência. Na abordagem caixa branca, os parâmetros dos circuitos são levados em conta e a modelagem pode ser realizada através de Wave Digital Filters ou de sistemas de equações diferenciais ordinárias em sua representação no espaço de estados, os quais são solucionados através de métodos numéricos. As simulações caixa branca apresentam re- sultados mais precisos, porém demandam maiores recursos computacionais, sendo necessário um compromisso entre precisão e eficiência para a simulação em tempo real.

  8. Atividades de modelagem matemática: que sentido os alunos podem lhe atribuir? Modelling Mathematics activities: what sense do students atribute to them?

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    Lourdes Maria Werle de Almeida

    2005-12-01

    Full Text Available Neste trabalho, abordamos a questão da atribuição de sentido às situações de ensino e aprendizagem e buscamos uma alternativa que permita ao aluno perceber a importância da matemática escolar. É com esta perspectiva que introduzimos as atividades de Modelagem Matemática e associamos o seu desenvolvimento em sala de aula com aspectos da Teoria da Atividade de Leontiev. O que o trabalho procura colocar é que duas idéias parecem convergir: por um lado, atribuir sentido e construir significados em Matemática demanda situações de ensino e aprendizagem que induzam relações entre a Matemática e a vida dos alunos; por outro lado, as atividades de Modelagem Matemática podem favorecer a aproximação da Matemática escolar com problemas extra-escolares vivenciados pelos alunos. Ao desenvolver uma proposta de atividades de Modelagem Matemática com alunos do Ensino Médio, a partir da análise das informações que coletamos, identificamos três condições que podem favorecer a atribuição de sentido e significado numa atividade de modelagem, levando em consideração as relações estabelecidas. A primeira condição refere-se a casos em que os alunos enfrentam um problema que tem para eles importância subjetiva, ou seja, quando o problema em estudo é de fato um problema para eles. A segunda condição refere-se a casos em que ocorre engajamento crítico e transferência de aprendizagem de uma situação de modelagem para outras situações vivenciadas pelos alunos. A terceira condição dáse quando os alunos procuram tornar relevante o uso da Matemática na abordagem de um problema.In this article, we approach the subject of the sense attribution to teaching and learning situations and we look for an alternative that allows the student to notice the importance of mathematics. It is with this perspective that we introduce mathematical modeling activities and we associate the students' development in classroom with aspects of the

  9. Modelagem conceitual para identificação de áreas com potencial para geração de energia por fonte renovável

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    Vivian Celestino

    2016-12-01

    Full Text Available O mundo enfrenta um desafio na busca de alternativas para atender a demanda de energia elétrica de forma sustentável e diminuir os efeitos dos Gases de Efeito Estufa. Uma maneira de minimizar estes efeitos e expandir o parque gerador é incrementar a produção com recurso a fontes renováveis. Mas para que, no momento de instalar um novo empreendimento, seja tomada uma decisão assertiva é necessário realizar a compilação de variáveis que sejam pertinentes ao tema e ao espaço geográfico. O objetivo deste artigo é apresentar uma modelagem conceitual por objetos (de acordo com o padrão OMT-G de forma a identificar áreas potenciais para gerar energia elétrica por fontes renováveis.

  10. MODELAGEM MATEMÁTICA E ETNOMATEMÁTICA NO CONTEXTO DA EDUCAÇÃO MATEMÁTICA: ASPECTOS FILOSÓFICOS E EPISTEMOLÓGICOS

    OpenAIRE

    TIAGO EMANUEL KLÜBER

    2007-01-01

    Esta dissertação voltou-se para duas tendências em Educação Matemática: 1) a Modelagem Matemática; e 2) a Etnomatemática. A escolha se justifica por serem, essas tendências, na atualidade, foco de discussão e de utilização no âmbito do ensino e da aprendizagem em Matemática e mais especificamente por estarem presentes no mundo-vida do pesquisador há cerca de quatro anos; da graduação à pós-graduação. A questão geradora da investigação foi: Quais os aspectos filosóficos e epistemológicos se...

  11. Modelagem matemática e a determinação de um novo método de cálculo do volume ventricular

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    José Sérgio Domingues

    2015-01-01

    Full Text Available Nesse trabalho, apresenta-se uma das aplicações da modelagem matemática no sistema cardiovascular, a sua utilização na estimação do volume ventricular esquerdo - um parâmetro fundamental no diagnóstico de doenças cardíacas. Para isso, prepara-se um molde de um ventrículo esquerdo bovino, seu volume real é determinado e, então, comparado com os resultados obtidos por métodos matemáticos médicos e com um novo método proposto, baseado na integral de revolução de uma função polinomial específica. Os resultados preliminares indicam que o método proposto é mais eficiente que os métodos médicos, com diferença de apenas 3,5% do volume real.Palavras-chave: Modelagem Matemática. Novo Método de Cálculo. Volume Ventricular. Mathematical modeling and the determination of a new method of the ventricular volume calculationABSTRACTIn this work, we presented one of the applications of mathematical modeling to the cardiovascular system, its use in the estimation of the left ventricular volume, which is a basic parameter in the diagnosis of heart disease. To do that, a mold of a bovine left ventricle is prepared, its real volume is determined and then it is compared to the results achieved by medical mathematical methods and with a new proposed method, based on the integral of revolution of a specific polynomial function. Preliminary results indicate that the proposed method is more efficient than medical methods, with a difference of only 3.5% of the actual volume.Keywords: Mathematical Modeling. New Calculation Method. Ventricular Volume.

  12. MODELAGEM MATEMÁTICA DOS IMPACTOS EXTRAMUROS DO RUÍDO PRODUZIDO POR UMA UNIVERSIDADE EM MOSSORÓ-RN

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    Carlos Enrique Jeronimo

    2015-04-01

    Full Text Available Neste trabalho, desenvolveu-se um estudo para quantificação do ruído produzido por uma universidade em Mossoró-RN, bem como, estimando-se os níveis de atenuação deste ruído com distanciamento, por meio da modelagem matemática. As medições do ruído ambiental foram realizadas por meio de um analisador de Ruído no período noturno no campus da instituição, variando de 0 a 100 m de distância em cada vértice. Aplicaram-se os modelos matemáticos para encontrar relações entre o nível de ruído e a distância de leitura dos dados. Após análise dos resultados, encontrou-se uma relação entre a atenuação pela distância em apenas dois vértices e que os níveis de ruídos estão acima do permitido. Foi possível a determinação do parâmetro K, para a atenuação dos níveis de ruído em dois vértices do prédio, obtendo-se valores de 5,94 e 8.44 dB(A.m-1 nos vértices 3 e 4, respectivamente. Por fim, espera-se que os resultados obtidos neste mapeamento acústico e modelagem de parâmetros matemáticos possam auxiliar no planejamento da implantação de empreendimentos e edificações futuras ao redor do campus da universidade, especialmente, pois é possível fazer a previsibilidade de certas zonas e orientar na indicação dos locais mais silenciosos e os locais mais ruidosos no seu entorno.

  13. Planejamento agregado da produção: modelagem e solução via planilha Excel & Solver

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    Oscar Salviano Silva Filho

    2009-07-01

    Full Text Available Este trabalho apresenta um aplicativo de apoio à tomada de decisão gerencial, baseado em planilha eletrônica e orientado à modelagem e solução de um problema de planejamento agregado da produção. Inicialmente, o problema a ser tratado é localizado dentro de um processo hierárquico de produção composto por três níveis de decisão. Em seguida é formulado um modelo matemático para representá-lo, o qual é baseado em programação linear. Este modelo possibilita a geração de planos agregados que podem ser utilizados pelo usuário na elaboração de cenários de produção. Por fim, um aplicativo interativo é proposto, onde se considera o uso da planilha Excel para entrada e saída de dados e o suplemento Solver como ferramenta de solução do modelo. As principais características deste aplicativo, no que diz respeito à formulação do problema de planejamento agregado, ao uso de interfaces gráficas para entrada e saída de dados e ao processo de decisão baseado em cenários, são discutidas e ilustradas através de um exemplo da literatura.

  14. Modelagem numérica em mapa temático: sítios florestais Numerical modelling in thematical map: forestal sites

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    Cláudia Weber Corseuil

    1998-12-01

    Full Text Available O presente trabalho tem por objetivo a utilização de programas de geoprocessamento e de tratamento de imagens, considerados de domínio público e de fácil operacionalidade, para modelagem numérica de um mapa temático. Esta modelagem é feita a partir da alimentação de um banco de dados digitais, para fins de planejamento e cadastro florestal. Mais especificamente, criou-se uma metodologia que utiliza a modelagem numérica para a visualização tridimensional de um plano de informação de sítios florestais georeferenciados, que permite o cruzamento (sobreposição com outros planos de informações, também georeferenciados, de interesse na área florestal. Foram utilizados os seguintes materiais: mapa de sítios naturais da Floresta Nacional de Passo Fundo, microcomputador, impressora, scanner de mesa, os softwares Idrisi 4.1 e Aldus PhotoStyler 2.0. A metodologia empregada baseou-se na digitalização, por varredura ótica, do mapa de sítios naturais existentes, sua edição de cores e georeferenciamento, para posterior modelagem numérica e visualização tridimensional dos diferentes sítios representados no mapa planimétrico da Floresta Nacional de Passo Fundo. Como resultado, obteve-se arquivos, que possibilitaram a identificação, através das diferentes alturas, dos sítios onde podem ser implantadas espécies mais adequadas às suas características naturais, demonstrando a viabilidade da aplicação da presente metodologia no planejamento florestal.The objective of this work was to utilize programs of geoprocessing and treatment of images, considerated to be well-knowm and easily operated, for numerical modelling of a thematical map. This modelling is carried out from feeding a digital base bank, for forest planning and cadaster. More specifically, a methodology that uses the numerical modelling for tridimensional visualization of a layer of geoindicated forest sites has been designed to permit the crossing (superposition

  15. Modelagem termoquímica da desinfecção por cloro gasoso

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    Luciano Nascimento

    2009-01-01

    Full Text Available Este trabalho apresenta o desenvolvimento de uma modelagem termoquímica da desinfecção por cloro gasoso. Levandoem consideração o sistema químico constituído pela adição de ácido fraco (Ácido Hipocloroso, HClO à água. Este modelo físicoquímicoproposto ao cloro gasoso mostra de forma sistemática, das reações envolvendo o cloro e as espécies do HClO + H2O bemcomo pH (potencial Hidrogeniônico e pCT (ponto de concentração total das espécies que, estão representados no diagramapCTxpH permitindo analisar a influência do ácido hipocloroso na reação de desinfecção e obter a fração do residual livre docomposto de cloro. Nesse modelo termodinâmico aplicado ao sistema 2 2(g H O+Cl + HClO+OCl- , com reações químicas eredox permitiram obter o valor da medida da energia livre padrão ( pe . Essas reações são analisadas a 25°C e os resultados sãosomente válidos para esta temperatura.Abstract This paper presents the development of athermochemical modeling of disinfection by chlorine gas. Takinginto account the chemical system consisting of the addition ofweak acid (hypochlorous acid, HClO to the water. Thisphysical-chemical model proposed shows the chlorine gas in asystematic way, the reactions involving chlorine andspecies 2 HClO + H O as well pH (hydrogen potential andpCT (point total concentration of species that are representedin the diagram pCTxpH allows to analyze the influence ofhypochlorous acid the reaction of disinfection and get thefraction of free residual chlorine compound. In thisthermodynamic model applied to the2 2(g H O+Cl + HClO+OCl- system, with chemicalreactions and redox possible to obtain the value of the measuredstandard free energy ( pe .These reactions are analyzed at 25°Cand the results are only valid for this temperature.

  16. Structural equation modeling in epidemiology Modelagem de equações estruturais em epidemiologia

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    Leila Denise Alves Ferreira Amorim

    2010-12-01

    Full Text Available Structural equation modeling (SEM is an important statistical tool for evaluating complex relations in several research areas. In epidemiology, the use and discussion of SEM have been limited thus far. This article presents basic principles and concepts in SEM, including an application using epidemiological data analysis from a study on the determinants of cognitive development in young children, considering constructs related to organization of the child's home environment, parenting style, and the child's health status. The relations between the constructs and cognitive development were measured. The results showed a positive association between psychosocial stimulus at home and cognitive development in young children. The article presents the contributions by SEM to epidemiology, highlighting the need for an a priori theoretical model for improving the study of epidemiological questions from a new perspective.A modelagem de equações estruturais (MEE é uma ferramenta estatística importante para avaliar relações complexas em várias áreas do conhecimento. Em Epidemiologia sua divulgação e uso são limitados. Este artigo apresenta princípios e conceitos básicos da MEE, com exemplo de aplicação na análise de dados epidemiológicos. A análise de dados é realizada em estudo que investiga determinantes do desenvolvimento cognitivo infantil, sendo definidos construtos relacionados à organização do ambiente da criança, ao seu status de saúde, e às práticas e estilo de vida dos pais. O impacto positivo da qualidade de estimulação psicossocial do ambiente doméstico sobre o índice de desempenho cognitivo (IDC esclarece que parte do efeito da estimulação sobre o IDC deve-se ao estilo parental de interação com a criança e às características físico-ambientais do contexto familiar. As potencialidades do uso da MEE em Epidemiologia são apresentadas, enfatizando-se a definição do modelo teórico e seu uso para

  17. Pesquisa em Modelagem Matemática no Brasil: a caminho de uma metacompreensão Research in mathematical modeling in Brazil: the way for a metacomprehension

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    Maria Aparecida Viggiani Bicudo

    2011-12-01

    Full Text Available Este estudo visou analisar as pesquisas em Modelagem Matemática na área da Educação Matemática no Brasil, investigando os trabalhos que adotam esse enfoque, publicados nos anais do 3º. Seminário Internacional de Pesquisa em Educação Matemática, em 2007. A postura assumida é a fenomenológica, e as interpretações são pautadas no movimento hermenêutico, que aponta para uma metacompreensão do tema. Os núcleos de ideias emergem dos invariantes articulados no processo de efetuar convergências, como, por exemplo, a pesquisa que se centra prioritariamente nos modos pelos quais o professor trabalha tópicos de conteúdos matemáticos com o recurso da modelagem. Esse invariante elucidativo pode indicar fragilidades quando os pesquisadores permanecem apenas no "como fazer"; pode também indicar possibilidades de compreender concepções e sua conversão em práticas desenvolvidas em sala de aula.The purpose of this study was to analyze researches in mathematical modeling in the area of Mathematics Education in Brazil. Is was investigated the mathematical modeling papers published in the Proceedings of the Third International Seminar for Research in Mathematics Education - Sipem (2007. The phenomenological point of view was adopted, basing the interpretations on the hermeneutic movement, aiming move toward a metacomprehension about this topic. The core ideas emerge from the invariants articulated in the process of making convergences as, for example, the research which the primary focus was on the modes through which teachers work some topics of mathematical program employing the modeling recourse. These invariants may indicate weaknesses when the researches remain only in the "how-to"; but they may also point out new possibilities for understanding conceptions and their conversion in classroom practices.

  18. Distorção do vento na área molhada por canhões hidráulicos: extensão da modelagem para aspersores médios Wind distortion in wetted area of gun sprinklers: extension of modeling to medium-sized sprinklers

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    Lessandro C. Faria

    2012-07-01

    Full Text Available A hipótese da existência de uma relação linear entre o alcance de canhões hidráulicos e a velocidade do vento, descrita no modelo de Richards & Weatherhead e amplamente utilizada na simulação da distribuição de água de canhões hidráulicos em condições de vento, foi avaliada neste trabalho para aspersores de tamanho médio. Na avaliação foram consideradas distâncias de alcance entre os aspersores modelos Agropolo/NY e Naan/5024 e os limites de sua área molhada, observadas em ensaios de campo, medidos nas direções: contrária, a favor e perpendicular ao vento. As retas ajustadas pelo método dos mínimos quadrados indicaram, em relação ao alcance do aspersor quando da ausência de vento, que para cada incremento de 1 m s-1 na velocidade do vento ocorreram: (i um decréscimo de 3,7% na direção contrária ao vento; (ii um decréscimo de 3,0% na direção perpendicular ao vento e (iii um acréscimo de 2,2% na mesma direção do vento, indicando que no intervalo de velocidades de vento consideradas (0 a 3 m s-1 a hipótese de uma relação linear entre o alcance de aspersores de tamanho médio e a velocidade do vento, foi mantida.The hypothesis of a linear relationship between wetted radius of gun sprinklers and wind velocity, as proposed by the Richards & Weatherhead model and widely used for simulation of water distribution by gun sprinklers under windy conditions, was evaluated in this study for medium-sized sprinklers. Distances from the sprinkler models used in this study (Agropolo/NY e Naan/5024 to the limit of the wetted area were determined through various field tests for upwind, downwind and crosswind conditions. Using the least square method it was found that, in relation to the no-wind radius, for each 1 m s-1 increase in wind velocity there was: (i a distance reduction of 3.7% for upwind edge; (ii a 3.0% decrease in distance for crosswind edge; and (iii a 2.2% increase in distance for downwind edge. These results

  19. Influência da função distribuição de quebra na modelagem e simulação do circuito de moagem de Carajás: parte 2 - simulação Influence of the distribution function on modeling and simulation of the Carajás grinding circuit: part 2 - simulation

    OpenAIRE

    Bianca Foggiatto; Homero Delboni Júnior

    2010-01-01

    Empregando-se o método descrito na Parte 1 desse artigo, foram realizadas caracterizações quanto à fragmentação dos principais tipos de minério de Carajás, provenientes das frentes de lavra das minas N4 e N5. A partir das características de tais minérios, foi empregado o modelo calibrado, para analisar, através de simulações, o desempenho do circuito de moagem de Carajás. Como resultado, foi possível verificar as variações de distribuição granulométrica do produto da moagem e do overflow dos ...

  20. Modelagem matemática dos perfis de temperatura do gás, do sólido e da parede do forno e dos perfis de concentração das principais espécies químicas presentes no interior do forno rotativo empregado na produção de clínquer

    Directory of Open Access Journals (Sweden)

    D. C. Q. Rodrigues

    Full Text Available Resumo O cimento é um dos materiais de construção mais utilizados no mundo, sendo o tipo mais comum conhecido como cimento Portland. O processo de fabricação do cimento envolve numerosas e complexas reações endotérmicas e exotérmicas que ocorrem a diferentes temperaturas, o que o torna não trivial. Dessa forma, há um grande interesse na otimização do processo de produção de cimento. A clinquerização é uma das principais etapas da fabricação de cimento e ocorre dentro de forno rotativo. Neste estudo, o processo de produção de clínquer é analisado em um forno rotativo de via seca que atua em contracorrente. Os principais fenômenos envolvidos na obtenção do clínquer são: evaporação da água livre residual da matéria-prima; decomposição do carbonato de magnésio; descarbonatação; formação da fase líquida composta por C3A e C4AF; formação do silicato dicálcico e silicato tricálcico. O principal objetivo deste estudo é a proposta de um modelo matemático que descreve de forma realística o perfil de temperatura e de concentração dos componentes do clínquer ao longo do forno rotativo, desenvolvido a partir de mudanças propostas a um trabalho da literatura. O modelo, composto por equações diferenciais parciais, foi adaptado e implementado em linguagem computacional no programa Mathcad. O modelo proposto foi satisfatório para a descrição do perfil de temperatura e concentração dos componentes do clínquer ao longo de um forno rotativo.

  1. Utilização da função pearson tipo V, Weibull e hiperbólica para modelagem da distribuição de diâmetros

    Directory of Open Access Journals (Sweden)

    Daniel Henrique Breda Binoti

    2013-09-01

    Full Text Available Objetivou-se neste estudo avaliar a eficiência da função log-Pearson tipo V para a descrição da estrutura diamétrica de povoamentos equiâneos de eucaliptos, bem como propor um modelo de distribuição diamétrica utilizando essa função. A modelagem realizada pela função log-Pearson tipo V foi comparada com a modelagem realizada com a função Weibull e hiperbólica. Para isso utilizou-se dados de parcelas permanentes de eucalipto, localizadas na região centro oeste do estado de Minas Gerais. A função Pearson tipo V foi testada em três diferentes configurações, com três e dois parâmetros, e tendo o parâmetro de locação substituído pelo diâmetro mínimo da parcela. A aderência das funções aos dados foi comprovada pela aplicação do teste Kolmogorov-Sminorv (K-S. Todos os ajustes apresentaram aderência aos dados pelo teste KS. As funções Weibull e hiperbólica apresentaram desempenho superior ao demonstrado pela função Pearson tipo V.

  2. Modelagem não-linear e análise dinâmica de sistemas de transmissão por correias pela formulação de coordenadas nodais absolutas

    OpenAIRE

    Henrique Leandro Silveira

    2015-01-01

    Sistemas de acionamento mecânico por correia serpentina são amplamente usados em aplicações automotivas e industriais para transmissão de torque e potência. Tais sistemas estão sujeitos a variações de tensão na correia devido à carga dinâmica nos acessórios, que levam ao desgaste prematuro e redução da vida útil dos componentes. A análise do comportamento dinâmico do conjunto é fundamental na fase de projeto e requer a modelagem não-linear do sistema incluindo polias, auto-tensionador, correi...

  3. Modelagem de desmatamento e emissões de gases de efeito estufa na região sob influência da rodovia Manaus-Porto Velho (BR-319 Modeling of deforestation and greenhouse-gas emissions in the area of influence of the Manaus-Porto Velho (BR-319 highway

    Directory of Open Access Journals (Sweden)

    Philip Martin Fearnside

    2009-06-01

    Full Text Available Uma simulação de desmatamento e emissões de gases de efeito estufa no período 2007-2050 foi executada para a Área sob Limitação Administrativa Provisória (ALAP ao longo da rota da Rodovia BR-319 (Manaus-Porto Velho; uma área de 153.995 km² que representa aproximadamente 10% do estado do Amazonas. O governo federal, por meio do Ministério dos Transportes, anunciou a sua intenção de reconstruir e pavimentar a Rodovia BR-319, que está abandonada desde 1988. A Secretaria de Estado do Meio Ambiente e Desenvolvimento Sustentável (SDS, do Governo do Estado do Amazonas, e o Ministério do Meio Ambiente (MMA têm planos para criar uma série de áreas protegidas dentro da ALAP. Nossa simulação compara cenários com e sem as reservas de proteção propostas. A reconstrução e a pavimentação da rodovia são presumidas a serem finalizadas em 2011, com a abertura de estradas laterais associadas em datas especificadas ao longo do período 2014-2024. A simulação de desmatamento acopla os programas computacionais DINAMICA e Vensim, e incorpora uma série de inovações para permitir que o total de desmatamento responda à melhoria do acesso por estradas, baseado em uma parametrização da relação entre desmatamento e expansão viária observada em imagens de satélite de uma área no noroeste de Rondônia, adjacente à ALAP. A expansão modelada de estradas endógenas não está limitada por uma presunção de um processo de desmatamento puramente "dirigido pela demanda". Esta suposição impediu que outros modelos de desmatamento na Amazônia, representassem o efeito sobre o desmatamento total causado por decisões relativas às reservas (visto que o desmatamento total especificado externamente, baseado na demanda, implica em um "vazamento" de 100% de qualquer benefício de criação de reservas. A mesma limitação se aplica ao efeito de estradas em modelos dirigidos por demanda. Os resultados obtidos pelo nosso modelo foram validados

  4. Crustal response to lithosphere evolution

    DEFF Research Database (Denmark)

    Artemieva, Irina; Thybo, Hans; Cherepanova, Yulia;

    2012-01-01

    We present a new model for the structure of the crust in an area which stretches from the North Atlantic region in the west to the Verkhoyansk Ridge in the east and encompasses Greenland, Iceland, most of Europe, West Siberian basin, and the Siberian cratons. The model is based on critically...... such as lower crust/lithospheric mantle delamination in the Variscan Europe and large-scale rifting across the entire West Siberian basin. The results are summarized in a series of maps of lateral variations in crustal properties, including the depth to the basement and to the Moho, average crustal velocity......, thicknesses of different crustal layers, and Pn seismic velocities....

  5. MODELAGEM E SIMULAÇÃO DO PROCESSO DE EXTRAÇÃO SUPERCRÍTICA DO ÓLEO ESSENCIAL DE ALECRIM

    Directory of Open Access Journals (Sweden)

    COELHO L. A. F

    1997-01-01

    Full Text Available Este trabalho objetiva a modelagem das curvas de extração características do processo de extração supercrítica do óleo essencial de alecrim (Rosmarinus officinallis l., obtidas nas isotermas de 310,15 e 320,15 K nas pressões de 100, 120, 140 e 160 bar, e interpretar os parâmetros e a função objetivo com conceitos estatísticos. Utilizou-se na resolução das equações do modelo o método das diferenças finitas, na obtenção dos parâmetros utilizou-se o método da máxima verossimilhança. Os resultados simulados indicam que o modelo utilizado constitui-se numa ferramenta capaz de representar as curvas de extração do processo de extração supercrítica.

  6. O ambiente e a modelagem matematica no ensino do calculo numerico

    OpenAIRE

    Nilson Sergio Peres Stahl

    2003-01-01

    Resumo: Este trabalho de pesquisa trata da utilização da Modelagem Matemática Aplicada a fenômenos Ambientais como meio de transformação de atitudes docentes e discentes no processo aprendizagem/ensino da disciplina de Cálculo Numérico. A pesquisa se desenvolveu numa instituição privada em que os alunos do quarto ano do curso de licenciatura em Matemática, em 1999, participaram como atores do processo. Foram aplicados 7 projetos enfocando o meio...

  7. Modelagem da bobina de Rogowski para medidas de pulsos de corrente elétrica /

    OpenAIRE

    2006-01-01

    Orientador: Vitoldo Swinka Filho Dissertaçăo (mestrado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduaçăo em Engenharia - PIPE. Defesa: Curitiba, 2006 Inclui bibliografia e anexos Resumo: O presente trabalho apresenta a modelagem de sensores de corrente baseados no efeito Rogowski. O objetivo é o desenvolvimento de um sensor para detectar pulsos de corrente de alta freqüęncia que percorrem um cabo isolado com polietileno reticulado XLPE de média tensăo...

  8. Modelagem da cinética de polimerização em lama de eteno

    OpenAIRE

    Adriano Giraldi Fisch

    2004-01-01

    A modelagem matemática é uma ferramenta que apresenta diversas vantagens no estudo de processos industriais como, por exemplo, entender e desenvolver tecnologias, avaliar o impacto de variáveis nas propriedades do produto, estudos de redução de custos de produção e de impacto ambiental. O objetivo deste trabalho é desenvolver e validar um modelo matemático para um reator de bancada de polimerização em lama de eteno, enfatizando o desenvolvimento do modelo cinético. O modelo do reator contempl...

  9. Modelagem no cárcere: Educação matemática para a paz. Modeling in prison: Mathematics education for peace

    Directory of Open Access Journals (Sweden)

    Gomes, Martha Joana Tedeschi

    2014-08-01

    Full Text Available Esta pesquisa teve como objetivo verificar a possibilidade de trabalhar a Modelagem Matemática junto aos alunos-detentos do Sistema Penitenciário do Paraná, Brasil, na cidade de Curitiba e região metropolitana. Propusemos uma investigação sustentada em pressupostos da pesquisa qualitativa numa perspectiva da pesquisa-ação. A pesquisa foi realizada com seis alunos-detentos matriculados no Centro Estadual de Educação Básica Para Jovens e Adultos (CEEBJA Dr. Mário Faraco, sendo este um estabelecimento de Ensino de Jovens e Adultos (EJA que atua dentro de todas as unidades penais de Curitiba e região metropolitana, e atende alunos-detentos, no que se refere à educação formal, do Departamento Penitenciário do Paraná. A utilização da Modelagem Matemática possibilitou aos alunos levantar dados e informações, formular, resolver e decidir questões de interesse, como também proporcionou o desenvolvimento da criatividade, do senso crítico, da elevação da autoestima, da intuição e da curiosidade, importantes no processo de ressocialização. As discussões geradas e o contato com dados e informações contribuíram para que os alunos compreendessem a necessidade do aprendizado escolar na sua realidade social e no seu cotidiano, visualizando a Matemática como um instrumento de análise e interpretação desta realidade. Dados desta pesquisa revelam que é possível, dentro de determinadas condições, trabalhar com a Modelagem Matemática junto aos alunos-detentos. The objective of this study was to investigate the potential for using mathematical modeling as a tool in the education of prisoners. The study group was composed of prisoners from the Penitentiary System of Parana State, Brazil, in the metropolitan area of Curitiba. Our research proposal was based on qualitative methodology from an action-research perspective. It was conducted with six prisoner-students enrolled in the State Center for Basic Education for Youth and

  10. USO DO MÉTODO HOMOGENEIZADO NA MODELAGEM DE VIGAS PAREDES DE CONCRETO ARMADO

    OpenAIRE

    Vieira, Agno Alves; de O. Miranda, Antônio Carlos

    2017-01-01

      Resumo. Esse trabalho apresenta simulações numéricas de vigas paredes de concreto armado utilizando o Método dos Elementos Finitos (MEF) onde é adotado o método homogeneizado ou “smeared” para discretização de estruturas de concreto armado. O método homogeneizado considera a armadura distribuída uniformemente no concreto, tal procedimento interpreta as regiões entre concreto e aço como um material novo com uma rigidez equivalente, tendo como principal vantagem o processo de discretização da...

  11. EQUACIONAMENTO E MODELAGEM DA BOBINA BIFILAR DE TESLA

    OpenAIRE

    Caio Marcelo de Marcelo de Miranda; Sérgio Francisco Pichorim

    2012-01-01

    A Biotelemetria apresenta-se como uma importante técnica que possui várias aplicações na área de Biomedicina e outras. A dimensão da unidade remota ou sensora constitui um grande desafio dentro desta área, sendo que na maioria dos casos,deseja-se uma unidade o menor possível. Desta maneira, sensores passivos são interessantes, pois possibilitam uma menor dimensão do dispositivo e não necessitam de uma fonte própria de energia, ou bateria, que pode causar danos ao indivíduo monitorado caso oco...

  12. Modelagem e Desenvolvimento de um Sistema Help-Desk para a Prefeitura Municipal de Lavras

    Directory of Open Access Journals (Sweden)

    Gabriel O. T. Cavalari

    2005-12-01

    Full Text Available Sistemas Help-Desk podem ser definidos como sendo um setor da empresa ao qual são endereçadas questões e onde são resolvidos problemas, tendo como principal característica a de ser um sistema facilitador de informações. A proposta deste trabalho é realizar a modelagem e o desenvolvimento de um sistema Help-Desk para a Prefeitura Municipal de Lavras. O presente trabalho se encontra organizado em cinco capítulos, onde são apresentados conceitos e análises de ferramentas Help-Desk. São discutidas também a arquitetura e as tecnologias deste tipo de sistema. É exposta ainda, uma descrição da funcionalidade do sistema implementado, bem com a sua modelagem. Finalmente, são apresentadas as principais conclusões referentes ao trabalho, assim como algumas propostas de trabalhos futuros e contribuições.

  13. Crustal thickness controlled by plate tectonics

    DEFF Research Database (Denmark)

    Artemieva, Irina M.; Meissner, Rolf

    2012-01-01

    /gabbro–eclogite phase transition in crustal evolution and the links between lithosphere recycling, mafic magmatism, and crustal underplating. We advocate that plate tectonics processes, togetherwith basalt/gabbro–eclogite transition, limit crustal thickness worldwide by providing effective mechanisms of crustal...... (lithosphere) recycling. The processes of crust–mantle interaction have created very dissimilar crustal styles in Europe, as seen by its seismic structure, crustal thickness, and average seismic velocities in the basement. Our special focus is on processes responsible for the formation of the thin crust...

  14. Índices topográficos aplicados à modelagem agrícola e ambiental Topographic indexes applied to agricultural and environmental modelling

    Directory of Open Access Journals (Sweden)

    Jean Paolo Gomes Minella

    2012-09-01

    Full Text Available Índices topográficos (IT obtidos computacionalmente a partir do modelo numérico de elevação do terreno (MNE têm sido incorporados em algoritmos computacionais aplicados na simulação de processos hidrológicos, erosivos e de transporte de poluentes. Por meio desses índices, zonas de acúmulo de umidade em uma bacia hidrográfica, por exemplo, podem ser previstas espacialmente através de IT, que levam em consideração efeitos de orientação de drenagem e declividade do terreno. Este trabalho tem como propósito o de apresentar uma revisão bibliográfica sobre esse tema e de demonstrar a aplicabilidade desses índices por meio de alguns exemplos, aplicada à modelagem agrícola e ambiental.Topographic indices obtained computationally from the numerical model of elevation have been incorporated into computer algorithms and used in hydrological simulating processes, erosion and pollutant transport. Through these indices, zones of water accumulation in a catchment, for example, can be predicted using topographic index that take into account the slope orientation and land slope. This study aims to present a review of the literature on this topic by means of some examples applied in agricultural and environmental modelling.

  15. EQUACIONAMENTO E MODELAGEM DA BOBINA BIFILAR DE TESLA

    Directory of Open Access Journals (Sweden)

    Caio Marcelo de Marcelo de Miranda

    2012-01-01

    Full Text Available A Biotelemetria apresenta-se como uma importante técnica que possui várias aplicações na área de Biomedicina e outras. A dimensão da unidade remota ou sensora constitui um grande desafio dentro desta área, sendo que na maioria dos casos,deseja-se uma unidade o menor possível. Desta maneira, sensores passivos são interessantes, pois possibilitam uma menor dimensão do dispositivo e não necessitam de uma fonte própria de energia, ou bateria, que pode causar danos ao indivíduo monitorado caso ocorra vazamento do seu conteúdo químico. Deste modo,o sensor indutivo autorressonante apresenta-se como uma boa solução, uma vez que este pode ser construído com apenas um componente, neste caso um indutor.Por apresentar pequenas dimensões, este tipo de sensor possui uma baixa capacitância parasita, o que torna a sua frequência de ressonância bastante alta. Neste caso, a bobina bifilar idealizada por Nikola Tesla pode constituir-se de uma solução, uma vez que a idéia de Tesla era de aumentar a capacitância intrínseca de suas bobinas. Portanto, um entendimento físico e devido equacionamento da bobina bifilar se faz necessário, uma vez que, até onde se sabe, este tipo de abordagem não existe na literatura.A partir de uma análise das tensões entre espiras adjacentes, foi desenvolvido neste trabalho um equacionamento da bobina bifilar de Tesla, possibilitando a determinação do aumento da capacitância interna e, consequente, redução na frequência de ressonância desta bobina. Um modelo elétrico equivalente da bobina foi também elaborado através desta análise. Isto possibilita o projeto de bobinas bifilares e predição dos parâmetros capacitância e frequência de autorressonância desta bobina. Testes foram realizados ao comparar a frequência de autorressonância calculada e medida para diversos números de espiras,comprovando a validade do modelo e das equações desenvolvidas.

  16. Crustal response to lithosphere evolution

    DEFF Research Database (Denmark)

    Artemieva, Irina; Thybo, Hans; Cherepanova, Yulia;

    2012-01-01

    assessed results from various seismic studies, including reflection and refraction profiles and receiver function studies. The region includes a nearly continuous age record for crustal evolution over ca. 3.6-3.8 billion years. We present an analysis of the crustal structure heterogeneity in relation...... to geological and tectono-thermal ages of the crust, and the tectonic setting. The results indicate that the Precambrian crust is as heterogeneous as Phanerozoic, and we do not observe any evidence for thickening from the Archean to Proterozoic crust. If anything, our analysis rather suggests the opposite trend...

  17. Crustal Ages of the Ocean Floor - Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Crustal Ages of the Ocean Floor Poster was created at NGDC using the Crustal Ages of the Ocean Floor database draped digitally over a relief of the ocean floor...

  18. Crustal structure beneath Eastern Greenland

    DEFF Research Database (Denmark)

    Reiche, Sönke; Thybo, H.; Kaip, G.

    2011-01-01

    these mountain belts is needed for assessing the isostatic balance of the crust and to gain insight into possible links between crustal composition, rifting history and present-day topography of the North Atlantic Region. However, the acquisition of geophysical data onshore Greenland is logistically complicated...

  19. Discussão sobre algumas contribuições da modelagem multinível para a investigação de desempenho no trabalho Discussing some multilevel models contributions to investigate performance at work

    Directory of Open Access Journals (Sweden)

    Francisco Antonio Coelho Junior

    2011-08-01

    Full Text Available O investimento no capital intelectual tornou-se o pilar norteador das ações de gerenciamento de pessoas. A literatura em comportamento organizacional investigada enfatiza o efeito de variáveis de contexto no desempenho dos indivíduos. Faz-se mister compreender como se dá o impacto dessas variáveis segundo seus níveis de análise. O presente artigo discute contribuições potenciais da modelagem multinível na investigação de desempenho no trabalho. Discute, ainda, a aplicação dessa modelagem para compreensão de fenômenos comumente investigados em comportamento organizacional. Tais contribuições poderão favorecer a estruturação de modelos preditivos que poderão melhor capturar o significado da inclusão de variáveis típicas do contexto laboral.Investing on intellectual capital became the guiding pillar for personnel management actions. The organizational behavior literature highlights the effect of contextual variables on the performance of individuals. The impact of these variables, which belong to different levels of analysis, needs a better comprehension. This paper discusses the potential multilevel modeling contributions for investigating predictors of that performance. In addition, it also discusses the application of this modeling for understanding usually studied organizational behavior. These contributions may favor structuring predictive models which may better grasp the meaning of the inclusion of diverse and complex levels of variables from the labor context.

  20. Modelagem de sensores e atuadores piezeletricos com aplicações em controle ativo de estruturas

    OpenAIRE

    1999-01-01

    Resumo: Apresenta-se uma metodologia para a modelagem analítica e numérica de estruturas, com elementos piezelétricos incorporados. Obtêm-se modelos analíticos de placa de Kirchhoff e Mindlin-Reissner e de viga de Euler-Bemoulli e Timoshenko, a partir das equações de movimento de casca, com a aplicação dos Postulados de Love e da escolha apropriada dos raios de curvaturas e dos Parâmetros de Lamé. Em seguida, são consideradas, nos modelos, as influências do elemento piezelétrico. O princípio ...

  1. Aplicação da modelagem matemática para estudo do crescimento populacional de Seropédica - RJ

    Directory of Open Access Journals (Sweden)

    Maurício de Carvalho

    2015-12-01

    Full Text Available A modelagem matemática deste trabalho se dá por meio da teoria de equações diferenciais, que é muito rica devido à sua aplicação em diversos problemas reais modelados e resolvidos nas áreas de engenharia, física e matemática, além de outras áreas. Primeiramente, adotou-se um modelo de crescimento clássico dessa teoria e cuja equação diferencial é linear e de primeira ordem. Posteriormente, um segundo modelo – mais preciso – foi também estudado, porém com utilização de uma equação diferencial não linear. A grande diferença entre os dois métodos, fora sua precisão, está em como calcular as constantes indeterminadas da solução de cada modelo. Na primeira, usa-se uma simples regressão linear com duas variáveis a serem determinadas, porém na outra, mesmo sendo possível aplicar igual método, usamos uma regressão não linear com três variáveis a serem determinadas. Com esta solução em mãos e com a utilização de dados fornecidos pelo Instituto Brasileiro de Geografia e Estatística (IBGE, é possível estimar a taxa de crescimento ou decrescimento, assim como o comportamento da população de Seropédica - RJ.

  2. Aplicação da modelagem matemática para estudo do crescimento populacional de Seropédica - RJ

    Directory of Open Access Journals (Sweden)

    Maurício de Carvalho

    2015-11-01

    Full Text Available A modelagem matemática deste trabalho se dá por meio da teoria de equações diferenciais, que é muito rica devido à sua aplicação em diversos problemas reais modelados e resolvidos nas áreas de engenharia, física e matemática, além de outras áreas. Primeiramente, adotou-se um modelo de crescimento clássico dessa teoria e cuja equação diferencial é linear e de primeira ordem. Posteriormente, um segundo modelo – mais preciso – foi também estudado, porém com utilização de uma equação diferencial não linear. A grande diferença entre os dois métodos, fora sua precisão, está em como calcular as constantes indeterminadas da solução de cada modelo. Na primeira, usa-se uma simples regressão linear com duas variáveis a serem determinadas, porém na outra, mesmo sendo possível aplicar igual método, usamos uma regressão não linear com três variáveis a serem determinadas. Com esta solução em mãos e com a utilização de dados fornecidos pelo Instituto Brasileiro de Geografia e Estatística (IBGE, é possível estimar a taxa de crescimento ou decrescimento, assim como o comportamento da população de Seropédica - RJ.

  3. Modelagem baseada em agentes para a simulação da dispersão de poluentes em cursos d'água

    Directory of Open Access Journals (Sweden)

    Fernando Mainardi Fan

    Full Text Available RESUMO A atividade antrópica em bacias hidrográficas frequentemente gera efluentes que poluem cursos d'água e tendem a gerar problemas ambientais diversos. Uma ferramenta muito útil para auxiliar a avaliação desses problemas é a modelagem matemática. Uma classe específica de modelos matemáticos com aplicações promissoras na área de recursos hídricos e controle da poluição são os modelos baseados em agentes. Neste trabalho se demonstrou como um modelo baseado em agentes pode ser desenvolvido e utilizado para a simulação de plumas de constituintes conservativos e não conservativos em cursos d'água. Foram apresentadas as suposições feitas para a representação dos fenômenos de advecção, dispersão e decaimento de primeira ordem no modelo. Posteriormente, foi feita uma comparação entre os resultados do modelo e a solução analítica unidimensional da equação de advecção-dispersão. Os resultados das comparações apontaram boa representação dos processos pelo modelo baseado em agentes e evidenciaram a importância da definição da discretização da massa dos constituintes lançados para essa classe de modelo. As soluções desenvolvidas e apresentadas mostram-se promissoras para a aplicação de modelos baseados em agentes na simulação de impactos de despejos em cursos d'água, bem como o modelo desenvolvido consiste atualmente em uma ferramenta educacional simples para o entendimento desses fenômenos.

  4. Crustal Seismic Anisotropy: Implications for Understanding Crustal Dynamics

    Science.gov (United States)

    Meltzer, A.; Christensen, N.; Okaya, D.

    2003-12-01

    The Nanga Parbat - Haramosh massif, in the core of the western syntaxis of the Himalaya, represents a unique exposure of mid-lower continental crust from beneath a collisional orogen. The exhumed core of the massif forms a large scale antiformal structure with axial orientation of N10E and associated lineation directed north-south with near-vertical dips. Laboratory measurements of seismic velocity on a suite of quartzofeldspathic gneisses from the massif show a relatively strong degree of anisotropy, up to 12.5% for compressional waves and up to 21% for shear waves. The degree of velocity anisotropy is primarily a function of mica content and rock fabric strength. The strong anisotropy measured in these rocks should be observable in recorded seismic field data and provides a means of mapping rock fabric at depth provided the rock fabric is coherent over appropriate length scales. An IRIS/PASSCAL deployment of 50 short period instruments recorded local and regional earthquakes to characterize seismicity and determine crustal structure beneath the massif as part of a multidisciplinary NSF Continental Dynamics study investigating the active tectonic processes responsible for exhumation and crustal reworking at Nanga Parbat. Microseismicity at Nanga Parbat is distributed along strike beneath the massif but exhibits a sharp drop-off laterally into adjacent terranes and with depth. This data set is ideal for studying crustal seismic anisotropy because the raypaths are restricted to the crust, sharp onsets in P and S allow for clear identification of arrivals, and source-receiver geometries sample a range of azimuths with respect to structure. Preliminary analysis indicates that the majority of local events exhibit some degree of splitting and that splitting patterns, while complicated, are coherent. While splitting delay normally increases with distance traveled through anisotropic material, the range of delay times can be due to heterogeneity in composition, lateral

  5. Crustal growth in subduction zones

    Science.gov (United States)

    Vogt, Katharina; Castro, Antonio; Gerya, Taras

    2015-04-01

    There is a broad interest in understanding the physical principles leading to arc magmatisim at active continental margins and different mechanisms have been proposed to account for the composition and evolution of the continental crust. It is widely accepted that water released from the subducting plate lowers the melting temperature of the overlying mantle allowing for "flux melting" of the hydrated mantle. However, relamination of subducted crustal material to the base of the continental crust has been recently suggested to account for the growth and composition of the continental crust. We use petrological-thermo-mechanical models of active subduction zones to demonstrate that subduction of crustal material to sublithospheric depth may result in the formation of a tectonic rock mélange composed of basalt, sediment and hydrated /serpentinized mantle. This rock mélange may evolve into a partially molten diapir at asthenospheric depth and rise through the mantle because of its intrinsic buoyancy prior to emplacement at crustal levels (relamination). This process can be episodic and long-lived, forming successive diapirs that represent multiple magma pulses. Recent laboratory experiments of Castro et al. (2013) have demonstrated that reactions between these crustal components (i.e. basalt and sediment) produce andesitic melt typical for rocks of the continental crust. However, melt derived from a composite diapir will inherit the geochemical characteristics of its source and show distinct temporal variations of radiogenic isotopes based on the proportions of basalt and sediment in the source (Vogt et al., 2013). Hence, partial melting of a composite diapir is expected to produce melt with a constant major element composition, but substantial changes in terms of radiogenic isotopes. However, crustal growth at active continental margins may also involve accretionary processes by which new material is added to the continental crust. Oceanic plateaus and other

  6. Estratégias de modelagem da extração de óleos essenciais por hidrodestilação e destilação a vapor

    Directory of Open Access Journals (Sweden)

    Nathália Viégas Busato

    2014-09-01

    Full Text Available Óleos essenciais são compostos químicos voláteis, característicos por sua fragrância e frequentes atividades antimicrobianas e antioxidantes. São extraídos dos tricomas de plantas aromáticas por meio do processo de destilação, seja ela utilizando apenas vapor (destilação por arraste a vapor, água e vapor ou somente água (hidrodestilação; ou ainda através do processamento mecânico dos pericarpos de frutos cítricos, extração com solventes orgânicos ou com fluido supercrítico, por exemplo. Em ambos os casos, a modelagem matemática é relevante: na destilação a vapor, com o objetivo de projetar plantas industriais com boas condições operacionais; na hidrodestilação, normalmente em escala laboratorial, com o objetivo de se obter uma melhor descrição do comportamento da extração e uma maior precisão na obtenção dos dados experimentais. Neste trabalho, são apresentados, analisados e discutidos quatro modelos do processo de extração.

  7. Analysis the 1978–2008 crustal and sub-crustal earthquake catalog of Vrancea region

    Directory of Open Access Journals (Sweden)

    L. Telesca

    2012-05-01

    Full Text Available The crustal and sub-crustal seismicity that occurred in the Vrancea area from 1978 to 2008 is investigated. Due to quarry blast contamination, the analysis of the crustal seismicity was restricted to events that occurred between 20 km and 60 km, considering sub-crustal events as all those that occurred at depths larger than 60 km. The completeness magnitude was estimated between 2.3 and 2.5 for the crustal seismicity and between 2.9 and 3.1 for the sub-crustal one. The Gutenberg-Richter b-values show clear differences between crustal and sub-crustal seismicity, with values around 0.9 and 1.3–1.4, respectively. The analysis performed in this study represents a preliminary issue for the seismic hazard assessment of surrounding regions like Moldova, for which the earthquakes generated in Vrancea represent an important threat.

  8. Mineração e modelagem de conceitos como praxis de gestão do conhecimento para inteligência competitiva

    Directory of Open Access Journals (Sweden)

    Ethel Airton Capuano

    2015-06-01

    Full Text Available Com o crescimento assintótico do volume de informação textual digital disponível sobre as organizações e acirramento da competição empresarial, métodos e técnicas de Engenharia do Conhecimento para recuperação e modelagem da informação relevante em repositórios abertos se tornam cada vez mais importantes para o desenvolvimento de processos de negócios. Com essa motivação, apresenta-se uma metodologia inovadora para mineração e modelagem conceitual de informação textual relevante para suporte a uma praxis de Gestão do Conhecimento apoiando o desenvolvimento de Inteligência Competitiva nas organizações. A metodologia, testada experimentalmente com simulação computacional, emprega recursos de Inteligência Artificial integrados em softwares de Processamento da Linguagem Natural, combinando, num construto epistemológico e tecnológico multidisciplinar de Ciência da Informação, conteúdos de várias áreas do conhecimento científico como Linguística, Filosofia, Matemática, Psicologia, Ciência da Computação e Engenharia. Os conceitos de autoinformação, de Shannon (1948, e da diferença que faz diferença (relativo à informação mais relevante, de Bateson (2002, Weick (1995 e Choo (2003, são centrais no processo de criação de significado, e o princípio da inteligência emergente, da Inteligência Artificial baseada na natureza, norteia o processo de apoio à construção do conhecimento proposto na tese. Os produtos resultantes da aplicação da metodologia são modelos ontológicos pictóricos com classes, objetos e relações povoados com sintagmas complexos extraídos dos textos digitais, com inspiração nas ideias de Gottschalg-Duque (2005. Esses modelos apresentam os conceitos e relações mais relevantes em contextos de negócio com objetivo de estimular, cognitivamente, os engenheiros do conhecimento nos seus processos mentais de criação de significados e construção do conhecimento útil para

  9. Crustal structure beneath Eastern Greenland

    DEFF Research Database (Denmark)

    Reiche, Sönke; Thybo, H.; Kaip, G.

    2011-01-01

    is recorded by 350 Reftek Texan receivers for 10 equidistant shot points along the profile. We use forward ray tracing modelling to construct a two-dimensional velocity model from the observed travel times. These results show the first images of the subsurface velocity structure beneath the Greenland ice...... these mountain belts is needed for assessing the isostatic balance of the crust and to gain insight into possible links between crustal composition, rifting history and present-day topography of the North Atlantic Region. However, the acquisition of geophysical data onshore Greenland is logistically complicated...

  10. A modelagem matemática como estratégia de ensino e aprendizagem do cálculo diferencial e integral nos cursos superiores de tecnologia

    OpenAIRE

    Ferruzzi, Elaine Cristina

    2003-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção. Neste trabalho investigamos a utilização da Modelagem Matemática como estratégia de ensino e aprendizagem da Matemática, especificamente, do Cálculo Diferencial e Integral. Levando em consideração um conjunto de argumentos que justificam a utilização da Modelagem Matemática em sala de aula, desenvolvemos e aplicamos uma proposta de ensino do conteúdo em ...

  11. Identificação de pontos de controle no ciclo de desenvolvimento de produto por meio de modelagem conceitual e mapeamento da informação

    Directory of Open Access Journals (Sweden)

    Leonardo Geraldo de Oliveira Gomes

    2014-06-01

    Full Text Available A complexidade do sistema produtivo e o conteúdo da informação relacionada a ele são os principais elementos deste trabalho. Traz como fio condutor a tentativa do melhor entendimento desta complexidade e da possibilidade do mapeamento e da representação da informação circulante em um sistema para a otimização de seu gerenciamento. O estudo ganha relevância ao se aproximar das atuais discussões e atitudes emergentes no tocante à sustentabilidade, principalmente nas áreas de desenvolvimento de produtos eco-orientados e no gerenciamento dos ciclos de vida. A proposta fundamenta-se na busca pela forma de representar a complexidade envolvida nos sistemas associados ao desenvolvimento do produto, de maneira a possibilitar a otimização da observação e do controle ao longo do seu ciclo de vida. Esta representação, necessariamente de alto nível, deve apresentar diagramas completos com possibilidades de evolução em detrimento das representações gráficas de baixa complexidade comumente utilizados, caracterizadas pelo reducionismo representativo. Procura-se o controle, o mais fino possível, da cadeia produtiva, objetivando maior organização, produtividade e conhecimento detalhado sobre um produto. O mapeamento da complexidade e a identificação dos pontos de controle propiciam um entendimento otimizado do ciclo de vida. Uma possibilidade de tratar a representação deste ciclo de maneira sistêmica, sem o perigo de uma redução em nível crítico da complexidade, está no uso da modelagem conceitual.

  12. Parametrização do transporte dispersivo de solutos em solos estruturados: heterogeneidade do meio, percurso de transporte e modelagem

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    S. L. Schlindwein

    1998-06-01

    Full Text Available O transporte dispersivo de solutos no solo é parametrizado por meio de equações difusivas e de modelos que partem da existência de uma relação de causalidade entre as características físicas do meio poroso, da sua condição de umidade e da manifestação macroscópica do processo nele ocorrente. A validade dessa proposição, como critério na elaboração de modelos dos processos que governam o transporte de solutos no solo, é discutida heuristicamente. Com base em índices obtidos a partir de uma análise de momentos de curvas de avanço (BTCs, é possível avaliar objetivamente o vínculo que as características do sistema estabelecem com o atendimento do pressuposto do equilíbrio local e, assim, com o sucesso ou não da adoção de uma abordagem de modelagem. Assim, BTCs assimétricas nada mais são do que a manifestação macroscópica de um processo incompleto, e o alcance de uma distribuição simétrica da concentração de solutos só pode ser garantido com a adoção de um "comprimento mínimo de mistura".

  13. Teleconnection mechanisms of northeast Brazil droughts: modeling and empirical evidence Mecanismos de teleconexões do nordeste do Brasil: modelagem numérica e evidência epirica

    Directory of Open Access Journals (Sweden)

    Fred Kucharski

    2008-06-01

    Full Text Available Targeted numerical modelling experimaents are conducted to complement the previous empirical diagnostics of circulation mechanisms leading from sea surface temperature (SST departures in the equatorial Pacific in January to anomalies in the March-April rainy season of Brazil's Nordeste. A weak interhemispheric northward directed SST gradient in the Atlantic favors a more southerly position of the hydrostatically controlled low pressure trough, embedded in which is the Intertropical Convergence Zone (ITCZ, which is the main rainbearing system for the Nordeste. In addition, anomalously warm waters in the equatorial Pacific in January tend to be followed by Nordeste drought. The underlying chain of causalities has been explored by empirical diagnostics and numerical modelling. During El Nino years, an upper-tropospheric wave train extends from the equatorial eastern Pacific to the tropical North Atlantic, affecting the patterns of upper-tropospheric topography and divergence, and hence of vertical motion over the Atlantic. This leads to a weaker meridional pressure gradient on the equatorward flank of the North Atlantic subtropical high, weaker North Atlantic tradewinds, an anomalously far northerly ITCZ position and thus Nordeste drought. The previous empirical diagnostics are overall supported by the modelling experiments.Experimentos específicos de modelagem numérica foram conduzidos para complementar diagnósticos empíricos realizados anteriormente dos mecanismos da circulação que relacionam anomalias na temperatura das águas superficiais do Pacífico equatorial em janeiro com as chuvas subsequentes em março-abril no Nordeste. Um gradiente térmico fraco (no sentido norte no Atlântico favorece a uma posição mais meridional do cavado de baixa pressão, controlado hidrostaticamente, dentro do qual se encontra a Zona de Convergência Inter-Tropical (ITCZ, que é a principal fonte de chuvas para o norte do Nordeste. Além disso,

  14. Modeling of soil penetration resistance using statistical analyses and artificial neural networks=Modelagem da resistência à penetração do solo usando análises estatísticas e redes neurais artificiais

    Directory of Open Access Journals (Sweden)

    Domingos Sárvio Magalhães Valente

    2012-04-01

    Full Text Available An important factor for the evaluation of an agricultural system’s sustainability is the monitoring of soil quality via its physical attributes. The physical attributes of soil, such as soil penetration resistance, can be used to monitor and evaluate the soil’s quality. Artificial Neural Networks (ANN have been employed to solve many problems in agriculture, and the use of this technique can be considered an alternative approach for predicting the penetration resistance produced by the soil’s basic properties, such as bulk density and water content. The aim of this work is to perform an analysis of the soil penetration resistance behavior measured from the cone index under different levels of bulk density and water content using statistical analyses, specifically regression analysis and ANN modeling. Both techniques show that soil penetration resistance is associated with soil bulk density and water content. The regression analysis presented a determination coefficient of 0.92 and an RMSE of 0.951, and the ANN modeling presented a determination coefficient of 0.98 and an RMSE of 0.084. The results show that the ANN modeling presented better results than the mathematical model obtained from regression analysis.Um importante fator para a avaliação da sustentabilidade de sistemas agrícolas é o monitoramento da qualidade do solo por meio de seus atritutos físicos. Logo, atributos físicos do solo, como resistência à penetração, podem ser empregados no monitoramento e na avaliação da qualidade do solo. Redes Neurais Artificiais (RNA tem sido empregadas na solução de vários problemas na agricultura, neste contexto, o uso desta técnica pode ser considerada uma abordagem alternativa para se predizer a resistência à penetração do solo a partir de suas propriedades básicas como densidade e teor de água. Portanto, o objetivo desse trabalho foi desenvolver um estudo do comportamento da resistência à penetração do solo, medida

  15. Modelagem do sistema de resfriamento por imersão de carcaças de frangos utilizando redes neurais artificiais - DOI: 10.4025/actascitechnol.v31i2.3358

    Directory of Open Access Journals (Sweden)

    Túlio Klassen

    2009-06-01

    Full Text Available A modelagem matemática fenomenológica do processo de resfriamento de carcaças de frango em chillers é complexa pela quantidade de variáveis que interferem no processo, além de tratar de um problema que envolve transferência de calor e de massa em regime transeniente. Uma alternativa para modelar este tipo de sistema é o emprego de Redes Neurais Artificiais. Neste trabalho foram investigadas diversas estruturas de redes com uma camada intermediária para modelar o processo de resfriamento de frangos. Foram testadas diferentes arquiteturas alterando os números de neurônios das camadas de entrada e intermediária. Foram utilizados dados coletados na empresa Sadia–Toledo, Estado do Paraná, para treinamento e validação das redes. As variáveis de entrada da rede eram: massa da carcaça, temperatura antes do resfriamento, temperatura da camisa de propilenoglicol, vazão de água em cada módulo, tempo de residência e temperatura da água de renovação; a temperatura do frango na saída do último tanque de resfriamento era a variável de saída. Os resultados obtidos mostraram que as redes representam apropriadamente o processo e que a rede com estrutura 8-24-1 foi a que melhor modelou o sistema investigado.

  16. Crustal thickness controlled by plate tectonics

    DEFF Research Database (Denmark)

    Artemieva, Irina M.; Meissner, Rolf

    2012-01-01

    The continental crust on Earth cannot be extracted directly from the mantle, and the primary crust extracted directly from an early magma ocean is not preserved on Earth. We review geophysical and geochemical aspects of global crust–mantle material exchange processes and examine the processes which...... magmatism. While both subduction and delamination recycle crustal material into the mantle, mafic magmatism transports mantle material upward and participates in growth of newoceanic and continental crusts and significant structural and chemicalmodification of the latter. We discuss the role of basalt....../gabbro–eclogite phase transition in crustal evolution and the links between lithosphere recycling, mafic magmatism, and crustal underplating. We advocate that plate tectonics processes, togetherwith basalt/gabbro–eclogite transition, limit crustal thickness worldwide by providing effective mechanisms of crustal...

  17. Modelagem do balanço hídrico em microbacia cultivada com plantio comercial de Eucalyptus grandis x urophylla no leste de Minas Gerais, Brasil

    Directory of Open Access Journals (Sweden)

    André Quintão Almeida

    2013-06-01

    Full Text Available No Brasil, o número de plantios comerciais de espécies florestais de crescimento rápido vem aumentando consideravelmente nas últimas décadas. Contudo, os possíveis impactos desse aumento sobre os recursos hídricos ainda são desconhecidos. O objetivo deste estudo foi realizar a modelagem do balanço hídrico em uma microbacia cultivada com plantio comercial de híbridos de Eucalyptus grandis x urophylla no Leste de Minas Gerais, Brasil. O trabalho foi realizado em uma microbacia experimental com área total de 40 ha durante o ano hidrológico, compreendido entre outubro de 2009 e setembro de 2010. A principal entrada de água no sistema via precipitação pluvial e os dados meteorológicos foram coletados por uma estação automática instalada no interior da área de estudo. As principais saídas foram estimadas pela equação modificada de Penman-Monteith e pela mensuração do deflúvio gerado na saída da bacia. Do total precipitado (1.123 mm durante o ano, 9% (106 mm retornaram à atmosfera via interceptação, 66% (740 mm via transpiração da cultura e 11% (119 mm pela evaporação do solo, que somados corresponderam à aproximadamente 86% da entrada de água na microbacia. Do deflúvio total gerado (~147 mm, apenas 4,29 mm (0,4% foram convertidos em escoamento superficial. Pode-se concluir que durante o ano hidrológico monitorado o balanço entre as principais entradas e as saídas de água na microbacia foi equalizado, não comprometendo a disponibilidade hídrica natural no curso d'água.

  18. Modelagem aplicada aos processos digestivos e metabólicos do suíno Applied modeling to the digestive and metabolic processes of the pig

    Directory of Open Access Journals (Sweden)

    Paulo Alberto Lovatto

    2001-08-01

    Full Text Available Esse estudo bibliográfico descreve os princípios mais importantes da modelagem aplicada aos processos digestivos e metabólicos do suíno. Essa forma de modelagem se apóia, sobretudo, em dois princípios matemáticos: a linearidade e a não-linearidade, sendo representada essencialmente pelas leis de ação de massa e de Michaelis-Menten, respectivamente. Os modelos foram classificados em explicativos, temporais e paramétricos. Os explicativos descrevem a forma de integração do conhecimento, podendo ser empíricos ou mecânicos. Os temporais definem a forma de integração do conhecimento em função do tempo, podendo ser estáticos ou dinâmicos. Os paramétricos associam os parâmetros temporais e explicativos, podendo ser deterministas ou estocásticos. Os modelos de crescimento foram integrados em níveis mais subjacentes que os de digestão. Os princípios metabólicos que envolvem o anabolismo e o catabolismo tissulares, bem como as vias de utilização dos nutrientes foram melhor estudados nos tecidos proteicos. A presente revisão mostra que os modelos de digestão e de metabolismo já desenvolvidos são dinâmicos, deterministas e empíricos. Na maioria dos casos, esses modelos representam parcialmente os fenômenos digestivos e metabólicos do suíno. Os novos modelos devem integrar as formas paramétricas estocásticas, o que os aproxima mais d realidade da cinética celular nos seres vivos, considerando os nutrientes desde a ingestão até sua utilização em nível molecular.This paper reviews the main principles and characterizes the evolution of modeling applied to the swine digestive and metabolic processes. Such modeling is largely based on two mathematical principles: linearity and non-linearity, which were represented essentially by action mass and Michaelis-Menten laws. The digestive and metabolic models were classified in explanatory, temporal and parametric. Explanatory ones describe the knowledge integration, and

  19. Análise da capacidade de reprodução de detalhes expressa por diferentes materiais de modelagem

    OpenAIRE

    Dias, Sérgio Candido; Ávila, Gisseli Bertozzi; Panzer,Heitor; Moisés, Marcos Ribeiro; Ribeiro, Jose Carlos Rabelo; Ribeiro, João Gustavo Rabelo; Agnelli, Jose Augusto M.

    2016-01-01

    Este estudo objetivou avaliar a capacidade de reprodução de detalhes presentes no molde por materiais de modelagem à base de gipsita Gesso pedra tipo IV, Durone, (Dentsply); Gesso pedra tipo IV, Fuji Rock EP, (GC); Gesso pedra tipo IV, Resinado Rock Plus, (Polidental); Gesso pedra tipo V, Durone, (Dentsply) epolímeros: resinas epóxicas Epoxiglass 1504, (Epoxiglass), resina epóxica Epoxiglass 1504 modificada com diatomita pura e silanizada. A resina e seu endurecedor foram carregados com diato...

  20. The Precambrian crustal structure of East Africa

    Science.gov (United States)

    Tugume, Fred Alex

    In this thesis, the Precambrian crustal structure of East African is investigated along with the crustal structures of three Cenozoic rift basins located in the western branch of the East African Rift System (EARS). In the first part of the thesis, P-wave receiver functions are modeled using the H-k method to obtain new insights about the bulk composition and thickness of the crust for Precambrian terrains throughout East Africa. The average crustal thickness for all but one of the terrains is between 37 and 39 km. An exception is the Ubendian terrain, which has an average crustal thickness 42 km. In all terrains, the average Poisson's ratio is similar, ranging from 0.25 to 0.26, indicating a bulk crustal composition that is felsic to intermediate. The main finding of this study is that crustal structure is similar across all terrains, which span more than 4.0 Ga of earth history. There is no discernable difference in the crustal thicknesses and Poisson's ratios between the Archean and Proterozoic terrains, or between the Proterozoic terrains, unlike the variability in Precambrian crustal structure found in many other continents. In the second part of the thesis, a joint inversion of Rayleigh wave phase and group velocities and receiver functions was used to investigate the shear wave velocity structure of the crust and uppermost mantle beneath the Precambrian terrains of East Africa. In comparison with other areas of similar age in southern and western Africa where the same joint inversion method has been applied, I find that while there is little difference in the mean shear wave velocities for the entire crust across all of the Precambrian terrains, and also few differences in the thickness of the crust, there exists substantial variability in lower crustal structure. This variability is reflected primarily in the thickness of the lower crustal layers with shear wave velocities ≥ 4.0 km/s. This variability is found both within terrains of the same age (i

  1. Modelagem por compartimentos para integrar e comunicar conhecimento em nutrição Compartmental modeling to integrate and communicate nutritional knowledge

    Directory of Open Access Journals (Sweden)

    Edgar O. Oviedo-Rondón

    2007-07-01

    Full Text Available Esta palestra tem o objetivo de apresentar e discutir metodologias utilizadas para modelar e integrar o conhecimento clássico em nutrição animal, e o produzido por novas ciências moleculares como nutrigenoma, proteoma e metaboloma. Estas ciências e a bioinformática estão ajudando a expandir rapidamente o conhecimento dos sistemas biológicos de interesse em nutrição animal. Na palestra discutirei como é importante dedicar parte de nosso tempo a integrar o conhecimento existente para esclarecer os problemas em pesquisa, utilizando as ferramentas mais adequadas para evitar duplicação de pesquisas, que causam desperdício de recursos humanos, econômicos, e de tempo. A modelagem matemática por compartimentos utilizando programas de computador pode ser a melhor maneira de acumular estas informações, integrar diferentes descobertas, e comunicar o conhecimento atual dos sistemas, e do metabolismo de nutrientes às novas gerações, e avançar na determinação mais adequada das exigências nutricionais.This presentation aims to present and discuss methodologies used to model and integrate classical knowledge in animal nutrition, and new discoveries produced by new molecular sciences like nutrigenomics, proteomics and metabolomics. These sciences and bioinformatics are helping to expand >very quickly the knowledge of the biological systems of interest in animal nutrition. I will discuss the importance of dedicating part of our efforts to integrate current knowledge to prioritize research problems using the most adequate tools. This will help to avoid research duplication that causes waste of valuable resources. Compartmental mathematical modeling using computer software could be one of the best ways to accumulate this information. It can help to integrate new discoveries, communicate the knowledge about animal systems and nutrient metabolism to a new generation of scientists, and advance to more accurate determination of nutrient

  2. Lower crustal mush generation and evolution

    Science.gov (United States)

    Karakas, Ozge; Bachmann, Olivier; Dufek, Josef; Wright, Heather; Mangan, Margaret

    2016-04-01

    Recent seismic, field, and petrologic studies on several active and fossil volcanic settings provide important constraints on the time, volume, and melt fraction of their lower crustal magma bodies. However, these studies provide an incomplete picture of the time and length scales involved during their thermal and compositional evolution. What has been lacking is a thermal model that explains the temporal evolution and state of the lower crustal magma bodies during their growth. Here we use a two-dimensional thermal model and quantify the time and length scales involved in the long-term thermal and compositional evolution of the lower crustal mush regions underlying the Salton Sea Geothermal Field (USA), Mt St Helens (USA), and the Ivrea-Verbano Zone (North Italy). Although a number of seismic, tectonic, petrologic, and field studies explained the tectonic and magmatic evolution of these regions, controversy remains on their lower crustal heat sources, melt fraction, and origin of erupted magmas. Our thermal modeling results suggest that given a geologically reasonable range of basalt fluxes (~10^-3 to 10^-4 km3/yr), a long-lived (>105 yr) crystalline mush is formed in the lower crust. The state of the lower crustal mush is strongly influenced by the magma flux, crustal thickness, and water content of intruded basalt, giving an average melt fraction of mush is mainly evolving through fractional crystallization of basalt with minor crustal assimilation in all regions, in agreement with isotopic studies. Quantification of the lower crustal mush regions is key to understanding the mass and heat balance in the crust, evolution of magma plumbing systems, and geothermal energy exploration.

  3. Aplicação de simuladores de eventos discretos no processo de modelagem de sistemas de operações de serviços Application of discrete event simulation in service industry modeling processes

    Directory of Open Access Journals (Sweden)

    Nelson Sakurada

    2009-03-01

    Full Text Available O presente trabalho discute a aplicação da simulação no estudo de sistemas de operação de serviços. Como objetos de estudo, são analisados tipos de serviços classificados como "Lojas de Serviços" e "Serviços de Massa". O trabalho inclui uma definição dos requisitos dos usuários para os softwares de simulação aplicáveis na modelagem e simulação de sistemas de operação de serviços, avalia a aplicação de dois simuladores disponíveis no mercado e analisa como o processo de modelagem varia de acordo com o tipo de serviço analisado. Ao final do trabalho, conclui-se que o desenvolvimento da tecnologia de simulação bem como os softwares de simulação em si, ainda precisam evoluir até incorporarem a capacidade de representar uma gama mais completa de elementos e relações envolvidos em processos de serviço, que não são presentes em aplicações convencionais da simulação no âmbito dos sistemas de manufatura.This work discusses the simulation modeling process applied in two types of service operation systems: Services Shops and Mass Services. An issue considered in this study is related to the requirements simulation software tools should fulfill in order to be applicable in the process of building service system simulation models. To analyze the differences in modeling process depending on the type of service considered, two simulators were selected. This study brought to light that the computer technology and simulation software tools still need to go through further developments so that their application can be extended to the modeling and simulation of a broader range of features comprised by service systems in general, which distinguish them from manufacturing systems.

  4. Modelagem molecular aplicada ao desenvolvimento de moléculas com atividade antioxidante visando ao uso cosmético Molecular modeling applied to the development of molecules with antioxidant activity for cosmetic use

    Directory of Open Access Journals (Sweden)

    Luciana Scotti

    2007-06-01

    Full Text Available Várias hipóteses e constantes estudos são realizados com o intuito de elucidar o envelhecimento cutâneo. Para prevenir e contornar este processo torna-se necessário reforçar nossas defesas naturais antioxidantes endógenas. Diversas substâncias antioxidantes exógenas, como vitaminas, extratos vegetais, dentre outras, são utilizadas pela Cosmetologia nos produtos antienvelhecimento. O objetivo deste artigo é apresentar de que forma a Modelagem Molecular pode ser uma ferramenta útil na pesquisa por novas substâncias cosméticas antioxidantes para combater o envelhecimento cutâneo.Some hypotheses and constants studies are made with intention to elucidate the aging process. To prevent and to attenuate the cutaneous aging it becomes necessary to strengthen our endogenous antioxidant natural defenses. Diverse exogenous antioxidant substances, as vitamins, vegetal extracts and others, have been used by the Cosmetology in antiaging products. The objective of this paper is to show how the Molecular Modeling can be an useful tool in the research for new antioxidant cosmetic substances to face the cutaneous aging.

  5. Aplicação das tecnologias de modelagem 3D conjugada às técnicas tradicionais para o registro das gravuras rupestres do rio Madeira, Rondônia, Brasil

    Directory of Open Access Journals (Sweden)

    Renato Kipnis

    Full Text Available Nos últimos anos, os estudos de arte rupestre no Brasil têm tido um grande avanço quanto à construção de modelos interpretativos deste tipo de vestígio arqueológico ainda pouco conhecido e explorado. Apesar dos desafios em localizar, registrar e preservá-las ao longo do vasto território brasileiro, um número pequeno, mas devotado, de pesquisadores tem documentado e estudado minuciosamente milhares de pinturas e gravuras rupestres em várias regiões do país por meio de técnicas tradicionais. Apresentamos aqui um estudo de caso realizado no rio Madeira, no estado de Rondônia, no qual conjugamos a metodologia tradicional com novas tecnologias para o registro de gravuras rupestres, o laser scanning terrestre e a fotogrametria de luz estruturada. Essas novas tecnologias proporcionam, entre outras vantagens, precisão, acuidade e rapidez na documentação de gravuras rupestres, assim como de seu entorno paisagístico. Em última instância, o trabalho do arqueólogo é gerar modelos interpretativos do registro arqueológico, baseados em uma documentação o mais fiel possível para que esses modelos possam ser testados e revistos. As tecnologias de modelagem 3D elevam nossa capacidade a um novo patamar metodológico.

  6. Crustal structure beneath northeast India inferred from receiver function modeling

    Science.gov (United States)

    Borah, Kajaljyoti; Bora, Dipok K.; Goyal, Ayush; Kumar, Raju

    2016-09-01

    We estimated crustal shear velocity structure beneath ten broadband seismic stations of northeast India, by using H-Vp/Vs stacking method and a non-linear direct search approach, Neighbourhood Algorithm (NA) technique followed by joint inversion of Rayleigh wave group velocity and receiver function, calculated from teleseismic earthquakes data. Results show significant variations of thickness, shear velocities (Vs) and Vp/Vs ratio in the crust of the study region. The inverted shear wave velocity models show crustal thickness variations of 32-36 km in Shillong Plateau (North), 36-40 in Assam Valley and ∼44 km in Lesser Himalaya (South). Average Vp/Vs ratio in Shillong Plateau is less (1.73-1.77) compared to Assam Valley and Lesser Himalaya (∼1.80). Average crustal shear velocity beneath the study region varies from 3.4 to 3.5 km/s. Sediment structure beneath Shillong Plateau and Assam Valley shows 1-2 km thick sediment layer with low Vs (2.5-2.9 km/s) and high Vp/Vs ratio (1.8-2.1), while it is observed to be of greater thickness (4 km) with similar Vs and high Vp/Vs (∼2.5) in RUP (Lesser Himalaya). Both Shillong Plateau and Assam Valley show thick upper and middle crust (10-20 km), and thin (4-9 km) lower crust. Average Vp/Vs ratio in Assam Valley and Shillong Plateau suggest that the crust is felsic-to-intermediate and intermediate-to-mafic beneath Shillong Plateau and Assam Valley, respectively. Results show that lower crust rocks beneath the Shillong Plateau and Assam Valley lies between mafic granulite and mafic garnet granulite.

  7. Análise do Espaço Aéreo Brasileiro por meio de simulação "fast time" - estudo de caso na área de controle terminal Recife.

    OpenAIRE

    Marcus Luiz Pogianelo

    2008-01-01

    O presente trabalho se propôs analisar por meio de simulação "fast time", diversos cenários na Área de Controle Terminal Recife, TMA-RF. A ferramenta computacional utilizada para tal foi o software RAMS PLUS, desenvolvido especialmente para avaliar a capacidade do espaço aéreo no EUROCONTROL e, adicionalmente, para mensurar a carga de trabalho dos controladores de tráfego aéreo. O escopo de análise inicialmente se direcionou para a modelagem dos cenários atualmente existentes na TMA-RF, e na ...

  8. Modelagem neural e análise estatística do processo de degradação de chorume por foto-Fenton solar

    Directory of Open Access Journals (Sweden)

    Alessandro Sampaio Cavalcanti

    2015-01-01

    Full Text Available O chorume em estudo é oriundo da cidade de Cachoeira Paulista-SP, apresentando baixa biodegradabilidade, devendo ser pré-tratado por um processo oxidativo. O objetivo desse trabalho foi obter um modelo neural em conjunto com análises estatísticas que representassem a degradação do chorume in natura pelo processo foto-Fenton solar, em função da redução da demanda química de oxigênio (DQO. Redes neurais apresentam-se como uma alternativa para a modelagem de processos não-lineares como os processos oxidativos avançados, que envolvem um grande número de variáveis de controle e complexas reações envolvidas. O processo fotocatalítico foi otimizado por um planejamento fatorial fracionado (24-1 em duplicata e triplicata no ponto central, sendo as variáveis de entrada em três níveis: pH, radiação solar e concentrações de H2O2 e Fe2+. O sistema de tratamento em escala de bancada utilizou um reator batelada, com volume constante (3 L de chorume, vazão 13 L min-1 e 2-h de reação. A otimização do processo mostrou que o efeito individual de cada variável de entrada deve operar em seu maior nível, sendo que a variável Fe2+ teve significância na forma combinada. A redução percentual de DQO do melhor experimento foi de 88,7 %, sendo esta avaliada em um custo de R$ 126,67 m-3 de chorume. O processo de degradação foi modelado via redes neurais feedforward backpropagation, com coeficientes de correlação linear para os conjuntos de treinamento, validação e teste acima de 0,9, indicando alta predição e generalização do modelo neural proposto. A rede neural proposta mapeou um espaço multidimensional da forma ∆DQO = f(t, pH,[H O ],P ,[Fe ] 2+ 2 2 UV .

  9. Modelagem do crescimento populacional do rebanho bovino brasileiro Modeling the growth of Brazilian cattle population

    Directory of Open Access Journals (Sweden)

    Alfredo Ribeiro de Freitas

    2005-12-01

    Full Text Available Considerando-se o número efetivo de animais e a taxa de abate do rebanho bovino brasileiro no período de 1983 a 2000, estimou-se o crescimento dessa população utilizando-se o modelo de Richards, ajustado pela técnica de verossimilhança profile. O modelo se mostrou adequado para descrever o crescimento da população brasileira de bovinos, pois as superestimavas e ou subestimavas dos valores se situaram entre 1 e 2,5%. A partir da modelagem por cadeia de Markov, foram calculados a probabilidade de o rebanho atingir 200 milhões de animais até o ano de 2015, em função da taxa de abate, e o tempo esperado para se atingir este tamanho populacional, em função da taxa de abate. A probabilidade de o rebanho atingir 200 milhões de animais até o ano de 2015, a uma taxa de abate de aproximadamente 17%, é 0,7. Com taxa de abate anual de 16%, o rebanho atingirá esse tamanho no período de 11 anos e, com taxa de abate de 18%, em 20 anos.The growth of the Brazilian bovine cattle population was evaluated using the effective number of animals and the annual slaughter rate from 1983 to 2000. The Richards model was fitted with the profile likelihood technique. Two population parameters were calculated by Markov chain modeling: a the probability of the cattle population to reach 200 million of animals in 2015 as a function of the slaughter rate; b the time to reach this size, considering different annual slaughter rates. The Richards model was adequate to estimate the Brazilian cattle population growth since overestimated and/or underestimated values ranged between one and 2.5%. The probability of the Brazilian herd to reach 200 millions animals in 2015 for an annual slaughter rate of approximately 17% is 0.7 and the expected time to reach 200 million animals for annual slaughter rates of 16% and 18% was 11 and 20 years respectively.

  10. On crustal movement in Mt. Qomolangma area

    Institute of Scientific and Technical Information of China (English)

    陈俊勇; 王泽民; 庞尚益; 张骥; 张全德

    2002-01-01

    Mt. Qomolangma lies in the collision zone between the fringe of Eurasia plate and Indian plate. The crustal movement there is still very active so far. In the past three decades China carried out five geodetic campaigns in Mt. Qomolangma and its north vicinal area, independently or cooperatively with other countries, including triangulation, leveling, GPS positioning, atmospheric, astronomical and gravity measurements. On the basis of the observation results achieved in the campaigns the crustal movements in the area were studied and explored. A non-stationary phenomenon both in time and space of the crustal vertical movement in the area is found. There seems to be some relevance between the phenomenon of non-stationary in time and seismic episode in China. The phenomenon of non-stationary in space is possibly relevant to the no-homo- geneity of crustal medium and non-uniform absorption of terrestrial stress. The horizontal crustal movement in the area is in the direction of NEE at a speed of 6—7 cm per year, and the trend of strike slip movement is manifested evidently in the collision fringe of Indian plate and Qinghai-Xizang block.

  11. Numerical modeling of compositional variation in petroleum secondary migration; Modelagem numerica da variacao composicional na migracao secundaria de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Marcia Santos de Almeida

    1999-07-01

    The secondary migration of petroleum is analyzed in this study from a compositional perspective, with phase separation, using a numerical simulator. The modeling is focused on two different geologic scenarios, where migration occurs along the formation rocks or through a fault. Each scenario is initialized with a single-phase hydrocarbon bank, with mixtures defined in the oil and gas zones and in the proximity of the critical point in their respective phase envelopes. These fluids are obtained using a PVT simulator based on four samples (Black-oil, volatile oil and two retrograde gases) which generate various hydrocarbon mixtures from which some are selected to meet the pressure and temperature conditions established for the models. The results obtained indicate that the phase separation process, the migration and the oil and gas differences are adequately represented, and that this type of modeling may be used to explain complex fluid distribution in a single accumulation or petroleum province. However, the analysis of post-filling processes indicate the need for the inclusion of a diffusive term in the flow equations used in the simulator and for a higher precision in the fluid properties outputs. (author)

  12. Use of 3D seismic in the reservoir modeling; Uso da sismica 3D na modelagem de reservatorios

    Energy Technology Data Exchange (ETDEWEB)

    Thedy, Edgar A.; Malagutti, Silvia R.; Paraizo, Paulo L.B. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    1999-07-01

    Characterization using seismic data. Cherne Field, off-shore Campos Basin, Brazil, was the target of a multidisciplinary geologic modelling project. The main reservoir is composed of albo-cenomanian turbidities of Macae Formation in a structural area, separated in blocks by salt tectonics. After structural interpretation, a stratigraphic inversion had made. Mapping of internal reservoir geometry was performed with the resulting impedance data. Various depositional cycles related with sea level variations were interpreted. Each cycle is represented by lowstand porous sandstone in low impedance reflectors, and transgressive deposits of high impedance (marls and interbedded fine sandstones). The first cycle was deposited in a restricted condition, resulting in a continuous reflector, onto a carbonatic platform. The next cycles were conditioned by the area creation due to the sea level variations and halocynesis, giving a progradational character to the horizons. The last event is a radioactive mark that indicates the basin flooding. The stratigraphic zoning of the reservoir was made with seismic background. The interwell correlation was guided by the horizons interpreted. Five events were identified. The attributes extraction was made according to the volumetric mean value in each seismic unit. A linear correlation between seismic attributes and electrofacies frequency was found for most of the zones. A permoporous cube was generated with geostatistical tools using attribute data as a secondary variable ready for usage in the numerical reservoir simulator. (author)

  13. Metodos matematicos em modelagem e simulação do craqueamento termico do 1,2-Dicloroetano

    OpenAIRE

    Helianildes Silva Ferreira

    2003-01-01

    Resumo: A simulação de processos químicos é de fundamental importância para a melhoria e otimização das unidades industriais existentes. A modelagem do processo envolve a descrição fenomenológica do mesmo e a resolução das equações obtidas através de métodos matemáticos adequados. Esta é a simulação dita convencional. Outra forma de abordagem do problema pode ser através da utilização de ferramentas computacionais que sejam capazes de "aprender' o comportamento do processo através dos seus da...

  14. CONTRIBUIÇÃO DA MODELAGEM BIM PARA PROJETOS COMPLEXOS - UM ESTUDO COM PROJETOS DE PARQUES TECNOLÓGICOS

    Directory of Open Access Journals (Sweden)

    Claudio Alcides Jacoski

    2015-02-01

    Full Text Available A economia do conhecimento como vem sendo chamada, trouxe consigo um nível de competitividade jamais visto pela sociedade. Da mesma forma a inovação passou a se constituir como um dos principais instrumentos de desenvolvimento econômico. Para dar condições a um ambiente propício para a inovação é que a sociedade, utilizando o conceito da Tríplice Hélice, buscou desenvolver espaços integrados que contemplam a associação do setor privado, com o setor público e a presença de Universidades, estruturando o que se passou a chamar de Parques Tecnológicos. Estes espaços contemplam uma quantidade de usos extremamente diversificados, o que se pode conceituar de projetos complexos, que demandam uma integração entre ambientes de inovação, criação, produção, industrialização, lazer, convivência, e até mais que isso. No modelo de projetação usual, a dificuldade de integração entre as diversas necessidades do projeto poderiam ser extremamente complicadas. Ocorre que com o uso da modelagem em projetos, ou seja o uso de BIM (Building Information Modeling, há prerrogativas que anteriormente não existiam e que poderão ser suplantadas com o uso da tecnologia. O estudo apresentado faz a análise no uso da modelagem BIM em projetos de Parques Tecnológicos, usando como caso de estudo os 11 Centros de Inovação do Estado de Santa Catarina.   PALAVRAS CHAVE: Parques Tecnológicos, BIM, projetos complexos.

  15. Trace element differences between Archean, Proterozoic and Phanerozoic crustal components: Implications for crustal growth processes

    Science.gov (United States)

    Tarney, J.; Wyborn, L. E. A.; Sheraton, J. W.; Wyborn, D.

    1988-01-01

    Critical to models for continental crust growth and recycling are the processes through which crustal growth takes place. In particular, it is important to know whether these processes have changed fundamentally with time in response to the earth's thermal evolution, and whether the crustal compositions generated are compatible with crustal remobilization, crustal recycling, or represent primary additions. There are some significant and consistent differences in the major and trace element compositions of crustal components with time which have important implications for crustal growth processes. These will be illustrated with reference to Archean rocks from a number of shield areas, Proterozoic granitoids from Australia and elsewhere, Palaeozoic granitoids from Australia and Scotland, and Mesozoic - recent granitoids from present continental margin belts. Surprisingly some rather simple and consistent patterns energy using this technique. There are then significant differences in compositions of granitoid crustal additions throughout geological time, with a particular type of granitoid apparently dominating a particular time period. This implies that the tectonic processes giving rise to granite generation have changed in response to the earth's thermal evolution.

  16. Reports on crustal movements and deformations

    Science.gov (United States)

    Cohen, S. C.; Peck, T.

    1981-01-01

    Studies of tectonic plate motions, regional crustal deformations, strain accumulation and release, deformations associated with earthquakes and fault motion, and micro-plate motion, were collected and are summarized. To a limited extent, papers dealing with global models of current plate motions and crustal stress are included. The data base is restricted to articles appearing in reveiwed technical journals during the years 1970-1980. The major journals searched include: Journal of Geophysical Research (solid earth), Tectonophysics, Bulletin of the Seismological Society of America, Geological Society of America Bulletin, Geophysical Journal of the Royal Astronomical Society, and the Journal of Geology.

  17. Crustal structure of the Khartoum Basin, Sudan

    CSIR Research Space (South Africa)

    El Tahir, N

    2013-05-01

    Full Text Available Tectonophysics Vol. 593 (2013) 151–160 Crustal structure of the Khartoum Basin, Sudan Nada El Tahir a,b,*, Andrew Nyblade a,b, Jordi Julià c, Raymond Durrheim a,d a School of Geosciences, The University of the Witwatersrand, Johannesburg, South... Centre for Mining Innovation, Johannesburg, South Africa *Corresponding author: nada_ahmed99@hotmail.com Abstract The crustal structure of the northern part of the Khartoum Basin has been investigated using data from 3 permanent seismic stations...

  18. Crustal accretion at high temperature spreading centres: Rheological control of crustal thickness

    Science.gov (United States)

    Schmeling, Harro

    2010-12-01

    New determinations of lateral crustal thickness variations at anomalous oceanic spreading centres such as Iceland have shown that the crust may be thinner at the ridge axis above the plume thickening towards the sides ( Bjarnason and Schmeling, 2009). To understand this behaviour crustal accretion models have been carried out solving the conservation equations of mass, momentum and energy with melting, melt extraction, and feedback of extracted material as newly formed crust for an extending lithosphere system underlain by a hot mantle plume. The dynamics of rifting are thermally and rheologically controlled by the feedback due to accreted new crust. Four accretional modes with characteristic crustal thickness variations are identified depending on the width of the volcanic emplacement zone, the accretional heating rate, which can be associated with the thickness of the surface layer in which magmatic emplacement takes place, and the spreading rate. Mode 1: zero crustal thickness at the spreading axis develops for cool accretion and a wide emplacement zone. Mode 2: strongly or moderately crustal thickening away from the axis develops in case of warm (deep reaching) accretion and wide emplacement zones. Mode 3: nearly constant crustal thickness develops in case of warm (deep reaching) accretion but narrow emplacement zones. Dynamic topography of mode 3 shows only a weak or no regional minimum at all near the axis. Modes 2 or 3 may be identified with the situation in Iceland. Mode 4: a stagnating central crustal block evolves for cool accretion and narrow emplacement. This mode disappears for increasing spreading rates. No accretional mode with maximum crustal thickness above the plume at the rift axis has been found. The absence of mode 1 accretion (with zero crust at ridge axis) on earth may be an indication that in general crustal accretion is not cold (and shallow). The model is also applied to other hotspot-ridge settings (Azores, Galapagos) and suggests modes 2

  19. Verossimilhança na seleção de modelos para predição espacial

    Directory of Open Access Journals (Sweden)

    Cristiano Nunes Nesi

    2013-04-01

    Full Text Available Na modelagem estatística da variabilidade espacial, estimam-se os parâmetros da dependência espacial, que são utilizados na interpolação de valores em locais não amostrados. Para tal, o processo de modelagem deve ser realizado com critérios estatísticos que garantam predições confiáveis e representem a real variabilidade local. Este trabalho avaliou diferentes formulações do modelo geoestatístico gaussiano para reconstituir a superfície que representa o fósforo (P na área, a partir de medições dos teores de P em 48 parcelas experimentais localizadas em Xanxerê, SC, destacando o método utilizado nas análises. A combinação da presença de covariáveis no modelo e a necessidade de transformação para normalidade dos dados definiram quatro alternativas para modelagem. Utilizou-se a função de correlação de Matèrn, avaliada nos valores 0,5; 1,5; e 2,5 para parâmetro de suavidade. Os modelos foram comparados pelo valor maximizado do logaritmo da função de verossimilhança e também por validação cruzada. O modelo selecionado foi o que incorporou a variável resposta transformada, as coordenadas da área como covariáveis e o valor 0,5 para o parâmetro de suavidade. As medidas de validação cruzada pouco acrescentaram aos resultados de comparação por verossimilhança, que evidenciaram que na modelagem geoestatística, o cuidado com observações globais ou locais atípicas, além da seleção com base em diferentes modelos, deve ser o foco para obter resultados compatíveis com a realidade.

  20. Modelagem de Equações Estruturais Baseada em Covariância (CB-SEM com o AMOS: Orientações sobre a sua aplicação como uma Ferramenta de Pesquisa de Marketing

    Directory of Open Access Journals (Sweden)

    Joseph F. Hair Jr.

    2014-05-01

    Full Text Available A modelagem de equações estruturais (Structural Equation Modeling -SEM é cada vez mais usada como um método para a conceituação e desenvolvimento de aspectos teóricos nas ciências sociais aplicadas, em particular na área de marketing, pois mais e mais há a necessidade de avaliar vários constructos e relações latentes complexas. Também, constructos de segunda ordem podem ser modelados fornecendo uma melhor compreensão teórica de relações com boa parcimônia. Modelagens do tipo SEM são, em particular, bem adequadas para investigar as relações complexas entre os vários constructos. Os dois métodos analíticos SEM mais prevalentes são os baseados em covariância SEM (CB-SEM e os baseados em variância SEM (PLS-SEM. Embora cada técnica tenha suas vantagens e limitações, neste artigo vamos nos concentrar no CB-SEM com o AMOS para ilustrar sua aplicação na análise das relações entre orientação para o cliente, a orientação para os funcionários e desempenho da empresa. Também será demonstrado como constructos de segunda ordem são úteis para modelar os componentes de pró-atividade e responsividade dessas relações. DOI: 10.5585/remark.v13i2.2718

  1. Modelagem hidrológica em microbacia hidrográfica parte II: teste do modelo HidroBacia Hydrologic modeling of a small watershed part II: HidroBacia model test

    Directory of Open Access Journals (Sweden)

    Sidney S. Zanetti

    2009-08-01

    Full Text Available Este trabalho consistiu na modelagem hidrológica de uma microbacia hidrográfica utilizando-se o modelo HidroBacia, no qual o processo de infiltração da água no solo é representado por meio da equação de Green-Ampt modificada por Mein e Larson. Obtiveram-se, dentre os parâmetros desta equação, o potencial matricial na frente de umedecimento, a condutividade hidráulica e a umidade do solo na zona de transmissão, através de diversos métodos apresentados na literatura; desta forma, foram preparadas e testadas 36 combinações de dados de entrada, visando identificar as que apresentam melhor desempenho nas simulações do hidrograma de escoamento superficial com o modelo e se selecionaram, dentre os eventos de chuva-vazão registrados na microbacia, os 14 mais relevantes para realização das simulações. Das 36 combinações de dados de entrada testadas, seis apresentaram melhor desempenho na estimação dos hidrogramas. O modelo HidroBacia ainda necessita de aprimoramentos, juntamente com análises de sensibilidade, com vista a identificar possíveis incompatibilidades entre os dados de entrada e os respectivos resultados das simulações, uma vez que o modelo apresentou resultados incoerentes em determinadas situações.This work consisted of the hydrologic modeling of a small watershed using the HidroBacia model. The soil water infiltration process is represented by means of the Green-Ampt equation, modified by Mein and Larson, in this model. Among the equation parameters, matric potential in the wetting front, hydraulic conductivity and soil moisture in the "field saturation" were obtained using different methods based on previous scientific literature. Thirty six input data combinations were tested in order to identify those that showed better performance on the runoff hydrograph simulations with the model. Between the rainfall-runoff events registered on watershed, the most relevant (14 of them were selected to perform the

  2. Avaliação do modelo J2000/JAMS para modelagem hidrológica em bacias hidrográficas brasileiras

    Directory of Open Access Journals (Sweden)

    Aline Ribeiro Machado

    Full Text Available RESUMO: A gestão de recursos hídricos no Brasil é prejudicada pela carência de informações hidrológicas, que pode ser suprida pelos modelos hidrológicos que simulam o comportamento das bacias hidrográficas. Entretanto, muitos modelos não geram bons resultados quando executados fora da área de estudo onde foram criados. Por isso, devido à sua adaptabilidade, o modelo J2000 inserido no framework Jena Adaptable Modelling System (JAMS foi avaliado para simulação de duas bacias hidrográficas inseridas na zona de afloramento do Sistema Aquífero Guarani, a Bacia Hidrográfica do Ribeirão da Onça (BRO e a Microbacia do Córrego Cavalheiro (BCC, nos municípios de Brotas e Analândia, respectivamente, no estado de São Paulo. O framework JAMS apresentou-se como um sistema simplificado para uso, flexível diante das adaptações necessárias para compatibilização com as características climatológicas e hidrológicas das áreas de estudo. O modelo J2000 mostrou-se eficiente na predição da resposta hidrológica das bacias hidrográficas, apresentando um coeficiente de Nash-Sutcliffe (NSE de 0,76 e 0,81, para os períodos de calibração e validação da BRO; e 0,76 e 0,56, para os períodos de calibração e validação da BCC, respectivamente. O erro absoluto, calculado pelo valor da raiz do erro quadrático médio, foi considerado baixo por apresentar valores de 0,14 e 0,18 m³.s-1 para os períodos de calibração e validação da BRO; e 0,02 e 0,03 m³s-1 para os períodos de calibração e validação da BCC, respectivamente. Portanto, o J2000/JAMS mostrou-se como um candidato potencial para modelagem hidrológica de bacias hidrográficas do estado de São Paulo, podendo ser utilizado para estudos sobre as relações entre a localização do uso do solo na bacia hidrográfica e a geração de escoamento.

  3. Crustal Movement Patterns of China Continent Measured by GPS

    Institute of Scientific and Technical Information of China (English)

    YAO Yibin

    2003-01-01

    This paper uses multi-quadric equations interpolation to es-tablish a widely covered and valuablespeed field model of China, withwhich the horizontal crustal movementpatterns are obtained. The present-dayvertical crustal movement velocity im-age of China is also expressed by GPSobservations, from which we canknow the vertical crustal movementpatterns.

  4. AVALIAÇÃO DA DISPERSÃO ATMOSFÉRICA DE COMPOSTOS ODORANTES EMITIDOS NA INDÚSTRIA PAPELEIRA

    Directory of Open Access Journals (Sweden)

    Waldir Nagel Schirmer

    2009-03-01

    Full Text Available O caráter odorante de compostos reduzidos de enxofre (TRS, tipicamente emitidos na indústria papeleira, tem gerado grande interesse por parte dessas indústrias em predizer a qualidade do ar nas proximidades de suas fontes emissoras. Desse modo, o presente trabalho tem por objetivo avaliar o impacto na atmosfera resultante das emissões de TRS de uma fabricante de papel e celulose de grande porte, por meio da modelagem dos compostos gasosos emitidos a partir de duas fontes pontuais (tomadas como as maiores contribuidoras. Para tanto, foi utilizado o “software” AID (Avaliação Instantânea de Dispersão baseado no modelo de Gauss para determinação das concentrações (no ar resultantes dessas emissões. Nessa determinação, foram abordados os principais parâmetros meteorológicos (dos últimos 3 anos e cinéticos de emissão necessários à modelagem. A máxima concentração de TRS obtida após a modelagem foi de 3,84 ppb (somatório das duas fontes avaliadas, ficando bem abaixo dos limites de percepção odorífera (LPO recomendado por órgãos internacionais (o Brasil não possui leis específicas para esse caso. Como os limites de toxicidade quase sempre estão bem acima dos LPO, é seguro afirmar que, no caso avaliado, a concentração máxima estimada não apresenta riscos de toxicidade à população exposta, uma vez, pelo valor obtido, nem o odor pode ser percebido.

  5. Modelagem do crescimento e do desenvolvimento de frangos de corte: validação

    Directory of Open Access Journals (Sweden)

    Vargas Gilberto D'Avila

    2006-01-01

    Full Text Available Foi desenvolvido um modelo com o objetivo de simular o metabolismo basal, a deposição de proteína na carcaça e nas penas e a deposição de gordura na carcaça. O modelo assume a existência de um "pool" de nutrientes disponíveis no corpo animal, sendo a simulação do metabolismo animal baseada no fluxo de entrada e saída de nutrientes desse "pool". Os nutrientes vêm da ingestão de alimentos ou do catabolismo tecidual, são removidos do "pool" com os destinos de mantença, deposição de proteína na carcaça, deposição de gordura na carcaça e deposição de proteína nas penas. O processo de simulação é dinâmico, com as exigências de mantença contabilizadas ao mesmo tempo que as deposições de tecidos. Três conjuntos de dados foram utilizados para o processo de calibração, de análise de sensibilidade dos parâmetros e de validação do modelo. O modelo é eficaz para simular a deposição de proteína e de gordura na carcaça, bem como a deposição de proteína nas penas. No entanto, há a necessidade de um ajuste nos parâmetros envolvidos nas deposições de acordo com o genótipo que se pretende simular, principalmente para a taxa de maturação da proteína na carcaça (B P, para a taxa de maturação da proteína nas penas (B F, para o peso maduro da proteína na carcaça (WmP e para o peso maduro da proteína nas penas (WmF. O modelo mostrou-se especialmente sensível a estes parâmetros na análise de sensibilidade, salientando-se a importância de serem corretamente determinados. As deposições de proteína na carcaça e nas penas apresentaram menores coeficientes de correlação (r² entre os valores observados e simulados em função da grande variação entre genótipos, o que reforça a necessidade de se determinar corretamente os parâmetros que caracterizam cada genótipo.

  6. Técnica de modelagem numérica pelo método dos elementos finitos para estudo da resposta acústica veicular

    Directory of Open Access Journals (Sweden)

    Tiago Simão Ferreira

    2015-06-01

    Full Text Available Este estudo aborda a técnica de modelagem da resposta acústica de um veículo automotor. Esta pesquisa discorre sobre a construção de modelos numéricos em elementos finitos para investigar o efeito da utilização de componentes móveis (capô, portas laterais e tampa do porta malas na resposta acústica de um veículo. Para tanto, foram construídos dois modelos: um que abrange a utilização de todos os componentes móveis, e outro, que substitui cada componente móvel por elementos unidimensionais (1D, contendo apenas a massa e a inércia que representa cada um destes componentes. A resposta obtida em cada uma das etapas da simulação numérica é comparada com os resultados experimentais, a fim de validar o procedimento e compreender a significância da utilização de um modelo numérico simplificado e assim, validar um modelo simplificado capaz de reproduzir computacionalmente e de forma satisfatória a resposta acústica de um veículo. A utilização do referido modelo simplificado possibilita a indústria automotiva realizar estudos sobre a performance acústica de um veículo de forma antecipada, uma vez que não necessita esperar o desenvolvimento destes componentes. Como investigado nesta pesquisa, a influência de componentes móveis sobre a resposta acústica do modelo numérico completo é pequena quando comparado à resposta obtida pelo modelo simplificado.  Por meio de uma segunda análise, “Participação de Painéis”, é visto que a contribuição na resposta acústica final dos componentes móveis somados é inferior a 3dB.Palavras-chave: Método dos Elementos Finitos. Análise Acústica. Participação de Painéis. Acústica Veicular.ABSTRACTNumerical modeling technique using the finite element method in vehicle acoustic response studyThis study examines a modeling technique of the acoustic response in automotive vehicle. This research focuses on the development of numerical models in finite elements that

  7. Modelagem e simulação de negócios: método scorecard dinâmico aplicado à formulação de estratégias

    Directory of Open Access Journals (Sweden)

    Josué Vitor

    2009-05-01

    Full Text Available Descreve a aplicação do método “Scorecard Dinâmico” no processo de formulação da
    estratégia de uma pequena empresa. Tal método incorpora ferramentas de modelagem
    qualitativa e simulação, propiciadas pela Dinâmica de Sistemas ao mapa estratégico provido
    pelo Balanced Scorecard, buscando tornar a gestão da estratégia flexível e condizente com
    a complexidade inerente à realidade organizacional. Utilizou-se a pesquisa-ação enquanto
    método de pesquisa e intervenção na organização, e buscou-se, através da observação
    participante, a construção de modelos estratégicos em interação com os diretores da
    empresa. Durante este processo, pôde-se avaliar aspectos organizacionais que interferem
    na formulação da estratégia da empresa, durante o processo de aplicação do “Scorecard
    Dinâmico”. Assim, os modelos mentais dos membros da empresa foram explicitados no
    mapa estratégico e modelo qualitativo, sendo ainda concebida uma ferramenta de simulação
    para análise de resultados passados e prospecção de alternativas de estratégias futuras e
    melhoria do nível de aprendizagem organizacional. Como resultado, pôde-se destacar a
    dificuldade da implantação do método em virtude da ausência de dados históricos
    quantitativos na empresa e a maior compreensão por parte dos participantes da pesquisa
    dos problemas decorrentes do comportamento da estrutura sistêmica na empresa.

  8. Modelagem de redes logísticas com custos de inventário calculados a partir da cobertura de estoque Logistic networks modeling with inventory carrying costs calculated using inventory turnover

    Directory of Open Access Journals (Sweden)

    Ricardo Hamad

    2011-01-01

    Full Text Available A consideração dos custos de inventário tem se tornado cada vez mais importante na análise dos trade-offs e na tomada de decisões sobre redes logísticas. O artigo propõe uma metodologia para tratamento do custo de inventário a partir da cobertura de estoque esperada em cada instalação, incorporada na modelagem matemática da localização de fábricas e/ou centros de distribuição em redes logísticas com vários elos, representando uma nova versão do modelo apresentado em Hamad e Gualda (2008. As principais contribuições desta metodologia em relação a outros métodos encontrados na literatura são a facilidade de aplicação do método, a inclusão de restrições ligadas à capacidade de armazenagem e a consideração do custo total de inventário, e não apenas do custo relacionado aos produtos modelados.Inventory carrying cost has become very important in the analysis of the trade-offs and an important component to be considered when taking decisions about a logistic network. This paper proposes a methodology incorporated in a multi-echelon sourcing decision model, to be considered as a new version of the model presented in Hamad, Gualda (2008. It treats the carrying costs using the inventory Days-on-hand estimate in each echelon of the chain (plants and/or Distribution Centers. The main contributions of this methodology compared to other options found in the literature are the simplicity of its application, the consideration of all inventory costs (not only the ones related to the products being modeled and, also, the inclusion of constraints related to warehousing capacity.

  9. Representações digitais e interação incorporada: um estudo etnográfico de práticas científicas de modelagem computacional

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    Marko Monteiro

    2009-10-01

    Full Text Available O objetivo deste trabalho é discutir como objetos virtuais participam interativamente da produção do conhecimento na prática científica. O artigo baseia-se numa observação etnográfica de uma equipe interdisciplinar de cientistas, cujo trabalho envolve modelagem computacional de transferência de calor na próstata humana. A etnografia constatou que, embora visualizações científicas sejam pensadas como uma forma de "simplificar" a apreensão de dados, há um intenso trabalho interpretativo necessário para alcançar sentidos compartilhados a respeito das imagens. Tais sentidos são construídos a partir de comunicação oral e de interações incorporadas com objetos virtuais no decorrer das interações entre os cientistas. Uma melhor compreensão dessas práticas interpretativas é importante na medida em que o uso de visualizações digitais em 3D e de modelos computacionais ganha importância na ciência contemporânea. Tais técnicas são crescentemente utilizadas não somente para descrever verdades sobre a natureza, mas como ferramentas poderosas de intervenção no mundo.This text discusses how virtual objects participate interactively in the production of knowledge in scientific practice. The article is based on the ethnographic observation of an interdisciplinary team of scientists whose work involves computer modelling of heat transfer in the human prostate. The ethnography found that although scientific imaging may be considered a form of 'simplifying' the apprehension of data, an intense interpretative process is required to achieve shared meanings concerning the images. These meanings are constructed through oral communication and embodied interactions with virtual objects during the interactions between scientists. A better understanding of these interpretative practices is needed given the growing importance of the use of 3D digital imaging and computational models in contemporary science. These techniques are

  10. Magnetar Field Evolution and Crustal Plasticity

    Science.gov (United States)

    Lander, S. K.

    2016-06-01

    The activity of magnetars is believed to be powered by colossal magnetic energy reservoirs. We sketch an evolutionary picture in which internal field evolution in magnetars generates a twisted corona, from which energy may be released suddenly in a single giant flare, or more gradually through smaller outbursts and persistent emission. Given the ages of magnetars and the energy of their giant flares, we suggest that their evolution is driven by a novel mechanism: magnetic flux transport/decay due to persistent plastic flow in the crust, which would invalidate the common assumption that the crustal lattice is static and evolves only under Hall drift and Ohmic decay. We estimate the field strength required to induce plastic flow as a function of crustal depth, and the viscosity of the plastic phase. The star’s superconducting core may also play a role in magnetar field evolution, depending on the star’s spindown history and how rotational vortices and magnetic fluxtubes interact.

  11. Modelo de projeção por classe diamétrica para florestas nativas: enfoque na função probabilística de Weibull Projection model by diameter class for native forests: focus on the Weibull probability function

    Directory of Open Access Journals (Sweden)

    Rodrigo Geroni Mendes Nascimento

    2012-06-01

    Full Text Available

    Em 1979 a técnica de modelagem de distribuições diamétricas por funções probabilísticas foi aplicada pela primeira vez por Hyink & Moser na prognose do crescimento e da produção de florestas multiâneas e heterogêneas. Entretanto, atualmente, poucos trabalhos a utilizam no planejamento da produção dessas florestas por desconhecerem a viabilidade operacional da técnica. Sendo assim, esse trabalho visa apresentar uma revisão das características que propiciam a modelagem do crescimento e da produção por classe diamétrica, destacando a importância da dinâmica do recrutamento, mortalidade, sobrevivência, bem como dos atributos populacionais correlacionados à modelagem da distribuição de Weibull, apresentando as particularidades estatísticas utilizadas na modelagem da produção por esse método.

    doi: 10.4336/2012.pfb.32.70.93

    In 1979 the technique of modeling diameter distributions by probabilistic functions was first applied for Hyink & Moser in forecasting growth and production of uneven aged and heterogeneous forests. However, today few studies use this method for planning the production in these forests for not knowing the operational feasibility of the technique. Therefore this paper presents a review of the characteristics that allow the modeling of growth and yield by diameter class, highlighting the importance of the dynamics of recruitment, mortality, survival, and population of attributes related to the modeling of Weibull distribution, with the specific statistics used in the modeling of yield by this method.

    doi: 10.4336/2012.pfb.32.70.93

  12. Reports on crustal movements and deformations. [bibliography

    Science.gov (United States)

    Cohen, S. C.; Peck, T.

    1983-01-01

    This Catalog of Reports on Crustal Movements and Deformation is a structured bibliography of scientific papers on the movements of the Earth crust. The catalog summarizes by various subjects papers containing data on the movement of the Earth's surface due to tectonic processes. In preparing the catalog we have included studies of tectonic plate motions, spreading and convergence, microplate rotation, regional crustal deformation strain accumulation and deformations associated with the earthquake cycle, and fault motion. We have also included several papers dealing with models of tectonic plate motion and with crustal stress. Papers which discuss tectonic and geologic history but which do not present rates of movements or deformations and papers which are primarily theoretical analyses have been excluded from the catalog. An index of authors cross-referenced to their publications also appears in the catalog. The catalog covers articles appearing in reviewed technical journals during the years 1970-1981. Although there are citations from about twenty journals most of the items come from the following publications: Journal of Geophysical Research, Tectonophysics, Geological Society of America Bulletin of the Seismological Society of America, Nature, Science, Geophysical Journal of the Royal Astronomical Society, Earth and Planetary Science Letters, and Geology.

  13. Antarctic Crustal Thickness from Gravity Inversion

    Science.gov (United States)

    Vaughan, A. P.; Kusznir, N. J.; Ferraccioli, F.; Jordan, T. A.

    2013-12-01

    Using gravity anomaly inversion, we have produced the first comprehensive regional maps of crustal thickness and oceanic lithosphere distribution for Antarctica and the Southern Ocean. We determine Moho depth, crustal basement thickness, continental lithosphere thinning (1-1/β) and ocean-continent transition location using a 3D spectral domain gravity inversion method, which incorporates a lithosphere thermal gravity anomaly correction. The continental lithosphere thinning distribution, used to define the initial thermal model temperature perturbation is derived from the gravity inversion and uses no a priori isochron information; as a consequence the gravity inversion method provides a prediction of ocean-continent transition location, which is independent of ocean isochron information. The gravity anomaly contribution from ice thickness is included in the gravity inversion, as is the contribution from sediments which assumes a compaction controlled sediment density increase with depth. Data used in the gravity inversion are elevation and bathymetry, free-air gravity anomaly, the most recent Bedmap2 ice thickness and bedrock topography compilation south of 60 degrees south (Fretwell et al., 2013) and relatively sparse constraints on sediment thickness. Our gravity inversion study predicts thick crust (> 45 km) under interior East Antarctica penetrated by narrow continental rifts that feature relatively thinner crust. The East Antarctic Rift System (EARS) is a major Permian to Cretaceous age rift system that appears to extend from the continental margin at the Lambert Rift to the South Pole region, a distance of 2500 km. This is comparable in scale to the well-studied East African rift system. Intermediate crustal thickness with an inferred linear rift fabric is predicted under Coates Land. An extensive region of either thick oceanic crust or highly thinned continental crust is predicted offshore Oates Land and north Victoria Land, and also off West Antarctica

  14. O PAPEL DA MEDIAÇÃO E DA INTENCIONALIDADE EM ATIVIDADES DE MODELAGEM MATEMÁTICA. THE ROLE OF MEDIATION AND INTENTIONALITY IN MATHEMATICAL MODELLING ACTIVITIES

    Directory of Open Access Journals (Sweden)

    Vertuan, Rodolfo Eduardo

    2013-12-01

    Full Text Available Com o propósito de voltar a atenção ao processo de aprendizagem dos alunos quando envolvidos em atividades de Modelagem Matemática, este texto busca associar aspectos teóricos da Mediação Semiótica, do ponto de vista de Vygotsky, bem como da Intencionalidade como atributo para a aprendizagem. A atividade de Modelagem que analisamos é oriunda de um trabalho de pesquisa desenvolvida com alunos durante um curso de extensão e será analisada tomando elementos dos referenciais teóricos mencionados, a partir de registros escritos dos alunos e de transcrições de diálogos ocorridos durante o desenvolvimento da atividade. Considerando um ambiente de sala de aula com atividades de Modelagem, inferimos que, a mediação leva à intencionalidade e a intencionalidade leva a mediação e é por meio da “interação” desses dois elementos que a internalização de conceitos se torna possível, favorecendo a aprendizagem. In order to pay attention to the process of learning, when involved in mathematical modelling activities, this text seeks to associate the theoretical aspects of Semiotic Mediation, from the standpoint of Vygotsky, and Intentionality as an attribute to learning. The modelling activity present in the text is derived from a research conducted with students during a course of extension, which will be analyzed by taking elements of the theoretical frameworks mentioned from students' written records and transcripts of conversations that occurred during the activity development. Taking into consideration a classroom environment with modelling activities, we infer that the mediation leads to intentionality and intentionality leads to mediation and it is through the "interaction" of these two elements that the internalization of concepts becomes possible, encouraging learning.

  15. Modelagem geoestatística das incertezas da distribuição espacial do fósforo disponível no solo, em área de cana-de-açúcar

    Directory of Open Access Journals (Sweden)

    Ismênia Ribeiro de Oliveira

    2013-12-01

    Full Text Available O fósforo destaca-se como um dos nutrientes limitantes ao desenvolvimento da cultura da cana-de-açúcar em solos brasileiros. Esse elemento apresenta grande variabilidade espacial, coordenada pelos atributos que regem as reações de adsorção e dessorção. Estimativas espaciais são conduzidas por meio de interpolações geoestatísticas para a caracterização dessa variabilidade. No entanto, tais estimativas apresentam incertezas inerentes ao procedimento que estão associadas à estrutura de variabilidade do atributo em estudo e à configuração amostral da área. Dessa forma, avaliar a incerteza das predições associada à distribuição espacial do fósforo disponível (Plábil é importante para otimizar o uso dos fertilizantes fosfatados. O objetivo deste estudo foi avaliar o desempenho da simulação sequencial gaussiana (SSG e da krigagem ordinária (KO na modelagem da incerteza das predições do fósforo disponível. Uma malha amostral com 626 pontos foi instalada em uma área experimental de 200 hectares de cana-de-açúcar no município de Tabapuã, São Paulo. Foram geradas 200 realizações por meio do algoritmo da SSG. As realizações da SSG reproduziram as estatísticas e a distribuição dos dados amostrais. A estatística G (0,81 indicou boa proximidade entre as frações dos valores simulados e as dos observados. As realizações da SSG preservaram a variabilidade espacial do Plábil, sem o efeito de suavização obtido pelo mapa da KO. A acurácia na reprodução do variograma dos dados amostrais, obtida pelas realizações da SSG foi, em média, 240 vezes maior que obtida por meio da KO. O mapa de incertezas, obtido por meio da KO, apresentou menor variação na área de estudo do que por SSG. Dessa forma, a avaliação das incertezas, pela SSG, evidenciou-se mais informativa, podendo ser utilizada para definir e delimitar, de forma mais precisa, as áreas de manejo específico.

  16. Considerações sobre impactos socioambientais de Pequenas Centrais Hidrelétricas (PCHs) : modelagem e análise

    OpenAIRE

    Leão, Larissa Lara

    2008-01-01

    O objetivo desta dissertação é discutir a problemática e os conflitos que envolvem a construção de Pequenas Centrais Hidrelétricas – PCHs. A avaliação entre os fatores socioambientais e econômicos que permeiam a discussão foi demonstrada a partir de uma modelagem sistêmica elaborada com o auxílio da ferramenta computacional STELLA - Structural Experimental Learning Laboratory with Animation, necessária para a visualização entre os componentes apresentados no estudo de caso. Para que modela...

  17. Modes of continental extension in a crustal wedge

    KAUST Repository

    Wu, Guangliang

    2015-07-01

    © 2015 Elsevier B.V. We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  18. Modes of continental extension in a crustal wedge

    Science.gov (United States)

    Wu, Guangliang; Lavier, Luc L.; Choi, Eunseo

    2015-07-01

    We ran numerical experiments of the extension of a crustal wedge as an approximation to extension in an orogenic belt or a continental margin. We study the effects of the strength of the lower crust and of a weak mid-crustal shear zone on the resulting extension styles. A weak mid-crustal shear zone effectively decouples upper crustal extension from lower crustal flow. Without the mid-crustal shear zone, the degree of coupling between the upper and the lower crust increases and extension of the whole crust tends to focus on the thickest part of the wedge. We identify three distinct modes of extension determined by the strength of the lower crust, which are characterized by 1) localized, asymmetric crustal exhumation in a single massif when the lower crust is weak, 2) the formation of rolling-hinge normal faults and the exhumation of lower crust in multiple core complexes with an intermediate strength lower crust, and 3) distributed domino faulting over the weak mid-crustal shear zone when the lower crust is strong. A frictionally stronger mid-crustal shear zone does not change the overall model behaviors but extension occurred over multiple rolling-hinges. The 3 modes of extension share characteristics similar to geological models proposed to explain the formation of metamorphic core complexes: 1) the crustal flow model for the weak lower crust, 2) the rolling-hinge and crustal flow models when the lower crust is intermediate and 3) the flexural uplift model when the lower crust is strong. Finally we show that the intensity of decoupling between the far field extension and lower crustal flow driven by the regional pressure gradient in the wedge control the overall style of extension in the models.

  19. Análise ergonômica do livro Aprenda a Costurar com vistas para o aperfeiçoamento da aprendizagem da modelagem plana do vestuário.

    Directory of Open Access Journals (Sweden)

    Fernanda Iervolino

    2015-01-01

    Full Text Available Este artigo faz parte da dissertação de mestrado intitulada “41 anos de estudos de modelagem do vestuário: uma proposta de aperfeiçoamento do ensino de modelagem através da usabilidade”, cujo objetivo é verificar, através das heurísticas de Nielsen (1993, quais são as desconformidades ergonômicas do conteúdo apresentado no livro “Aprenda a Costurar”, de Gil Brandão, escrito em 1967. A escolha pela obra que data de mais de quarenta anos justifica-se pelo fato de que até os dias atuais a mesma serve de suporte para o ensino e aprendizagem da modelagem plana do vestuário. A pesquisa se propõe a identificar oportunidades de melhorias no conteúdo do livro em questão com vistas para a usabilidade. No presente trabalho, utiliza-se o método de observação indireta, aplicando-se entrevista semi-estruturada com professores de modelagem como instrumento de coleta de dados. O resultado encontrado revela que o autor apresenta desconformidades ergonômicas nos seus textos, cada uma relativa a um critério de usabilidade.

  20. Crustal permeability: Introduction to the special issue

    Science.gov (United States)

    Ingebritsen, Steven E.; Gleeson, Tom

    2015-01-01

    The topic of crustal permeability is of broad interest in light of the controlling effect of permeability on diverse geologic processes and also timely in light of the practical challenges associated with emerging technologies such as hydraulic fracturing for oil and gas production (‘fracking’), enhanced geothermal systems, and geologic carbon sequestration. This special issue of Geofluids is also motivated by the historical dichotomy between the hydrogeologic concept of permeability as a static material property that exerts control on fluid flow and the perspective of economic geologists, geophysicists, and crustal petrologists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. Issues associated with fracking, enhanced geothermal systems, and geologic carbon sequestration have already begun to promote a constructive dialog between the static and dynamic views of permeability, and here we have made a conscious effort to include both viewpoints. This special issue also focuses on the quantification of permeability, encompassing both direct measurement of permeability in the uppermost crust and inferential permeability estimates, mainly for the deeper crust.

  1. Coesite-Diamond Assemblage in Ultrahigh Pressure Crustal and Mantle rocks: Evidence for Carbon Recycling

    Science.gov (United States)

    Sobolev, N. V.

    2010-12-01

    Coesite, a high-pressure polymorph of silica, was first discovered as part of a coesite-eclogite assemblage (coesite, garnet, omphacite) in equilibrium with diamond as diamond inclusion (DI) in Siberian diamond placers (Sobolev et al., 1976, Dokl. Akad. Nauk SSSR, 230: 1442). In recent years, coesite has become a key mineral coexisting with diamond both in kimberlite (DIs) and in UHP metamorphic rocks of the Kokchetav massif, Kazakhstan (diamondiferous gneisses and calcsilicate rocks). In the UHPM rocks of Kokchetav massif, coesite was first detected as inclusions in zircon associated with diamonds (Sobolev et al., 1991, Dokl. Akad. Nauk SSSR, 321: 184), as a result of the initial studies that had identified diamonds as inclusions in garnets and zircons (Sobolev, Shatsky, 1990, Nature, 343: 742). Garnet and omphacitic clinopyroxene are the principal primary minerals associated with coesite and diamond in UHP mantle and crustal rocks. Their compositions plot distinctly within the eclogitic compositional field and substantiate the existence of coesite presence as DIs in eclogitic (E-type) diamonds, as well as sometimes in xenoliths of diamondiferous eclogites (Shatsky et al., 2008, Lithos, 105:289). One of the major significant features of these eclogitic minerals in both UHPM and kimberlitic mantle occurrences is the K2O contents of the clinopyroxenes, reaching 1.6 wt.%, with Na2O and MnO in Ca-Mg-Fe garnets reaching 0.3 and 6.0 wt.%, respectively. Stable isotope data for C in diamonds and O in garnet, pyroxene and coesite have resulted in establishing a very wide range for these isotopes most typical for crustal conditions - i.e., atypical of mantle values. This is clearly shown for coesite DIs (Schulze et al., 2003, Nature, 428:68), garnets from diamondiferous eclogite xenoliths from Siberian kimberlites (Spetsius et al., 2008, Eur. J. Min., 20:375), garnets and clinopyroxenes from UHP calcsilicate diamondiferous rocks of the Kokchetav massif (Sobolev et al., in

  2. Distribuição espacial do risco: modelagem da mortalidade infantil em Porto Alegre, Rio Grande do Sul, Brasil Spatial risk distribution: modeling infant mortality in Porto Alegre, Rio Grande do Sul State, Brazil

    Directory of Open Access Journals (Sweden)

    Silvia E. Shimakura

    2001-10-01

    Full Text Available Estimação e mapeamento de perfis de risco são interesses da Epidemiologia. Neste trabalho, é analisada a distribuição espacial de casos de mortalidade infantil, comparados a controles de nascidos vivos amostrados do Sistema de Informações sobre Nascidos Vivos da cidade de Porto Alegre, Rio Grande do Sul, Brasil. A modelagem adotada neste trabalho baseia-se em um processo pontual espacial, na qual se define uma medida de risco que varia continuamente sobre a região de estudo e estimada por meio de métodos de modelos aditivos generalizados. Essa abordagem possui a vantagem de permitir a incorporação, no modelo, de efeitos de determinantes individuais e ecológicos de risco sob forma simples e de fácil interpretação. Também permite a construção de contornos de tolerância que auxiliam na identificação de áreas de alto/baixo risco e de um teste global da hipótese nula de risco constante relativa à região. A aplicação do método aos dados de mortalidade infantil mostrou variação espacial no risco altamente significativa para mortalidade neonatal e não significativa para mortalidade pós-neonatal.Estimation and mapping of risk profiles are the main concerns of epidemiology. This paper analyzes spatial distribution of infant mortality cases as compared to live-born controls from Porto Alegre, Rio Grande do Sul. The modeling framework adopted in this research work is a spatial point process. Under this structure, a risk measure which continuously varies over the study region is defined and estimated using generalized additive model methods. This approach has the advantage of allowing for risk factors that are simple and easy to interpret. The procedure also allows the construction of tolerance contours which help identify areas of significantly high/low risk and an overall test for the null hypothesis of constant risk over the region. Application of this method to infant mortality data showed a highly significant spatial

  3. Modelagem do sistema de resfriamento por imersão de carcaças de frangos utilizando redes neurais artificiais = Modeling of the poultry carcass immersion chilling system using artificial neural networks

    Directory of Open Access Journals (Sweden)

    Túlio Klassen

    2009-04-01

    Full Text Available A modelagem matemática fenomenológica do processo de resfriamento decarcaças de frango em chillers é complexa pela quantidade de variáveis que interferem no processo, além de tratar de um problema que envolve transferência de calor e de massa em regime transeniente. Uma alternativa para modelar este tipo de sistema é o emprego deRedes Neurais Artificiais. Neste trabalho foram investigadas diversas estruturas de redes com uma camada intermediária para modelar o processo de resfriamento de frangos. Foram testadas diferentes arquiteturas alterando os números de neurônios das camadas de entrada e intermediária. Foram utilizados dados coletados na empresa Sadia–Toledo, Estado do Paraná, para treinamento e validação das redes. As variáveis de entrada da rede eram: massa da carcaça, temperatura antes do resfriamento, temperatura da camisa de propilenoglicol,vazão de água em cada módulo, tempo de residência e temperatura da água de renovação; a temperatura do frango na saída do último tanque de resfriamento era a variável de saída. Os resultados obtidos mostraram que as redes representam apropriadamente o processo e que arede com estrutura 8-24-1 foi a que melhor modelou o sistema investigado.The process of cooling chicken carcasses by immersing themin mixture of cold water and ice (chillers is complex. It is very difficult to represent it by a transport phenomenon model. In this work, artificial neural networks were used with an intermediary layer in the description and modeling of the cooling process of chickens.Different architectures of the neural network were tested, altering the numbers of input and hidden units. Data supplied by the Sadia-Toledo Company were used for training and validation of the neural networks. The input variables selected for the model were thefollowing: carcass weight, initial temperature, propylene glycol temperature with external circulation, water flow rate of water in each tank, renewal

  4. Reports on block rotations, fault domains and crustal deformation

    Science.gov (United States)

    Nur, Amos

    1990-01-01

    Studies of block rotations, fault domains and crustal deformation in the western United States, Israel, and China are discussed. Topics include a three-dimensional model of crustal fracture by distributed fault sets, distributed deformation and block rotation in 3D, stress field rotation, and multiple strike slip fault sets.

  5. THE CRUSTAL STRUCTURE OF ELLESMERE ISLAND FROM RECEIVER FUNCTION MODELLING

    DEFF Research Database (Denmark)

    Schiffer, Christian; Stephenson, Randell Alexander; Oakey, Gordon

    . Preliminary results give estimates of Moho depths and crustal velocity structure and these are discussed with a focus on the relationship to topography, regional geological units and fault zones. The receiver functions reveal crustal roots underneath the Victoria and Albert Mountains (45km) and the Grantland...

  6. Horizontal crustal movement in Chinese mainland from 1999 to 2001

    Institute of Scientific and Technical Information of China (English)

    顾国华; 符养; 王武星

    2004-01-01

    The paper introduces the horizontal crustal movement obtained from GPS observations in the regional networks(including the basic network and the fiducial network) of the Crustal Movement Observation Network of China(CMONOC) carried out in 1999 and 2001. This paper is characterized by the acquisition of the horizontal dis-placement velocities during the period from 1999 to 2001 at the observation stations in the regional networks withdatum definition of a group of stable stations with small mutual displacements in east China. Based on the mostdetailed map of horizontal crustal movement in Chinese mainland, the division of blocks, their displacements anddeformations are studied. An approach to analysis of the intensity of the horizontal crustal deformation is proposed.The general characteristics of the recent horizontal crustal movement in Chinese mainland and that before theKunlunshan earthquake of M=8.1 on November 14, 2001 are analyzed.

  7. Constraints on Crustal Viscosity from Geodetic Observations

    Science.gov (United States)

    Houseman, Gregory

    2015-04-01

    Laboratory measurements of the ductile deformation of crustal rocks demonstrate a range of crystal deformation mechanisms that may be represented by a viscous deformation law, albeit one in which the effective viscosity may vary by orders of magnitude, depending on temperature, stress, grain size, water content and other factors. In such measurements these factors can be separately controlled and effective viscosities can be estimated more or less accurately, though the measured deformation occurs on much shorter time scales and length scales than are typical of geological deformation. To obtain bulk measures of the in situ crustal viscosity law for actual geological processes, estimated stress differences are balanced against measured surface displacement or strain rates: at the continental scale, surface displacement and strain rates can be effectively measured using GPS, and stress differences can be estimated from the distribution of gravitational potential energy; this method has provided constraints on a depth-averaged effective viscosity for the lithosphere as a whole in regions that are actively deforming. Another technique measures the post-seismic displacements that are interpreted to occur in the aftermath of a large crustal earthquake. Stress-differences here are basically constrained by the co-seismic deformation and the elastic rigidity (obtained from seismic velocity) and the strain rates are again provided by GPS. In this technique the strain is a strong function of position relative to the fault, so in general the interpretation of this type of data depends on a complex calculation in which various simplifying assumptions must be made. The spatial variation of displacement history on the surface in this case contains information about the spatial variation of viscosity within the crust. Recent post-seismic studies have shown the potential for obtaining measurements of both depth variation and lateral variation of viscosity in the crust beneath

  8. The crustal composition of the Falkland Plateau

    Science.gov (United States)

    Klemt, Claudia; Jokat, Wilfried

    2015-04-01

    The Falkland Islands are situated in the South Atlantic Ocean 500 km east of Patagonia, South America. The islands are part of the Falkland Plateau, which stretches eastward for more than 1500 km. A bathymetric high, the Maurice Ewing Bank, terminates the plateau in the east. Until Late Jurassic the Falkland Islands were part of Gondwana and were located adjacent to the east coast of South Africa. While the Falkland Islands and Maurice Ewing Bank are proved to be of continental composition, the nature and structure of the Falkland Plateau's basement in between is debatable. The first crustal model derived from sonobuoy data contradicts an only recently published 3D-gravity model. To enhance the understanding of Gondwana break-up considering timing, geometry and amount of volcanism, further knowledge about the structure and thickness of the crust is inevitable. During the ANT-XXIX/5 Polarstern cruise seismic refraction measurements were conducted using Ocean Bottom Seismometers (OBS) and Reftek land stations onshore of East Falkland. The OBS were deployed at 78 locations along an approximately 1500 km east-west stretching profile. For the western transect a P-wave velocity model is calculated using 2D-raytracing techniques. The results are presented in combination with potential field data showing the extension of the Falkland Islands basement, the continent-ocean transition zone and the crustal structure of the plateau. On the Falkland Plateau Basin sediment thickness is about 6 km with velocities ranging from 1.7 to 4.1 km/s in the upper part and about 4.7 km/s above basement. The crust is of oceanic composition with an igneous section that is considerably thicker than average oceanic crust (up to 17 km). The velocity structure in the upper crustal part is typical for layer 2 with a velocity gradient ranging from 5.4 km/s to 6.5 km/s and thicknesses between 1.5 km and 4 km. Layer 3 is about 14 km thick with a velocity gradient from 6.6 km/s to 7.6 km/s, which is

  9. Georeferenced database generation with the purpose of hydrologic molding in reservoirs of the hydrographic basin of Jaguaribe river in the state of Ceará, Brazil Geração de base de dados georreferenciada com finalidade de modelagem hidrológica em reservatórios da bacia hidrográfica do rio Jaguaribe, Ceará, Brasil

    Directory of Open Access Journals (Sweden)

    Raimundo A. de O. Leão

    2013-04-01

    Full Text Available The edafoclimatic conditions of the Brazilian semiarid region favor the water loss by surface runoff. The state of Ceará, almost completely covered by semiarid, has developed public policies for the construction of dams in order to attend the varied water demand. Several hydrological models were developed to support decisive processes in the complex management of reservoirs. This study aimed to establish a methodology for obtaining a georeferenced database suitable for use as input data in hydrological modeling in the semiarid of Ceará. It was used images of Landsat satellite and SRTM Mission, and soil maps of the state of Ceará. The Landsat images allowed the determination of the land cover and the SRTM Mission images, the automatic delineation of hydrographic basins. The soil type was obtained through the soil map. The database was obtained for Jaguaribe River hydrographic basin, in the state of Ceará, and is applicable to hydrological modeling based on the Curve Number method for estimating the surface runoff.As condições edafoclimáticas do semiárido brasileiro favorecem a perda de água por escoamento superficial. O Estado do Ceará,quase totalmente abrangido pelo semiárido, desenvolveu políticas públicas voltadas para a construção de açudes,a fim de atender à demanda hídrica diversificada. Vários modelos hidrológicos foram desenvolvidos para subsidiar os processos decisórios no complexo manejo dos reservatórios. Este trabalho teve como objetivo estabelecer uma metodologia para a obtenção de uma base de dados georreferenciada e adequada para uso como dados de entrada na modelagem hidrológica,no semiárido cearense. Foram utilizadas imagens de satélite Landsat e da missão SRTM, e mapa de solos do Estado do Ceará. As imagens Landsat possibilitaram determinar a cobertura do solo,e as imagens da missão SRTM, a delimitação automática das bacias hidrográficas. O tipo de solo foi obtido por meio do mapa de solos. A

  10. Alternatives in modeling of body mass index as a continuous response variable and relevance of residual analysis Alternativas para modelagem do índice de massa corporal como variável contínua e relevância da análise de resíduos

    Directory of Open Access Journals (Sweden)

    Maria de Jesus Mendes da Fonseca

    2008-02-01

    ajuste foi alcançado e a variância permaneceu constante. Na modelagem de dados epidemiológicos, cabe aos pesquisadores buscarem o melhor equilíbrio entre a aplicação adequada de técnicas estatísticas e a facilidade de interpretação dos dados.

  11. Visualization and dissemination of global crustal models on virtual globes

    Science.gov (United States)

    Zhu, Liang-feng; Pan, Xin; Sun, Jian-zhong

    2016-05-01

    Global crustal models, such as CRUST 5.1 and its descendants, are very useful in a broad range of geoscience applications. The current method for representing the existing global crustal models relies heavily on dedicated computer programs to read and work with those models. Therefore, it is not suited to visualize and disseminate global crustal information to non-geological users. This shortcoming is becoming obvious as more and more people from both academic and non-academic institutions are interested in understanding the structure and composition of the crust. There is a pressing need to provide a modern, universal and user-friendly method to represent and visualize the existing global crustal models. In this paper, we present a systematic framework to easily visualize and disseminate the global crustal structure on virtual globes. Based on crustal information exported from the existing global crustal models, we first create a variety of KML-formatted crustal models with different levels of detail (LODs). And then the KML-formatted models can be loaded into a virtual globe for 3D visualization and model dissemination. A Keyhole Markup Language (KML) generator (Crust2KML) is developed to automatically convert crustal information obtained from the CRUST 1.0 model into KML-formatted global crustal models, and a web application (VisualCrust) is designed to disseminate and visualize those models over the Internet. The presented framework and associated implementations can be conveniently exported to other applications to support visualizing and analyzing the Earth's internal structure on both regional and global scales in a 3D virtual-globe environment.

  12. Uma proposta de modelagem da lista de materiais Bill of materials' modeling: a proposal

    Directory of Open Access Journals (Sweden)

    Eduardo Vila Gonçalves Filho

    1996-08-01

    Full Text Available Este trabalho propõe uma nova forma de estruturação da lista de materiais, para empresas fabricantes de bens de capital, apesar dos conceitos gerais serem passíveis de utilização em outros tipos de companhias de manufatura. A lista de materiais, como elemento fomentador da integração, é modelada com base em necessidades-chave de diversos usuários, desde o orçamento até a expedição. O objetivo é facilitar as atividades de administração de materiais e gestão da produção. A metodologia desenvolvida consiste em estruturar uma lista de materiais paralela, delineada em função do organograma fabril da empresa e da seqüência de fabricação do produto no tempo. Esses conceitos foram aplicados na formação de grupos de dispositivos dedicados, utilizados na fabricação de hidrogeradores, na SADE VIGESA S/A., fábrica de Araraquara.This paper suggests a new idea to form a Bill of Materials (BOM, for heavy equipment manufacturing companies, with the general concepts applied in others kind of manufacturing companies. The bill of materials, as an essential element of integration, from marketing to delivery, aims to facilitate the activities of Production Planning and of the Control System. The methodology developed is based on a new approach to build parallel bill of materials, using concepts of pseudo levels and assemblies, mainly based on the industrial organizational structure of the company and on the sequence of product fabrication in time. The implementation of this system for dedicated fixtures resulted in expressive reduction of lead time, project hours, fabrication hours and costs.

  13. Detailed crustal thickness variations beneath the Illinois Basin area: Implications for crustal evolution of the midcontinent

    Science.gov (United States)

    Yang, Xiaotao; Pavlis, Gary L.; Hamburger, Michael W.; Marshak, Stephen; Gilbert, Hersh; Rupp, John; Larson, Timothy H.; Chen, Chen; Carpenter, N. Seth

    2017-08-01

    We present high-resolution imaging results of crustal and upper mantle velocity discontinuities across the Illinois Basin area using both common conversion point stacking and plane wave migration methods applied to P wave receiver functions from the EarthScope Ozark, Illinois, Indiana, and Kentucky experiment. The images reveal unusually thick crust (up to 62 km) throughout the central and southeastern Illinois Basin area. A significant Moho gradient underlies the NW trending Ste. Genevieve Fault Zone, which delineates the boundary between the Illinois Basin and Ozark Dome. Relatively thinner crust (convergent margin tectonics around 1.55-1.35 Ga; (3) by Late Precambrian magmatic underplating at the base of older crust, associated with the creation of the Eastern Granite-Rhyolite Province around 1.3 Ga; and (4) through crustal "relamination" during an episode of Proterozoic flat-slab subduction beneath the Illinois Basin, possibly associated with the Grenville Orogeny.

  14. Modelagem integrada do problema de programação de tripulantes de aeronaves.

    OpenAIRE

    Wagner de Paula Gomes

    2014-01-01

    Esta pesquisa trata o Problema de Programação de Tripulantes (PPT), presente no planejamento operacional das empresas aéreas. O principal objetivo do PPT é atribuir o conjunto de tripulantes requeridos para a operação dos voos de uma malha aérea de maneira a minimizar o custo total da tripulação, levando em conta a legislação pertinente e a satisfação dos tripulantes. O PPT é normalmente dividido na literatura em dois subproblemas independentes, modelados e resolvidos sequencialmente: Problem...

  15. Modelagem por compartimentos para integrar e comunicar conhecimento em nutrição

    OpenAIRE

    2007-01-01

    Esta palestra tem o objetivo de apresentar e discutir metodologias utilizadas para modelar e integrar o conhecimento clássico em nutrição animal, e o produzido por novas ciências moleculares como nutrigenoma, proteoma e metaboloma. Estas ciências e a bioinformática estão ajudando a expandir rapidamente o conhecimento dos sistemas biológicos de interesse em nutrição animal. Na palestra discutirei como é importante dedicar parte de nosso tempo a integrar o conhecimento existente para esclarecer...

  16. Tectonic implications of Mars crustal magnetism.

    Science.gov (United States)

    Connerney, J E P; Acuña, M H; Ness, N F; Kletetschka, G; Mitchell, D L; Lin, R P; Reme, H

    2005-10-18

    Mars currently has no global magnetic field of internal origin but must have had one in the past, when the crust acquired intense magnetization, presumably by cooling in the presence of an Earth-like magnetic field (thermoremanent magnetization). A new map of the magnetic field of Mars, compiled by using measurements acquired at an approximately 400-km mapping altitude by the Mars Global Surveyor spacecraft, is presented here. The increased spatial resolution and sensitivity of this map provide new insight into the origin and evolution of the Mars crust. Variations in the crustal magnetic field appear in association with major faults, some previously identified in imagery and topography (Cerberus Rupes and Valles Marineris). Two parallel great faults are identified in Terra Meridiani by offset magnetic field contours. They appear similar to transform faults that occur in oceanic crust on Earth, and support the notion that the Mars crust formed during an early era of plate tectonics.

  17. Moroccan crustal response to continental drift.

    Science.gov (United States)

    Kanes, W H; Saadi, M; Ehrlich, E; Alem, A

    1973-06-01

    The formation and development of a zone of spreading beneath the continental crust resulted in the breakup of Pangea and formation of the Atlantic Ocean. The crust of Morocco bears an extremely complete record of the crustal response to this episode of mantle dynamics. Structural and related depositional patterns indicate that the African margin had stabilized by the Middle Jurassic as a marine carbonate environment; that it was dominated by tensile stresses in the early Mesozoic, resulting in two fault systems paralleling the Atlantic and Mediterranean margins and a basin and range structural-depositional style; and that it was affected by late Paleozoic metamorphism and intrusion. Mesozoic events record the latter portion of African involvement in the spreading episode; late Paleozoic thermal orogenesis might reflect the earlier events in the initiation of the spreading center and its development beneath significant continental crust. In that case, more than 100 million years were required for mantle dynamics to break up Pangea.

  18. Current crustal movement in Chinese mainland

    Institute of Scientific and Technical Information of China (English)

    王琪

    2003-01-01

    The quantification of tectonic deformation in the Eastern and Central Asia is of great significance for the study on global plate motion and lithospheric dynamics. In the past four years, the velocity field of horizontal crustal movement for the Chinese mainland has been established for the first time thanks to the intensified GPS measurements and its improved accuracy. The velocity field derived from GPS measurements delineates the patterns of tectonic deformation in the Chinese mainland in the unprecedented detail, and thus reveals the new features of the ongoing tectonic process resulted from the collision of Indian plate to Eurasian plate. Meanwhile, the surface offset induced by two strong earthquakes occurred in Chinese mainland was sampled precisely using InSAR technique.

  19. Crustal evolution in Asia: Correlations and connections

    Science.gov (United States)

    Tsunogae, Toshiaki; Kwon, Sanghoon; Santosh, M.

    2016-11-01

    The Asian region records multiple subduction, accretion and collision processes related to the breakup of Gondwana and Pangea, and the ongoing formation of the future supercontinent Amasia. The oldest geological record of Asia is preserved in Archean crustal fragments which were welded together by later collisional events related to the assembly of several supercontinents. The Asian region also records recent geological events such as volcanic activities and mega-earthquakes related to subduction of oceanic plates along active continental margins and collision of microplates. This region is thus regarded as an excellent field laboratory for examining the evolution of continental crust and cratons, formation and destruction of continents and supercontinents, and related metallogenic and surface environmental processes.

  20. Fractal behavior in continental crustal heat production

    Directory of Open Access Journals (Sweden)

    N. Vedanti

    2011-02-01

    Full Text Available The distribution of crustal heat production, which is the most important component in the elucidation of continental thermal structure, still remains a theoretical assumption. In general the heat production values must decrease with depth, but the form of decrease of heat production in the crust is not well understood. The commonly used heat production models are: "block model", in which heat production is constant from the surface to a given depth and the "exponential model", in which heat production diminishes as an exponential function of depth. The exponential model is more widely used wherein sources of the errors are heterogeneity of rock and long wavelength changes due to changes in lithology and tectonic elements, and as such exponential distribution does not work satisfactorily for the entire crust. In the present study, we analyze for the first time, deep crustal heat production data of six global areas namely Dharwar craton (India, Kaapvaal craton (South Africa, Baltic shield (Kola, Russia, Hidaka metamorphic belt (Japan, Nissho pluton (Japan and Continental Deep Drilling site (KTB, Germany. The power spectrum of all the studied data sets exhibits power law behaviour. This would mean slower decay of heat production with depth, which conforms to the known geologic composition of the crust. Minimum value of the scaling exponent has been found for the KTB borehole, which is apparently related to higher heat production of gneisses, however for other study areas, scaling exponent is almost similar. We also found that the lower values of scaling exponents are related to higher heat production in the crust as is the case in KTB. Present finding has a direct relevance in computation of temperature-depth profiles in continental regions.

  1. The Glacial BuzzSaw, Isostasy, and Global Crustal Models

    Science.gov (United States)

    Levander, A.; Oncken, O.; Niu, F.

    2015-12-01

    The glacial buzzsaw hypothesis predicts that maximum elevations in orogens at high latitudes are depressed relative to temperate latitudes, as maximum elevation and hypsography of glaciated orogens are functions of the glacial equilibrium line altitude (ELA) and the modern and last glacial maximum (LGM) snowlines. As a consequence crustal thickness, density, or both must change with increasing latitude to maintain isostatic balance. For Airy compensation crustal thickness should decrease toward polar latitudes, whereas for Pratt compensation crustal densities should increase. For similar convergence rates, higher latitude orogens should have higher grade, and presumably higher density rocks in the crustal column due to more efficient glacial erosion. We have examined a number of global and regional crustal models to see if these predictions appear in the models. Crustal thickness is straightforward to examine, crustal density less so. The different crustal models generally agree with one another, but do show some major differences. We used a standard tectonic classification scheme of the crust for data selection. The globally averaged orogens show crustal thicknesses that decrease toward high latitudes, almost reflecting topography, in both the individual crustal models and the models averaged together. The most convincing is the western hemisphere cordillera, where elevations and crustal thicknesses decrease toward the poles, and also toward lower latitudes (the equatorial minimum is at ~12oN). The elevation differences and Airy prediction of crustal thickness changes are in reasonable agreement in the North American Cordillera, but in South America the observed crustal thickness change is larger than the Airy prediction. The Alpine-Himalayan chain shows similar trends, however the strike of the chain makes interpretation ambiguous. We also examined cratons with ice sheets during the last glacial period to see if continental glaciation also thins the crust toward

  2. Evolution of crustal thickening in the central Andes, Bolivia

    Science.gov (United States)

    Eichelberger, Nathan; McQuarrie, Nadine; Ryan, Jamie; Karimi, Bobak; Beck, Susan; Zandt, George

    2015-09-01

    Paleoelevation histories from the central Andes in Bolivia have suggested that the geodynamic evolution of the region has been punctuated by periods of large-scale lithospheric removal that drive rapid increases in elevation at the surface. Here, we evaluate viable times and locations of material loss using a map-view reconstruction of the Bolivian orocline displacement field to forward-model predicted crustal thicknesses. Two volumetric models are presented that test assumed pre-deformation crustal thicknesses of 35 km and 40 km. Both models predict that modern crustal thicknesses were achieved first in the northern Eastern Cordillera (EC) by 30-20 Ma but remained below modern in the southern EC until ≤10 Ma. The Altiplano is predicted to have achieved modern crustal thickness after 10 Ma but only with a pre-deformation thickness of 50 km, including 10 km of sediment. At the final stage, the models predict 8-25% regional excess crustal volume compared to modern thickness, largely concentrated in the northern EC. The excess predicted volume from 20 to 0 Ma can be accounted for by: 1) crustal flow to the WC and/or Peru, 2) localized removal of the lower crust, or 3) a combination of the two. Only models with initial crustal thicknesses >35 km predict excess volumes sufficient to account for potential crustal thickness deficits in Peru and allow for lower crustal loss. However, both initial thickness models predict that modern crustal thicknesses were achieved over the same time periods that paleoelevation histories indicate the development of modern elevations. Localized removal of lower crust is only necessary in the northern EC where crustal thickness exceeds modern by 20 Ma, prior to paleoelevation estimates of modern elevations by 15 Ma. In the Altiplano, crustal thicknesses match modern values at 10 Ma and can only exceed modern values by 5 Ma, post-dating when modern elevations were thought to have been established. Collectively, these models predict that

  3. Moldes de ABS construídos pelo processo de modelagem por fusão e deposição para injeção de PP e PEBD PP and LDPE injection in ABS molds built with fused deposition modeling

    Directory of Open Access Journals (Sweden)

    José A. Foggiatto

    2004-12-01

    Full Text Available Os processos de prototipagem rápida (Rapid Prototyping - RP e ferramental rápido (Rapid Tooling - RT surgiram para reduzir os tempos de desenvolvimento de produtos na fase de projeto diminuindo a necessidade de retrabalhos e, conseqüentemente, antecipando a entrada de novos produtos no mercado. Neste trabalho foi utilizada uma das tecnologias de prototipagem rápida, denominada Modelagem por Fusão e Deposição (FDM, na construção de moldes em ABS com o objetivo de investigar sua aplicação na moldagem por injeção de termoplásticos. Amostras das peças injetadas foram submetidas a ensaios de difração de raios X, dureza Shore D e tração. Os resultados mostraram a viabilidade de fabricar pequenos lotes de peças em PEBD e PP com propriedades mecânicas bastante similares às encontradas em peças moldadas em moldes metálicos.Rapid Prototyping and Rapid Tooling are aimed at reducing the development time of products in the design phase by minimizing re-workings and, consequently, reducing the time to launch new products. In this work one of the technologies of rapid prototyping, called Fused Deposition Modeling (FDM, was used in the construction of ABS molds with the objective of investigating its application in the injection molding of thermoplastics. Specimens of the molded parts were characterized with X-ray diffraction, Shore D hardness and tensile tests. The results demonstrated the viability to manufacture small batches of LDPE and PP parts with mechanical properties similar to those molded parts in metallic molds.

  4. Modelagem estatística em estudos de bioequivalência sob o enfoque Bayesiano

    OpenAIRE

    Roberto Molina de Souza

    2015-01-01

    O interesse pelos estudos de bioequivalência iniciou-se na década de 60, sendo o FDA (EUA) a primeira agência reguladora a se interessar por esta questão. No Brasil, uma lei de 1999 regulamentou o medicamento genérico no país, sendo este um importante meio de acesso aos medicamentos pela população e fazendo parte da política de medicamentos do SUS. No Brasil, a ANVISA e responsável por inspecionar os centros de bioequivalência bem como dar as diretrizes para estes. Um modelo paramétrico padrã...

  5. Modelagem matemática da secagem de espuma de graviola

    OpenAIRE

    Fernanda M. Baptestini; Corrêa,Paulo C.; Junqueira,Mateus S.; Ramos,Afonso M.; Vanegas,Jaime D. B.; Costa,Cristian F.

    2015-01-01

    RESUMO Objetivou-se, com este trabalho, propor e ajustar modelos matemáticos ao processo de secagem de espuma de graviola em diferentes condições de ar, determinar o coeficiente de difusão efetivo e obter a energia de ativação. Para a formação da espuma foi adicionada, à polpa, albumina, na concentração de 7,43% em massa e submetida à agitação em batedeira doméstica, durante 15 min; em seguida, esta foi espalhada sobre bandejas formando uma camada fina de cerca de 5,0 mm de espessura cujas co...

  6. Modelagem de Equações Estruturais com Utilização do Smartpls

    Directory of Open Access Journals (Sweden)

    Christian M. Ringle

    2014-05-01

    Full Text Available O objetivo deste artigo é a apresentação de um exemplo de forma mais didática de uso da modelaem de Equações Estruturais com o software SmathPLS 2.0 M3. O referido programa usa o método de Mínimos Quadrados Parciais e busca atender situações muito frequentes na pesquisa de Marketing: Ausência de distribuições simétricas das variáveis mensuradas, teoria ainda em fase inicial ou com pouca “cristalização”, modelos formativos e/ou quantidade menor de dados. O uso crescente do SmartPLS vem mostrado a robusteza e aplicabilidade do modelo nas pesquisas da área. DOI: 10.5585/remark.v13i2.2717   

  7. Proposta de Melhoria do Processo de Contratação de Serviços de TI e da Gestão dos Contratos na Administração Pública Federal

    Directory of Open Access Journals (Sweden)

    José Gonçalo dos Santos

    2013-06-01

    Full Text Available Este trabalho se baseou numa análise exploratória com objetivo de analisar e mapear os processos de contratação de serviços de TI na Administração Pública Federal, tomando como base o Ministério da Ciência, Tecnologia e Inovação – MCTI, com uso das técnicas de modelagem de processos baseados na notação BPMN. Inicialmente, foi feita a modelagem dos processos atuais (AS-IS, e em seguida foi feita uma análise dos resultados. O trabalho foi feito com base na análise da IN 02/2010, Lei 10520/2002 e Lei 8666/1993. Com base nesta análise, os processos atuais foram mapeados. Os principais objetivos foram: identificar os processos de contratação de serviços de TI que estão relacionados com os projetos do órgão; analisar os processos de contratação de serviços de TI; modelar os processos de contratação de serviços de TI com notação BPMN; identificar os processos críticos de contratação de serviços de TI e propor melhorias.

  8. Satellite measurements of the earth's crustal magnetic field

    Science.gov (United States)

    Schnetzler, C. C.

    1989-01-01

    The literature associated with the Magsat mission has evaluated the capabilities and limitations of satellite measurements of the earth's crustal magnetic field, and demonstrated that there exists a 300-3000 km magnetic field, related to major features in the earth's crust, which is primarily caused by induction. Due to its scale and sensitivity, satellite data have been useful in the development of models for such large crustal features as subduction zones, submarine platforms, continental accretion boundaries, and rifts. Attention is presently given to the lack of agreement between laboratory and satellite estimates of lower crustal magnetization.

  9. Identificação e modelagem da autocorrelação residual no ajuste do modelo de Wood às curvas de lactação de cabras Identification and modeling of residual autocorrelation in the adjustments of Wood’s model to lactation curves of goats

    Directory of Open Access Journals (Sweden)

    Ana Lúcia Puerro de Melo

    2011-10-01

    Full Text Available Objetivou-se com este trabalho apresentar uma metodologia de identificação e modelagem da autocorrelação residual considerando ajustes individuais do modelo de Wood às lactações de cabras leiteiras e também avaliar a influência de tal modelagem na qualidade do ajuste. O modelo de Wood foi ajustado individualmente às lactações, considerando três estruturas residuais. Na primeira, assumiu-se independência dos erros (EI para todas as lactações, na segunda, assumiu-se a estrutura de erros autoregressivos de primeira ordem (AR1 para todas as lactações e, na terceira, nomeada por EI-AR1, foi utilizada a estrutura de erros AR1 somente para as lactações que apresentaram autocorrelação residual, segundo o teste de Durbin-Watson, e de EI para as demais. As três situações de ajuste foram comparadas pelos percentuais de convergência e pelas médias dos quadrados médios dos erros (QME e dos coeficientes de determinação ajustados (R²aj. As médias dos QME e dos R²aj apresentaram valores semelhantes nas três situações de estrutura residual. No entanto, o modelo com estrutura EI-AR1 apresentou maior convergência, o que consiste em uma vantagem, já que permite que um maior número de animais seja avaliado quanto à sua curva de lactação. Portanto, em função da maior convergência obtida, o ajuste do modelo de Wood com a estrutura EI-AR1 consiste na opção mais indicada para grandes conjuntos de dados.The objective of this research was to present a methodology for identification and modeling of residual autocorrelation considering individual adjustments of the Wood's model to lactation dairy goats and evaluate the influence of such modeling in the quality of adjustment. The Wood's model was adjusted individually for lactations in three different ways, the first have assumed independence of errors (IE for all lactations, the second have assumed autoregressives first order errors (AR1 for all lactations and the third, named

  10. Sete motivações teóricas para o uso da modelagem baseada no indivíduo em ecologia Seven theoretical reasons for using individual-based modeling in Ecology

    Directory of Open Access Journals (Sweden)

    Henrique C. Giacomini

    2007-01-01

    Full Text Available A modelagem baseada no indivíduo tem sido crescentemente empregada para analisar processos ecológicos, desenvolver e avaliar teorias, bem como para fins de manejo da vida silvestre e conservação. Os modelos baseados no indivíduo (MBI são bastante flexíveis, permitem o uso detalhado de parâmetros com maior significado biológico, sendo portanto mais realistas do que modelos populacionais clássicos, mais presos dentro de um rígido formalismo matemático. O presente artigo apresenta e discute sete razões para a adoção dos MBI em estudos de simulação na Ecologia: (1 a inerente complexidade de sistemas ecológicos, impassíveis de uma análise matemática formal; (2 processos populacionais são fenômenos emergentes, resultando das interações entre seus elementos constituintes (indivíduos e destes com o meio; (3 poder de predição; (4 a adoção definitiva, por parte da Ecologia, de uma visão evolutiva; (5 indivíduos são entidades discretas; (6 interações são localizadas no espaço e (7 indivíduos diferem entre si.Individual-based modeling has been increasingly used to analyze ecological processes, to develop and to evaluate theories, as well as to the management of wild life and conservation. The individual-based models (IBM are quite flexible, allowing a detailed inclusion of parameters with greater biological meaning, therefore being more realistic than classical population models, which are too constrained inside mathematical formalisms. The present paper discuss seven reasons for IBM to be adopted in simulation studies inside Ecology: (1 ecological systems are inherently complex, being not open to a complete formal mathematical analysis; (2 population processes are emergent outputs from the interactions among individuals and the environment; (3 predictive power; (4 the evolutive view as a definitive guide for ecological studies; (5 individuals are discrete entities; (6 interactions are localized in space and (7

  11. O potencial das redes de Petri em modelagem e análise de processos de negócio The potencial of Petri nets in modeling and analysis of workflow

    Directory of Open Access Journals (Sweden)

    Sílvia Inês Dallavalle de Pádua

    2004-04-01

    Full Text Available A tecnologia de gerenciamento workflow procura oferecer uma solução flexível em apoio aos processos de negócios, por meio da facilitação de modificações e da criação de novos processos. Entretanto, a falta de definição bem formalizada no que se refere à sintaxe e à semântica de tais técnicas dificulta análises mais complexas dos modelos. Nesse caso, redes de Petri atuam com excelente potencial, uma vez que possuem representação gráfica, são de fácil aprendizado, funcionam como linguagem de comunicação entre especialistas de diversas áreas, possibilitam descrever aspectos estáticos e dinâmicos do sistema a ser representado e ainda possuem o formalismo matemático necessário para métodos de análise já consagrados. O presente trabalho tem por objetivo, primeiramente, oferecer uma visão atualizada do estado da arte na área de modelagem de workflow baseada em redes de Petri e expor um exemplo de modelo de workflow com parâmetros de tempo e custo associados às transições da rede. O objetivo secundário é apresentar conceitos importantes de redes de Petri, workflow e rotas de processos.Unfortunately these systems and techniques do not have well-defined syntax and semantic, which makes harder the complex analysis of models. In this case, Petri nets have excellent potential to solve the problem, once they present graphic representation and easy understanding. They are used as a communication language among expert people in different areas, and may allow the description of static and dynamic aspects of the systems that have to be represented. Also, they have mathematic formalism, which make possibly the use of the analysis methods. The objective of this work is to present the potential of Petri nets in studies of Enterprise Modelling and Workflow, showing an example of application, with time and cost parameters.

  12. MATHEMATICAL MODELING OF PHOSPHORUS CONCENTRATION: A TOOL FOR WATER RESOURCES MANAGEMENT = MODELAGEM MATEMÁTICA DA CONCENTRAÇÃO DE FÓSFORO: UMA FERRAMENTA PARA A GESTÃO DOS RECURSOS HÍDRICOS

    Directory of Open Access Journals (Sweden)

    Camila Pereira Montovani

    2013-01-01

    Full Text Available Water is a key asset to life, it is imperative to guarantee their quality, among other reasons, to the survival of living beings. Nowadays, with the range of the anthropogenic activities, it is important that rivers, reservoirs and springs are with physical, chemical and biological character according to the standards established by government, according to the class as intended. With the purpose to develop a tool to support the management of water resources for analysis of behavior pollutants, we carried out a phosphorus modeling based on mathematical and computational tools, in a public water supply source. The results feature the pollutant evolutionary behavior, allowing to analyze scenarios and make decisions with a view to preventive or remedial about a component that, in excess, interfere with water quality, mainly, in the eutrophication process that undertakes all the local biota. = A água é um bem essencial à vida, dessa forma é imprescindível a garantia de sua qualidade para, dentre outras razões, a sobrevivência dos seres vivos. Hoje em dia, com a amplitude e o desenvolvimento das atividades antrópicas, é importante que rios, reservatórios e mananciais estejam com características físicas, químicas e biológicas dentro dos padrões estabelecidos pelos órgãos governamentais, de acordo com a classe a que se destinam. Com o intuito de se desenvolver uma ferramenta de suporte à gestão de recursos hídricos para análises de comportamento de poluentes, realizou-se uma modelagem da concentração do componente fósforo baseado em instrumentos matemáticos e computacionais, num manancial de abastecimento público. Os resultados obtidos apresentam o comportamento evolutivo do poluente e possibilitam a geração de cenários e a tomada de decisões com vistas a ações preventivas ou de remediação acerca de um componente que, em excesso, interfere na qualidade das águas devido, principalmente, ao processo de eutrofiza

  13. Crustal Thickness and Lower Crustal Velocity Structure Beneath the Endeavour Segment of the Juan de Fuca Ridge

    Science.gov (United States)

    Hill, R.; Soule, D. C.; Wilcock, W. S. D.; Toomey, D. R.; Hooft, E. E. E.; Weekly, R. T.

    2014-12-01

    In 2009, a multi-scale seismic tomography experiment was conducted on the Endeavour segment of the Juan de Fuca Ridge aboard the R/V Marcus G. Langseth. Ocean bottom seismometers were deployed at 64 sites and recorded 5567 shots of a 36-element, 6600 in.3 airgun array. The experiment extended 100 km along-axis and 60 km cross-axis. Two crustal tomographic analyses have previously been completed using data from the experiment. First, 93,000 manually picked crustal refraction arrivals (Pg) were used to develop a three-dimensional model of crustal velocity and thickness in the upper crust (Weekly et al. 2014). Second, this model was used as the starting model in an analysis that incorporated ~19,000 Moho reflection arrivals (PmP) for non-ridge crossing paths to image lower crustal velocity structure and crustal thickness off-axis. A key feature of this model is a ~0.5-1 km increase in crustal thickness beneath a bathymetric plateau that extends to either side of the central portion of the Endeavour segment. We present a tomographic inversions that incorporates ridge-crossing paths to examine spatial variations in lower crustal velocity and crustal thickness beneath the ridge axis. The preliminary results from an inversion that incorporates ~8700 manually picked ridge-crossing PmP arrival times reveals a ~10-km-wide low velocity zone extending throughout the lower crust with a velocity anomaly of -0.3 to -0.5 km/s at ≥4 km depth. This low velocity zone extends both to the north and south of the axial magma chamber reflector imaged previously beneath the central Endeavour. The inversion also shows significant variations in apparent crustal thickness along axis but additional analysis is required to understand whether these variations are well resolved.

  14. Crustal seismicity of the Black Sea areal

    Science.gov (United States)

    Diaconescu, Mihail; Moldovan, Iren-Adelina; Petruta Constantin, Angela

    2014-05-01

    The main target of the study is to decipher the seismicity of the Black Sea areal from the tsunami-genetic potential. From the seismotectonical point of view the earthquakes which are responsible for tsunami are those associated with thrust faults (subduction zones), normal and inverse faults and less strike slip faults (only if the oblique-slip and deep slip components are predominant), with magnitude higher than 6.5 (even the USGS cited tsunami at 5.1 magnitude) and depth, a shallow one, less than 20 km depth. In order to delimit the seismic sources from Black Sea and to discrimate among them the tsunamigenic ones, the following elements have been taken into account: - depth of the earthquakes foci, that allow separation of two major categories: deeper than 40 km depth and crustal, normal, (less than 40 km deep); - development of the earthquakes epicenters in the orogen zone or in zones with active tectonics (fault systems); - establishment of the areas of active faults along which the earthquakes epicenters are aligned; - the absence of a recent or actual tectonic activity; the epicenters recorded in these tectonically stable zones are considered as the result of a diffuse, accidental seismicity. The studies on active tectonics have clearly shown the position of the seismic sources (connected to well define active fault) which do not interfere and do not result in alternatives of other seismotectonic model constructions. According to the distribution map of earthquakes and as well as to the map of the areas with active tectonics, ten seismic sources were established: Central Dobrogea(S1), Shabla(S2), Istanbul(S3), North Anatolian Fault(S4), Georgia(S5), Novorossjsk(S6), Crimea(S7), West Black Sea Fault(S8) and Mid Black Sea Ridge(S9). The maximum possible magnitude of each seismic source was obtained through three aproaches: (i) using seismotectonics and geological database (the length of the faults, possible apparition on surface, geomorphology, etc

  15. Modelagem da Densidade do Solo em Profundidade sob Vegetação Nativa em Minas Gerais

    Directory of Open Access Journals (Sweden)

    Eduane José de Pádua

    2015-06-01

    Full Text Available A densidade do solo (Ds é um importante indicador da qualidade física do solo, mas há pouca disponibilidade de informações sobre seus valores a maiores profundidades em razão da dificuldade amostral envolvida. Portanto, funções de pedotransferência têm sido utilizadas para estimar a Ds com relativo êxito, mas ainda sem especificidade aos diferentes biomas brasileiros. O objetivo deste trabalho foi desenvolver funções matemáticas capazes de descrever a Ds até 1 m de profundidade em áreas de vegetação nativa das regiões central e sul de Minas Gerais. A Ds foi amostrada pelo método do anel volumétrico em 53 perfis de solo de diferentes ordens, em seis profundidades (0-5, 5-10, 10-20, 30-40, 50-60 e 90-100 cm. A Ds variou entre 0,66 e 1,74 kg dm-3, com média de 1,25 kg dm-3, e foi geralmente menor nas camadas de 0-5 e 5-10 cm. Por meio de regressão linear múltipla (stepwise, foram gerados modelos com base nas propriedades químicas de rotina e granulometria, que permitiram estimar a Ds até 1 m de profundidade. Os teores de C orgânico do solo, areia, silte e argila e a capacidade de troca catiônica potencial (T foram as variáveis de maior relevância nos modelos, que alcançaram maior acurácia para a ordem Latossolos (R2ajust = 0,85, seguida por Cambissolos (R2ajust = 0,69, Nitossolos (R2ajust = 0,67 e Argissolos (R2ajust = 0,51. Uma vez que a modelagem para a base de dados completa atingiu R2ajust de 0,50, pode-se concluir que a estratificação por ordem taxonômica foi útil para melhorar os ajustes obtidos, com exceção da ordem Argissolo.

  16. MODELAGEM DE ÁREAS DE ESCOAMENTO SUPERFICIAL A PARTIR DO MODELO DIGITAL DE TERRENO

    Directory of Open Access Journals (Sweden)

    Angelo Moura Araújo

    2011-04-01

    Full Text Available  O presente estudo foi desenvolvido no município Teofilândia, Bahia, de clima semi-árido, com população total de 21.461 habitantes. Este artigo baseia-se na análise e identificação de áreas potenciais de umidade e da morfodinâmica dos canais de drenagem em regiões semi-áridas. A abordagem metodológica compreende: a discussão teórica da utilização do MDT e do uso do SIG. Foram produzidos mapas de sinuosidade, cotas e umidade para classificação do padrão de drenagem existente e avaliar as áreas potenciais de umidade disponível. A partir do índice de sinuosidade e níveis de cotas, rios e riachos foram analisados, demonstrando a tendência dos fluxos de superfície nos canais. Usando álgebra de mapas foi possível separar áreas com diferentes níveis de umidade na área estudada. As áreas de alta umidade, em geral, são identificadas como potenciais para a construção de barragens, uma vez que são as mais prováveis para a manutenção por um longo período de tempo da água existente, favorecendo a implantação destas barragens. O mapa final nos permite avaliar e identificar áreas com maior possibilidade de acúmulo de água de superfície, permitindo desenvolver planos de ação para a utilização dessas áreas para fins diversos, como áreas agrícolas e construção de barragens.

  17. Modelagem da retração por secagem de concretos produzidos com agregados reciclados

    Directory of Open Access Journals (Sweden)

    A. E. B. Cabral

    Full Text Available A preocupação com a conservação dos recursos não renováveis tem levado o meio acadêmico a pesquisar sobre a utilização dos agregados reciclados na produção de concretos. A retração por secagem do concreto é um fenômeno que está intimamente ligado à perda de água da massa do concreto, a qual é quase inevitável, desde que o concreto esteja exposto a um ambiente de umidade abaixo da condição de saturação. Este artigo apresenta um estudo experimental, onde foram produzidos concretos variando-se a relação água/cimento (de 0,4 a 0,8 e o tipo e a proporção dos três principais constituintes do resíduo de construção e demolição (concreto, argamassa e cerâmica vermelha usados como agregados graúdos e miúdos reciclados, produzindo-se modelos matemáticos que correlacionam tais variáveis com a retração por secagem dos concretos aos 56 e 224 dias de idade. Os resultados apontam que, para a idade de 56 dias, o modelo apresentou uma excessiva variabilidade, manifestando somente 4 das 7 variáveis como termos significativos. Para a idade de 224 dias, o modelo proposto ainda apresentou uma elevada variabilidade, entretanto todas as variáveis foram tidas como significativas. Os resultados apontam que a substituição do agregado natural pelo reciclado propicia um acréscimo na retração por secagem, sendo este efeito mais sentido para a substituição do agregado miúdo. O efeito mais pronunciado está associado ao emprego do agregado miúdo reciclado de concreto e o menor, ao do agregado graúdo reciclado de concreto.

  18. MODELAGEM TERMOQUÍMICA DA DESINFECÇÃO POR CLORO GASOSO

    Directory of Open Access Journals (Sweden)

    Luciano Nascimento

    2009-12-01

    Full Text Available Este trabalho mostra o desenvolvimento de (1 um sistema químico constituído pela adição de ácido fraco monoprótico (ácido hipocloroso, HOCl à água e (2 um modelo termodinâmico que mostra, de forma sistemática, as reações envolvendo o Cloro. As espécies do sistema HOCl + H2O bem como pH e pCT são representadas pictoricamente no diagrama pCT x pH que permite analisar a influência do ácido hipocloroso na reação de desinfecção e obter a fração do residual livre do composto de cloro. No modelo termodinâmico aplicado ao sistema H2O +Cl2(g + HOCl + OCl-, as reações redox permitiram obter os parâmetros pε e pH. Essas reações são analisadas a 25°C e os resultados são somente válidos para esta temperatura.

  19. Modelagem matemática da secagem de espuma de graviola

    Directory of Open Access Journals (Sweden)

    Fernanda M. Baptestini

    2015-12-01

    Full Text Available RESUMO Objetivou-se, com este trabalho, propor e ajustar modelos matemáticos ao processo de secagem de espuma de graviola em diferentes condições de ar, determinar o coeficiente de difusão efetivo e obter a energia de ativação. Para a formação da espuma foi adicionada, à polpa, albumina, na concentração de 7,43% em massa e submetida à agitação em batedeira doméstica, durante 15 min; em seguida, esta foi espalhada sobre bandejas formando uma camada fina de cerca de 5,0 mm de espessura cujas condições de secagem foram: de 40, 50, 60, 70 e 80 °C, 5,6 m s-1 e 60%. O modelo para determinar o binômio teor de água crítico e tempo crítico e o de Midili se ajustaram bem aos dados experimentais da secagem de espuma de graviola e se obteve acréscimo no coeficiente de difusão efetiva com a elevação da temperatura de secagem e energia de ativação de 33,10 kJ mol-1.

  20. Crustal structure and active tectonics in the Eastern Alps

    DEFF Research Database (Denmark)

    Brückl, E.; Behm, M.; Decker, K.

    2010-01-01

    During the last decade, a series of controlled source seismic experiments brought new insight into the crustal and lithospheric structure of the Eastern Alps and their adjacent tectonic provinces. A fragmentation of the lithosphere into three blocks, Europe (EU), Adria (AD), and the new Pannonian...... fragment (PA), was interpreted and a triple junction was inferred. The goal of this study has been to relate these deep crustal structures to active tectonics. We used elastic plate modeling to reconsider the Moho fragmentation. We interpret subduction of EU below AD and PA from north to south...... and underthusting of AD mantle below PA from southwest to northeast. The Moho fragmentation correlates well with major upper crustal structures and is supported by gravity, seismic, and geodetic data. An analysis of crustal thickening suggests that active convergence is associated with continued thrusting...

  1. Oligocene crustal anatexis in the Tethyan Himalaya, southern Tibet

    Science.gov (United States)

    Gao, Li-E.; Zeng, Lingsen; Gao, Jiahao; Shang, Zhen; Hou, Kejun; Wang, Qian

    2016-11-01

    Recent studies in the Xiaru and Malashan gneiss dome of the Tethyan Himalaya, southern Tibet identify that Xiaru and Paiku tourmaline-bearing leucogranite dike formed at 28-29 Ma. Together with 28 Ma Kuday garnet-bearing leucogranites, it is demonstrated that the Himalayan orogenic belt experienced a major episode of crustal melting in the Mid-Oligocene. Geochemical data indicate that three suites of leucogranite are characterized by large variations in the major and trace element compositions as well as Sr-Nd isotope systematics, which could be explained by combined fractional crystallization and relative contributions of micas and accessory phases dissolved into a crustal melt during decompressional melting of metapelitic rocks. Documentation of Oligocene partial melting of crustal rocks could indicate that the exhumation of deep crustal rocks in the Himalayan orogenic belt could have started as early as Oligocene.

  2. Crustal fingering: solidification on a moving interface

    Science.gov (United States)

    Fu, Xiaojing; Jimenez-Martinez, Joaquin; Porter, Mark; Cueto-Felgueroso, Luis; Juanes, Ruben

    2016-11-01

    Viscous fingering-the hydrodynamic instability that takes place when a less viscous fluid displaces a more viscous fluid-is a well known phenomenon. Motivated by the formation of gas hydrates in seafloor sediments and during the ascent of gas bubbles through ocean water, here we study the interplay of immiscible viscous fingering with solidification of the evolving unstable interface. We present experimental observations of the dynamics of a bubble of Xenon in a water-filled and pressurized Hele-Shaw cell. The evolution is controlled by two processes: (1) the formation of a hydrate "crust" around the bubble, and (2) viscous fingering from bubble expansion. To reproduce the experimental observations, we propose a phase-field model that describes the nucleation and thickening of a porous solid shell on a moving gas-liquid interface. We design the free energy of the three-phase system (gas-liquid-hydrate) to rigorously account for interfacial effects, mutual solubility, and phase transformations (hydrate formation and disappearance). We introduce a pseudo-plasticity model with large variations in viscosity to describe the plate-like rheology of the hydrate shell. We present high-resolution numerical simulations of the model, which illustrate the emergence of complex "crustal fingering" patterns as a result of gas fingering dynamics modulated by hydrate growth at the interface.

  3. Ionospheric precursors for crustal earthquakes in Italy

    Directory of Open Access Journals (Sweden)

    L. Perrone

    2010-04-01

    Full Text Available Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979–2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8–5.9 tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.

  4. Modelagem de conhecimento baseada em ontologias aplicada às Políticas Públicas de Habitação

    Directory of Open Access Journals (Sweden)

    Alexandre Mori

    2011-04-01

    Full Text Available Este estudo tem como objetivo propor um método de modelagem de conhecimento baseado em Linguística Computacional e ontologias com participação direta de especialistas no domínio pesquisado. O modelo foi aplicado às intervenções governamentais no campo habitacional com intuito de verificar a variação terminológica nas diversas regiões do país. Com isto, produz-se uma base de conhecimento modelada através das definições conceituais emitidas pelos usuários. O objetivo é reduzir as divergências semânticas em conceitos utilizados no monitoramento de políticas habitacionais.

  5. Uma proposta de modelagem para integração de sistemas de gestão de produção em empresas de manufatura

    OpenAIRE

    Renato Campos

    1998-01-01

    Resumo: Este trabalho apresenta conceitos de modelagem e integração de empresa. Também são apresentados modelos para a implementação de uma hierarquia de planejamento e controle de produção (PCP) de um ambiente experimental PIPEFA (Plataforma Industrial para Pesquisa Ensino e Formação em Automação) que simula um sistema integrado de produção. Inicialmente são descritos conceitos e funções clássicas de PCP, destacando a necessidade de modelar aspectos de funções, informações, recursos, organiz...

  6. MODELAGEM DA DISTRIBUIÇÃO DIAMÉTRICA DE POVOAMENTOS EQUIÂNEOS DE EUCALIPTO UTILIZANDO A FUNÇÃO LOGÍSTICA GENERALIZADA

    OpenAIRE

    Daniel Henrique Breda Binoti; Mayra Luiza Marques da Silva Binoti; Helio Garcia Leite

    2015-01-01

    RESUMOObjetivou-se neste estudo analisar a aplicação da função logística generalizada para a descrição da estrutura diamétrica de povoamentos de eucalipto, bem como propor um modelo de distribuição diamétrica utilizando a função. Realizou-se também a modelagem da distribuição diamétrica utilizando a função Weibull para fins comparativos. Utilizaram-se dados de parcelas permanentes de um inventário florestal contínuo nas idades de 28, 40, 52, 64, 76 e 84 meses. Ajustou-se a função logística ge...

  7. Modelagem Sísmica via métodos das diferenças finitas: caso da bacia do Amazonas Seismic Modeling by finites difference method: case of Amazon basin

    Directory of Open Access Journals (Sweden)

    Lindemberg Lima Fernandes

    2009-03-01

    Full Text Available Este trabalho tem por objetivo apresentar os resultados da modelagem sísmica em meios com fortes descontinuidades de propriedades físicas, com ênfase na existência de difrações e múltiplas reflexões, tendo a Bacia do Amazonas como referência à modelagem. As condições de estabilidade e de fronteiras utilizadas no cálculo do campo de ondas sísmicas foram analisadas numericamente pelo método das diferenças finitas, visando melhor compreensão e controle da interpretação de dados sísmicos. A geologia da Bacia do Amazonas é constituída por rochas sedimentares depositadas desde o Ordoviciano até o Recente que atingem espessuras da ordem de 5 km. Os corpos de diabásio, presentes entre os sedimentos paleozóicos, estão dispostos na forma de soleiras, alcançam espessuras de centenas de metros e perfazem um volume total de aproximadamente 90000 Km³. A ocorrência de tais estruturas é responsável pela existência de reflexões múltiplas durante a propagação da onda sísmica o que impossibilita melhor interpretação dos horizontes refletores que se encontram abaixo destas soleiras. Para representar situações geológicas desse tipo foram usados um modelo (sintético acústico de velocidades e um código computacional elaborado via método das diferenças finitas com aproximação de quarta ordem no espaço e no tempo da equação da onda. A aplicação dos métodos de diferenças finitas para o estudo de propagação de ondas sísmicas melhorou a compreensão sobre a propagação em meios onde existem heterogeneidades significativas, tendo como resultado boa resolução na interpretação dos eventos de reflexão sísmica em áreas de interesse. Como resultado dos experimentos numéricos realizados em meio de geologia complexa, foi observada a influência significativa das reflexões múltiplas devido à camada de alta velocidade, isto provocou maior perda de energia e dificultou a interpretação dos alvos. Por esta raz

  8. Pb isotopic geochemical study on the crustal structure of Tongbaishan

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Pb isotopic composition of the Tongbai complex, distributed in the Tongbaishan to the west of the Dabieshan, ranges between the Dabie core complex and the Dabie ultral-high pressure (UHP) metamorphic complex, the latter having more radiogenic Pb isotopic composition than the former. Granites from the Jigongshan pluton, which intruded mainly into the Tongbai complex, are distinct from the Tongbai complex but similar to the Dabie core complex in Pb isotopic composition, showing that the magma of the Jigongshan granites was derived from the partial melting of the Dabie core complex. According to Pb isotopic compositional variation model in the vertical crustal section and magma source from the Jigongshan pluton, it is suggested that the Tongbai complex was an upper rock serial of the Dabie core complex, which is beneath the Dabie UHP metamorphic complex in the crustal structure of the Tongbai-Dabie orogenic belt. The Tongbai complex was not well preserved in the Dabie area due to the high exhumed crustal section. However, the crustal section in the Tongbai area was exhumed less than that in the Dabie area, and the deep crust in the Tongbai area still contains the basement composition similar to the Dabie core complex. Therefore, the crustal basements from the Dabie to Tongbai areas are united. The present distribution of the basement blocks in different locations of the Tongbai-Dabie orogenic belt reflects different exposure of the crustal section.

  9. CRUSTAL THICKNESS VARIATIONS AND SEISMICITY OF NORTHWESTERN SOUTH AMERICA

    Directory of Open Access Journals (Sweden)

    Woo Kim Jeong

    2007-06-01

    Full Text Available Any uncompensated mass of the northern Andes Mountains is presumably under pressure to adjust within the Earth to its ideal state of isostatic equilibrium. Isostasy is the ideal state that any
    uncompensated mass seeks to achieve in time. These pressures interact with the relative motions between adjacent plates that give rise to earthquakes along the plate boundaries. By combining the
    gravity MOHO estimates and crustal discontinuities with historical and instrumental seismological catalogs the correlation between isostatically disturbed terrains and seismicity has been established.
    The thinner and thicker crustal regions were mapped from the zero horizontal curvature of the crustal thickness estimates. These boundaries or edges of crustal thickness variations were compared to
    crustal discontinuities inferred from gravity and magnetic anomalies and the patterns of seismicity that have been catalogued for the last 363 years. The seismicity is very intense along the Nazca-North
    Andes, Caribbean-North American and North Andes-South American collision zones and associated with regional tectonic compressional stresses that have locally increased and/or diminished by
    compressional and tensional stress, respectively, due to crustal thickness variations. High seismicity is also associated with the Nazca-Cocos diverging plate boundary whereas low seismicity is associated with the Panama-Nazca Transform Fault and the South American Plate.

  10. Population Dynamics Modeling of Arapaima gigas Modelagem da dinâmica populacional de Arapaima gigas

    Directory of Open Access Journals (Sweden)

    Eliane dos Santos de Souza Coutinho

    2010-01-01

    âmica populacional do pirarucu considerando as peculiaridades da espécie, particularmente o cuidado parental do macho sobre seus descendentes. A solução dos sistemas dinâmicos indicaram três possíveis pontos de equilíbrio para a população. O primeiro corresponde à extinção; o terceiro corresponde a uma população estável próxima da capacidade suporte do ambiente. O segundo corresponde a um equilíbrio instável localizado entre a extinção e a capacidade suporte do ambiente. Foi mostrado que a falta do cuidado parental de machos aproxima o ponto que corresponde ao equilíbrio instável e o ponto de equilíbrio estável não trivial. Se a falta de cuidado dos machos alcança um ponto crítico, os dois pontos coincidem e a população tende irreversivelmente à extinção. Os parâmetros introduzidos para resolver o sistema de equações foram derivados parcialmente de limitados, mas confiáveis dados de campo coletados na Reserva de Desenvolvimento Sustentável Mamirauá (RDSM na Amazônia brasileira.

  11. Petrographic, geochemical and isotopic evidence of crustal assimilation processes in the Ponte Nova alkaline mafic-ultramafic massif, SE Brazil

    Science.gov (United States)

    Azzone, Rogério Guitarrari; Montecinos Munoz, Patricio; Enrich, Gaston Eduardo Rojas; Alves, Adriana; Ruberti, Excelso; Gomes, Celsode Barros

    2016-09-01

    be responsible for the increse in the K2O/Na2O, Ba/Sr and Rb/Sr ratios. This enrichment was associated with the relevant role of biotite breakdown in the assimilated host rock partial melts. The petrological model for the Ponte Nova massif is explained as repeated influxes of antecryst-laden basanite magmas that deposited most of their suspended crystals on the floor of the upper-crust magma chamber. Each intrusion is representative of relatively primitive olivine- and clinopyroxene-phyric basanites that had assimilated different degrees of partial melts of heterogeneous host rocks. This study reveals the relevant role of crustal assimilation processes in the magmatic evolution of nepheline-normative rocks, especially in upper-crust chamber environments.

  12. Monitoring Crustal Movement of the Coastal Zone in Eastern China with GPS Technique

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    In this paper, various dominating factors affecting crustal movement of the coastal zone in eastern China are analyzed, and major characteristics of crustal movement are summarized. Subduction of the pacific plate and Philippine plate and southeastward "escape" of Qinghai-Tibet plateau are believed to be dominating factors affecting crustal movement of that zone. Undoubtedly, it is a best way to monitor this kind of large-scale crustal movement with GPS technique. The feasibility of monitoring crustal m...

  13. Modelagem da adsorção de compostos orgânicos voláteis sobre nanotubos de carbono cup-stacked usando o modelo da força motriz linear - doi: 10.4025/actascitechnol.v32i2.4817

    Directory of Open Access Journals (Sweden)

    Waldir Nagel Schirmer

    2010-07-01

    Full Text Available Os compostos orgânicos voláteis (COV são importante classe de poluentes do ar, e a adsorção tem sido largamente empregada no seu tratamento há vários anos. O presente trabalho utilizou metodologias analíticas convencionais para avaliar o nanotubo cup-stacked(CSCNT na purificação de correntes gasosas contaminadas com COV. O CSCNT é constituído de múltiplas camadas de grafeno em formato cônico, apresentando extremidades abertas em sua superfície externa e canais centrais vazios. Foi adotado o Carbotrap como suporte do cup-stacked. O adsorvente-parâmetro de comparação do desempenho desse compósito foi o próprio Carbotrap (sem o nanotubo. Foi avaliada a capacidade de adsorção de cada adsorvente, bem como suas capacidades de saturação para cada uma das concentrações trabalhadas com os dois adsorbatos utilizados (1, 5, 20 e 35 ppm de tolueno e fenol. Na modelagem das curvas massaxtempo, utilizou-se o modelo da força motriz linear (LDF – linear driving force. A metodologia proposta para determinação das curvas massatempo mostrou-se aplicável a análises desta natureza. Em relação ao desempenho dos adsorventes, o compósito obteve clara vantagem em relação ao Carbotrap; os valores das capacidades de saturação para o compósito foram, em média, 67% superiores aos obtidos para o Carbotrap.

  14. Modelagem da biomassa total e da lenha por unidade de área para bracatingais nativos

    Directory of Open Access Journals (Sweden)

    Ronan Felipe de Souza

    2014-02-01

    Full Text Available A bracatinga (Mimosa scabrella Benth. é uma espécie pioneira nativa da Floresta Ombrófila Mista de rápido crescimento e cultivada, predominantemente, na forma de povoamentos puros ou consorciada com culturas agrícolas pelos pequenos e médios produtores da região metropolitana de Curitiba. O objetivo deste estudo foi selecionar equações estimativas da biomassa total e da lenha de bracatingais por unidade de área nas diferentes idades, disponibilizando, assim, uma ferramenta simples e de fácil aplicação durante o processo de comercialização dos povoamentos. Os dados são provenientes de 272 parcelas temporárias com idades variando de 3 a 18 anos. Foram testados 21 modelos tradicionais: 10 aritméticos e semilogarítmicos e 11 logarítmicos. Foram também desenvolvidas equações pelo processo Stepwise a partir de uma matriz de correlação. As equações ajustadas foram comparadas pelo Coeficiente de determinação ajustado (R²aj, Erro-padrão da estimativa percentual (Syx%, teste F e Distribuição gráfica de resíduos. Duas equações para cada caso foram selecionadas, sendo uma tradicional e a outra desenvolvida por Stepwise. Para a biomassa total, foram selecionadas a equação de Clutter e a equação aritmética desenvolvida por Stepwise; e para a biomassa da lenha, a equação da variável combinada, proposta por Spurr, e a equação aritmética de Stepwise. Por fim, realizou-se teste Qui-quadrado (x² a partir de uma amostra de 17 parcelas extraídas da base de dados, em que as quatro equações selecionadas foram consideradas válidas para a estimativa da biomassa total e da lenha dos bracatingais da região metropolitana de Curitiba.

  15. Nitrogen speciation in mantle and crustal fluids

    Science.gov (United States)

    Li, Yuan; Keppler, Hans

    2014-03-01

    Seventy-nine experiments have been carried out at 600-1400 °C, 2-35 kbar, and oxygen fugacities ranging from the Fe-FeO to the Re-ReO2 buffer to investigate the nitrogen speciation in mantle and crustal N-H-O fluids. Laser Raman analyses of fluid inclusions trapped in situ in quartz and olivine crystals show that N2 and/or NH3 are the only detectable nitrogen species in the fluids at the conditions of the present study. The results further show that in the fluids of the oxidized shallow upper mantle, nitrogen is mostly present as N2, while in the deep reduced upper mantle, NH3 is the dominant nitrogen species. Nitrogen speciation in subduction zone fluids is also calculated from the experimental data to constrain the efficiency of nitrogen recycling. The data show that a hot, oxidized slab is an efficient barrier for deep nitrogen subduction, while a cold, reduced slab would favor recycling nitrogen into the deep mantle. The nitrogen species in magmatic fluids of mid-ocean ridge basalt and arc magmas are predominantly N2, but a significant fraction of nitrogen can be NH3 at certain conditions. The nitrogen species in fluids released from the solidifying magma ocean and the reduced young mantle may have been mostly NH3. The release of such fluids may have created a reduced atmosphere on the every early Earth, with an elevated concentration of NH3. This may not only resolve the faint young Sun paradox but may also have created favorable conditions for the formation of biomolecules through Miller-Urey type reactions.

  16. Estimativa do crescimento de povoamentos de Eucalyptus baseada na teoria dos modelos não lineares em multinível de efeito misto.

    Directory of Open Access Journals (Sweden)

    Natalino Calegario

    2010-08-01

    Full Text Available O presente estudo foi baseado na utilização da teoria dos modelos não-lineares de efeito misto em multiníveis para a modelagem do crescimento em altura de povoamentos clonais de Eucalyptus. A base de dados utilizada representa medições de árvores individuais, tomadas em diferentes locais e no tempo, sendo a mesma classificada de longidudinal, irregularmente espaçada, não-balanceada, com autocorrelação e com a presença de heterogeneidade de variância. O modelo logístico de três parâmetros foi utilizado para a estimativa do crescimento em altura. Os parâmetros do modelo foram estimados como de efeitos fixos e aleatórios em dois níveis: unidade amostral (nível 1 e árvore individual dentro das unidades amostrais (nível 2. A inclusão de tais níveis reduziu sensivelmente o erro padrão da estimativa para o modelo. As estimativas também foram melhoradas com a modelagem da heterogeneidade da variância, utilizando estruturas diagonais, e da autocorrelação, com a estrutura ARMA(2,1.

  17. Crustal-thickness variations in the central Andes

    Science.gov (United States)

    Beck, Susan L.; Zandt, George; Myers, Stephen C.; Wallace, Terry C.; Silver, Paul G.; Drake, Lawrence

    1996-05-01

    We estimated the crustal thickness along an east-west transect across the Andes at lat 20°S and along a north-south transect along the eastern edge of the Altiplano from data recorded on two arrays of portable broadband seismic stations (BANJO and SEDA). Waveforms of deep regional events in the downgoing Nazca slab and teleseismic earthquakes were processed to isolate the P-to-S converted phases from the Moho in order to compute the crustal thickness. We found crustal-thickness variations of nearly 40 km across the Andes. Maximum crustal thicknesses of 70 74 km under the Western Cordillera and the Eastern Cordillera thin to 32 38 km 200 km east of the Andes in the Chaco Plain. The central Altiplano at 20°S has crustal thicknesses of 60 to 65 km. The crust also appears to thicken from north (16°S, 55 60 km) to south (20°S, 70 74 km) along the Eastern Cordillera. The Subandean zone crust has intermediate thicknesses of 43 to 47 km. Crustal-thickness predictions for the Andes based on Airy-type isostatic behavior show remarkable overall correlation with observed crustal thickness in the regions of high elevation. In contrast, at the boundary between the Eastern Cordillera and the Subandean zone and in the Chaco Plain, the crust is thinner than predicted, suggesting that the crust in these regions is supported in part by the flexural rigidity of a strong lithosphere. With additional constraints, we conclude that the observation of Airy-type isostasy is consistent with thickening associated with compressional shortening of a weak lithosphere squeezed between the stronger lithosphere of the subducting Nazca plate and the cratonic lithosphere of the Brazilian craton.

  18. Índice de cobertura vegetal e sua modelagem para cultivares de soja no sul de Minas Gerais Index of vegetal cover and its modeling for soybean cultivars in the south of Minas Gerais

    Directory of Open Access Journals (Sweden)

    Vitor Corrêa de Mattos Barreto

    2010-10-01

    Full Text Available A cobertura vegetal do solo é decisiva para redução dos efeitos erosivos do impacto direto das gotas de chuva na superfície do solo. Desta forma, objetivou-se com este estudo determinar o índice de cobertura vegetal (CV e desenvolver modelos para sua estimativa para a cultura da soja, usando os atributos climáticos no período de chuvas intensas no Sul de Minas Gerais. As determinações da CV foram feitas semanalmente, na área experimental do Departamento de Ciência do Solo, Universidade Federal de Lavras, no período de novembro de 1999 a maio de 2000, em 28 cultivares de soja com potencial para cultivo nesta região. Para avaliação da cobertura vegetal foi utilizada a metodologia descrita por Stocking (1988. Na modelagem procurou-se relacionar a CV com os valores acumulados dos seguintes atributos climáticos: temperatura média (Tmed, precipitação (PREC e umidade relativa do ar (UR. Os valores de cobertura vegetal apresentaram uma amplitude de variação de 56 a 83%, sendo BR 162, LO 12 L e M. Soy 108 as cultivares mais eficientes e FT Abyara e Tucano as menos eficientes. O hábito diferencial de crescimento das cultivares ajuda a explicar esse comportamento. O modelo ajustado adequado para estimativa da CV foi: CV = 116589,976 + 0,422 . Tmed + 0,132 . PREC - 0,095 . UR + 0,000024 . Tmed², R² = 0,99 (P Vegetal cover of soil is decisive to reduce the erosive effects of direct impact of raindrops on the soil surface. Therefore, the objective of this study was to determine the vegetal cover (CC index and to develop models to estimate it for soybean cultivars, using climatic attributes in the period of intense rains in the South of the State of Minas Gerais in Brazil. CC was measured weekly in the experimental area of the Department of Soil Science, Federal University of Lavras, from November 1999 to May 2000, for 28 soybean cultivars with yield potential in this region. To evaluate the vegetal cover, the method described by

  19. Rheology of Melt-bearing Crustal Rocks

    Science.gov (United States)

    Rosenberg, C. L.; Medvedev, S.; Handy, M. R.

    2006-12-01

    A review and reinterpretation of previous experimental data on the deformation of melt-bearing crustal rocks (Rosenberg and Handy, 2005) revealed that the relationship of aggregate strength to melt fraction is non-linear, even if plotted on a linear ordinate and abscissa. At melt fractions, Φ 0.07, the dependence of aggregate strength on Φ is significantly greater than at Φ > 0.07. This melt fraction (Φ= 0.07) marks the transition from a significant increase in the proportion of melt-bearing grain boundaries up to this point to a minor increase thereafter. Therefore, we suggest that the increase of melt-interconnectivity causes the dramatic strength drop between the solidus and a melt fraction of 0.07. A second strength drop occurs at higher melt fractions and corresponds to the breakdown of the solid (crystal) framework, corresponding to the well-known "rheologically critical melt percentage" (RCMP; Arzi, 1978). Although the strength drop at the RCMP is about 4 orders of magnitude, the absolute value of this drop is small compared to the absolute strength of the unmelted aggregate, rendering the RCMP invisible in a linear aggregate strength vs. melt fraction diagram. Predicting the rheological properties and thresholds of melt-bearing crust on the basis of the results and interpretations above is very difficult, because the rheological data base was obtained from experiments performed at undrained conditions in the brittle field. These conditions are unlikely to represent the flow of partially melted crust. The measured strength of most of the experimentally deformed, partially-melted samples corresponds to their maximum differential stress, before the onset of brittle failure, not to their viscous strength during "ductile" (viscous) flow. To overcome these problems, we extrapolated a theoretically-derived flow law for partially melted granite deforming by diffusion-accommodated grain-boundary sliding (Paterson, 2001) and an experimentally-derived flow law for

  20. Crustal structure of southern Madagascar from receiver functions and ambient noise correlation: Implications for crustal evolution

    Science.gov (United States)

    Rindraharisaona, E. J.; Tilmann, F.; Yuan, X.; Rümpker, G.; Giese, J.; Rambolamanana, G.; Barruol, G.

    2017-02-01

    The Precambrian rocks of Madagascar were formed and/or modified during continental collision known as the Pan-African orogeny. Aborted Permo-Triassic Karoo rifting and the subsequent separation from Africa and India resulted in the formation of sedimentary basins in the west and volcanic activity predominantly along the margins. Many geological studies have documented the imprint of these processes, but little was known about the deeper structure. We therefore deployed seismic stations along an SE-NW trending profile spanning nearly all geological domains of southern Madagascar. Here we focus on the crustal structure, which we determined based on joint analysis of receiver functions and surface waves derived from ambient noise measurements. For the sedimentary basin we document a thinning of the underlying crystalline basement by up to ˜60% to 13 km. The crustal velocity structure demonstrates that the thinning was accomplished by removal or exhumation of the lower crust. Both the Proterozoic and Archean crust have a 10 km thick upper crust and 10-12 km thick midcrust. However, in contrast to the typical structure of Proterozoic and Archean aged crust, the Archean lower crust is thicker and faster than the Proterozoic one, indicating possible magmatic intrusions; an underplated layer of 2-8 km thickness is present only below the Archean crust. The Proterozoic mafic lower crust might have been lost during continental collision by delamination or subduction or thinned as a result of extensional collapse. Finally, the Cretaceous volcanics along the east coast are characterized by thin crust (30 km) and very large VP/VS ratios.

  1. Crustal Heat Production and Mantle Heat Flow in Southeast China

    Institute of Scientific and Technical Information of China (English)

    胡圣标; 汪集旸

    1994-01-01

    The correlation between seismic velocity (vp) and radiogenic heat production (A) en-ables the distribution of crustal heat production to be evaluated,from which the mantle heat flow for 21seismic velocity-depth profiles located along the two continental geotraverses in Southeast China can bededuced.Several approaches have been proposed to special problems connected with the conversion ofseismic velocities into heat production in orogenic areas.The results show that the crustal heat flow inSoutheast China is quite inhomogeneous,varying between 17.8 and 46 mW·m-2,which can be attribut-ed to the complicated crustal structure related to overthrusting and overlapping in the upper crust.The re-markable regional variation in the mantle heat flow,ranging from 23.2 to 41.6 mW·m-2,correspondsto the large-scale tectonothermal evolution of the orogenic belts.

  2. The Computation of Potential Harmonic Coefficients Using Global Crustal Information

    Science.gov (United States)

    Tsoulis, D.

    Topographic/isostatic potential harmonic coefficients can be computed from a global elevation model, when one accounts for the compensation of the upper crust according to a certain model of isostasy. The theory is based on a series expansion of the inverse distance function, which enables an efficient computation of the dimensionless poten- tial coefficients on the sphere. The availability of global crustal models permits the application of the same theory, with the exception that here the theoretically defined boundary between upper crust and mantle is replaced with crustal thickness informa- tion derived mainly from processing repeated seismic observations. The present paper deals with the spherical harmonic analysis of such a model, namely the CRUST 2.0 global crustal model, and compares the derived spectrum with the respective coeffi- cient sets delivered by the application of idealized isostatic models such as those of Airy/Heiskanen or Pratt/Hayford.

  3. Elaboração multidisciplinar e participativa de jogos de papéis: uma experiência de modelagem de acompanhamento em torno da gestão dos mananciais da Região Metropolitana de São Paulo Multidisciplinary elaboration of and participation in role-playing games: an experiment in companion modeling about catchment management in the metropolitan region of São Paulo

    Directory of Open Access Journals (Sweden)

    Raphaèle Ducrot

    2008-01-01

    Full Text Available O desenvolvimento de ferramentas de simulação, como os jogos de papéis, pressupõe a integração das várias representações e conhecimentos, o que garante a sua legitimidade e a possibilidade de os utilizar como plataforma de mediação na discussão dos conflitos socioambientais. Este artigo discute a utilização da abordagem de modelagem de acompanhamento no desenvolvimento de dois jogos de papéis sobre a gestão da água e do solo em mananciais periurbanos da Região Metropolitana de São Paulo (RMSP.The development of simulation tools like role-playing games require the integration of some knowledge and several representations which guarantee its legitimacy and the possibility to be used as a mediation platform in collective discussions about environmental conflicts. The paper presents and discusses the use of the companion modeling approach in the development of two role-playing games dealing with water and land management in the periurban catchment of the metropolitan region of São Paulo.

  4. Highly explosive 2010 Merapi eruption: Evidence for shallow-level crustal assimilation and hybrid fluid

    Science.gov (United States)

    Borisova, Anastassia Y.; Martel, Caroline; Gouy, Sophie; Pratomo, Indyo; Sumarti, Sri; Toutain, Jean-Paul; Bindeman, Ilya N.; de Parseval, Philippe; Metaxian, Jean-Philippe; Surono

    2013-07-01

    -silicate crustal material, corresponding to introduction of additional 0.19 to 2.1 Mt of CO2 to the magma. Experimental leaching of the ash samples documents the release of an aqueous fluid enriched in Cl, Na, Ca, Cd, Sb and Zn during the paroxysmal subplinian eruption. The paroxysmal eruption may have been produced by saturation of the pre-eruptive basaltic andesite magma with hybrid aqueous carbonic NaCl-HCl-rich fluid due to bulk assimilation creating elevated partial pressure of CO2 at shallow crustal conditions of about 200 MPa. In contrast, mildly explosive block-and-ash flows (typical Merapi-type) may result from selective assimilation of the carbonate-bearing xenoliths and lower CO2 partial pressure that may not lead to explosive degassing.

  5. Experimental study and modeling of the rheology and hydraulics in the foam drilling; Estudos experimentais e modelagem da reologia e da hidraulica na perfuracao com espuma

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Andre L.; Sa, Carlos H.M. de; Lourenco, Affonso M.F.; S. Junior, Valter [PETROBRAS, S.A, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas]. E-mails: aleibsohn@cenpes.petrobras.com.br; chsa@cenpes.petrobras.com.br; affonso-lourenco@utulsa.edu; vsj@cenpes.petrobras.com.br

    2000-07-01

    This article describes the extense experimental effort for analyzing the foam stability and rheological properties for application as light drilling fluid. The study considered the influence of the foaming and concentration on the foam rheology and the gas volumetric fraction on the foam rheological properties. Simple correlations were proposed for quantification of the experimental behaviour. Field tests were performed to evaluate one of the foaming agents analyzed in laboratory by using 16 combinations of the gas-fluid flow.

  6. Petroleum generation 3D modeling of Espirito Santo Basin, Brazil; Modelagem 3D da geracao de petroleo na Bacia do Espirito Santo, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Daniella A.; Lemgruber, Adriana; Goncalves, Felix T.T. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Modelagem Multidisciplinar de Bacias Sedimentares (LAB2M); Petersohn, Eliane [Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Intervals of potential source rocks were identified and characterized by the analysis and interpretation of total organic carbon (TOC) and Rock-Eval pyrolysis data. The rift section presents the best conditions for hydrocarbon generation, especially in Mariricu formation, that presents high TOC, hydrogen index and type I Kerogen. The drift section possesses low source rock potential, the intervals with best organic matter characteristic (quantity and quality) are represented by thin packages positioned in the superior portion of Regencia and Sao Mateus formation and in the basis of Urucutuca formation. The geochemistry data was integrated, on a regional scale, into the thermal maturation and petroleum generation three-dimensional model. Four potentially source rock intervals were simulated, two in the pre-salt section and two in the post-salt section. The results point out that the pre-salt intervals have reached thermal maturity in the proximal shelf and were overmatured in deep water. The thermal evolution obtained for the post-salt zone was very similar to those obtained for the rift section (pre-salt section). (author)

  7. Modeling and simulation of the atomization process in the ceramic tile industry; Modelagem e simulacao do processo de atomizacao na industria de revestimento ceramico

    Energy Technology Data Exchange (ETDEWEB)

    Favalli, Renata Cristina

    2002-07-01

    The aim of the present work is to numerically simulate the behaviour of the drying system for several sets of operating conditions in order to improve and optimize this process. However, the mathematical modeling adopted here can be employed to simulate other systems such as the processes that occur in liquid-fueled engines with direct spray injection and ceramic spraying for hard surfacing. Then, mathematical and physical models were established to simulate the interaction of continuous and disperse phases in drying processes of ceramic slurries. Solving the set of governing coupled partial differential equations, it is possible to study the influence of drying air on the atomized droplets of alumina slurry, and vice-versa. The materials used as continuous and disperse phase, air and alumina slurry respectively, are representative since any kind of gas and slurry can be used if its thermodynamic and transport properties are known. Several experimental tests were carried out in a spray dryer in the 'Laboratorio de Insumos', at IPEN - Instituto de Pesquisas Energeticas e Nucleares for different sets of operating conditions: initial temperature of the drying air, the gas flow rate, the slurry feed rate and atomiser configuration among others. Measurements of the wet and the dry bulb temperatures were made in some experimental tests to allow the calculations of the air humidity. The dynamic pressure were also measured in order to determine the gas flow rate. Some samples of the material used in the tile industry and of the one produced at IPEN were analysed to determine: the morphology of the atomized material and the range of granules diameter through scanning electron microscopy; the amount of pores and the bulk density through porosimetry; the residual moisture of the material through thermogravimetry; and the granulometric distribution of granules and particles through laser diffraction. Important information about the process and the final material are given by the experimental test and analyses allowing the consistency of computer code and models to be verified. The first numerical tests were carried out for the evaporation of water droplets in a flow of hot air. After that, the water is changed to alumina slurry and the air velocity, temperature and humidity, as well as the droplets mass and temperature history, are obtained. For such condition, several sets of injection angle and type of flow of the droplets were simulated; it shows the versatility of the programme. At last, some experimental tests carried in the laboratory dryer were simulated to verify the model and computer code consistency; the difference between the rate of water vapor calculated by the programme (and the one obtained through the measurements of wet and dry bulb temperatures is 10%, approximately, confirming the consistency of both the computer code and mathematical model. The influence of many operating parameters on continuous and disperse phases were studied. The parameters varied were: gas flow rate; initial temperature of the drying media; slurry feed rate; different amount and sizes for the droplets and initial velocity of droplets. The results of the parametric study were compared to the experimental ones and also confirm the model consistency. (author)

  8. Aplicação de modelagem de turbulência na camada limite atmosférica para verificar efeitos locais de topografia /

    OpenAIRE

    Dorweiler, Roger Paul

    2007-01-01

    Orientador : Maurício Felga Gobbi Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciencias Exatas e Setor de Tecnologia, Programa de Pós-Graduaçao em Métodos Numéricos em Engenharia. Defesa: Curitiba, 2007 Inclui bibliografia

  9. Petroleum generation: 3D modeling of Cumuruxatiba Basin, Brazil; Modelagem 3D da geracao de petroleo na Bacia de Curumuxatiba, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Lemgruber, Adriana; Ferreira, Daniella A.; Goncalves, Felix T.T. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Modelagem Multidisciplinar de Bacias Sedimentares (LAB2M); Vieira, Juliana R. [Agencia Nacional do Petroleo, Gas Natural e Biocombustiveis (ANP), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    In order to update and improve the knowledge of the tectonic-sedimentary evolution of Cumuruxatiba's petroleum systems, and also to call the attention of the petroleum companies, the National Agency of Oil, Gas and Biofuels (ANP) signed contract with COPPE / UFRJ for carrying out an extensive project of basin analysis. This paper presents the results of the integration geochemical data and three-dimensional maturation and petroleum generation modeling, on a regional scale. The results present an important progress in understanding the dynamic of the petroleum system in the area, and may be used as a basis for more consistent evaluation of the oil and gas potential and also of the exploitation risk at Cumuraxatiba basin. Three potential source rock intervals were simulated in the 3D model. Two intervals have been defined in the pre-salt zone, at the upper and basal portions of the rift section, and an interval at the post-salt section, at the top of Regencia formation/ basis of Urucutuca formation. The results point out that there is a significant oil and gas potential in deep-water regions and in the south portion of the continental shelf. (author)

  10. Proposta de uma estrutura conceitual de modelagem de empresas para implementação do ERP5 baseada na ISO 19440:2007

    OpenAIRE

    Rochetti, Angela Teresa [UNESP

    2009-01-01

    Para o aumento da capacidade gerencial e competitiva das empresas um dos principais recursos é o uso dos sistemas integrados de gestão ou Enterprise Resource Planning (ERP). Os ERPs livres de código aberto têm ganhado uma aceitação cada vez maior, oferecendo vantagens como diminuição dos custos e o acesso ao código. Para usufruir destas vantagens são necessários métodos e ferramentas adequadas para o levantamento do modelo de requisitos de negócios, visando facilitar o desenvolvimento ou impl...

  11. Modelagem e simulação do sistema neuromuscular responsável pelo controle do torque gerado na articulação do tornozelo.

    OpenAIRE

    Leonardo Abdala Elias

    2013-01-01

    O estudo do controle neurofisiológico do movimento tem sido realizado sob várias perspectivas. Experimentos com seres humanos são realizados durante a execução de uma dada tarefa motora e, frequentemente, mediante a aplicação de estímulos externos (elétrico, magnético ou mecânico) ao sistema neuromuscular. Estes experimentos fornecem uma grande quantidade de dados referentes ao funcionamento das redes neuronais e dos atuadores biomecânicos envolvidos nos procedimentos. Entretanto, alguns acha...

  12. ESTRATÉGIAS DE MODELAGEM NA ANÁLISE DE EXPERIMENTOS EM DELINEAMENTO DE BLOCOS AUMENTADOS EM TESTES CLONAIS DE Eucalyptus spp.

    Directory of Open Access Journals (Sweden)

    Paulo Eduardo Rodrigues Prado

    2013-01-01

    Full Text Available The objective of this work was to compare analyses of experiment strategies when there is a large number of clones and a reduced number of seedlings to be evaluated. Data from girth at breast height of two seasons of evaluation, 30 and 90 months, from a clonal test of Eucalyptus were analyzed in three locations. The experiments were carried out in the augmented block design with 400 regular clones distributed in 20 blocks and with four common clones (controls. Each plot consisted of five plants spaced 3 x 3 meters. The individual statistic analyses were carried out by season and local, a combined one by local at each season and a combined one involving the three locals and the two seasons. Each analysis was carried out according to two models: augmented design (AD and one way classification (OWC. The variance components, the heritability, the Speaman’s rank correlation and the coincidence indexes in the clone selection at the two models were estimated. It was found that the augmented block design and the one way classification provide similar results in eucalypt clone evaluation. The coincidence indexes between the two models in the clone selection, in general, were high, showing values of 100% in the local combined analyses at 90 months. The Spearman’s rank correlation showed estimates in accordance with the coincidence indexes. It was also checked that the clones by seasons interaction was expressive and the coincidence indexes in clones selection at 30 months with selection at 90 months in the combined by local analyses were from 42% in the OWC and 47% in AD, when a selection intensity of 5% was applied.

  13. Modelagem da proteção do solo por plantas de cobertura no sul de Minas Gerais = Modeling of soil protection by cover crops in southern Minas Gerais, Brazil.

    Directory of Open Access Journals (Sweden)

    Diego Antonio França de Freitas

    2012-08-01

    Full Text Available A cobertura do solo é o fator de maior importância relativa no controle da erosão hídrica. Assim, objetivou-se no presente estudo elaborar a modelagem da cobertura vegetal de vinte e quatro plantas de cobertura, em diversos sistemas de plantio e históricos de uso, com potencial para cultivo no Sul de Minas Gerais. Para avaliação da cobertura vegetal foram realizadas avaliações no campo utilizando uma régua de classificação da cobertura vegetal, sendo o delineamento experimental inteiramente casualizado, com três repetições, utilizado neste experimento. As plantas cultivadas sobre a palhada de feijãoirrigado apresentaram alto índice de cobertura do solo, o que pode estar relacionado à maior disponibilidade de nutrientes deixado por esta cultura na palhada e a maior reserva de água no solo, promovido pela irrigação do feijão. O milheto cultivado em nível e sobre a palhada de milheto e feijão-de-porco apresentou o menor índice de cobertura entre as plantas testadas. Na região sul de Minas Gerais os padrões de chuvas ocorrem em maior quantidade nos períodos de outubro a março, com elevação em dezembro e janeiro. Neste período o solo deve estar protegido do impacto da gota de chuva, pois o risco de erosão hídrica é maior. Assim, a utilização das plantas de cobertura é de grande importância, pois estas protegem o solo do impacto direto dasgotas de chuvas e diminuem os picos de temperatura do solo, sendo que estas devem ser cultivadas, preferencialmente, sobre a palhada de feijão.The ground cover is the most important factor relative to control erosion. Thus, the objective of this study was to develop a model plant cover for 24 cover crops used in several cropping systems and historical use, with potential for cultivation in southern Minas Gerais State, Brazil. To evaluate the vegetation cover field assessments using the strip land cover classification. A completely randomized design with three replications was

  14. Scaling behaviour in temporal fluctuations of crustal seismicity in Taiwan

    Directory of Open Access Journals (Sweden)

    L. Telesca

    2009-12-01

    Full Text Available The crustal seismicity of Taiwan was investigated by means of the Allan Factor analysis and Count-based Periodogram, which allow to identify scaling behaviour in point processes and to quantify their temporal fluctuations by means of the estimate of the scaling exponent. Our findings point out to the presence of two time-scaling regions in the crustal Taiwanese seismicity. The first region, involving the intermediate timescales can be probably linked with aftershock activity, while the second region, involving the large timescales could be related with the background seismicity.

  15. Geodynamical basis for crustal deformation under the Tibetan Plateau

    Science.gov (United States)

    Liu, H.-S.

    1985-01-01

    Plate tectonics and satellite-derived gravity data are used to examine crustal deformation under the Tibetan Plateau. A spherical harmonic analysis is given for the global plate boundary system, and the crustal stresses in Tibet are calculated from satellite gravity data. A superimposed stress system is constructed. The stress patterns reveal that the cold downwelling mantle convection flow beneath southern Tibet pulls the Indian plate down but applies a bending moment on the end of the plate to uplift and support the mass of the Himalayas.

  16. Monitoring Crustal Deformations with Radar Interferometry:A Review

    Institute of Scientific and Technical Information of China (English)

    刘国祥; 丁晓利; 黄丁发

    2004-01-01

    The crustal movements, probably motivating earthquakes, are considered as one of the main geodynamic sources. The quantitative measurements of ground surface deformations are vital for studying mechanisms of the buried faults or even estimating earthquake potential. A new space-geodetic technology, synthetic aperture radar interferometry (InSAR), can be applied to detect such large-area deformations, and has demonstrated some prominent advantages. This paper reviews the capacity and limitations of InSAR, and summarises the existing applications including some of our results in studying the earthquake-related crustal motions.Finally it gives the outlook for the future development of InSAR.

  17. Crustal Gravitational Potential Energy Change and Subduction Earthquakes

    Science.gov (United States)

    Zhu, P. P.

    2017-05-01

    Crustal gravitational potential energy (GPE) change induced by earthquakes is an important subject in geophysics and seismology. For the past forty years the research on this subject stayed in the stage of qualitative estimate. In recent few years the 3D dynamic faulting theory provided a quantitative solution of this subject. The theory deduced a quantitative calculating formula for the crustal GPE change using the mathematic method of tensor analysis under the principal stresses system. This formula contains only the vertical principal stress, rupture area, slip, dip, and rake; it does not include the horizontal principal stresses. It is just involved in simple mathematical operations and does not hold complicated surface or volume integrals. Moreover, the hanging wall vertical moving (up or down) height has a very simple expression containing only slip, dip, and rake. The above results are significant to investigate crustal GPE change. Commonly, the vertical principal stress is related to the gravitational field, substituting the relationship between the vertical principal stress and gravitational force into the above formula yields an alternative formula of crustal GPE change. The alternative formula indicates that even with lack of in situ borehole measured stress data, scientists can still quantitatively calculate crustal GPE change. The 3D dynamic faulting theory can be used for research on continental fault earthquakes; it also can be applied to investigate subduction earthquakes between oceanic and continental plates. Subduction earthquakes hold three types: (a) crust only on the vertical up side of the rupture area; (b) crust and seawater both on the vertical up side of the rupture area; (c) crust only on the vertical up side of the partial rupture area, and crust and seawater both on the vertical up side of the remaining rupture area. For each type we provide its quantitative formula of the crustal GPE change. We also establish a simplified model (called

  18. Modelagem Matemática: as discussões técnicas e as experiências prévias de um grupo de alunos

    Directory of Open Access Journals (Sweden)

    Jonson Ney Dias da Silva

    2011-05-01

    Full Text Available Este artigo tem o objetivo de analisar como as experiências prévias dos alunos influenciam a produção de discussões técnicas em um ambiente de modelagem matemática. Por discussão técnica, entendemos como toda tradução de um fenômeno eleito (oriundo do dia-a-dia, do campo das profissões ou de outras áreas da ciência em termos matemáticos. Esta pesquisa foi realizada com um grupo de alunos de um Curso de Licenciatura em Matemática, em uma sala de aula de uma universidade pública. A natureza da pesquisa é qualitativa e os dados foram coletados através da observação e entrevistas, a qual foi registrada através da filmagem. Os resultados sugerem que as discussões técnicas seguem uma lógica escolar, mobilizando conhecimentos matemáticos previamente estudados pelos alunos, porém com a incorporação de argumentos externos à sala de aula. Palavras-chave: Modelagem matemática. Interação aluno-aluno. Discussões técnicas. Alunos. Sala de aula. Mathematical Modeling: technical discussions and previous experiences of a group of students Abstract This paper aims to present an analysis of how students´ previous experiences may influence the production of technical discussions in an environment of mathematical modeling. By technical discussion, we mean “all translation of a selected phenomenon (from the daily routine, vocational settings or from other fields of science into mathematical terms. This research was carried out with a group of students of an undergraduate course in mathematics in a classroom of a public university. This research is a qualitative one, and the data were collected through observation and interviews, which have been registered through video recording. The results suggest that technical discussions follow the school logic, mobilizing students’ previous school mathematical experiences but also incorporating in some degree outside arguments into classroom. Keywords: Mathematical

  19. Impact Melt Cover on Central Peaks of Complex Craters: Implications for Deriving Crustal Composition

    Science.gov (United States)

    Dhingra, D.; Pieters, C. M.

    2017-05-01

    The use of impact crater central peaks for deriving crustal mineralogy at depth assumes pristine nature of the peaks. Impact melt on several central peaks is evidence for contamination. Central-peaks-derived crustal mineralogy may be affected.

  20. VOLATILITY MODELING IN PERIODS OF CRISIS: ANALYSES OF ALTERNATIVE DISTRIBUTIONS IN BRIC AND THE US MODELADO DE LA VOLATILIDAD EN PERIODOS DE CRISIS: ANÁLISIS DE LAS DISTRIBUCIONES ALTERNATIVAS EN LOS BRIC Y EEUU MODELAGEM DA VOLATILIDADE EM PERÍODOS DE CRISE: ANÁLISE DAS DISTRIBUIÇÕES ALTERNATIVAS NO BRIC E NOS EUA

    Directory of Open Access Journals (Sweden)

    Fernanda Galvão de Barba

    2013-01-01

    , normal asimétrica, t-student, t-student asimétrica, generalizada y generalizada asimétrica. Como resultado del estudio, se constató que hay variación en la  distribución mejor ajustada durante el periodo de crisis para casi todos los países. A variación tanto de las distribuciones cuanto de los significados y magnitudes de los coeficientes puede llevar a creer que periodos de oscilación e instabilidad financiera pueden influenciar en el  modelado de series financieras, alterando la magnitud y significado de coeficientes, y ser decurrentes del efecto contagio.A crise no mercado imobiliário norte-americano, em 2007, atingiu fortemente os mercados de capitais dos EUA e dos países europeus. Crises financeiras com a magnitude da crise de 2007/2008 trazem à tona importantes questões relativas aos mercados financeiros. Este trabalho visa investigar como a especificação da distribuição influenciou a modelagem da volatilidade no período que abrangeu a crise financeira de 2007/2008. Foram utilizados, para a análise,por meio do modelo APARCH,  dados semanais dos índices das principais bolsas do BRIC (Brasil, Rússia, Índia e Chi    na e dos Estados Unidos. A modelagem foi realizada em três subdivisões da amostra, supondo-se seis distribuições distintas: normal, normal assimétrica,  tstudent, t-student assimétrica, generalizada e generalizada assimétrica. Como resultado do estudo, constatouse que há variação na distribuição melhor ajustada durante o período de crise para quase todos os países. A variação tanto das distribuições quanto das significâncias e magnitudes dos coeficientes pode levar a crer que períodos de oscilação e instabilidade financeira podem influenciar na modelagem de séries financeiras, alterando a magnitude e significância de coeficientes, e ser decorrentes de efeito contágio.

  1. Lateral variations of crustal structure beneath the Indochina Peninsula

    Science.gov (United States)

    Yu, Youqiang; Hung, Tran D.; Yang, Ting; Xue, Mei; Liu, Kelly H.; Gao, Stephen S.

    2017-08-01

    Crustal thickness (H) and Vp/Vs (κ) measurements obtained by stacking P-to-S receiver functions recorded at 32 broadband seismic stations covering the Indochina Peninsula reveal systematic spatial variations in crustal properties. Mafic bulk crustal composition as indicated by high κ (>1.81) observations is found to exist along major strike-slip faults and the southern part of the Peninsula, where pervasive basaltic magmatism is found and is believed to be the results of lithospheric thinning associated with the indentation of the Indian into the Eurasian plates. In contrast, crust beneath the Khorat Plateau, which occupies the core of the Indochina Block, has relatively large H values with a mean of 36.9 ± 3 km and small κ measurements with an average of 1.74 ± 0.04, which indicates an overall felsic bulk composition. Those observations for the Khorat Plateau are comparable to the undeformed part of the South China Block. The laterally heterogeneous distribution of crustal properties and its correspondence with indentation-related tectonic features suggest that the Indochina lithosphere is extruded as rigid blocks rather than as a viscous flow.

  2. Combined crustal-geological cross-section of Ellesmere Island

    DEFF Research Database (Denmark)

    Stephenson, Randell Alexander; Schiffer, Christian; Oakey, Gordon

    (Eurekan “Orogeny”). An almost complete absence of information about the crustal or lithosphere structure of Ellesmere Island has been addressed by the acquisition of teleseismic data between 2010 and 2012 on a passive seismological array called ELLITE (“Ellesmere Island Teleseismic Experiment...

  3. Crustal growth at active continental margins: Numerical modeling

    NARCIS (Netherlands)

    Vogt, Katharina|info:eu-repo/dai/nl/370618947; Gerya, Taras; Castro, Antonio

    2012-01-01

    The dynamics and melt sources for crustal growth at active continental margins are analyzed by using a 2D coupled petrological–thermomechanical numerical model of an oceanic-continental subduction zone. This model includes spontaneous slab retreat and bending, dehydration of subducted crust, aqueous

  4. Microbial Turnover of Fixed Nitrogen Compounds in Oceanic Crustal Fluids

    Science.gov (United States)

    Kraft, B.; Wankel, S. D.; Glazer, B. T.; Huber, J. A.; Girguis, P. R.

    2014-12-01

    Oceanic crust is the largest aquifer on Earth, with a massive volume of seawater advecting through the basaltic crust. The microbiome of this deep marine subsurface biosphere has been estimated to be substantial, and consequently their metabolic activity may have major influences on global biogeochemical cycles. While earlier and recent studies provide insight into the microbial community composition of oceanic crustal fluids, information on the microbial ecophysiology is broadly missing. Therefore, to investigate the microbial transformation of fixed nitrogen compounds in crustal aquifer fluids, fluids were sampled from different horizons of two neighbouring CORK (Circulation Obviation Retrofit Kit) observatories at the North Pond sediment pond. This site is located on the western flank of the Mid Atlantic Ridge and is characterized by relatively young oceanic crust and cold fluids. The crustal fluids contain oxygen and nitrate, which potentially both may serve as electron acceptor for respiration. In a multidisciplinary approach we combined stable isotope incubations, determination of the natural isotopic compositions and plan to analyse relevant functional genes from a metagenomic dataset to investigate the nitrogen cycling at North Pond. The turnover of fixed nitrogen in oceanic crustal fluids may have important implications for the understanding of the global nitrogen cycle.

  5. A proposed concept for a crustal dynamics information management network

    Science.gov (United States)

    Lohman, G. M.; Renfrow, J. T.

    1980-01-01

    The findings of a requirements and feasibility analysis of the present and potential producers, users, and repositories of space-derived geodetic information are summarized. A proposed concept is presented for a crustal dynamics information management network that would apply state of the art concepts of information management technology to meet the expanding needs of the producers, users, and archivists of this geodetic information.

  6. Petrology and geochemistry of charnockites (felsic ortho-granulites) from the Kerala Khondalite Belt, Southern India: Evidence for intra-crustal melting, magmatic differentiation and episodic crustal growth

    Science.gov (United States)

    Ravindra Kumar, G. R.; Sreejith, C.

    2016-10-01

    The Kerala Khondalite Belt (KKB) of the southern India encompasses volumetrically significant magmatic components. Among these, orthopyroxene-bearing, felsic ortho-granulites, popularly known as charnockites in Indian context, constitute an important lithology. In contrast to the well-known phenomena of arrested charnockitization, the geochemical characteristics and petrogenesis of these ortho-granulite suites remain poorly studied, leaving geodynamic models envisaged for the KKB highly conjectural. In this paper, we try to bridge this gap with detailed results on orthopyroxene-bearing, felsic ortho-granulites spread over the entire KKB and propose a new petrogenetic and crustal evolution model. Based on geochemical characteristics, the orthopyroxene-bearing, felsic ortho-granulites (charnockites sensu lato) of KKB are classified into (1) tonalitic (TC), (2) granitic (GC), and (3) augen (AC) suites. Members of the TC follow sodic (characterized by decreasing CaO/Na2O), whereas those of the GC and AC follow calc-alkaline trends of differentiation. Geochemical patterns of the TC resemble those of the Archaean tonalite-trondhjemite-granodiorite (TTG) suites, with slightly magnesian character (average Mg# = 33), moderate LREE (average LaN = 154), low HREE (average YbN = 6) and Y (1-53 ppm; average 11 ppm). The TC is also characterized by positive to slightly negative europium anomalies (Eu/Eu* = 0.7 to 1.67). The GC and AC suites, on the other hand, resemble post-Archaean arc-related granites. The GC displays ferroan nature (average Mg# = 22), low to moderate degrees of REE fractionation (average [La/Yb]N = 34.84), high contents of Y (5-128 ppm; average 68), and low Sr/Y (1-98) ratios. Significant negative Eu anomalies (Eu/Eu* = 0.18-0.91; average 0.50) and low Sr (65-690 ppm) are also noted in the GC. Similar chemical characteristics are shown by the AC, with ferroan nature (average Mg# = 21), low to moderate degrees of REE fractionation (average [La/Yb]N = 26), high

  7. Crustal structure across the Filchner Ronne Shelf, Antarctica

    Science.gov (United States)

    Herter, U.; Jokat, W.

    2012-04-01

    Crustal structure across the Filchner Ronne Shelf, Antarctica U. Herter, W. Jokat One large gap in understanding the tectonic evolution of Antarctica beside the few rock outcrops on the continent is the missing information on crustal thickness along its margins but also in its interior. E.g., the few marine deep seismic lines are located mainly along the Antarctic Peninsula/Pacific margin, but for most of the East Antarctic margins such information is not available. In this contribution we concentrate on one of the most remote areas in Antarctica, the Filchner Ronne Shelf (FRS). The area is underlain by approximately 12 km of sediments, but its crustal fabric is questionable. Thus, some existing deep seismic sounding data were modeled and reinterpreted. Especially, data gathered in 1995 have been analyzed, and a more detailed 2D P-wave velocity model has been calculated. For the profiles in total 12 RefTek stations each with nine geophone chains were placed on the ice shelf and 3175 airgun shots along a 480 km transect were fired by two 32 l BOLT-Airguns each 60 s. Signals were recorded up to distances of 180 km. Due to the ice coverage it was not possible to acquire the data without gaps or along straight lines, which caused some difficulties in the modeling process. Furthermore, in the new model all data from older experiments of the AWI and Soviet Antarctic expeditions acquired with dynamite sources were incorporated. The model shows a sedimentary basin with a thickness up to 12 km and a large velocity inversion in a deeper sediment unit. The crustal thickness varies from 40 km beneath the Antarctic Peninsula, and 14 km of basement in the center part of the profile. Towards Berkner Island the crust thickens again, but the top of the basement is still 11 km deep. The lower crustal velocities range between 6.8 and 7.2 km/s. We interpret the crustal structure as clear evidence for the presence of a failed rift. The initial stretching of the continental crust

  8. Crustal Seismicity and Recent Faults in Southern Peru

    Science.gov (United States)

    David, C.; Comte, D.; Tavera, H.; Audin, L.; Herail, G.

    2004-12-01

    Most seismological studies in southern Peru have been focused on the downgoing slab seismicity in order to constrain the Wadati-Benioff zone. This study deals with the intra-continental seismicity of the southern Peru forearc (17,3° S - 18,5° S) in a post-seismic context (Arequipa thrust earthquake, Mw=8.4, 23 June, 2001). It is difficult to identify historical crustal earthquake from available catalogues, however some crustal events teleseismically recorded can be found since 1976; they exhibit normal focal mechanism solutions in the southern Peru volcanic arc and inverse focal mechanism solutions in the Central Depression. Following a notable increase of shallow crustal seismicity located close to the Western Cordillera after the 23 June 2001, a temporary seismic network was deployed between January and March 2003 in order to study the Wadati-Benioff zone and monitoring the crustal seismicity in southern Peru. From the about 1700 events locally recorded by the local network, 300 crustal earthquakes were identified in the Peruvian forearc between Tacna and Moquegua. This crustal seismicity is distributed along a lineament located at depths between 0 and 60 km, dipping at about 45° from the Western Cordillera towards the coast, almost perpendicular to the subducting slab; this behaviour was previously observed in northern Chile and in southern Peru, north of the study zone (16° S). In the Central Depression, seismic activity is not superficial occurring between 25-60 km depth and it is mostly characterized by inverse focal mechanism solutions. Superficial faults situated in the Central Depression and in the Coastal Cordillera can not be associated with the seismic activity observed in this area. However, in the Pre-Cordillera, crustal seismicity occurs at depths between 0-15 km and can be correlated with shallow fault systems recognized by satellite images and on the field. For examples, the Incapuquio fault system which was a transpressive system in Cretaceous

  9. Central Andean crustal structure from receiver function analysis

    Science.gov (United States)

    Ryan, Jamie; Beck, Susan; Zandt, George; Wagner, Lara; Minaya, Estela; Tavera, Hernado

    2016-07-01

    The Central Andean Plateau (15°-27°S) is a high plateau in excess of 3 km elevation, associated with thickened crust along the western edge of the South America plate, in the convergent margin between the subducting Nazca plate and the Brazilian craton. We have calculated receiver functions using seismic data from a recent portable deployment of broadband seismometers in the Bolivian orocline (12°-21°S) region and combined them with waveforms from 38 other stations in the region to investigate crustal thickness and crust and mantle structures. Results from the receiver functions provide a more detailed map of crustal thickness than previously existed, and highlight mid-crustal features that match well with prior studies. The active volcanic arc and Altiplano have thick crust with Moho depths increasing from the central Altiplano (65 km) to the northern Altiplano (75 km). The Eastern Cordillera shows large along strike variations in crustal thickness. Along a densely sampled SW-NE profile through the Bolivian orocline there is a small region of thin crust beneath the high peaks of the Cordillera Real where the average elevations are near 4 km, and the Moho depth varies from 55 to 60 km, implying the crust is undercompensated by 5 km. In comparison, a broader region of high elevations in the Eastern Cordillera to the southeast near 20°S has a deeper Moho at 65-70 km and appears close to isostatic equilibrium at the Moho. Assuming the modern-day pattern of high precipitation on the flanks of the Andean plateau has existed since the late Miocene, we suggest that climate induced exhumation can explain some of the variations in present day crustal structure across the Bolivian orocline. We also suggest that south of the orocline at 20°S, the thicker and isostatically compensated crust is due to the absence of erosional exhumation and the occurrence of lithospheric delamination.

  10. Effects of Martian crustal magnetic field on its ionosphere

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The effect of the Martian crustal magnetic field is one of the hot topics of the study of Martian ionosphere.The studies on this topic are summarized in this paper.Main data of the Martian ionosphere were resulted from radio occultation experiments.According to the observations,the electron density scale height and the peak electron density of the Martian ionosphere are influenced by its crustal magnetic field.The strong horizontal magnetic field prevents the vertical diffusion of the plasma and makes the electron density scale height in the topside ionosphere close to that in the photo equilibrium region.In the cusp-like regions with strong vertical magnetic field,the enhanced vertical diffusion leads to a larger electron density scale height in the diffusion equilibrium region.The observation of radio occultation experiment onboard Mars Global Surveyor (MGS) showed that the averaged peak electron density observed in the southern hemisphere with strong crustal magnetic field was slightly larger than that in the northern hemisphere with weak crustal magnetic field.The Mars advanced radar for subsurface and ionosphere sounding (MARSIS) onboard Mars Express (MEX) was the first topside sounder to be used to observe Martian ionosphere.The MARSIS results confirmed that the enhancement of the peak electron density occurred in cusp-like regions with open field lines,and the amount of the enhancement was much larger than that observed by the radio occultation experiment.There are two possible mechanisms for the peak electron density enhancement in the cusp-like crustal magnetic field regions:One is the precipitation of the energetic particles and the other is the heating by the waves excited by plasma instabilities.It’s difficult to determine which one is the key mechanism for the peak electron density enhancement.Based on these studies,several interesting problems on the Martian ionosphere and plasma environment are presented.

  11. Modelagem da distribuição diamétrica em povoamentos de eucalipto submetidos a desbaste utilizando autômatos celulares

    Directory of Open Access Journals (Sweden)

    Daniel Henrique Breda Binoti

    2012-10-01

    Full Text Available Este estudo apresenta um modelo de distribuição diamétrica baseado em um modelo de Autômatos celulares (AC unidimensionais e redes neurais artificiais (RNA para a simulação de desbaste. Cada célula do AC proposto representa uma classe de dap, sendo o estado futuro previsto em função do estado atual dessa célula, do estado de suas quatro células vizinhas e de sua idade atual e futura. Como regra de evolução, utilizou-se uma RNA. A exatidão foi avaliada empregando-se o procedimento estatístico L relação entre frequências observada e estimada e realismo biológico do modelo construído. Entre as redes treinadas, foram selecionadas as 10 que representavam a evolução da distribuição diamétrica com maior exatidão. Entre essas 10 RNA, sete apresentaram valores estimados estatisticamente iguais aos observados (p>0,01. O enfoque de modelagem proposto permite estimar distribuições diamétricas futuras com exatidão.

  12. Stochastic modeling: temperature forecast for the city of Pelotas/RS/Brazil = Modelagem estocástica: previsão das temperaturas para a localidade de Pelotas/RS/Brasil.

    Directory of Open Access Journals (Sweden)

    Rita de Cássia Fraga Damé

    2014-04-01

    , realizar a predição da variável. Para tanto foram utilizados os testes de Cox-Stuart, Wald-Wolfowitz, Spearman e Mann-Kendall, para comprovar ou não, a existência de tendência das séries de temperatura ao longo do tempo. Para a modelagem foram utilizados os modelos Autorregressivos Integrados Média Móvel e, para a seleção do modelo mais adequado, o teste de Porteau Monteau. O teste não-paramétrico de Spearman foi considerado o mais robusto para a detecção de tendência nas séries temporais, o que permitiu observar um acréscimo de 1,12ºC nas temperaturas médias mínimas anuais da localidade em estudo. As temperaturas médias mínimas anuais de Pelotas, RS, podem ser previstas pelos modelos autorregressivos – AR (1, cuja inclusão de outro parâmetro regressivo não apresentou ganho de informação na previsão das mesmas. Time series, Stochastic, Autoregressive models = Séries temporais, Processo estocástico, Modelos autorregressivos

  13. Modelo hierarquizado: uma proposta de modelagem aplicada à investigação de fatores de risco para diarréia grave Hierarchical model: a proposal for model to be applied in the investigation of risk factors for dehydrating diarrhea

    Directory of Open Access Journals (Sweden)

    Sandra C Fuchs

    1996-04-01

    Full Text Available Os estudos epidemiológicos de doenças que acometem as crianças geralmente envolvem grande número de variáveis. As associações entre potenciais fatores de risco e doença freqüentemente são avaliadas através de modelagem estatística sem descrição das estratégias empregadas. No estudo realizado apresenta-se uma abordagem hierarquizada aplicada à avaliação de fatores de risco para diarréia grave. As variáveis foram hierarquicamente agrupadas em características socioeconômicas, ambientais, reprodutivas maternas, nutricionais e demográficas. Na análise univariada todas as variáveis associaram-se com diarréia grave. Em cada bloco selecionaram-se fatores de confusão através de um algoritmo, utilizando-se o processo retrógado de seleção, através do módulo em passos, segundo um p=0,10. Os fatores de risco foram avaliados através de regressão logística após o ajuste para fatores de confusão de cada conjunto e para aqueles hierarquicamente superiores. As variáveis incluídas no modelo permitiram identificar corretamente uma proporção elevada de casos (gamma=0,74 e todos os blocos contribuíram significativamente para a modelagem.In epidemiological investigations of infant diseases, data are usually collected on a large set of variables. The associations between presumptive risk factors and the outcome is commonly evaluated through statistical modeling, but the model-building strategies are seldom described. In the project, data collected in a case-control study of risk factors for dehydrating diarrhea in infants have been used to present a hierarchized approach to the assessment of risk factors. The variables were grouped into a hierarchy of categories, ranging from distal determinants to proximate ones. These categories included, in this order, socioeconomic, environmental, reproductive maternal, nutritional and demographic sets. According to the univariate analyses all variables were associated with the outcome. As

  14. Modelagem e simulação do processo industrial de deslignificação com oxigênio e de branqueamento ECF de polpa celulósica

    OpenAIRE

    Vianna, Viridiane

    2010-01-01

    Resumo: O setor produtivo brasileiro de celulose e papel contribui de forma relevante para o desenvolvimento do Brasil. Para aumentar a competitividade das empresas brasileiras a nível internacional, os produtos devem possuir alto padrão de qualidade e alto valor agregado. Assim, a modelagem matemática e a simulação dos processos industriais garante a estabilização da produção. Este estudo apresenta o ajuste de modelos matemáticos para os processos de deslignificação com oxigênio e o desenvol...

  15. MODELAGEM DO SISTEMA DE AVALIAÇÃO DE CONHECIMENTO, SEGUNDO PARÂMETROS DO ENADE, APLICÁVEL AOS CURSOS SUPERIORES DE GRADUAÇÃO: uma proposta quanto a forma de avaliação nas IES

    OpenAIRE

    CLÉBER AUGUSTO PEREIRA

    2010-01-01

    A proposta de modelagem de sistema de avaliação dos cursos superiores de graduação, segundo os parâmetros exigidos pelo ENADE, emerge da necessidade das IES adequarem sua metodologia e procedimentos de avaliação aos moldes estabelecidos pelo exame. A solução proposta não se dirige a um curso específico de graduação, podendo ser utilizada para qualquer área do conhecimento. O uso de agentes de software em seu desenvolvimento justifica-se em razão de uma aplicação computaciona...

  16. Modelagem dinâmica e simulação computacional de poços de petróleo verticais e direcionais com elevação por bombeio mecânico

    OpenAIRE

    Filipe, C. A. Lins; Kayo, G. SIlva; Medeiros, Adelardo Adelino Dantas de; Costa, Rutácio O.

    2009-01-01

    LINS, Filipe C. A. et al. Modelagem dinâmica e simulação computacional de poços de petróleo verticais e direcionais com elevação por bombeio mecânico. In: CONGRESSO BRASILEIRO DE PESQUISA E DESENVOLVIMENTO EM PETRÓLEO E GÁS, 5. 2009, Fortaleza, CE. Anais... Fortaleza: CBPDPetro, 2009. This paper presents a dynamic model of vertical oil wells using artificial elevation by suckerrod pumping. The modeling of the system is separated by modules that provide a good understanding of the sys...

  17. Metodologias para modelagem e análise da fadiga em ligações rebitadas com aplicação em pontes metálicas ferroviárias.

    OpenAIRE

    Ritermayer Monteiro Teixeira

    2015-01-01

    O processo de fadiga em pontes metálicas ferroviárias é um relevante problema de infraestrutura, largamente reconhecido como uma questão de segurança estrutural que precisa ser melhor compreendida. Apesar dos recentes avanços no campo da modelagem computacional, a aplicação de abordagens modernas para avaliação do comportamento à fadiga de ligações rebitadas típicas de pontes ainda é pouco explorada e impõe desafios. Nesse contexto, esta tese visa implementar metodologias de análise global-lo...

  18. Crustal Thickness Along the Central American Volcanic Front

    Science.gov (United States)

    MacKenzie, L. S.; Abers, G. A.; Rondenay, S.; Fischer, K. M.; Syracuse, E. M.; Protti, J. M.; Gonzalez, V.; Strauch, W.

    2007-12-01

    Subduction zone processes alter the upper plate in a number of ways, including accretion, magmatic addition, serpentinization of the mantle wedge and formation of mafic cumulates in the lower crust. All of these changes affect seismic velocities, and characterizing the structure of underlying terranes in Central America establishes a baseline for composition and continental growth. Tomography Under Costa Rica and Nicaragua (TUCAN) is a PASSCAL deployment of broadband seismometers over an 18-month period. The network has two dense cross arc lines and two along arc lines that cross terrane boundaries. Teleseismic P and PP arrivals recorded on the TUCAN network have been used to estimate crustal thickness and Vp/Vs, and to develop receiver function images. Surface reflected mode conversions (Ppms and Psms) enhance resolution. Crustal thickness ranges from 25 to 44 km with formal errors ranging 1.6-9.2 km. The thinnest crust (24.6 +/- 3.5 km) lies directly beneath the arc in Nicaragua, whereas the thickest crust (43.5 +/- 2.5 km) lies in the backarc in Nicaragua and beneath the Costa Rican arc (37.9 +/- 5.2). Changes in crustal thickness and Vp/Vs show two distinct terrane boundaries crossing the arc. Vp/Vs indicate continental crust (Vp/Vs=1.71-1.77) in Nicaragua, with a transition to gabbroic crust (Vp/Vs=1.82-1.88) in Costa Rica where fragments of the Caribbean large Igneous Province have been found. Crustal thickness beneath the arc in Costa Rica yields a crustal growth rate of 16-36 km3/km/Ma, assuming a base crustal thickness of 30-32 km with 6-14 Ma of magmatism. The Moho shows strong velocity contrasts throughout the study area, and is the only interface seen in the backarc, but it is complicated by interferences caused by shallow structure beneath the arc and forearc. Forward modeling indicates that reverberations in sediment layers interfere with the Ps arrival, however surface reflected arrivals (Ppms) require a velocity contrast on the order of 0.5-1.0 km

  19. The Crustal Structure and Seismicity of Eastern Venezuela

    Science.gov (United States)

    Schmitz, M.; Martins, A.; Sobiesiak, M.; Alvarado, L.; Vasquez, R.

    2001-12-01

    Eastern Venezuela is characterized by a moderate to high seismicity, evidenced recently by the 1997 Cariaco earthquake located on the El Pilar Fault, a right lateral strike slip fault which marks the plate boundary between the Caribbean and South-American plates in this region. Recently, the seismic activity seems to migrate towards the zone of subduction of the Lesser Antilles in the northeast, where a mb 6.0 earthquake occurred in October 2000 at 120 km of depth. Periodical changes in the seismic activity are related to the interaction of the stress fields of the strike-slip and the subduction regimes. The seismic activity decreases rapidly towards to the south with some disperse events on the northern edge of the Guayana Shield, related to the Guri fault system. The crustal models used in the region are derived from the information generated by the national seismological network since 1982 and by microseismicity studies in northeastern Venezuela, coinciding in a crustal thickness of about 35 km in depth. Results of seismic refraction measurements for the region were obtained during field campains in 1998 (ECOGUAY) for the Guayana Shield and the Cariaco sedimentary basin and in 2001 (ECCO) for the Oriental Basin. The total crustal thickness decreases from about 45 km on the northern edge of the Guayana Shield to some 36 km close to El Tigre in the center of the Oriental Basin. The average crustal velocity decreases in the same sense from 6.5 to 5.8 km/s. In the Cariaco sedimentary basin a young sedimentary cover of 1 km thickness with a seismic velocity of 2 km/s was derived. Towards the northern limit of the South-American plate, no deep seismic refraction data are available up to now. The improvement of the crustal models used in that region would constitute a step forward in the analysis of the seismic hazard. Seismic refraction studies funded by CONICIT S1-97002996 and S1-2000000685 projects and PDVSA (additional drilling and blasting), recording equipment

  20. Atributos Relevantes de Destinos Turísticos na Percepção de Internautas Brasileiros

    Directory of Open Access Journals (Sweden)

    Iomara Scandelari Lemos

    2010-09-01

    Full Text Available Resumo Este artigo objetiva identificar, na percepção do turista brasileiro, a estrutura subjacente da importância de atributos que caracterizam os destinos turísticos. Trata-se de uma pesquisa do tipo survey disponibilizada em website e respondida por 471 internautas brasileiros. Utilizaram-se procedimentos estatísticos de análise fatorial; validade de construto; construção de escalas e análise fatorial confirmatória com modelagem de equações estruturais. Conclui-se que, tomados isoladamente, os atributos considerados mais relevantes foram: sensação de segurança; qualidade do aspecto visual do destino; sensação de não estar sendo explorado e facilidade de acesso ao destino turístico, totalizando 70,5% das respostas. Contudo, analisados em conjunto, três fatores respondem por 62,2% da variância explicada. Palavras-chave: análise fatorial; modelagem de equação estrutural; atributos relevantes de turismo. Abstract This article aims to identify, in the perception of Brazilian tourists, the subjacent structure of the importance of attributes that characterize the tourist places destinations. This research is a survey available on website and answered by 471 Brazilians internet users. It used statistical procedures such as factorial analysis, construct reliability, construction of scales and structural equation modeling for confirmatory factorial analysis. It was concluded that, taken alone, the attributes considered most important were: sensation of visiting a safety place, visual aspect quality of the tourism destination areas, sensation of not being exploited and facilities concerned to the tourism destination areas. These totalized 70.5% of responses. However, taken together, three factors account for 62.2% of variance explained. Keywords: factorial analysis; structural equation modeling; tourism's relevant attributes.

  1. Verossimilhança na seleção de modelos para predição espacial Likelihood in the selection of models for spatial prediction

    Directory of Open Access Journals (Sweden)

    Cristiano Nunes Nesi

    2013-04-01

    Full Text Available Na modelagem estatística da variabilidade espacial, estimam-se os parâmetros da dependência espacial, que são utilizados na interpolação de valores em locais não amostrados. Para tal, o processo de modelagem deve ser realizado com critérios estatísticos que garantam predições confiáveis e representem a real variabilidade local. Este trabalho avaliou diferentes formulações do modelo geoestatístico gaussiano para reconstituir a superfície que representa o fósforo (P na área, a partir de medições dos teores de P em 48 parcelas experimentais localizadas em Xanxerê, SC, destacando o método utilizado nas análises. A combinação da presença de covariáveis no modelo e a necessidade de transformação para normalidade dos dados definiram quatro alternativas para modelagem. Utilizou-se a função de correlação de Matèrn, avaliada nos valores 0,5; 1,5; e 2,5 para parâmetro de suavidade. Os modelos foram comparados pelo valor maximizado do logaritmo da função de verossimilhança e também por validação cruzada. O modelo selecionado foi o que incorporou a variável resposta transformada, as coordenadas da área como covariáveis e o valor 0,5 para o parâmetro de suavidade. As medidas de validação cruzada pouco acrescentaram aos resultados de comparação por verossimilhança, que evidenciaram que na modelagem geoestatística, o cuidado com observações globais ou locais atípicas, além da seleção com base em diferentes modelos, deve ser o foco para obter resultados compatíveis com a realidade.Statistical modeling of spatial attributes aims to estimate dependence parameters, used to interpolate values at unsampled locations within the study area. Thus, the modeling process is conducted with some statistical criteria that ensure reliable predictions representing the actual local variability. This study evaluates different formulations of the Gaussian geostatistical model to reconstruct the surface of phosphorus over

  2. Vertical Crustal Displacements Due to Surface Fluid Changes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shiyu; ZHONG Min

    2007-01-01

    Using the model data for surface mass changes of the atmosphere, ocean, soil moisture and snow depth, the vertical crustal displacements of 25 ficual stations in China were calculated according to the loading theory. From the spectral analysis of the results, we can see that the periods of displacements are 12 months and the semi-periods are 6 months. The results also show that the maximum seasonal displacements can reach 20 mm and even larger. The covariance analyses and significance tests show that the coefficients of 96 percent of the stations are significant at the 0.1 significance level. The results show that one of the reasons of the vertical crustal displacements is the changing surface fluid loads.

  3. Crustal structure of the Eastern Alps and their foreland

    DEFF Research Database (Denmark)

    Grad, M.; Brückl, E.; Majdanski, M.

    2009-01-01

    plate, Adriatic microplate and the recently identified Pannonian fragment. The seismic data along the presented profile originate from two large experiments: CELEBRATION 2000 and ALP 2002. The wavefield observed in the Eastern Alps is more complex than in the Bohemian Massif. Strong first arrivals (Pg......The subject of this paper concerns the seismic modelling of the crustal structure in the transition zone from the Bohemian Massif, across the Molasse basin and the Eastern Alps to the Southern Alps, mainly on the territory of Austria. The CEL10/Alp04 profile crosses the triple point of the European......) are distinct up to 60-90 km offset and are characterized by large variations in apparent velocity and amplitude. The contact between the Molasse basin and the Eastern Alps represents a barrier for seismic waves. Mid-crustal reflections (Pc) are usually recorded at short distance intervals (20-50 km...

  4. Efficacy of crustal superfluid neutrons in pulsar glitch models

    CERN Document Server

    Hooker, J; Li, Bao-An

    2013-01-01

    Within the framework of recent hydrodynamic models of pulsar glitches, we explore systematically the dependence on the stiffness of the nuclear symmetry energy at saturation density $L$, of the fractional moment of inertia of the pinned neutron superfluid in the crust $G$ and the initial post-glitch relative acceleration of the crust $K$, both of which are confronted with observational constraints from the Vela pulsar. We allow for a variable fraction of core superfluid neutrons coupled to the crust on glitch rise timescales, $Y_{\\rm g}$. We assess whether the crustal superfluid neutrons are still a tenable angular momentum source to explain the Vela glitches when crustal entrainment is included. The observed values $G$ and $K$ are found to provide nearly orthogonal constraints on the slope of the symmetry energy, and thus taken together offer potentially tight constraints on the equation of state. However, when entrainment is included at the level suggested by recent microscopic calculations, the model is un...

  5. Crustal displacements in Greenland caused by ice mass variability

    DEFF Research Database (Denmark)

    Nielsen, Karina

    The climate of the Earth is changing. A consequence of this is observed at the polar regions such as Greenland, where the ice sheet is melting with an increasing rate. The unloading of ice causes the Earth to respond elastically in terms of uplift and an outward horizontal deformation of the crust....... This motion can be measured by permanent Global Positioning System (GPS) receivers. Hence, the rates of crustal displacement are an indirect measure of the occurring mass changes. Currently, 55 GPS sites are located around the margin of the Greenland ice sheet, continuously providing information about...... the state of the ice sheet. However, the Earth is also adjusting viscoelastically to variations in the late Pleistocene ice sheets i.e. glacial isostatic adjustment (GIA). Observed rates of crustal displacement therefor contain signals from both past and present ice mass variations. Hence, to interpret...

  6. Geoid, topography, and convection-driven crustal deformation on Venus

    Science.gov (United States)

    Simons, Mark; Hager, Bradford H.; Solomon, Sean C.

    1993-01-01

    High-resolution Magellan images and altimetry of Venus reveal a wide range of styles and scales of surface deformation that cannot readily be explained within the classical terrestrial plate tectonic paradigm. The high correlation of long-wavelength topography and gravity and the large apparent depths of compensation suggest that Venus lacks an upper-mantle low-viscosity zone. A key difference between Earth and Venus may be the degree of coupling between the convecting mantle and the overlying lithosphere. Mantle flow should then have recognizable signatures in the relationships between the observed surface topography, crustal deformation, and the gravity field. Therefore, comparison of model results with observational data can help to constrain such parameters as crustal and thermal boundary layer thicknesses as well as the character of mantle flow below different Venusian features. We explore in this paper the effects of this coupling by means of a finite element modelling technique.

  7. Mechanisms of crustal deformation in the western US

    Science.gov (United States)

    Turcotte, Donald L.

    1986-01-01

    The deformation processes in the western United States were studied, considering both deterministic models and random or statistical models. The role of the intracrustal delamination and mechanisms of crustal thinning were also examined. The application of fractal techniques to understand how the crust is deforming was studied in complex regions. Work continued on the development of a fractal based model for deformation in the western United States. Fractal studies were also extended to the study of topography and the geoid.

  8. Crustal blocks and seismicity in the Central Apennines of Italy

    Energy Technology Data Exchange (ETDEWEB)

    Bella, F.; Della Monica, G. (Rome, Univ. ' Roma III' (Italy). Dip di Fisica ' E. Amaldi' ); Caputo, M. (Rome, Univ. ' La Sapienza' (Italy). Dip. di Fisica ' E. Fermi' )

    Kinematics and geo dynamics of crustal-block structures separated by compliant zones with viscoelastic rheology play an important role in defining the conditions for many deformation events such as ordinary seismic ruptures, silent and slow earthquakes and aseismic fault creep phenomena. New seismological data from the Latium-Abruzzi carbonatic platform of central Italy fit a block-tectonic modelling previously proposed for this area on the basis of structural and paleomagnetic evidences.

  9. Spatial variation of crustal coda Q in California

    Science.gov (United States)

    Philips, W.S.; Lee, W.H.K.; Newberry, J.T.

    1988-01-01

    Coda wave data from California microearthquakes were studied in order to delineate regional fluctuations of apparent crustal attenuation in the band 1.5 to 24 Hz. Apparent attenuation was estimated using a single back scattering model of coda waves. The coda wave data were restricted to ???30 s following the origin time; this insures that crustal effects dominate the results as the backscattered shear waves thought to form the coda would not have had time to penetrate much deeper. Results indicate a strong variation in apparent crustal attenuation at high frequencies between the Franciscan and Salinian regions of central California and the Long Valley area of the Sierra Nevada. Although the coda Q measurements coincide at 1.5 Hz (Qc=100), at 24 Hz there is a factor of four difference between the measurements made in Franciscan (Qc=525) and Long Valley (Qc=2100) with the Salinian midway between (Qc=900). These are extremely large variations compared to measures of seismic velocities of comparable resolution, demonstrating the exceptional sensitivity of the high frequency coda Q measurement to regional geology. In addition, the frequency trend of the results is opposite to that seen in a compilation of coda Q measurements made worldwide by other authors which tend to converge at high and diverge at low frequencies, however, the worldwide results generally were obtained without limiting the coda lengths and probably reflect upper mantle rather than crustal properties. Our results match those expected due to scattering in random media represented by Von Karman autocorrelation functions of orders 1/2 to 1/3. The Von Karman medium of order 1/3 corresponding to the Franciscan coda Q measurement contains greater amounts of high wavenumber fluctuations. This indicates relatively large medium fluctuations with wavelengths on the order of 100 m in the highly deformed crust associated with the Franciscan, however, the influence of scattering on the coda Q measurement is

  10. Topographic Expression of Deep Crustal and Mantle Processes

    Science.gov (United States)

    Whipple, K. X.; Ouimet, W. B.; Baldwin, J. A.

    2006-12-01

    The topography of mountain ranges records much information about the history of tectonic events and climatic conditions. Although this record is not easily read, as there are many imperfectly understood factors that influence landscape morphology, there is much encouraging evidence that the river steepness index (a cousin of the Hack gradient index) exhibits a robust correlation with rock uplift rate. Published, and soon to be published, examples span a wide range of field conditions from sites around the globe (e.g., Western US, Bolivia, Nepal, China, Taiwan). Differences in substrate rock properties can have a pronounced influence on channel steepness for a given rock uplift rate, however, and analyses are best limited to regional studies where climatic conditions and lithology are largely uniform. In such settings, careful analysis of river profiles and the relief structure of the landscape can reveal important information about the history of rock uplift, recording temporal changes in uplift/river incision rates. This potential adds considerably to the value of topographic analyses, especially where uplift is driven by deep crustal or mantle processes and not clearly expressed in upper crustal structures and geodetic shortening data. However, this potential comes at the price of complicating the interpretation of the relationship between topography and the modern snapshot of deep crustal/mantle conditions provided by geophysical imaging techniques. Over what timescales does topography retain a record of past events in earth's interior? Important questions remain unanswered about the age of topography in many landscapes where deep crustal or mantle dynamics have been invoked. We discuss the factors that control landscape response time, both to an increase in rock uplift rate and to the cessation of tectonic activity, and present constraints on the antiquity of topography in several field settings.

  11. History of crustal recycling recorded in transition zone diamonds

    Science.gov (United States)

    Pearson, D. G.; Stachel, T.; Palot, M.; Ickert, R. B.

    2015-12-01

    The Earth's transition zone (TZ) is a key region within the Earth that, from seismology, may be composed of a mixture of relatively primitive material together with the products of crustal recycling throughout the history of plate tectonics. The only samples of the TZ come in the form of inclusions in diamonds, that, for the most-part are retrogressed lower pressure equivalents of their precursor phases that formed at depth. Recent work by our group and others [1] on transition zone diamonds indicate that both peridotite and eclogitic paragenesis diamonds may record the products of crustal recycling. In-situ ion probe nitrogen and carbon isotopic measurements indicate the crystallisation of TZ diamonds from fluids bearing crustal signatures, of both oxidised and reduced forms. At the same time, majoritic garnets record extreme oxygen isotope compositions that track the interaction of oceanic crust with seawater at low temperature [2]. Such an origin is consistent with the few measured Sr-Nd isotope compositions of majorite garnet inclusions which resemble depleted MORB [3]. We have found considerably more enriched Sr isotope compositions (87Sr/86S ranging to > 0.8) in CaSiO3 inclusions that are from deep asthenosphere to TZ depths, supporting an origin that includes incorporation of recycled crustal sediment, in addition to the basaltic oceanic crust required to explain the phase equilibria [4]. Lastly, the discovery of hydrous ringwoodite in a diamond [5] containing more water than is soluble at the lower TZ adiabat indicates the possible role of recycling in transporting water as well as carbon into the TZ via a cool thermally unequilibrated slab. [1] Thomson et al (2014) CMP, 168, 1081. [2] Ickert et al (2015) Geochemical perspectives Letters, 1, 65-74. [3] Harte & Richardson (2011) Gondwana Research, 21, 236-235. [4] Walter et al. (2011) Science, 334, 54-57.[Pearson et al. (2014) Nature, 507, 221-224.

  12. Crustal radial anisotropy beneath Cameroon from ambient noise tomography

    Science.gov (United States)

    Ojo, Adebayo Oluwaseun; Ni, Sidao; Li, Zhiwei

    2017-01-01

    To increase the understanding of crustal deformation and crustal flow patterns due to tectonic processes in Cameroon, we study the lateral variability of the crustal isotropic velocity and radial anisotropy estimated using Ambient Noise Tomography (ANT). Rayleigh and Love wave Noise Correlation Functions (NCFs) were retrieved from the cross-correlation of seismic ambient noise data recorded in Cameroon, and phase velocities at periods of 8 to 30 s were measured to perform surface wave tomography. Joint inversion of Rayleigh and Love wave data for isotropic velocity models could not fit the observed dispersions simultaneously. We attribute the Love-Rayleigh discrepancy to the presence of radial anisotropy in the crust and estimated its magnitude. Our 3-D radial anisotropic model reveals the spatial variation of strong to weak positive (Vsh > Vsv) and negative (Vsv > Vsh) radial anisotropy in the crust. We observe negative radial anisotropy in the upper crust that is associated mainly with the location of a previously reported mantle plume. The anisotropy could be attributed to the vertical alignment of fossil microcracks or metamorphic foliations due to the upwelling of plume material. A strong positive radial anisotropy is centered at the location of an inferred boundary between the Congo Craton and the Oubanguides Belt that might be related to the preferred orientation of crustal anisotropic minerals associated with shearing in this fault zone. The middle crust is characterized by a widespread negative radial anisotropy that is likely caused by the flow-induced alignment of anisotropic minerals that crystallized during magma intrusion. The magnitude of the radial anisotropy varies systematically from predominantly negative in the middle crust to positive in the lower crust. The imaged patterns of the isotropic velocity and radial anisotropy are consistent with previous studies and agree with regional tectonics.

  13. Plate tectonics and crustal deformation around the Japanese Islands

    Science.gov (United States)

    Hashimoto, Manabu; Jackson, David D.

    1993-01-01

    We analyze over a century of geodetic data to study crustal deformation and plate motion around the Japanese Islands, using the block-fault model for crustal deformation developed by Matsu'ura et al. (1986). We model the area including the Japanese Islands with 19 crustal blocks and 104 faults based on the distribution of active faults and seismicity. Geodetic data are used to obtain block motions and average slip rates of faults. This geodetic model predicts that the Pacific plate moves N deg 69 +/- 2 deg W at about 80 +/- 3 mm/yr relative to the Eurasian plate which is much lower than that predicted in geologic models. Substantial aseismic slip occurs on the subduction boundaries. The block containing the Izu Peninsula may be separated from the rigid part of the Philippine Sea plate. The faults on the coast of Japan Sea and the western part of the Median Tectonic Line have slip rates exceeding 4 mm/yr, while the Fossa Magna does not play an important role in the tectonics of the central Japan. The geodetic model requires the division of northeastern Japan, contrary to the hypothesis that northeastern Japan is a part of the North American plate. Owing to rapid convergence, the seismic risk in the Nankai trough may be larger than that of the Tokai gap.

  14. Effect of Crustal Density Structures on GOCE Gravity Gradient Observables

    Directory of Open Access Journals (Sweden)

    Robert Tenzer and Pavel Novák

    2013-01-01

    Full Text Available We investigate the gravity gradient components corrected for major known anomalous density structures within the _ crust. Heterogeneous mantle density structures are disregarded. The gravimetric forward modeling technique is utilized to compute the gravity gradients based on methods for a spherical harmonic analysis and synthesis of a gravity field. The _ gravity gradient components are generated using the global geopotential model GOCO-03s. The topographic and stripping gravity corrections due to the density contrasts of the ocean and ice are computed from the global topographic/bathymetric model DTM2006.0 (which also includes the ice-thickness dataset. The discrete data of sediments and crust layers taken from the CRUST2.0 global crustal model are then used to apply the additional stripping corrections for sediments and remaining anomalous crustal density structures. All computations are realized globally on a one arc-deg geographical grid at a mean satellite elevation of 255 km. The global map of the consolidated crust-stripped gravity gradients reveals distinctive features which are attributed to global tectonics, lithospheric plate configuration, lithosphere structure and mantle dynamics (e.g., glacial isostatic adjustment, mantle convection. The Moho signature, which is the most pronounced signal in these refined gravity gradients, is superimposed over a weaker gravity signal of the lithospheric mantle. An interpretational quality of the computed (refined gravity gradient components is mainly limited by a low accuracy and resolution of the CRUST2.0 sediment and crustal layer data and unmodeled mantle structures.

  15. Moho depth and crustal composition in Southern Africa

    DEFF Research Database (Denmark)

    Soliman, Mohammad Youssof Ahmad; Thybo, Hans; Artemieva, Irina;

    2013-01-01

    heterogeneous crustal structure with short wavelength variations in thickness (H), Vp/Vs-ratio (composition), and Moho sharpness, which defines ~20 blocks that do not everywhere coincide with surface tectonic features. In the Zimbabwe Craton, the Tokwe block has H = 35–38 km and Vp/Vs = 1.74–1.79 whereas...... the thicker crust in the Tati block (H = 47–51 km)may be related to deformation of the Archean crust along the cratonicmargin. Two distinct crustal blocks with similar crustal thickness (42–46 km) but significantly different Vp/Vs-ratios are recognized in the Limpopo Belt. Extreme values of 1......-existing lower crust, which is further supported by a very sharp Moho transition. The exposed cross-section in the Vredefort impact crater is non-representative of cratonic crust due to shallowMoho (34 km) and high Vp/Vs ~ 1.80 attributed to shock metamorphism. High Vp/Vs = 1.76 is typical of the Witwatersrand...

  16. Boron isotope fractionation in magma via crustal carbonate dissolution.

    Science.gov (United States)

    Deegan, Frances M; Troll, Valentin R; Whitehouse, Martin J; Jolis, Ester M; Freda, Carmela

    2016-08-04

    Carbon dioxide released by arc volcanoes is widely considered to originate from the mantle and from subducted sediments. Fluids released from upper arc carbonates, however, have recently been proposed to help modulate arc CO2 fluxes. Here we use boron as a tracer, which substitutes for carbon in limestone, to further investigate crustal carbonate degassing in volcanic arcs. We performed laboratory experiments replicating limestone assimilation into magma at crustal pressure-temperature conditions and analysed boron isotope ratios in the resulting experimental glasses. Limestone dissolution and assimilation generates CaO-enriched glass near the reaction site and a CO2-dominated vapour phase. The CaO-rich glasses have extremely low δ(11)B values down to -41.5‰, reflecting preferential partitioning of (10)B into the assimilating melt. Loss of (11)B from the reaction site occurs via the CO2 vapour phase generated during carbonate dissolution, which transports (11)B away from the reaction site as a boron-rich fluid phase. Our results demonstrate the efficacy of boron isotope fractionation during crustal carbonate assimilation and suggest that low δ(11)B melt values in arc magmas could flag shallow-level additions to the subduction cycle.

  17. Crustal structure of the Eastern Gulf of Mexico

    Science.gov (United States)

    Nwafor, Emeka

    The Gulf of Mexico initiated in the Late Triassic as South America and Africa separated from North America during the break up of Pangea. Previous studies indicate three models for the opening of the GOM. These include counter clockwise rotation of the Yucatan Block, rotation of the Yucatan Block about the same pole of rotation as those describing seafloor spreading in the central North Atlantic, and clockwise rotation of the Yucatan Block. There is much debate about the margin type and the crustal structure of the Eastern Gulf of Mexico (EGOM), especially below the depth of 6 km where crustal structure is poorly imaged on seismic reflection data. Two 2.5-D forward gravity and magnetic models across the margin are presented. These are constrained by basement picks from sparse seismic reflection and refraction data, spectral analysis of gravity data to determine the depth to source, magnetic susceptibility derived from results from other margins, the empirical relationship between P-wave velocity and density, and crustal scale isostatic modeling. The models, combined with a kinematic reconstruction of the GOM, show that: 1) it is a rifted margin; 2) the point where the Moho deepens downward from ˜17 km to ˜32 km is approximately 50 km outboard of the topographic shelf edge; 3) the carbonate bank retreated by several kilometers from its original termination due to the action of contourite currents; 4) extension and subsidence was accommodated with little shallow brittle faulting; 5) oceanic lithosphere is possibly outboard of the EGOM continental slope.

  18. Plate tectonics and crustal deformation around the Japanese Islands

    Science.gov (United States)

    Hashimoto, Manabu; Jackson, David D.

    1993-01-01

    We analyze over a century of geodetic data to study crustal deformation and plate motion around the Japanese Islands, using the block-fault model for crustal deformation developed by Matsu'ura et al. (1986). We model the area including the Japanese Islands with 19 crustal blocks and 104 faults based on the distribution of active faults and seismicity. Geodetic data are used to obtain block motions and average slip rates of faults. This geodetic model predicts that the Pacific plate moves N deg 69 +/- 2 deg W at about 80 +/- 3 mm/yr relative to the Eurasian plate which is much lower than that predicted in geologic models. Substantial aseismic slip occurs on the subduction boundaries. The block containing the Izu Peninsula may be separated from the rigid part of the Philippine Sea plate. The faults on the coast of Japan Sea and the western part of the Median Tectonic Line have slip rates exceeding 4 mm/yr, while the Fossa Magna does not play an important role in the tectonics of the central Japan. The geodetic model requires the division of northeastern Japan, contrary to the hypothesis that northeastern Japan is a part of the North American plate. Owing to rapid convergence, the seismic risk in the Nankai trough may be larger than that of the Tokai gap.

  19. Modelagem heurística no problema de distribuição de cargas fracionadas de cimento.

    OpenAIRE

    Marcos Miura

    2008-01-01

    Esta dissertação trata do problema do agrupamento de cargas fracionadas na distribuição de cimento ensacado partindo de um depósito central. O problema consiste em definir quais entregas de cimento serão carregadas juntas em um determinado veículo, de modo a aproveitar ao máximo sua capacidade e ao mesmo tempo reduzir o custo com o frete pago aos transportadores que farão sua distribuição. Em especial, o método de resolução proposto pode ser dividido em três fases. Na primeira fase, as entreg...

  20. Early Archaean crustal collapse structures and sedimentary basin dynamics

    Science.gov (United States)

    Nijman, W.; de Vries, S. T.

    2003-04-01

    Observations in the Lower Archaean (>3.3 Ga) of the Pilbara and Kaapvaal Cratons point to a direct genetic relationship between the thickness and facies distribution of volcano-sedimentary basin fills and non-linear patterns of extensional faults in early Earth. The basin fills consist of mafic volcanic products, largely pillow basalts, with distinct phases of intermediate to felsic volcanism and concentration of silica, either primary or secondary, in sediments deposited near base-level. The extensional structures are listric growth-faults, arranged in superposed arrays, that migrated upwards with the growth of the Early Archaean stratigraphical column. The faults linked intermittently occurring shallow-level felsic intrusions via porphyry pipes, veins and hydrothermal circulations with the surficial sedimentary basin fill of cherty sediments, concurrent mineralisation and alteration products. The non-linear pattern of the fault systems is recorded by their restored facing directions over large areas and corresponds best with over 100 km-wide (semi)circular crustal collapse structures. Crustal collapse, and therefore basin formation, did not represent a reaction to compression and crustal thickening. It also had no relationship with the present-day distribution of granitoid domes and greenstone belts. Collapse followed crustal uplift recorded by shallowing of the basin fill from a general subaqueous level of deposition of pillow basalts towards zero water level for the sediments and low-relief emersion. Maxima of extension coincide with the appearance of intermediate or felsic volcanic rocks in the overall mafic environment. The geodynamical setting is most appropriately explained by crustal delamination and related plume activity. Although individual features may be compared to Phanerozoic and Recent geological phenomena, like calderas, for the collapse structures as a whole such younger counterparts cannot be found. Rather they have their equivalents in collapse

  1. MODELAGEM E SIMULAÇÃO DA DESTERPENAÇÃO DO ÓLEO DA CASCA DE LARANJA COM CO2 SUPERCRÍTICO EM MODO SEMI-CONTÍNUO

    Directory of Open Access Journals (Sweden)

    VIEIRA DE MELO Silvio A. B.

    1997-01-01

    Full Text Available A desterpenação do óleo da casca de laranja com CO2 supercrítico foi investigada através da modelagem e simulação da separação de uma mistura sintética de limoneno (90 % em peso e linalol (10 %, em um extrator operando em modo semi-contínuo. A modelagem matemática da extração supercrítica foi realizada por analogia com a destilação de uma mistura binária, em batelada, expressando-se a composição das fases em equilíbrio numa base molar livre de CO2. O cálculo das variáveis do processo foi feito por integração numérica da equação de Rayleigh empregando-se o método de Runge-Kutta de quarta ordem. Para a determinação da relação de equilíbrio entre as fases, adotou-se a equação de Peng-Robinson modificada, com os parâmetros de interação obtidos de dados de ELV dos sistemas binários CO2+limoneno e CO2+linalol e do ternário CO2+limoneno+linalol.

  2. "Storms of crustal stress" and AE earthquake precursors

    Directory of Open Access Journals (Sweden)

    G. P. Gregori

    2010-02-01

    Full Text Available Acoustic emission (AE displays violent paroxysms preceding strong earthquakes, observed within some large area (several hundred kilometres wide around the epicentre. We call them "storms of crustal stress" or, briefly "crustal storms". A few case histories are discussed, all dealing with the Italian peninsula, and with the different behaviour shown by the AE records in the Cephalonia island (Greece, which is characterized by a different tectonic setting.

    AE is an effective tool for diagnosing the state of some wide slab of the Earth's crust, and for monitoring its evolution, by means of AE of different frequencies. The same effect ought to be detected being time-delayed, when referring to progressively lower frequencies. This results to be an effective check for validating the physical interpretation.

    Unlike a seismic event, which involves a much limited focal volume and therefore affects a restricted area on the Earth's surface, a "crustal storm" typically involves some large slab of lithosphere and crust. In general, it cannot be easily reckoned to any specific seismic event. An earthquake responds to strictly local rheological features of the crust, which are eventually activated, and become crucial, on the occasion of a "crustal storm". A "crustal storm" lasts typically few years, eventually involving several destructive earthquakes that hit at different times, at different sites, within that given lithospheric slab.

    Concerning the case histories that are here discussed, the lithospheric slab is identified with the Italian peninsula. During 1996–1997 a "crustal storm" was on, maybe elapsing until 2002 (we lack information for the period 1998–2001. Then, a quiet period occurred from 2002 until 26 May 2008, when a new "crustal storm" started, and by the end of 2009 it is still on. During the 1996–1997 "storm" two strong earthquakes occurred (Potenza and

  3. A felsic MASH zone of crustal magmas - Feedback between granite magma intrusion and in situ crustal anatexis

    Science.gov (United States)

    Schwindinger, Martin; Weinberg, Roberto F.

    2017-07-01

    Magma mixing and mingling are described from different tectonic environments and are key mechanisms in the evolution of granitoids. The literature focuses on the interaction between mafic and felsic magmas with only limited research on the interaction between similar magmas. Here, we investigate instead hybridization processes between felsic magmas formed during the 500 Ma Delamerian Orogeny on the south coast of Kangaroo Island. Field relations suggest that a coarse, megacrystic granite intruded and interacted with a fine-grained diatexite that resulted from combined muscovite dehydration and water-fluxed melting of Kanmantoo Group turbidites. The two magmas hybridized during syn-magmatic deformation, explaining the complexity of relationships and variability of granitoids exposed. We suggest that granite intrusion enhanced melting of the turbidites by bringing in heat and H2O. With rising melt fraction, intrusive magmas became increasingly unable to traverse the partially molten terrane, creating a positive feedback between intrusion and anatexis. This feedback loop generated the exposed mid-crustal zone where magmas mixed and homogenized. Thus, the outcrops on Kangaroo Island represent a crustal and felsic melting-assimilation-storage-homogenization (felsic MASH) zone where, instead of having direct mantle magma involvement, as originally proposed, these processes developed in a purely crustal environment formed by felsic magmas.

  4. Gamificação: modelagem de conteúdos para programas e aplicativos educativos no ambiente da TV digital interativa

    Directory of Open Access Journals (Sweden)

    Marcos Américo

    2015-04-01

    Full Text Available Com a implantação da TV Digital no Brasil, surge a necessidade de se fomentar a concepção e produção de conteúdos audiovisuais interativos de qualidade que apresentem mensagens educativas a partir do Edutretenimento. Este estudo propõe a aplicação da gamificação como elo comunicacional para incentivar e modificar o comportamento dos usuários, através de uma narrativa que incentive a motivação intrínseca para o entretenimento e o aprendizado nesses meios. Existem poucos modelos de roteiros para a produção de aplicativos, sobretudo educacionais, com aplicações interativas simultâneas para o fluxo televisivo ou para o conteúdo complementar da programação ofertada. Por essa razão, é atribuída uma atenção especial ao roteiro, em virtude de se inserir, em sua construção, os elementos que compõem a mecânica e a dinâmica dos jogos. Como resultado, é apresentado o verbete “Gamificação-TVDI”, bem como o desenvolvimento de uma metodologia de modelagem de conteúdo e de processo, apoiada em mapas conceituais, wireframes e roadmaps, fundamentando a concepção e a elaboração de um protótipo de roteiro com elementos de gamificação para programas educativos e seus aplicativos de interação.

  5. Estudo e modelagem da cinética de desidratação osmótica do mamão formosa (Carica papaya L.

    Directory of Open Access Journals (Sweden)

    El-Aquar Ânoar Abbas

    2003-01-01

    Full Text Available O presente trabalho teve como objetivo o estudo da cinética e modelagem do processo de desidratação osmótica de cubos de mamão Formosa (Carica papaya L., assim como da qualidade do produto final. O tratamento osmótico foi conduzido a 30ºC, com agitação de 110rpm, utilizando-se dois tipos de soluções de sacarose 70ºBrix: a primeira contendo lactato de sódio 2,4% p/p e ácido láctico 0,1M e a segunda com lactato de sódio 2,4% p/p e ácido cítrico 0,1M. O estudo da cinética de desidratação osmótica mostrou que a solução contendo ácido cítrico apresentou valor de perda de água (WL, ao final de 48 horas de processo, ligeiramente superior ao encontrado para a solução contendo ácido láctico. Comportamento contrário ocorreu para o ganho de sólidos (SG. O ajuste dos dados experimentais foi realizado através do modelo difusional para geometria cúbica, sem considerar encolhimento durante o processo e um modelo empírico de dois parâmetros. Os coeficientes de difusividade efetiva de água (Def variaram de 1,27 a 5,03 x 10-10 m²/s. A qualidade da fruta após processamento foi avaliada através de análises de vitamina C, carotenóides totais, acidez e pH.

  6. Formulação estratégica da manutenção industrial com base na confiabilidade dos equipamentos Strategic formulation of industrial maintenance supported by equipment's reliability

    Directory of Open Access Journals (Sweden)

    Miguel Afonso Sellitto

    2005-04-01

    Full Text Available Este trabalho relata o uso da confiabilidade e da manutenibilidade na formulação de estratégias de manutenção industrial. O método utilizado foi o estudo de dois casos. Inicia-se revisando conceitos ligados a variáveis e processos aleatórios como base para definir conceitos e características de estudos de confiabilidade e de modelagem aplicados na gestão da manutenção industrial. A seguir se descrevem os casos estudados, em que se aplicam técnicas de modelagem de tempos até a falha e até o reparo no estabelecimento de estratégias de manutenção em fábricas do setor metal-mecânico. Com base nos resultados, discute-se o caso, estabelecendo condições para o uso da confiabilidade na formulação estratégica da manutenção, principalmente quanto ao sistema de informações necessárias.This paper reports the use of reliability and maintainability assessments in the strategic formulation of industrial maintenance. The method was a double case study. The paper begins by a theoretical review of related concepts of stochastic variables and processes as a basis to address concepts and features from reliability studies and modeling, suited to use in managing the industrial maintenance. One then describes the two studied cases, in which the reliability techniques were applied, in modeling the times to failure and times to the repair for the sake of settling the strategic formulation of industrial maintenance in metal-mechanic plants. Supported by results, this paper discusses the cases, arising requirements to the use of the reliability, mainly related to the information system.

  7. Effects of Crustal Fields on the Ionosphere of Mars as seen by MAVEN

    Science.gov (United States)

    Vogt, Marissa F.; Withers, Paul; Flynn, Casey L.; Andersson, Laila; Brain, David; Mitchell, David; Connerney, Jack; Espley, Jared R.

    2016-10-01

    Mars lacks a global intrinsic magnetic field but possesses regions of strong crustal magnetic field that are concentrated in the southern hemisphere. Previous studies have used Mars Global Surveyor or Mars Express data to show that these crustal fields influence the electron densities in the Martian ionosphere. However, many of these studies relied on remote radio occultation or radar sounding measurements and therefore relied on models to infer the crustal magnetic field strength and direction. In fall 2015 the MAVEN spacecraft passed through these crustal field regions at low altitudes, on the day side, and collected comprehensive measurements of the local plasma and magnetic field properties. The MAVEN observations therefore provide an excellent dataset with which to examine the effects of crustal fields on the ionosphere. We report on the MAVEN electron density measurements in the southern crustal field regions and discuss the influence of the magnetic field direction and topology on the dayside Martian ionosphere.

  8. Trincheiras de infiltração como tecnologia alternativa em drenagem urbana: modelagem experimental e numérica

    OpenAIRE

    Melissa Cristina Pereira Graciosa

    2005-01-01

    A infiltração das águas de chuva dentro dos lotes urbanos é uma possível forma de promover o controle descentralizado do escoamento superficial na origem, com vistas ao gerenciamento das águas pluviais urbanas e conseqüente atenuação das cheias. Neste trabalho, foram conduzidos ensaios de campo com trincheiras de infiltração, em dois solos distintos, um arenoso e outro argiloso, com o objetivo de avaliar quantitativamente o comportamento hidráulico das estruturas de infiltração em resposta a ...

  9. Crustal structure beneath the Songpan-Garze orogenic belt

    Institute of Scientific and Technical Information of China (English)

    王椿镛; 韩渭宾; 吴建平; 楼海; 白志明

    2003-01-01

    The Benzilan-Tangke deep seismic sounding profile in the western Sichuan region passes through the Songpan-Garze orogenic belt with trend of NNE. Based on the travel times and the related amplitudes of phases in the record sections, the 2-DP-wave crustal structure was ascertained in this paper. The velocity structure has quite strong lateral variation along the profile. The crust is divided into 5 layers, where the first, second and third layer belong to the upper crust, theforth and fifth layer belong to the lower crust. The low velocity anomaly zone generally exists in the central part of the upper crust on the profile, and it integrates into the overlying low velocity basement in the area to the north of Ma.erkang. The crustal structure in the section can be divided into 4 parts: in the south of Garze-Litang fault, between Garze-Litang fault and Xianshuihe fault,between Xianshuihe fault and Longriba fault and in the north of Longriba fault,which are basically coincided with the regional tectonics division. The crustalthickness decreases from southwest to northeast along the profile, that is, from 62 km in the region of the Jinshajiang River to 52 km in the region of the Yellow River. The Moho discontinuity does not obviously change across the Xianshuihe fault based on the PmP phase analysis. The crustal average velocity along the profile is lower, about 6.30 km/s. The Benzilan-Tangke profile reveals that the crust in the study area is orogenic. The Xianshuihe fault belt is located in thecentral part of the profile, and the velocity is positive anomaly on the upper crust, and negative anomaly on the lower crust and upper mantle. It is considered as a deep tectonic setting in favor of strong earthquake's accumulation and occurrence.

  10. Effect of Crustal Density Structures on GOCE Gravity Gradient Observables

    Directory of Open Access Journals (Sweden)

    Robert Tenzer Pavel Novák

    2013-01-01

    Full Text Available We investigate the gravity gradient components corrected for major known anomalous density structures within the Earth¡¦s crust. Heterogeneous mantle density structures are disregarded. The gravimetric forward modeling technique is utilized to compute the gravity gradients based on methods for a spherical harmonic analysis and synthesis of a gravity field. The Earth¡¦s gravity gradient components are generated using the global geopotential model GOCO-03s. The topographic and stripping gravity corrections due to the density contrasts of the ocean and ice are computed from the global topographic/bathymetric model DTM2006.0 (which also includes the ice-thickness dataset. The discrete data of sediments and crust layers taken from the CRUST2.0 global crustal model are then used to apply the additional stripping corrections for sediments and remaining anomalous crustal density structures. All computations are realized globally on a one arc-deg geographical grid at a mean satellite elevation of 255 km. The global map of the consolidated crust-stripped gravity gradients reveals distinctive features which are attributed to global tectonics, lithospheric plate configuration, lithosphere structure and mantle dynamics (e.g., glacial isostatic adjustment, mantle convection. The Moho signature, which is the most pronounced signal in these refined gravity gradients, is superimposed over a weaker gravity signal of the lithospheric mantle. An interpretational quality of the computed (refined gravity gradient components is mainly limited by a low accuracy and resolution of the CRUST2.0 sediment and crustal layer data and unmodeled mantle structures.

  11. Recent crustal deformation in west-central South America

    Science.gov (United States)

    Pritchard, Matthew Earl

    I use interferometric synthetic aperture radar (InSAR) to create maps of crustal deformation along the coast and within the volcanic arc of central South America. I image deformation associated with six subduction zone earthquakes, four volcanic centers, at least one shallow crustal earthquake, and several salt flats. In addition, I constrain the magnitude and location of post-seismic deformation from the aforementioned subduction zone earthquakes. I combine InSAR observations with data from the Global Positioning System (GPS) and teleseismic data to explore each source of deformation. I use the observations to constrain earthquake and volcanic processes of this subduction zone, including the plumbing system of the volcanoes and the decadal along strike variations in the subduction zone earthquake cycle. I created interferograms of over 900 volcanoes in the central Andes spanning 1992--2002, and found four areas of deformation. I constrained the temporal variability of the deformation, the depth of the sources of deformation assuming a variety of source geometries and crustal structures, and the possible cause of the deformation. I do not observe deformation associated with eruptions at several volcanoes, and I discuss the possible explanations for this lack of deformation. In addition, I constrain the amount of co-seismic and post-seismic slip on the subduction zone fault interface from the following earthquakes: 1995 Mw 8.1 Antofagasta, Chile; 1996 Mw 7.7 Nazca, Peru; 1998 Mw 7.1 Antofagasta, Chile; and 2001 Mw 8.4 Arequipa, Peru. In northern Chile, I compare the location and magnitude of co-seismic slip from 5 Mw > 7 earthquakes during the past 15 years with the post-seismic slip distribution. There is little post-seismic slip from the 1995 and 1996 earthquakes relative to the 2001 event and other recent subduction zone earthquakes.

  12. Caracterização, modelagem e simulação de enlace congestionado de uma universidade

    Directory of Open Access Journals (Sweden)

    Mariana Vazquez

    2015-01-01

    Full Text Available ResumoEste trabalho apresenta um estudo de avaliação de desempenho de uma rede de comunicação congestionada de uma Universidade. Nesta rede, é comum a formação de filas, devido à alta demanda e ao descarte de requisições em horários de pico, resultando diretamente na queda da qualidade de serviço aos usuários, que têm suas conexões demoradas ou interrompidas e não conseguem acessar páginas na web. O objetivo deste trabalho foi caracterizar o problema de congestionamento empiricamente, capturando rastros de pacotes em logs e estudando atrasos e perdas, e modelar e analisar esse sistema, com base nas teorias de filas e simulação discreta, para avaliar seu desempenho, identificar gargalos e propor soluções para a melhoria da qualidade de serviço. O estudo mostrou que em situações de pico de tráfego no sistema, a abordagem quantitativa que produziu resultados mais próximos do empírico foi a simulação, pois os modelos analíticos de filas estudados não forneceram boas aproximações, principalmente por não refletirem o controle exercido pelo protocolo TCP.

  13. Testing Predictions of Continental Insulation using Oceanic Crustal Thicknesses

    Science.gov (United States)

    Hoggard, Mark; Shorttle, Oliver; White, Nicky

    2016-04-01

    The thermal blanketing effect of continental crust has been predicted to lead to elevated temperatures within the upper mantle beneath supercontinents. Initial break-up is associated with increased magmatism and the generation of flood basalts. Continued rifting and sea-floor spreading lead to a steady reduction of this thermal anomaly. Recently, evidence in support of this behaviour has come from the major element geochemistry of mid-ocean ridge basalts, which suggest excess rifting temperatures of ˜ 150 °C that decay over ˜ 100 Ma. We have collated a global inventory of ˜ 1000 seismic reflection profiles and ˜ 500 wide-angle refraction experiments from the oceanic realm. Data are predominantly located along passive margins, but there are also multiple surveys in the centres of the major oceanic basins. Oceanic crustal thickness has been mapped, taking care to avoid areas of secondary magmatic thickening near seamounts or later thinning such as across transform faults. These crustal thicknesses are a proxy for mantle potential temperature at the time of melt formation beneath a mid-ocean ridge system, allowing us to quantify the amplitude and duration of thermal anomalies generated beneath supercontinents. The Jurassic break-up of the Central Atlantic and the Cretaceous rifting that formed the South Atlantic Ocean are both associated with excess temperatures of ˜ 50 °C that have e-folding times of ˜ 50 Ma. In addition to this background trend, excess temperatures reach > 150 °C around the region of the Rio Grande Rise, associated with the present-day Tristan hotspot. The e-folding time of this more local event is ˜ 10 Ma, which mirrors results obtained for the North Atlantic Ocean south of Iceland. In contrast, crustal thicknesses from the Pacific Ocean reveal approximately constant potential temperature through time. This observation is in agreement with predictions, as the western Pacific was formed by rifting of an oceanic plate. In summary

  14. THE CRUSTAL STRUCTURE OF ELLESMERE ISLAND FROM RECEIVER FUNCTION MODELLING

    DEFF Research Database (Denmark)

    Schiffer, Christian; Stephenson, Randell Alexander; Oakey, Gordon

    Atlantic region. The intraplate Eurekan orogeny in the Cenozoic caused additional crustal shortening in the area, related to the opening of Baffin Bay, the North Atlantic and the Arctic Ocean basins and the complex plate tectonic responses to these plate boundary reconfigurations. Geophysically Ellesmere...... stations was installed and maintained from 2010 to 2012 with the support of the Geological Survey of Canada and SEIS-UK. The two closest permanent stations (Eureka and Alert) in the area as well as two wide angle seismic profiles across the Canadian Arctic margin have been included to the interpretation...

  15. Imaging the Western Iberia Crustal Structure by Noise Analysis

    Science.gov (United States)

    Silveira, G. M.; Dias, N. A.; Custodio, S.; Kiselev, S.; Dündar, S.

    2014-12-01

    Portugal lies close to the Eurasian-African boundary, a region of tectonic regime transition from convergence in the Mediterranean to strike-slip in the Atlantic. Such broad convergence area, characterized by a slow rate of about 4.5-5.6 mm/yr, translates unto a scattered seismicity concentrated mainly in the offshore. Therefore, the irregular source-receiver geometry resulting from the inland seismic stations networks does not permit to derive high-resolution models of the Portuguese crustal structure using traditional passive seismology. Seismic interferometry/ambient noise surface-waves tomography allows imaging regions with a resolution that mainly depends on the seismic network coverage. Over the last decade, both Portuguese and Spanish permanent broadband (BB) seismic networks expanded significantly. This densification enabled to build a detailed image of the crustal structure of the Iberian Peninsula using ambient seismic noise. However, due to the existing network gaps towards west, the crustal image of Western Iberia is on the limit of resolution. The two years temporary deployment by the WILAS project contributed to fill those gaps and provide an excellent opportunity to study the Portuguese crustal structure. Dispersion measurements were computed for each pair of stations using empirical Green's functions generated by cross-correlating one-day-length seismic ambient-noise records. To improve the signal-to-noise ratio of the empirical Green functions computed from ambient noise records, we applied a phase cross-correlation method, followed by time-frequency domain phase weighted stack. Group-velocities were computed using the S-transform and we use the Fast Marching Surface Tomography algoritm to compute group velocity perturbation maps. Group velocities were then inverted as a function of depth to obtain S-wave velocity maps for diferent depths. The models will be compared with results from Ps receiver functions. The results obtained for the crust using

  16. Magnetar Outbursts from Avalanches of Hall Waves and Crustal Failures

    CERN Document Server

    Li, Xinyu; Belovorodov, Andrei M

    2016-01-01

    We explore the interaction between Hall waves and mechanical failures inside a magnetar crust, using detailed one-dimentional models that consider temperature-sensitive plastic flow, heat transport and cooling by neutrino emission, as well as the coupling of the crustal motion to the magnetosphere. We find that the dynamics is enriched and accelerated by the fast, short-wavelength Hall waves that are emitted by each failure. The waves propagate and cause failures elsewhere, triggering avalanches. We argue that these avalanches are the likely sources of outbursts in transient magnetars.

  17. Spectral Properties of the Martian Crustal Magnetic Field

    Science.gov (United States)

    Lewis, K. W.; Simons, F. J.

    2010-12-01

    Although the planet Mars no longer possesses an internal dynamo, its crustal rocks retain strong remanent magnetization thought to have been induced by an ancient core-sourced field. The strength and distribution of the crustal field is extremely heterogeneous, and particularly strong in the Terra Cimmeria region of the southern hemisphere. The field as a whole is inconsistent with induction from a single dipolar source, although previous studies have attempted to isolate individual magnetic anomalies to deduce paleopolar orientations. While several areas of the planet appear to have been demagnetized, including large impact basins and the Tharsis volcanic province, the distribution of the field is generally poorly correlated with surface geologic structures. However, beyond the spatial pattern of crustal magnetization, the magnetic power spectrum can provide information about the nature of the source and formation processes. Previous studies have used the power spectrum of the Martian field to estimate the approximate depth of the magnetic anomalies. We extend this approach by applying the spatiospectral localization technique of Wieczorek and Simons (2005) and Dahlen and Simons (2008) to isolate the magnetic power spectra of several areas of the Martian surface. This method allows us to look beyond the strongly magnetized Terra Cimmeria region, which dominates the global power spectrum. Localized spectral estimates, along with their appropriate errors, allow us to examine the significance of observed variations between distinct regions of the planet, and to evaluate the validity of analyses which operate on the whole sphere. Significant differences are observed between spectra of the Terra Cimmeria region and the remainder of the planet, a result of the concentration of power at certain spherical harmonic degrees in this anomalous region. Approximate depths to the magnetic sources are calculated for tiled windows on the planet using the stochastic magnetized

  18. Quantifying Precambrian crustal extraction: the root is the answer

    Science.gov (United States)

    Abbott, Dallas; Sparks, David; Herzberg, Claude; Mooney, Walter; Nikishin, Anatoly; Zhang, Yu Shen

    2000-07-01

    We use two different methods to estimate the total amount of continental crust that was extracted by the end of the Archean and the Proterozoic. The first method uses the sum of the seismic thickness of the crust, the eroded thickness of the crust, and the trapped melt within the lithospheric root to estimate the total crustal volume. This summation method yields an average equivalent thickness of Archean crust of 49±6 km and an average equivalent thickness of Proterozoic crust of 48± 9 km. Between 7 and 9% of this crust never reached the surface, but remained within the continental root as congealed, iron-rich komatiitic melt. The second method uses experimental models of melting, mantle xenolith compositions, and corrected lithospheric thickness to estimate the amount of crust extracted through time. This melt column method reveals that the average equivalent thickness of Archean crust was 65±6 km, and the average equivalent thickness of Early Proterozoic crust was 60±7 km. It is likely that some of this crust remained trapped within the lithospheric root. The discrepancy between the two estimates is attributed to uncertainties in estimates of the amount of trapped, congealed melt, overall crustal erosion, and crustal recycling. Overall, we find that between 29 and 45% of continental crust was extracted by the end of the Archean, most likely by 2.7 Ga. Between 51 and 79% of continental crust was extracted by the end of the Early Proterozoic, most likely by 1.8-2.0 Ga. Our results are most consistent with geochemical models that call upon moderate amounts of recycling of early extracted continental crust coupled with continuing crustal growth (e.g. McLennan, S.M., Taylor, S.R., 1982. Geochemical constraints on the growth of the continental crust. Journal of Geology, 90, 347-361; Veizer, J., Jansen, S.L., 1985. Basement and sedimentary recycling — 2: time dimension to global tectonics. Journal of Geology 93(6), 625-643). Trapped, congealed, iron-rich melt

  19. Modelagem do problema de localização/roteirização para o transporte de carga fracionada.

    OpenAIRE

    André Alarcon de Almeida Prado

    2016-01-01

    As localizações dos terminais e as rotas de entrega que partem desses terminais são decisões importantes que surgem na concepção de redes de transporte de carga fracionada. Nesses casos, dois problemas independentes precisam ser tratados: o problema da localização de instalações (LAP) e o problema da roteirização dos veículos (VRP). Este trabalho apresenta um modelo matemático para resolver o LAP e o VRP de forma integrada, ou seja, para a resolução do problema de Localização/Roteirização (Lo...

  20. Modelagem do processo de adsorção das proteínas do soro em tanques agitados

    Directory of Open Access Journals (Sweden)

    Sérgio Henriques Saraiva

    2013-12-01

    Full Text Available O objetivo desse trabalho foi modelar o processo de adsorção das proteínas do soro, α-la e β-lg, pela resina de troca aniônica Streamline Q XL em tanques agitados. Foi desenvolvido um procedimento numérico para a solução do modelo de transferência de massa para adsorção em tanques agitados que considera difusão dentro da partícula, resistência à transferência de massa no filme líquido na superfície da partícula e equilíbrio local. O modelo foi capaz de simular rapidamente, com um tempo de simulação variando de 10 segundos a 47 segundos, a adsorção simultânea das proteínas do soro, α-lactoalbumina (α-la e β-lactoglobulina (β-lg, por uma resina de troca iônica. A comparação de curvas de cinética obtidas experimentalmente com as curvas simuladas mostrou que o modelo é adequado para o estudo desses sistemas. A partir do modelo desenvolvido várias simulações foram feitas para estudar o efeito dos parâmetros de transferência de massa, coeficiente de difusão e coeficiente de transferência de massa, na cinética de adsorção das proteínas α-la e β-lg. Palavras-chave α-lactoalbumina; β-lactoglobulina; simulação; proteínas do soro.

  1. Modelagem da infiltração de água no solo sob condições de estratificação utilizando-se a equação de Green-Ampt Modeling of water infiltration in soil under stratified conditions using the Green-Ampt equation

    Directory of Open Access Journals (Sweden)

    Roberto A. Cecílio

    2003-12-01

    Full Text Available A infiltração de água no solo é um dos mais significantes processos do ciclo hidrológico. A equação de Green-Ampt (GA é bastante utilizada na modelagem da infiltração; entretanto, diversos autores alertam para a necessidade de adequação de seus parâmetros de entrada (umidade de saturação (tetas; condutividade hidráulica do solo saturado (K0 e potencial matricial na frente de umedecimento (psi. Neste sentido, avaliou-se a aplicabilidade do modelo de GA, assim como as diversas proposições de adequação de K0 e psi, em um Latossolo Vermelho-Amarelo sob condições de estratificação. Determinaram-se a infiltração acumulada (I, a taxa de infiltração (Ti e as características físicas do perfil necessárias para a aplicação do modelo. Foram feitas simulações com base na combinação de seis metodologias para a determinação de psi e três para a condutividade hidráulica da zona de transmissão (Kw, verificando-se que as combinações seguintes simularam bem o processo de infiltração: Kw igual a 0,5 K0 associado a psi determinado com base na umidade inicial do solo (psi (tetai; Kw igual à taxa de infiltração estável (Tie associado a psi igual à média entre psi (tetai e psi relativo à umidade de saturação de campo (psi (tetaw; e Kw igual a K0 associado a psi calculado com base na textura e porosidade do solo (psi(textura e Kw igual à Tie associado a psi(textura.Soil water infiltration is one of the most important processes of the hydrological cycle. The Green and Ampt equation (GA is quite used to simulate the infiltration process, however, several authors showed the necessity of some adaptations in the GA parameters: saturation moisture (thetas, hydraulic conductivity (K0 and mean suction in the wetting front (psi. An evaluation was made of the GA model and of the several correction propositions of K0 and psi, applied in a stratified Red-Yellow Latosol. A soil box filled with soil material belonging to three

  2. The crustal structure of Egypt and the northern Red Sea region

    Science.gov (United States)

    Hosny, Ahmed; Nyblade, Andrew

    2016-09-01

    P-wave receiver functions from 26 stations in the Egyptian National Seismic Network (ENSN) have been modeled using the H-k stacking method and in a joint inversion method with Rayleigh wave group velocities to investigate crustal structure across Egypt and the northern Red Sea region. The new estimates of crustal structure, when combined with previous results, show that along the rifted margins of the Red Sea, Gulf of Suez and Gulf of Aqaba crustal thickness ranges from 25 to 30 km, the average crustal Vp/Vs ratio is 1.77, and the average crustal shear-wave velocity is 3.6 km/s. Beneath northern and central Egypt, including the Sinai Peninsula, crustal thickness ranges from 32 to 38 km, the average crustal Vp/Vs ratio is 1.79, and the average crustal shear-wave velocity is 3.5 km/s. Beneath southern Egypt, crustal thickness ranges from 35 to 40 km, the average crustal Vp/Vs ratio is 1.76, and the average crustal shear-wave velocity is 3.7 km/s. In southern Egypt, the crust is also characterized by a 10-20 km thick mafic lower crust. These findings indicate that crust along the rifted margins of the northern Red Sea, and Gulfs of Suez and Aqaba have been thinned by about 5 to 10 km. The thick mafic lower crust in southern Egypt can be attributed to suturing during the Neoproterozoic collision of east Gondwana against the Sahara metacraton. Overall, the structure of the crust in Egypt away from the northern Red Sea region is similar to the structure of Precambrian crust in many other parts of Africa.

  3. Lower crustal xenoliths, Chinese Peak lava flow, central Sierra Nevada.

    Science.gov (United States)

    Dodge, F.C.W.; Calk, L.C.; Kistler, R.W.

    1986-01-01

    This assemblage of pyroxenite, peridotite and mafic granulite xenoliths in the toe of a 10 m.y. trachybasalt flow remnant overlying late Cretaceous granitic rocks, indicates the presence of a mafic-ultramafic complex beneath this part of central California; orthopyroxenites, websterites and clinopyroxenites are dominant. A few of the xenoliths contain ovoid opaque patches that are apparently pseudomorphs after garnet and have pyralspite garnet compositions; using a garnet-orthopyroxene geobarometer, they indicate a lower crustal depth of approx 40 km. Abundant mafic granulites can be subdivided into those with Al2O3 = or 15% and showing considerable scatter on oxide variation diagrams. The high-alumina granulite xenoliths have relatively low 87Rb/86Sr but high 87Sr/86Sr, whereas the low-alumina and ultramafic xenoliths have a wide range of 87Rb/86Sr, but lower 87Sr/86Sr; the isotopic data indicate roughly the same age as that of overlying granitic plutons (approx 100 m.y.). However, the granitic rocks have initial 87Sr/86Sr ratios intermediate between those of the high-alumina and ultramafic xenoliths, suggesting that they result from the mixing of basaltic magma (represented by the ultramafic rocks) and crustal materials, with subsequent crystal fractionation.-R.A.H.

  4. Continental crust composition constrained by measurements of crustal Poisson's ratio

    Science.gov (United States)

    Zandt, George; Ammon, Charles J.

    1995-03-01

    DECIPHERING the geological evolution of the Earth's continental crust requires knowledge of its bulk composition and global variability. The main uncertainties are associated with the composition of the lower crust. Seismic measurements probe the elastic properties of the crust at depth, from which composition can be inferred. Of particular note is Poisson's ratio,Σ ; this elastic parameter can be determined uniquely from the ratio of P- to S-wave seismic velocity, and provides a better diagnostic of crustal composition than either P- or S-wave velocity alone1. Previous attempts to measure Σ have been limited by difficulties in obtaining coincident P- and S-wave data sampling the entire crust2. Here we report 76 new estimates of crustal Σ spanning all of the continents except Antarctica. We find that, on average, Σ increases with the age of the crust. Our results strongly support the presence of a mafic lower crust beneath cratons, and suggest either a uniformitarian craton formation process involving delamination of the lower crust during continental collisions, followed by magmatic underplating, or a model in which crust formation processes have changed since the Precambrian era.

  5. A reverse energy cascade for crustal magma transport

    Science.gov (United States)

    Karlstrom, Leif; Paterson, Scott R.; Jellinek, A. Mark

    2017-08-01

    Direct constraints on the ascent, storage and eruption of mantle melts come primarily from exhumed, long-frozen intrusions. These structures, relics of a dynamic magma transport network, encode how Earth's crust grows and differentiates over time. Furthermore, they connect mantle melting to an evolving distribution of surface volcanism. Disentangling magma transport processes from the plutonic record is consequently a seminal but unsolved problem. Here we use field data analyses, scaling theory and numerical simulations to show that the size distribution of intrusions preserved as plutonic complexes in the North American Cordillera suggests a transition in the mechanical response of crustal rocks to protracted episodes of magmatism. Intrusion sizes larger than about 100 m follow a power-law scaling expected if energy delivered from the mantle to open very thin dykes and sills is transferred to intrusions of increasing size. Merging, assimilation and mixing of small intrusions into larger ones occurs until irreversible deformation and solidification dissipate available energy. Mantle magma supply over tens to hundreds of thousands of years will trigger this regime, a type of reverse energy cascade, depending on the influx rate and efficiency of crustal heating by intrusions. Identifying regimes of magma transport provides a framework for inferring subsurface magmatic processes from surface patterns of volcanism, information preservation in the plutonic record, and related effects including climate.

  6. Glacio-Seismotectonics: Ice Sheets, Crustal Deformation and Seismicity

    Science.gov (United States)

    Sauber, Jeanne; Stewart, Iain S.; Rose, James

    2000-01-01

    The last decade has witnessed a significant growth in our understanding of the past and continuing effects of ice sheets and glaciers on contemporary crustal deformation and seismicity. This growth has been driven largely by the emergence of postglacial rebound models (PGM) constrained by new field observations that incorporate increasingly realistic rheological, mechanical, and glacial parameters. In this paper, we highlight some of these recent field-based investigations and new PGMs, and examine their implications for understanding crustal deformation and seismicity during glaciation and following deglaciation. The emerging glacial rebound models outlined in the paper support the view that both tectonic stresses and glacial rebound stresses are needed to explain the distribution and style of contemporary earthquake activity in former glaciated shields of eastern Canada and Fennoscandia. However, many of these models neglect important parameters, such as topography, lateral variations in lithospheric strength and tectonic strain built up during glaciation. In glaciated mountainous terrains, glacial erosion may directly modulate tectonic deformation by resetting the orogenic topography and thereby providing an additional compensatory uplift mechanism. Such effects are likely to be important both in tectonically active orogens and in the mountainous regions of glaciated shields.

  7. Mineralogy of the Martian Surface: Crustal Composition to Surface Processes

    Science.gov (United States)

    Mustard, John F.

    1997-01-01

    The main results have been published in the refereed literature, and thus this report serves mainly to summarize the main findings and indicate where the detailed papers may be found. Reflectance spectroscopy has been an important tool for determining the mineralogic makeup of the near surface materials on Mars. Analysis of the spectral properties of the surface have demonstrated that these attributes are heterogeneous from the coarse spatial but high spectral resolution spectra obtained with telescopes to the high spatial but coarse spectral resolution Viking data (e.g. Arvidson et al., 1989; McEwen et al., 1989). Low albedo materials show strong evidence for the presence of igneous rock forming minerals while bright materials are generally interpreted as representing heavily altered crustal material. How these materials are physically and genetically related has important implications for understanding martian surface properties and processes, weathering histories and paths, and crustal composition. The goal of this research is to characterize the physical and chemical properties of low albedo materials on Mars and the relationship to intermediate and high albedo materials. Fundamental science questions to be pursued include: (1) the observed distributions of soil, rock, and dust a function of physical processes or weathering and (2) different stages of chemical and physical alteration fresh rock identified. These objectives will be addressed through detailed analyses and modelling of the ISM data from the Phobos-2 mission with corroborating evidence of surface composition and properties provided by data from the Viking mission.

  8. Gravitational radiation from neutron stars deformed by crustal Hall drift

    CERN Document Server

    Suvorov, Arthur George; Geppert, Ulrich

    2016-01-01

    A precondition for the radio emission of pulsars is the existence of strong, small-scale magnetic field structures (`magnetic spots') in the polar cap region. Their creation can proceed via crustal Hall drift out of two qualitatively and quantitatively different initial magnetic field configurations: a field confined completely to the crust and another which penetrates the whole star. The aim of this study is to explore whether these magnetic structures in the crust can deform the star sufficiently to make it an observable source of gravitational waves. We model the evolution of these field configurations, which can develop, within $\\sim 10^4$ -- $10^5$ yr, magnetic spots with local surface field strengths $\\sim 10^{14}$ G maintained over $\\gtrsim 10^6$ yr. Deformations caused by the magnetic forces are calculated. We show that, under favourable initial conditions, a star undergoing crustal Hall drift can have ellipticity $\\epsilon\\sim 10^{-6}$, even with sub-magnetar polar field strengths, after $\\sim 10^5$ ...

  9. Gravitational radiation from neutron stars deformed by crustal Hall drift

    Science.gov (United States)

    Suvorov, A. G.; Mastrano, A.; Geppert, U.

    2016-07-01

    A precondition for the radio emission of pulsars is the existence of strong, small-scale magnetic field structures (`magnetic spots') in the polar cap region. Their creation can proceed via crustal Hall drift out of two qualitatively and quantitatively different initial magnetic field configurations: a field confined completely to the crust and another which penetrates the whole star. The aim of this study is to explore whether these magnetic structures in the crust can deform the star sufficiently to make it an observable source of gravitational waves. We model the evolution of these field configurations, which can develop, within ˜104-105 yr, magnetic spots with local surface field strengths ˜1014 G maintained over ≳106 yr. Deformations caused by the magnetic forces are calculated. We show that, under favourable initial conditions, a star undergoing crustal Hall drift can have ellipticity ɛ ˜ 10-6, even with sub-magnetar polar field strengths, after ˜105 yr. A pulsar rotating at ˜102 Hz with such ɛ is a promising gravitational wave source candidate. Since such large deformations can be caused only by a particular magnetic field configuration that penetrates the whole star and whose maximum magnetic energy is concentrated in the outer core region, gravitational wave emission observed from radio pulsars can thus inform us about the internal field structures of young neutron stars.

  10. Magma-compensated crustal thinning in continental rift zones.

    Science.gov (United States)

    Thybo, H; Nielsen, C A

    2009-02-12

    Continental rift zones are long, narrow tectonic depressions in the Earth's surface where the entire lithosphere has been modified in extension. Rifting can eventually lead to rupture of the continental lithosphere and creation of new oceanic lithosphere or, alternatively, lead to formation of wide sedimentary basins around failed rift zones. Conventional models of rift zones include three characteristic features: surface manifestation as an elongated topographic trough, Moho shallowing due to crustal thinning, and reduced seismic velocity in the uppermost mantle due to decompression melting or heating from the Earth's interior. Here we demonstrate that only the surface manifestation is observed at the Baikal rift zone, whereas the crustal and mantle characteristics can be ruled out by a new seismic profile across southern Lake Baikal in Siberia. Instead we observe a localized zone in the lower crust which has exceptionally high seismic velocity and is highly reflective. We suggest that the expected Moho uplift was compensated by magmatic intrusion into the lower crust, producing the observed high-velocity zone. This finding demonstrates a previously unknown role for magmatism in rifting processes with significant implications for estimation of stretching factors and modelling of sedimentary basins around failed rift structures.

  11. A view into crustal evolution at mantle depths

    Science.gov (United States)

    Kooijman, Ellen; Smit, Matthijs A.; Ratschbacher, Lothar; Kylander-Clark, Andrew R. C.

    2017-05-01

    Crustal foundering is an important mechanism in the differentiation and recycling of continental crust. Nevertheless, little is known about the dynamics of the lower crust, the temporal scale of foundering and its role in the dynamics of active margins and orogens. This particularly applies to active settings where the lower crust is typically still buried and direct access is not possible. Crustal xenoliths derived from mantle depth in the Pamir provide a unique exception to this. The rocks are well-preserved and comprise a diverse set of lithologies, many of which re-equilibrated at high-pressure conditions before being erupted in their ultrapotassic host lavas. In this study, we explore the petrological and chronological record of eclogite and felsic granulite xenoliths. We utilized accessory minerals - zircon, monazite and rutile - for coupled in-situ trace-element analysis and U-(Th-)Pb chronology by laser-ablation (split-stream) inductively coupled plasma mass spectrometry. Each integrated analysis was done on single mineral zones and was performed in-situ in thin section to maintain textural context and the ability to interpret the data in this framework. Rutile thermo-chronology exclusively reflects eruption (11.17 ± 0.06Ma), which demonstrates the reliability of the U-Pb rutile thermo-chronometer and its ability to date magmatic processes. Conversely, zircon and monazite reveal a series of discrete age clusters between 55-11 Ma, with the youngest being identical to the age of eruption. Matching age populations between samples, despite a lack of overlapping ages for different chronometers within samples, exhibit the effectiveness of our multi-mineral approach. The REE systematics and age data for zircon and monazite, and Ti-in-zircon data together track the history of the rocks at a million-year resolution. The data reveal that the rocks resided at 30-40 km depth along a stable continental geotherm at 720-750 °C until 24-20 Ma, and were subsequently

  12. Evaluation of ensemble atmospheric simulations in oil dispersion models at Itaguai Port region; Avaliacao do uso de resultados numericos de previsao atmosferica por conjunto na modelagem da dispersao de oleo na regiao do Porto de Itaguai

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Renato Goncalves dos; Silva, Mariana P.R.; Silva, Ricardo Marcelo da; Torres Junior, Audalio R. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Lab. de Modelagem de Processos Marinhos e Atmosfericos (LAMMA); Landau, Luiz [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Lab. de Metodos Computacinais em Engenharia (LAMCE); Sa, Reginaldo Ventura de; Hochleitner, Fabio; Correa, Eduardo Barbosa [AQUAMET Meteorologia e Projeto de Sistemas, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    This work discusses the use of numerical prediction using ensemble as boundary condition in pollutants dispersion models, applied in a hypothetical case of an oil spill occurrence in Itaguai Port. The Princeton Ocean Model (POM) has been used to simulate hydrodynamics and NICOIL Eulerian model to forecast oil spill dispersion, and ensemble wind forecast from Global Forecast System (GFS), aiming to assess the importance of this parameter variability in oil dispersion at sea. The wind scenarios using ensemble members has showed significant dispersion when compared to control simulation, demonstrating that the uncertainty in the atmospheric modeling can generate considerable variations in the placement of the final spot of oil. The region of interest was the Sepetiba Bay, located on the southern coast of the Rio de Janeiro state; because of port operations carried out around the Port of Itaguai where they can, eventually, oil leaks occur. (author)

  13. Uso da modelagem multicritério para apoio ao decisor na alocação de produtos na matriz mercadológica do ciclo de vida dos produtos

    Directory of Open Access Journals (Sweden)

    Marcos Felipe Falcão Sobral

    2013-01-01

    Full Text Available The appropriate allocation of products in the life-cycle matrix is critical for marketing, operational and logistical strategies. However, the procedure for classification of products often involves multiple criteria, which may conflict with each other. Furthermore, they need to be weighed in decision making. This makes the sorting task very delicate and complex. In view of this, in this paper we propose using the multi-criteria decision method, ELECTRE TRI, as support in the allocation process of the product portfolio in the life- cycle matrix. Since its conception, ELECTRE TRI has been successfully used in several business contexts, providing stable solutions. Its use to allocate products in the life-cycle matrix will provide a structured methodology to handle this task, supporting companies in their business analysis and strat- egy development.

  14. Regional scale modeling of erosion related to land cover evolution: a case study in brazilian southeastern region Modelagem em escala regional da erosão relacionada com a evolução da cobertura do solo: um estudo de caso no sudeste do Brasil

    Directory of Open Access Journals (Sweden)

    Alexandre Marco Da Silva

    2008-12-01

    Full Text Available Accelerated soil erosion is, at present, one of the most widespread environmental problems in the world. Geographic Information Systems (GIS have become an essential tool in soil erosion studies and consequently in the development of appropriate soil conservation strategies. The objective of this paper was to assess the degree of soil erosion associated with land cover dynamics through GIS analysis and to validate the modeling with indicators of soil erosion. Universal Soil Loss Equation (USLE model, GIS technology and ground-truth dataset (erosion indicators were employed to elaborate the soil loss maps for four dates at Sorocaba Municipality (SP, Brazil. It was verified that, although the predicted soil loss rate is normally small along the study area, such rate is significantly greater than the soil formation rate. This shows a non-sustainable situation of soil and land cover management. Unplanned urban expansion seems be the main driving force that acts in increasing the erosion risk/occurrence along the study area.A erosão acelerada é um dos maiores problemas ambientais ocorrentes em larga escala na atualidade. Por sua vez, Sistemas de Informação Geográfica (SIG tornou-se uma ferramenta essencial em estudos de erosão e conseqüentemente no desenvolvimento de estratégias apropriadas para a conservação do solo. O objetivo deste trabalho foi avaliar o grau de erosão do solo associada com a dinâmica da cobertura do solo através de uma análise geoespacial e validar a modelagem com indicadores de erosão. Utilizou-se a Equação Universal de Perda de Solo (EUPS, recursos de SIG e dados de campo (indicadores de erosão para elaborar os mapas de perda de solo para quatro datas para o município de Sorocaba (SP, Brasil. Verificou-se que, embora a taxa de perda de solo ao longo da área de estudo é normalmente baixa, esta taxa é expressivamente maior que as taxas de formação do solo. Isto mostra uma situação não sustentável de

  15. Using nanogranitoids and phase equilibria modeling to unravel anatexis in the crustal footwall of the Ronda peridotites (Betic Cordillera, S Spain)

    Science.gov (United States)

    Bartoli, Omar; Acosta-Vigil, Antonio; Tajčmanová, Lucie; Cesare, Bernardo; Bodnar, Robert J.

    2016-07-01

    Anatexis in the crustal footwall of Ronda peridotites (Betic Cordillera, S Spain) is apparently related to the hot emplacement of this mantle slab over metasedimentary rocks. In this study, we combine the analysis of melt inclusions (MI) and phase equilibria calculations on quartzo-feldspathic mylonites (former migmatites) occurring at the contact with the mantle rocks, in the region of Sierra Alpujata (Ojén unit). The goal is to better characterize anatexis in these rocks and to provide new constraints on the geodynamic evolution of the crustal footwall. Such data are important for understanding the mechanisms of crustal emplacement of the mantle slice. The quartzo-feldspathic mylonites are characterized by the mineral assemblage Qtz + Pl + Kfs + Sil + Grt + Ilm + Bt ± Ap ± Gr. Clusters of MI are observed both at the core and toward the rim of peritectic garnet. In each cluster, MI range from totally glassy to nanogranitoids, consisting of Qtz + Kfs + Bt + Ms + Pl aggregates. The trapped melt is leucogranitic and peraluminous with variable Na2O/K2O values and low H2O contents (≈ 2-4 wt%). Phase equilibria modeling in the MnO-Na2O-CaO-K2O-FeO-MgO-Al2O3-SiO2-H2-TiO2-O2-C (MnNCaKFMASHTOC) system with graphite-saturated fluid constrains the P-T conditions of melting at ≈ 6 kbar, ≈ 820 °C. MI data support the fluid-absent character of melting. The investigated MI represent the primary anatectic melts produced during prograde anatexis of the host rocks via biotite dehydration melting. Field, compositional, and textural observations indicate that mylonitic migmatites represent strongly deformed former diatexites. The comparison between the new data and some recently published information on migmatites located further from the contact with the peridotites and toward the bottom of the crustal footwall, raises some important issues which question the previously proposed geodynamic models for this region. Among them, (i) the crustal footwall at Sierra Alpujata

  16. Receiver functions and crustal structure of the northwestern Andean region, Colombia

    Science.gov (United States)

    Poveda, Esteban; Monsalve, Gaspar; Vargas, Carlos Alberto

    2015-04-01

    We used the receiver function technique to deduce crustal thickness beneath the northwestern Andean system, using data from the permanent seismic network of Colombia, combined with some of the IRIS and CTBTO stations in Colombia and Ecuador. The estimation of crustal thickness was made using the primary P to s conversion and crustal reverberations. The bulk crustal VP/VS ratio was constrained using a crustal thickness versus VP/VS stacking method, in addition to estimations using a time to depth conversion technique based on results of a modified Wadati diagram analysis. We observed a wide range of crustal thicknesses, including values around 17 km beneath the Malpelo Island on the Pacific Ocean, 20 to 30 km at the coastal Pacific and Caribbean plains of Colombia, 25 to 40 km beneath the eastern plains and foothills, 35 km beneath the Western Cordillera, 45 km at the Magdalena River intermountain valley, 52 to 58 km under the northern Central Cordillera, and reaching almost 60 km beneath some of the volcanoes of the Southern Cordilleran system of Colombia; crustal thickness can be slightly greater than 60 km beneath the plateau of the Eastern Cordillera. The values of VP/VS are particularly high for some of the stations on the volcanic centers, reaching values above 1.79, probably related to the addition of mafic materials to the lower crust, and in the plateau of the Eastern Cordillera near Bogota, where we speculate about the possibility of crustal seismic anisotropy associated with shear zones.

  17. Crustal Flows beneath the Eastern Tibetan Plateau Revealed by Magnetotelluric Observations

    Institute of Scientific and Technical Information of China (English)

    BAI Dengha; TENG Jiwen; MA Xiaobing; KONG Xiangru

    2011-01-01

    The ongoing collision of the Indian and Asian continents has created the Himalayan and Tibetan plateau through a range of deformation processes that include crustal thickening, delamination, lateral extrusion and crustal flow. A debate continues as to which of these processes are most significant in terms of the overall mass balance of this continent-continent collision.

  18. Crustal and upper mantle structure of Siberia from teleseismic receiver functions

    DEFF Research Database (Denmark)

    Soliman, Mohammad Youssof Ahmad; Thybo, Hans; Artemieva, Irina

    2015-01-01

    -frequency P-RF component as it has about an order of magnitude better resolution than S-RF. We find no indication for significant crustal anisotropy in the cratonic areas of Siberia. The preliminary crustal thickness results from the Hk stacking and from the inversion approach agree with a previous study...

  19. NACr14: A 3D model for the crustal structure of the North American Continent

    NARCIS (Netherlands)

    Tesauro, Magdala; Kaban, Mikhail; Mooney, Walter; Cloetingh, Sierd

    2014-01-01

    Based on the large number of crustal seismic experiments carried out in the last decadeswe create NACr14, a 3D crustal model of the North American continent at a resolution of 1° × 1°. We present maps of thickness and average velocities of the main layers that comprise the North American crystalline

  20. NACr14: A 3D model for the crustal structure of the North American Continent

    NARCIS (Netherlands)

    Tesauro, Magdala; Kaban, Mikhail; Mooney, Walter; Cloetingh, Sierd

    2014-01-01

    Based on the large number of crustal seismic experiments carried out in the last decadeswe create NACr14, a 3D crustal model of the North American continent at a resolution of 1° × 1°. We present maps of thickness and average velocities of the main layers that comprise the North American crystalline

  1. Crustal and upper mantle structure of Siberia from teleseismic receiver functions

    DEFF Research Database (Denmark)

    Soliman, Mohammad Youssof Ahmad; Thybo, Hans; Artemieva, Irina;

    2015-01-01

    -frequency P-RF component as it has about an order of magnitude better resolution than S-RF. We find no indication for significant crustal anisotropy in the cratonic areas of Siberia. The preliminary crustal thickness results from the Hk stacking and from the inversion approach agree with a previous study...

  2. Density heterogeneity of the North American upper mantle from satellite gravity and a regional crustal model

    DEFF Research Database (Denmark)

    Herceg, Matija; Artemieva, Irina; Thybo, Hans

    2014-01-01

    and by introducing variations into the crustal structure which corresponds to the uncertainty of its resolution by highquality and low-quality seismic models. We examine the propagation of these uncertainties into determinations of lithospheric mantle density. Given a relatively small range of expected density......We present a regional model for the density structure of the North American upper mantle. The residual mantle gravity anomalies are based on gravity data derived from the GOCE geopotential models with crustal correction to the gravity field being calculated from a regional crustal model. We analyze...... how uncertainties and errors in the crustal model propagate from crustal densities to mantle residual gravity anomalies and the density model of the upper mantle. Uncertainties in the residual upper (lithospheric) mantle gravity anomalies result from several sources: (i) uncertainties in the velocity-density...

  3. Mapping sub-crustal reflectors in southwestern Spain

    Science.gov (United States)

    Palomeras, I.; Ayarza, P.; Carbonell, R.; Ehsan, S. A.; Afonso, J. C.; Diaz Cusi, J.

    2015-12-01

    During the last 15 years, the IBERSEIS and ALCUDIA controlled source experiments have acquired vertical incidence and wide angle seismic reflection data in southwest Spain, in the Variscan Sub-Portuguese, Ossa-Morena and Central-Iberian Zones. Apart from providing detailed information of the crust, these datasets have also imaged a conspicuous sub-crustal reflector. First identified on the IBERSEIS wide-angle reflection dataset, this interface seemed to feature a positive seismic impedance contrast. A boundary located between 61-72 km depth, with a Vp increase from 8.2 km/s to 8.3 km/s allowed us to model clear wide-angle reflections found above 180 km offsets. The fact that this reflector was not identified in the coincident vertical incidence dataset led us to interpret it as a gradient zone. A correlation with the 'Hales gradient zone', i.e. the boundary between spinel and garnet peridotites was our preferred interpretation. The ALCUDIA experiment, later acquired northwards of the IBERSEIS profiles, also shows prominent sub-crustal arrivals with the same characteristics as those observed in the IBERSEIS wide-angle data. However, these reflections also appear, locally and at 19 s TWT, in the vertical incidence dataset, further constraining the depth at which this feature is located. In addition, the ALCUDIA wide-angle dataset shows deeper sub-horizontal reflectivity (at Vred=8 km/s) that maybe preliminarily associated with mantle anisotropy or even, with the lithosphere-astenosphere boundary. Integration of the information provided by the IBERSEIS and ALCUDIA datasets with older and lower resolution data from the ILIHA project, where three sub-crustal phases were identified in SW Iberia, allows us to conclude that, in this area, mantle reflectivity is outstanding. Also, modeling of all the datasets contributes to map, at a regional scale, the Hales discontinuity or gradient zone in southwest Iberia. Further research, involving receiver function analysis is

  4. Kinematics of the crustal velocity field in the western US

    Science.gov (United States)

    Pollitz, F. F.

    2008-12-01

    GPS measurements embodied in PBO and PBO Nucleus allow the crustal velocity field of the western US to be constructed in unprecedented detail. Velocity and strain fields span the entire San Andreas fault system and Cascadia subduction zone from Baja California to northern Washington as well as the continental interior including the Great Basin and Wasatch Front. Rationalizing the GPS velocity field over the several tectonic regimes provides key tests of prevailing notions of interseismic crustal deformation. In our interpretation, we begin with the premise that the load-carrying portion of the lithosphere coincides with the (seismogenic) upper crust with an effective elastic thickness of ~20 km at the time scales of interseimic motions (Thatcher and Pollitz, 2008). End member kinematic models include (1) viscoelastic relaxation of the ductile lower crust and upper mantle following large earthquakes, and (2) slip in the lower elastic lithosphere, each of which serves to localize strain around major faults during interseismic periods. More detailed kinematic models emphasize the roles of lateral variations in rigidity and/or effective elastic plate thickness as well as distributed deformation. Our modeling of western US kinematics shows that the GPS velocity field is well explained with a range of models involving a combination of all of the above components; no single endmember suffices. Zones of inferred distributed deformation in the continental interior coincide with well-known seismic belts (Eastern California Shear Zone; Walker Lane; Interseismic Mountain Belt). Continued acquisition of vector constraints on crustal motions and study of available geodetic data are needed to clarify active deformation patterns in several areas. Some outstanding issues are: The nature of distributed faulting at the margins of the Great Basin (southern Nevada Transverse Zone, northern Walker Lane); understanding how dextral shear from the eastern boundary of the Sierra Nevada

  5. Modelagem numérica da composição química da atmosfera e seus impactos no tempo, clima e qualidade do ar Numerical modeling of the atmosphere chemistry composition and of its impacts on weather, climate and air quality

    Directory of Open Access Journals (Sweden)

    Saulo R. Freitas

    2009-06-01

    Full Text Available Uma descrição geral da modelagem numérica da composição química da atmosfera é fornecida neste trabalho. Os papéis relevantes de alguns gases traço e aerossóis no balanço radiativo do planeta, na alteração do ciclo hidrológico e na poluição do ar são discutidos. Partindo da equação da continuidade, integrada no sistema de equações governantes da atmosfera, os diversos termos que constituem a emissão, deposição, reatividade química e transporte (resolvido e sub-grade são apresentados juntamente com formas de obter a solução numérica. Dentre os componentes desta equação, o termo de reatividade química se destaca pela complexidade do problema em si, na obtenção da solução numérica e no alto custo computacional envolvido. Exemplos são fornecidos utilizando o modelo CCATT-BRAMS com recente inclusão de reatividade química. Em particular, a simulação do ozônio troposférico constitui uma tarefa complexa pela falta de dados de emissões, porém resultados obtidos são compatíveis com outros modelos validados. Simulações numéricas realizadas, para a estação seca de 2002, permitiram estudar possíveis ciclos biogeoquímicos e corredores de formação e deposição de ozônio e aerossóis de queimadas, assim como o papel destes últimos na estabilização termodinâmica e precipitação.A general description of the numerical modeling of the atmospheric chemical composition is presented. The relevant role played by some trace gases and aerosols on the Earth radiative budget, hydrological cycle and air quality are discussed. The formulation for emission, deposition, chemical reactions and transport (resolved and sub-grid scale processes are introduced within the mass continuity equation integrated to the basic equations system for the Earth atmosphere. The numerical aspects of this formulation are as well discussed, specially the intrinsic complexity and the high computational costs of the chemical reactions

  6. MODELAGEM BIOECONÔMICA DA TRANSFERÊNCIA DE EMBRIÕES EM BOVINOS BIOECONOMIC MODEL IN BOVINE EMBRYO TRANSFER

    Directory of Open Access Journals (Sweden)

    Renato Travassos Beltrame

    2010-04-01

    Full Text Available

    O objetivo deste trabalho foi desenvolver um modelo matemático orientado a eventos de simulação, para auxiliar tomadas de decisão relativas à transferência de embriões em bovinos, considerando-se as dinâmicas de dois componentes da transferência de embriões: receptoras e embriões. Na simulação, não se avaliaram respostas individuais de doadoras a coletas consecutivas e eventos correspondentes na transferência de embriões. Simulou-se o mesmo protocolo para superovulação a todas as doadoras. Receptoras foram sincronizadas simulando-se o uso de prostaglandina. O número de embriões viáveis produzido por doadora e sua variabilidade tiveram como base um processo aleatório de simulação de Monte Carlo, que pressupôs uma distribuição exponencial negativa de densidade de probabilidade. Custos e receitas foram inseridos no modelo por meio de um cenário-base para calcular indicadores econômicos de rentabilidade. A análise sugeriu a impraticabilidade da atividade, se realizada diante do cenário proposto (VPL – R$: 57.596,69. A partir do cenário proposto, o custo médio estimado foi de R$ 1.178,19, e de R$ 980,03, para se obter uma prenhez a partir de uma situação otimizada, sugerida pelo modelo (5/100; 5/190.

    PALAVRAS-CHAVES: Otimização, receptoras, simulação, transferência de embriões, viabilidade econômica.

    A simulation model related to embryo transfer programs in bovine was carried out through a mathematical model directed to events, considering the dynamic of two resources: recipients and embryos. Individual answers of donors to consecutive collections and corresponding events in embryo transfer were not evaluated. The same protocol for superovulation was simulated for all the donor collections, using similar doses of hormones and drugs for all the animals. Recipients were synchronized using prostaglandin. Meantime, the number of viable embryos produced by donor and its variability were based at

  7. Crustal deformations at permanent GPS sites in Denmark

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Knudsen, Per; Tscherning, Carl Christian

    2005-01-01

    The National Survey and Cadastre (KMS) is responsible for the geodetic definition of the reference network in Denmark. Permanent GPS stations play an important role in the monitoring and maintenance of the geodetic network. During 1998 and 1999 KMS established three permanent GPS station in Denmark......, SMID, SULD and BUDP. Using almost 4.5 years of continuous data from the Danish station and the Swedish station, ONSA, we analyse the daily GPS solution due to crustal deformation caused by glacial isostatic adjustment (GIA). Although, displacements due to GIA are only 1–3 mm/year at the Danish GPS...... sites, the current precision of positioning using GPS allows us to observe these effects. The modelled horizontal GIA velocities and the observed horizontal residuals obtained from GPS show almost the same direction for all station. However, the observed velocity residuals are larger than the modelled...

  8. A new model of crustal structure of Siberia

    DEFF Research Database (Denmark)

    Cherepanova, Yulia; Artemieva, Irina; Thybo, Hans

    2010-01-01

    We report a new model of the structure of the crust in Siberia that encompasses two large tectonic regions, the Paleozoic West Siberian Basin and the Precambrian Siberian craton. The area of study covers a significant part of the north Eurasia and extends from the Ural mountains in the west...... and receiver functions studies, based on old and newly acquired seismic data (from the late 1960-ies until present). Seismic structure along seismic profiles is digitized with a 50 km lateral spacing which is comparable with the resolution of seismic models. Structural parameters based on gravity modeling...... is paid to the data quality problem, and quality parameters are incorporated into the new database of regional crustal structure. The present database comprises detailed and reliable information on the seismic structure of the crust for most of the tectonic structures of the region and provides valuable...

  9. The crustal micro-deformation anomaly and the credible precursor*

    Institute of Scientific and Technical Information of China (English)

    张雁滨; 蒋骏; 钱家栋; 陈京; 和升棋; 张燕; 和平

    2002-01-01

    @@ What is a credible seismic precursor in observation of deformation A real seismic precursor ought to be resulted from the variations in the earth strain and stress. The deformation observation can provide the information during earthquake gestation and occurrence period for us. Usually the seismic precursors can be divided into field and epicentral region precursors. The precursor information is very useful for seismic prediction from epicentral region or near epicentral region. Micro-deformation observation mainly includes tilt, strain and gravity observation. Compared with GPS, geodesy and mobile deformation observation, micro-deformation (tilt, strain) shows the change of deformation which is continual in a limited volume with dominant observed range of 10(6~10(10 m. Because the variation of the crustal nature and cracking can be directly obtained by micro-deformation observation, it is an effective way to find middle-short term and short-term precursor.

  10. Lower crustal intrusions beneath the southern Baikal Rift Zone

    DEFF Research Database (Denmark)

    Nielsen, Christoffer; Thybo, Hans

    2009-01-01

    The Cenozoic Baikal Rift Zone (BRZ) is situated in south-central Siberia in the suture between the Precambrian Siberian Platform and the Amurian plate. This more than 2000-km long rift zone is composed of several individual basement depressions and half-grabens with the deep Lake Baikal at its...... centre. The BEST (Baikal Explosion Seismic Transect) project acquired a 360-km long, deep seismic, refraction/wide-angle reflection profile in 2002 across southern Lake Baikal. The data from this project is used for identification of large-scale crustal structures and modelling of the seismic velocities...... of the crust and uppermost mantle. Previous interpretation and velocity modelling of P-wave arrivals in the BEST data has revealed a multi layered crust with smooth variation in Moho depth between the Siberian Platform (41 km) and the Sayan-Baikal fold belt (46 km). The lower crust exhibits normal seismic...

  11. Crustal deformations at permanent GPS sites in Denmark

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Knudsen, Per; Tscherning, Carl Christian

    2005-01-01

    The National Survey and Cadastre (KMS) is responsible for the geodetic definition of the reference network in Denmark. Permanent GPS stations play an important role in the monitoring and maintenance of the geodetic network. During 1998 and 1999 KMS established three permanent GPS station in Denmark......, SMID, SULD and BUDP. Using almost 4.5 years of continuous data from the Danish station and the Swedish station, ONSA, we analyse the daily GPS solution due to crustal deformation caused by glacial isostatic adjustment (GIA). Although, displacements due to GIA are only 1–3 mm/year at the Danish GPS...... sites, the current precision of positioning using GPS allows us to observe these effects. The modelled horizontal GIA velocities and the observed horizontal residuals obtained from GPS show almost the same direction for all station. However, the observed velocity residuals are larger than the modelled...

  12. Present-day crustal deformation around Sagaing fault, Myanmar

    Science.gov (United States)

    Vigny, Christophe; Socquet, Anne; Rangin, Claude; Chamot-Rooke, Nicolas; Pubellier, Manuel; Bouin, Marie-NoëLle; Bertrand, Guillaume; Becker, M.

    2003-11-01

    Global Positioning System (GPS) measurement campaigns in Myanmar, conducted in 1998 and 2000, allow quantifying the present-day crustal deformation around the Sagaing fault system in central Myanmar. Both a regional network installed at four points within the country and a local 18-station network centered on the city of Mandalay across the Sagaing fault demonstrate that active deformation related to the northward motion of India is distributed across Myanmar in a platelet that extends from the western edge of the Shan Plateau in the east to the Andaman Trench in the west. In this platelet, deformation is rather diffuse and distributed over distinct fault systems. In the east, the Sagaing/Shan Scarp fault system absorbs 10 mm/yr). This GPS study combined with an on land geotectonic survey demonstrate that oblique slip of India along the rigid Sundaland block is accommodated by a partitioned system characterized by distribution of deformation over a wide zone.

  13. Observatory crustal magnetic biases during CHAMP satellite mission

    Science.gov (United States)

    Verbanac, G.; Mandea, M.; Bandić, M.; Subašić, S.

    2015-01-01

    Taking advantage of nine years of CHAMP satellite mission (June 2000-August 2009), we investigate the temporal evolution of the observatory monthly crustal magnetic biases. To determine biases we compute X (northward), Y (eastward) and Z (vertically downward) monthly means from 42 observatory one-minute or hourly values, and compare them to synthetic monthly means obtained from a GRIMM3 core field model (V. Lesur, personal communication, 2014). Both short period variations and long term trends in the monthly bias time series are analyzed. A comparison with biases based on MAGSAT and Ørsted satellite data, related to the 1979.92 and 1992.92 epochs is performed. Generally, the larger biases averaged over nine years and the larger differences between biases based on different models are found in Z component. This can be the signature of the induced magnetic fields. Although annual trends in most bias series are observed, no clear evidence that the constant crustal field changed significantly over the studied period is found. Time series of monthly biases exhibit distinct oscillatory pattern in the whole time span, which we assign to the external field contributions. The amplitudes of these variations are linked with the phase of the solar cycle, being significantly larger in the period 2000-2005 than in the period 2006-2009. Clear semi-annual variations are evident in all components, with extremes in spring and fall months of each year. Common external field pattern is found for European monthly biases. A dependence of the bias monthly variations on geomagnetic latitudes is not found for the non-European observatories. The results from this study represent a base to further exploit the observatory and repeat stations magnetic biases together with the data from the new satellite mission SWARM.

  14. GPS derived Crustal Deformation and Strain determination in India

    Directory of Open Access Journals (Sweden)

    Abhay P. Singh,

    2011-06-01

    Full Text Available The theory of Plate tectonics has revolutionized the way thinking about the processes of Earth. According to this theory, the surface of the Earth is broken into large plates. The size and position of these plates change over time. The edges of these plates, where they move against each other, are sites of intense tectonic activity, suchas earthquakes, volcanism, and mountain building. It is well known that Indian Plate is currently moving in the northeast direction, while the Eurasian Plate is moving north. This is causing the Indian and Eurasian Plate to deform at the point of contact besides its interior. Modern geophysical and space geodetic techniques such asseismology and GPS (Global Positioning system, have become important tools in the study of the deformation in the Earth due to tectonic processes, leading to earthquakes. Geodesy has provided an important role for plate tectonics study with high temporal resolution of the plate movements, particular from space technologies such as GPS and VLBI. The Global Positioning System (GPS provides accurate measurements of the rate of displacement of crustal. Indeed, the GPS velocity field can only be compared to finite strain if one assumes adeformation mechanism and that the style of deformation has been the same over long periods of geological time. For study of crustal deformation National Center of Mineralogy and Petrology, University of Allahabad, Allahabad installed highly efficient and accurate LEICA GRX1200 Pro receiver at Ghoorpur near to Allahabad. This instrument is also equipped withMET3A sensor to record pressure, temperature, humidity at regular interval of 30 second. The Latitude and longitude of the GPS sites is 25.21N, 81.28E.

  15. Current knowledge on the crustal properties of Italy

    Directory of Open Access Journals (Sweden)

    C. Morelli

    1994-06-01

    Full Text Available The recent advances in experimental petrography together with the information derived from the super-deep drilling projects have provided additional constraints for the interpretation of refraction and reflection seismic data. These constraints can also be used in the interpretation of magnetic and gravity data to resolve nonuniqueness. In this study, we re-interpret the magnetic and gravity data of the Italian peninsula and neighbouring areas. In view of the constraints mentioned above, it is now possible to find an agreement between the seismic and gravity models of the Central Alps. By taking into account the overall crustal thickness, we have recognized the existence of three types of Moho: 1 European which extends to the north and west of the peninsula and in the Corsican-Sardinian block. Its margin was the foreland in the Alpine Orogeny and it was the ramp on which European and Adriatic mantle and crustal slices were overthrusted. This additional load caused bending and deepening and the Moho which now lies beneath the Adriatic plate reaching a maximum depth of approximately 75 km. 2 Adriatic (or African which lies beneath the Po plain, the Apennines and the Adriatic Sea. The average depth of the Moho is about 30-35 km below the Po plain and the Adriatic Sea and it increases toward the Alps and the Tyrrhenian Sea (acting as foreland along this margin. The maximum depth (50 km is reached in Calabria. 3 Pery-Tyrrhenian. This is an oceanic or thinned continental crust type of Moho. It borders the oceanic Moho of the Tyrrhenian Sea and it acquires a transitional character in the Ligurian and Provençal basins (<15 km thickness while further thickening occurs toward the East where the Adriatic plate is overthrusted. In addition, the interpretation of the heat flow data appears to confirm the origin of this Moho and its geodynamic allocation.

  16. Crustal structure of Australia from ambient seismic noise tomography

    Science.gov (United States)

    Saygin, Erdinc; Kennett, B. L. N.

    2012-01-01

    Surface wave tomography for Australian crustal structure has been carried out using group velocity measurements in the period range 1-32 s extracted from stacked correlations of ambient noise between station pairs. Both Rayleigh wave and Love wave group velocity maps are constructed for each period using the vertical and transverse component of the Green's function estimates from the ambient noise. The full suite of portable broadband deployments and permanent stations on the continent have been used with over 250 stations in all and up to 7500 paths. The permanent stations provide a useful link between the various shorter-term portable deployments. At each period the group velocity maps are constructed with a fully nonlinear tomographic inversion exploiting a subspace technique and the Fast Marching Method for wavefront tracking. For Rayleigh waves the continental coverage is good enough to allow the construction of a 3D shear wavespeed model in a two stage approach. Local group dispersion information is collated for a distribution of points across the continent and inverted for a 1D SV wavespeed profile using a Neighbourhood Algorithm method. The resulting set of 1D models are then interpolated to produce the final 3D wavespeed model. The group velocity maps show the strong influence of thick sediments at shorter periods, and distinct fast zones associated with cratonic regions. Below the sediments the 3D shear wavespeed model displays significant heterogeneity with only moderate correlation with surface tectonic features. For example, there is no evident expression of the Tasman Line marking the eastern edge of Precambrian outcrop. The large number of available inter-station paths extracted from the ambient noise analysis provide detailed shear wavespeed information for crustal structure across the Australian continent for the first time, including regions where there was no prior sampling because of difficult logistics.

  17. Komsomolskaya diamondiferous eclogites: evidence for oceanic crustal protoliths

    Science.gov (United States)

    Pernet-Fisher, John F.; Howarth, Geoffrey H.; Liu, Yang; Barry, Peter H.; Carmody, Laura; Valley, John W.; Bodnar, Robert J.; Spetsius, Zdislav V.; Taylor, Lawrence A.

    2014-03-01

    The Komsomolskaya kimberlite is one of numerous (>1,000) kimberlite pipes that host eclogite xenoliths on the Siberian craton. Eclogite xenoliths from the adjacent Udachnaya kimberlite pipe have previously been geochemically well characterized; however, data from surrounding diamond-bearing kimberlite pipes from the center of the craton are relatively sparse. Here, we report major- and trace-element data, as well as oxygen isotope systematics, for mineral separates of diamondiferous eclogite xenoliths from the Komsomolskaya kimberlite, suggesting two distinct subgroups of a metamorphosed, subducted oceanic crustal protolith. Using almandine contents, this suite can be divided into two subgroups: group B1, with a high almandine component (>20 mol%) and group B2, with a low almandine component (oxygen isotope values, which are interpreted to reflect isotopic exchange with seawater at low temperatures (oxygen isotope values, suggesting an origin deep within the crustal pile, where little-to-no interaction with hydrothermal fluids has occurred. Major-element systematics were reconstructed based on mineral modes; group B1 eclogites have higher MgO wt% and lower SiO2 wt%, with respect to typical oceanic basalts, reflecting a partial melting event during slab subduction. Calculated residues from batch partial melt modeling of a range of Precambrian basalts overlap with group B1 trace-element chemistry. When taken together with the respective partial melt trajectories, these melting events are clearly linked to the formation of Tonalite-Trondhjemite-Granodiorite (TTG) complexes. As a result, we propose that many, if not all, diamondiferous eclogite xenoliths from Komsomolskaya represent mantle `restites' that preserve chemical signatures of Precambrian oceanic crust.

  18. Trajectory models and reference frames for crustal motion geodesy

    Science.gov (United States)

    Bevis, Michael; Brown, Abel

    2014-03-01

    We sketch the evolution of station trajectory models used in crustal motion geodesy over the last several decades, and describe some recent generalizations of these models that allow geodesists and geophysicists to parameterize accelerating patterns of displacement in general, and postseismic transient deformation in particular. Modern trajectory models are composed of three sub-models that represent secular trends, annual oscillations, and instantaneous jumps in coordinate time series. Traditionally the trend model invoked constant station velocity. This can be generalized by assuming that position is a polynomial function of time. The trajectory model can also be augmented as needed, by including one or more logarithmic transients in order to account for typical multi-year patterns of postseismic transient motion. Many geodetic and geophysical research groups are using general classes of trajectory model to characterize their crustal displacement time series, but few if any of them are using these trajectory models to define and realize the terrestrial reference frames (RFs) in which their time series are expressed. We describe a global GPS reanalysis program in which we use two general classes of trajectory model, tuned on a station by station basis. We define the network trajectory model as the set of station trajectory models encompassing every station in the network. We use the network trajectory model from the each global analysis to assign prior position estimates for the next round of GPS data processing. We allow our daily orbital solutions to relax so as to maintain their consistency with the network polyhedron. After several iterations we produce GPS time series expressed in a RF similar to, but not identical with ITRF2008. We find that each iteration produces an improvement in the daily repeatability of our global time series and in the predictive power of our trajectory models.

  19. Distribution of crustal types in Canada Basin, Arctic Ocean

    Science.gov (United States)

    Chian, D.; Jackson, H. R.; Hutchinson, D. R.; Shimeld, J. W.; Oakey, G. N.; Lebedeva-Ivanova, N.; Li, Q.; Saltus, R. W.; Mosher, D. C.

    2016-11-01

    Seismic velocities determined from 70 sonobuoys widely distributed in Canada Basin were used to discriminate crustal types. Velocities of oceanic layer 3 (6.7-7.1 km/s), transitional (7.2-7.6 km/s) and continental crust (5.5-6.6 km/s) were used to distinguish crustal types. Potential field data supports the distribution of oceanic crust as a polygon with maximum dimensions of 340 km (east-west) by 590 km (north-south) and identification of the ocean-continent boundary (OCB). Paired magnetic anomalies are associated only with crust that has oceanic velocities. Furthermore, the interpreted top of oceanic crust on seismic reflection profiles is more irregular and sometimes shallower than adjacent transitional crust. The northern segment of the narrow Canada Basin Gravity Low (CBGL), often interpreted as a spreading center, bisects this zone of oceanic crust and coincides with the location of a prominent valley in seismic reflection profiles. Data coverage near the southern segment of CBGL is sparse. Velocities typical of transitional crust are determined east of it. Extension in this region, close to the inferred pole of rotation, may have been amagmatic. Offshore Alaska is a wide zone of thinned continental crust up to 300 km across. Published longer offset refraction experiments in the Basin confirm the depth to Moho and the lack of oceanic layer 3 velocities. Further north, toward Alpha Ridge and along Northwind Ridge, transitional crust is interpreted to be underplated or intruded by magmatism related to the emplacement of the High Arctic Large Igneous Province (HALIP). Although a rotational plate tectonic model is consistent with the extent of the conjugate magnetic anomalies that occupy only a portion of Canada Basin, it does not explain the asymmetrical configuration of the oceanic crust in the deep water portion of Canada Basin, and the unequal distribution of transitional and continental crust around the basin.

  20. The role of crustal quartz in controlling Cordilleran deformation.

    Science.gov (United States)

    Lowry, Anthony R; Pérez-Gussinyé, Marta

    2011-03-17

    Large-scale deformation of continents remains poorly understood more than 40 years after the plate tectonic revolution. Rock flow strength and mass density variations both contribute to stress, so both are certain to be important, but these depend (somewhat nebulously) on rock type, temperature and whether or not unbound water is present. Hence, it is unclear precisely how Earth material properties translate to continental deformation zones ranging from tens to thousands of kilometres in width, why deforming zones are sometimes interspersed with non-deforming blocks and why large earthquakes occasionally rupture in otherwise stable continental interiors. An important clue comes from observations that mountain belts and rift zones cyclically form at the same locations despite separation across vast gulfs of time (dubbed the Wilson tectonic cycle), accompanied by inversion of extensional basins and reactivation of faults and other structures formed in previous deformation events. Here we show that the abundance of crustal quartz, the weakest mineral in continental rocks, may strongly condition continental temperature and deformation. We use EarthScope seismic receiver functions, gravity and surface heat flow measurements to estimate thickness and seismic velocity ratio, v(P)/v(S), of continental crust in the western United States. The ratio v(P)/v(S) is relatively insensitive to temperature but very sensitive to quartz abundance. Our results demonstrate a surprising correlation of low crustal v(P)/v(S) with both higher lithospheric temperature and deformation of the Cordillera, the mountainous region of the western United States. The most plausible explanation for the relationship to temperature is a robust dynamical feedback, in which ductile strain first localizes in relatively weak, quartz-rich crust, and then initiates processes that promote advective warming, hydration and further weakening. The feedback mechanism proposed here would not only explain

  1. Crustal composition in southern Norway from active and passive source seismology

    Science.gov (United States)

    Stratford, W. R.; Frassetto, A. M.; Thybo, H.

    2010-12-01

    Crustal composition and structure beneath the Fennoscandian shield are highly variable due to the method of crustal accretion and the long history of extensional and compressional tectonics. In southern Norway, the Moho and crust are inferred to be the youngest of the shield, however, it is likely that a large discrepancy between crustal age and Moho age exists beneath the high southern Scandes where the Caledonian orogeny was in effect and beneath the Oslo Graben where 60 million years of rifting and magmatism has altered the crust. Crustal structure in southern Norway was targeted with a multi-disciplinary seismic study (Magnus-Rex - Mantle investigations of Norwegian uplift Structure). Three ~400 km long active source seismic profiles across the southern Norway and a region wide array of broadband seismometers were deployed. P and S-wave arrivals were recorded in the Magnus-Rex project, from which Poisson ratios for the crust in southern Norway are calculated from both active source profiling and receiver functions. Unusually strong S-wave arrivals allow rare insight into crustal Poisson’s ratio structure, within crustal layers, that is not normally available from active source data and are usually determined by earthquake tomography studies where only bulk crustal values are available. An average Poisson’s ratio of 0.25 is calculated for the crust in southern Norway, suggesting it is predominantly of felsic-intermediate composition and lacks any significant mafic lower crust. This differs significantly from the adjacent crust in the Svecofennian domain of the Fennoscandian shield where Moho depths reach ~50 km and an up to 20 km thick mafic lower crust is present. The vast difference in Moho depths in the Fennoscandian shield are, therefore, mostly due to the variation in thickness of the high Vp lower crust. Estimates of crustal composition and the effect of Magma intrusion within the Oslo Graben, and possible delamination of the lowermost crust beneath

  2. Crustal uplift of the Precambrian cratons due to metamorphism in crustal rocks under infiltration of mantle fluids

    Science.gov (United States)

    Artyushkov, Eugene; Chekhovich, Peter; Korikovsky, Sergey; Massonne, Hans-Joachim

    2017-04-01

    Precambrian cratons cover about 70% of the total area of the continents. During the last several million years cratonic areas underwent rapid uplift, from 100-200 m in East Europe to 1000-1500 m Southern Africa. Shortening of the Precambrian crust terminated half a billion years ago or earlier and this popular mechanism cannot be applied to its recent uplift. Large thickness of cratonic mantle lithosphere, 100-200 km in most regions, together with its low density precludes delamination of this layer and magmatic underplating as possible causes of recent uplift. It cannot be precluded that in some cratonic regions recent uplift occurred due to delamination of the lower part of mantle lithosphere with the density increased by metasomatism. Even a small uplift of ≥ 100-200 m would require delamination of a thick layer of mantle lithosphere. As a result a temperature drop of > 200 C would arise at the base of the lithosphere producing a shear wave velocities drop of > 2%. According to the seismic tomography data such a drop in VS is observed only in some regions with the Precambrian lithosphere, e.g., in Northeastern Africa. Spatial distribution of the Precambrian cratons is quite different from that predicted by the main models of dynamic topography in the mantle. Moreover, many uplifted blocks are bounded by steep slopes hundreds of meters to one kilometer high and only tens of kilometers wide. Such slopes could not have been formed by bending of thick cratonic lithosphere under the forces acting from below. Their recent formation indicates rock expansion within the crust at shallow depth comparable with the slope width. Rocks formed at the pressure P ˜ 0.5-1.0 GPa are widespread on the Precambrian cratons. This indicates that during their lifetime a layer of rocks ˜ 15-30 km thick has been removed from the crustal surface by denudation. As a result rocks which were initially located in the lower crust emerged to the middle or upper crust. Due to metamorphic

  3. Electrons on closed field lines of lunar crustal fields in the solar wind wake

    Science.gov (United States)

    Nishino, Masaki N.; Saito, Yoshifumi; Tsunakawa, Hideo; Takahashi, Futoshi; Fujimoto, Masaki; Harada, Yuki; Yokota, Shoichiro; Matsushima, Masaki; Shibuya, Hidetoshi; Shimizu, Hisayoshi

    2015-04-01

    Plasma signature around crustal magnetic fields is one of the most important topics of the lunar plasma sciences. Although recent spacecraft measurements are revealing solar-wind interaction with the lunar crustal fields on the dayside, plasma signatures around crustal fields on the night side have not been fully studied yet. Here we show evidence of plasma trapping on the closed field lines of the lunar crustal fields in the solar-wind wake, using SELENE (Kaguya) plasma and magnetic field data obtained at 14-15 km altitude from the lunar surface. In contrast to expectation on plasma cavity formation at the strong crustal fields, electron flux is enhanced above Crisium Antipode (CA) anomaly which is one of the strongest lunar crustal fields. The enhanced electron fluxes above CA are characterised by (1) occasional bi-directional field-aligned beams in the lower energy range (<150 eV) and (2) a medium energy component (150-300 eV) that has a double loss-cone distribution representing bounce motion between the two footprints of the crustal magnetic fields. The low-energy electrons on the closed field lines may come from the lunar night side surface, while supply mechanism of medium-energy electrons on the closed field line remains to be solved. We also report that a density cavity in the wake is observed not above the strongest magnetic field but in its vicinity.

  4. Crustal structure of Nigeria and Southern Ghana, West Africa from P-wave receiver functions

    Science.gov (United States)

    Akpan, Ofonime; Nyblade, Andrew; Okereke, Chiedu; Oden, Michael; Emry, Erica; Julià, Jordi

    2016-04-01

    We report new estimates of crustal thickness (Moho depth), Poisson's ratio and shear-wave velocities for eleven broadband seismological stations in Nigeria and Ghana. Data used for this study came from teleseismic earthquakes recorded at epicentral distances between 30° and 95° and with moment magnitudes greater than or equal to 5.5. P-wave receiver functions were modeled using the Moho Ps arrival times, H-k stacking, and joint inversion of receiver functions and Rayleigh wave group velocities. The average crustal thickness of the stations in the Neoproterozoic basement complex of Nigeria is 36 km, and 23 km for the stations in the Cretaceous Benue Trough. The crustal structure of the Paleoproterozoic Birimian Terrain, and Neoproterozoic Dahomeyan Terrain and Togo Structural Unit in southern Ghana is similar, with an average Moho depth of 44 km. Poisson's ratios for all the stations range from 0.24 to 0.26, indicating a bulk felsic to intermediate crustal composition. The crustal structure of the basement complex in Nigeria is similar to the average crustal structure of Neoproterozoic terrains in other parts of Africa, but the two Neoproterozoic terrains in southern Ghana have a thicker crust with a thick mafic lower crust, ranging in thickness from 12 to 17 km. Both the thicker crust and thick mafic lower crustal section are consistent with many Precambrian suture zones, and thus we suggest that both features are relict from the collisional event during the formation of Gondwana.

  5. NA44 experiment

    CERN Document Server

    1990-01-01

    General view of NA44 experiment. NA44 is one of the seven experiments (NA44, NA45, NA49, NA50, NA52, WA97/NA57 and WA98) involved in CERN'S Heavy Ion programme which provided evidence for the existence of a new state of matter in which quarks, instead of being bound up into more complex particles such as protons and neutrons, are liberated and roam freely. Theory predicts that this state must have existed at about 10 microseconds after the Big Bang, before the formation of matter as we know it today.

  6. Coupling Flow & Transport Modeling with Electromagnetic Geophysics to Better Understand Crustal Permeability

    Science.gov (United States)

    Pepin, J.; Folsom, M.; Person, M. A.; Kelley, S.; Gomez-Velez, J. D.; Peacock, J.

    2016-12-01

    Over the last 30 years, considerable effort has focused on understanding the distribution of permeability within the earth's crust and its implications for flow and transport. The scarcity of direct observations makes the description of permeabilities beyond depths of about 3 km particularly challenging. Numerous studies have defined depth-decay relationships for basement permeability, while others note that it is too complex to be characterized by a general relationship. Hydrothermal modeling studies focusing on two geothermal systems within the tectonically active Rio Grande rift of New Mexico suggest that there may be laterally extensive regions of highly permeable (10-14 to 10-12 m2) basement rocks at depths ranging between 4 and 8 km. The NaCl groundwater signature, elevated fracture density, and secondary mineralization of fractured basement outcrops associated with these geothermal systems indicate that there may indeed be significant groundwater flow within the basement rocks of the rift. We hypothesize that there are extensive regions of highly permeable crystalline basement rocks at depths greater than 3 km within the Rio Grande rift. These fractured zones serve as large conduits for geothermal fluids before they ascend to shallow depths through gaps in overlying confining sediments or along faults. To test these hypotheses, we use a combination of geophysical observations and flow and transport modeling. We used electromagnetic geophysics (TEM & MT) to image resistivity in one of the hypothesized deep circulation geothermal systems near Truth or Consequences, NM. The resistivity dataset, in tandem with geochemical and thermal observations, is then used to calibrate a hydrothermal model of the system. This new calibration methodology has the potential to change the way researchers study crustal fluid flow and geothermal systems; thereby providing a tool to explore depths greater than 3 km where minimal data is available. In addition, it has the advantage

  7. Fluvial archives, a valuable record of vertical crustal deformation

    Science.gov (United States)

    Demoulin, A.; Mather, A.; Whittaker, A.

    2017-06-01

    The study of drainage network response to uplift is important not only for understanding river system dynamics and associated channel properties and fluvial landforms, but also for identifying the nature of crustal deformation and its history. In recent decades, geomorphic analysis of rivers has proved powerful in elucidating the tectonic evolution of actively uplifting and eroding orogens. Here, we review the main recent developments that have improved and expanded qualitative and quantitative information about vertical tectonic motions (the effects of horizontal deformation are not addressed). Channel long profiles have received considerable attention in the literature, and we briefly introduce basic aspects of the behaviour of bedrock rivers from field and numerical modelling perspectives, before describing the various metrics that have been proposed to identify the information on crustal deformation contained within their steady-state characteristics. Then, we review the literature dealing with the transient response of rivers to tectonic perturbation, through the production of knickpoints propagating through the drainage network. Inverse modelling of river profiles for uplift in time and space is also shown to be very effective in reconstructing regional tectonic histories. Finally, we present a synthetic morphometric approach for deducing the tectonic record of fluvial landscapes. As well as the erosional imprint of tectonic forcing, sedimentary deposits, such as fluvial terrace staircases, are also considered as a classical component of tectonic geomorphology. We show that these studies have recently benefited from rapid advances in dating techniques, allowing more reliable reconstruction of incision histories and estimation of incision rates. The combination of progress in the understanding of transient river profiles and larger, more rigorous data sets of terrace ages has led to improved understanding of river erosion and the implications for terrace

  8. Crustal Velocity Model of the Altai-Sayan Region

    Science.gov (United States)

    Behrend, M. J.; Mackey, K. G.

    2016-12-01

    We have developed a crustal velocity model for the the region encompassed by the Altai-Sayan Seismic Network of South-Central Russia (45o-55o N. X 79o-98o E.). Geographically, the study area includes the Altai and Sayan Mountain Ranges, Western Mongolia, Eastern Kazakhstan, and Northwest China. To develop our model we used phase arrival data from approximately 175 larger earthquakes recorded by the Altai-Sayan Seismic Network between 1977 and 1981 and reported in the bulletin Materialy po Seismichnosti Sibiri. To develop our model, we divided the region into 1o N-S x 2o E-W cells. Events within each cell, plus a small surrounding area, were relocated multiple times using a grid-search routine, in effort to determine the best fitting Pg and Sg velocities. Pg and Sg phase arrivals are generally from the 100-1000 km range and represent secondary arriving phases. These arrivals are dominant in this region and we consider the time picks and phase identifications to be reliable. Velocities tested range from 5.650 to 6.350 km/s for Pg and from 3.310 to 3.710 km/s for Sg. The best fitting velocities for each cell were then assigned to the geographic coordinates of the cell's center point. The standard Jeffreys-Bullen model was used for Pn velocities. The best fitting Pg and Sg velocities are those that minimize the average event residuals in a cell. High residual arrivals were omitted from the location process. In our model, Pg velocities range from 5.975-6.325 km/s, while Sg velocities range from 3.510-3.630 km/s, though the higher velocity extremes are constrained by one event and are not statistically significant. The average Pg velocity of the study area was, 6.147 km/s, and average Sg, 3.576 km/s. Geologically, these velocities are associated with the Central Asiatic Foldbelt and are consistent with regional crustal velocities along the southern edge of the Siberian Craton to the East as determined by previous studies.

  9. A numerical model for dynamic crustal-scale fluid flow

    Science.gov (United States)

    Sachau, Till; Bons, Paul; Gomez-Rivas, Enrique; Koehn, Daniel

    2015-04-01

    Fluid flow in the crust is often envisaged and modeled as continuous, yet minimal flow, which occurs over large geological times. This is a suitable approximation for flow as long as it is solely controlled by the matrix permeability of rocks, which in turn is controlled by viscous compaction of the pore space. However, strong evidence (hydrothermal veins and ore deposits) exists that a significant part of fluid flow in the crust occurs strongly localized in both space and time, controlled by the opening and sealing of hydrofractures. We developed, tested and applied a novel computer code, which considers this dynamic behavior and couples it with steady, Darcian flow controlled by the matrix permeability. In this dual-porosity model, fractures open depending on the fluid pressure relative to the solid pressure. Fractures form when matrix permeability is insufficient to accommodate fluid flow resulting from compaction, decompression (Staude et al. 2009) or metamorphic dehydration reactions (Weisheit et al. 2013). Open fractures can close when the contained fluid either seeps into the matrix or escapes by fracture propagation: mobile hydrofractures (Bons, 2001). In the model, closing and sealing of fractures is controlled by a time-dependent viscous law, which is based on the effective stress and on either Newtonian or non-Newtonian viscosity. Our simulations indicate that the bulk of crustal fluid flow in the middle to lower upper crust is intermittent, highly self-organized, and occurs as mobile hydrofractures. This is due to the low matrix porosity and permeability, combined with a low matrix viscosity and, hence, fast sealing of fractures. Stable fracture networks, generated by fluid overpressure, are restricted to the uppermost crust. Semi-stable fracture networks can develop in an intermediate zone, if a critical overpressure is reached. Flow rates in mobile hydrofractures exceed those in the matrix porosity and fracture networks by orders of magnitude

  10. Deep crustal reflections from a Vibroseis survey in northern Switzerland

    Science.gov (United States)

    Finckh, P.; Ansorge, J.; Mueller, St.; Sprecher, Chr.

    1984-10-01

    In 1982 a Vibroseis survey comprising 180 km of reflection profiles was run in northern Switzerland in order to investigate the suitability of the crystalline basement for the deposition of highly radioactive waste. A configuration was chosen with 144 channels, 25 m of geophone spacing, 20 s sweeps ranging from 11 to 61 Hz and stacking of 4 or 8 sweeps of 3 simultaneous vibrators at twice the geophone spacing. The listening time was generally 4 s and at 4 sites it was extended to 11s for the detection of deeper crustal reflectors. This survey unravelled the complicated fault and thrust system beneath the Swiss folded Jura mountains. The stack from 4 s to 11 s reveals clearly a strong sloping reflector between 3.0 and 3.5 s which is strong evidence for a pronounced differentiation in the upper crust. A series of reflections is observed between 5.8 and 7.2 s the top of which can be correlated with the Conrad discontinuity. A strong "layered" signal between 9.0 and 9.5 s is interpreted as reflections from the M-discontinuity. The main features are compatible with results from nearby refraction surveys in the southern Rhinegraben rift system which show a distinct velocity increase of about 0.5 km/s in the lower crust at a depth ranging from 15 to 20 km, followed by an inversion zone or a laminated structure before reaching the Moho at about 27 km depth. The correlation of the field recordings with the first 10 s of the up-sweep only, shows some loss of resolution in the uppermost 3 s because of the lower frequency content of the signal. However, the lower parts of the sections are nearly identical. The fact that the deeper reflectors in the sections can consistently be traced laterally is a strong argument for using this processing technique. Thus high-coverage Vibroseis surveys utilizing up-sweep can be processed for deep crustal reflections even if the recording time is restricted to the standard 4 s, provided the surface static corrections are carried out with high

  11. Crustal and deep seismicity in Italy (30 years after

    Directory of Open Access Journals (Sweden)

    G. Selvaggi

    1997-06-01

    Full Text Available The first modern studies of seismicity in Italy date back to the late 60's and early 70's. Although with a sparse seismic network available and only a few telemetered short-period stations, significant studies were carried out that outlined the main features of Italian seismicity (see, e.g., Boschi et al., 1969. Among these studies, one of the most important achievements was the reconnaissance of a Wadati-Benioff zone in Southern Tyrrhenian, described for the first time in detail in the papers of Caputo et al.(1970, 1973. Today, after three decades of more and more detailed seismological monitoring of the Italian region and tens of thousands earthquakes located since then, the knowledge of the earthquake generation processes in our country is much improved, although some of the conclusions reached in these early papers still hold. These improvements were made possible by the efforts of many institutions and seismologists who have been working hard to bring seismological research in Italy to standards of absolute quality, under the pivoting role of the Istituto Nazionale di Geofisica (ING. From the relocation of about 30000 crustal earthquakes and detailed studies on intermediate and deep shocks carried out in the last few years, we show that seismic release in peninsular Italy is only weakly related to the Africa-Eurasia convergence, but rather is best explained by the existence of two separate subduction/collision arcs (Northern Apennines and Southern Apennines-Calabria-Sicily. The width of the deforming belt running along peninsular Italy is 30 to 60 km, it is broader in the north than in the south, and the two arcs are separated by a region of more distributed deformation and stress rotations in the Central Apennines. Along the belt, the reconnaissance of regions of continuous and weak release of seismic energy, adjacent to fault areas which are currently «locked» (and therefore are the best candidates for future earthquakes is another

  12. Crustal structure of the Nordland region, northern Norway

    Science.gov (United States)

    Maystrenko, Yuriy P.; Olesen, Odleiv; Gernigon, Laurent; Gradmann, Sofie

    2016-04-01

    To understand the major structural features of the sedimentary cover and crystalline crust within the Nordland County area of Norway, a data-based 3D structural model has been constructed in the framework of the Neonor2 project, "Neotectonics in Nordland - implications for petroleum exploration". The 3D structural model covers the Lofoten Ridge, the Ribban and Vestfjorden basins and adjacent areas of the Norwegian mainland. The model also covers the northern part of the adjacent Vøring Basin. At the regional scale, the 3D model includes the rifted margin which is located at the transition from the exposed crystalline rocks of the Fennoscandian Shield in the east to the Cenozoic oceanic domain of the Norwegian-Greenland Sea in the west. During the construction of the 3D structural model, all recently published and/or released data have been compiled in order to set the initial model. This initial 3D model has been validated by a 3D density modelling in order to obtain a gravity-consistent 3D structural model of the entire study area. The 3D density modelling has been carried out by using the IGMAS plus software (the Interactive Gravity and Magnetic Application System). During the 3D density modelling, densities have been assigned as constant values for the crystalline rocks. In contrast, densities of sedimentary rocks have been set to be depth-dependent in order to reflect the compaction of sedimentary rocks with depth. According to the results of the 3D density modeling, the crystalline crust of the investigated region consists of several layers with different densities. The deepest crustal layer is the high-density lower crust which corresponds to the high-velocity lower crustal layer. The regional-scale gravity response associated with the positions of the Moho and lithosphere-asthenosphere boundary is one of the key factors for performing a proper 3D density model of the study area. At the regional scale, the Moho and lithosphere-asthenosphere boundary are

  13. Crustal thinning and tectonic geomorphology: redefining the passive margin

    Science.gov (United States)

    Redfield, T.; Osmundsen, P. T.

    2012-04-01

    We describe Scandinavia's passive margin in terms of a hyper-extended distal margin, a variably tapered proximal margin that includes the outer onshore areas, and an upwarped, unstretched, continent-sloping hinterland that terminates against the "undeformed" cratonic interior. Two benchmark locations, defined as the taper break (TB) and the Hinterland Break in Slope (HBSL), occur at the inner boundary of the distal margin and at the transition from the continent-sloping hinterland and craton, respectively. The elevation of the seaward-facing escarpment is directly scaled to the distance between the taper break and the Hinterland Break in Slope. Scaling relationships between the taper of the crystalline crust in the direction of the distal margin and the length/dip of the hinterland backslope follow directly. The shape factors of major catchments are directly scaled to the taper of the proximal margin and drainage azimuths are parallel to the mean transport lineation recorded from a distinct population of range-bounding normal faults. Topographic expressions of the footwalls and offsets in apatite fission-track age-patterns indicate that fault movement controlled topography, locally and regionally inboard of sharp crustal tapers long after the main phase of crustal thinning. We extend our definition of the passive margin to other post-breakup margins. One particularly fine example is SE Brasil. New data (Zalan et al., 2011) suggest the direct correlation of SE Brasil's Taper Break with its escarpment elevation in a manner consistent with our Scandinavian and global observations. The Taper Hypothesis appears to hold across old and young, glaciated, and unglaciated margins. Following the stretching, thinning, and exhumation phase, an "accommodation phase" is warranted. During accommodation, the initially elevated escarpments can be eroded to very low base levels and subsequently undergo inboard rejuvenation by footwall uplift, in response to tensile stresses

  14. JERS-1 Synthetic Aperture Radar Interferometry Applications: Mapping of Rain Forest Environments and Crustal Deformation Studies

    Science.gov (United States)

    Rosen, P.; Hensley, S.; Peltzer, G.; Rignot, E.; Werner, C.

    1999-01-01

    This research using JERS-1 SAR data has been very fruitful, resulting in a strong collaboration with geodesists and geophysicists in Japan, and several important papers characterizing crustal deformation, and the capabilities and limitations of JERS data for these studies.

  15. A New System for Understanding Mid-crustal Sheeted Complexes in a Tilted Crustal Section, Joshua Tree National Park, California

    Science.gov (United States)

    Ianno, A. J.; Paterson, S. R.

    2011-12-01

    The western portion of Joshua Tree National Park exposes a tilted crustal section through continental arc crust from 0-30 km. A significant portion of the middle crust is represented by Mesozoic, tabular, intrusive, igneous bodies ranging from 0.1 to 100 m in thickness. While these igneous bodies range in composition (gabbro to peraluminous granites), texture (equigranular to porphyritic), and grain size (very fine to coarse), patterns emerge between different regions of "sheeted complexes" that may be related to their emplacement and geochemical history. No consistent method of describing and comparing sheeted complexes exists in the literature, so we have developed a method of classifying sheeted complexes at Joshua Tree NP, which may be broadly applicable to all sheeted bodies. We classify these sheeted complexes using the terms homogeneous/heterogeneous and focused/defocused. A homogeneous sheeted complex generally contains magmas within a 10 wt% SiO2 range, although we are still testing the validity of this number. A focused sheeted complex has adjacent sheets or close spacing between sheets and Jurassic to Cretaceous sheeted complexes in western Joshua Tree NP. At Keys View, we observe a heterogeneous, spatially focused sheeted complex with 0.1-2 m thick sheets recording pressures indicating 15-22 km depth from top to bottom. Compositions range from gabbro to peraluminous granite, although tonalites-granodiorites and two-mica garnet granites are volumetrically dominant. A zone of elongate plutons (in map view) lying structurally above this could potentially be considered as a very thickly sheeted, homogeneous, focused sheeted complex and is composed of granodiorites, granites, and two-mica garnet granites. A more thickly sheeted (2-10 m), homogeneous, focused, sheeted granite complex with pressures indicating a depth of approximately 12 km is found along the northern edge of the park. The number of sheets decreases and the average thickness increases as this

  16. Diamonds from the Juina-5 kimberlite provide evidence for crustal volatile recycling into the deep Earth

    Science.gov (United States)

    Thomson, Andrew; Walter, Michael; Kohn, Simon; Burnham, Antony; Bulanova, Galina; Smith, Chris; Araujo, Debora

    2014-05-01

    'Superdeep' diamonds originate from a depth range spanning the asthenospheric upper mantle, transition zone and shallowest parts of the lower mantle [1]. Sporadically they entrap small inclusions of pre-existing or co-precipitating minerals during their crystallisation from volatile-rich melts or fluids. Such samples therefore preserve important petrologic, tectonic and geodynamic information about their growth environment together with evidence of the deep volatile cycling. The Juina-5 kimberlite has previously been recognised as a source of 'superdeep' diamonds [2]. Here we present and discuss data from an extended collection of Juina-5 diamonds. This work has revealed that these diamonds are dominantly composed of isotopically light carbon and contain a mineral inclusion cargo mostly of eclogitic affinity consisting of many former Mg- and Ca-perovskite, NAL-phase, CF-phase, stishovite, majoritic garnet, sodic pyroxene, ferropericlase, Fe or Fe-carbide and sulphide minerals. Together these observations suggest that the diamonds form from material of a subducted crustal origin. The high enrichment of the inclusions' trace element compositions implies that they cannot represent trapped fragments of formerly subsolidus mantle material. Geochemical modelling instead allows the compositions of Ca-perovskite and majorite inclusions to be directly linked to formation from a slab-derived carbonate bearing melt. It is suggested that the formation of 'superdeep' diamonds, and their inclusions, is the result of 'redox-freezing' during the interaction of oxidised slab melts and reducing mantle rocks [3]. It is expected that such melts will be produced during slab foundering and thermal equilibration in the upper/lower mantle boundary region, where tomographic evidence suggests slab subduction often stalls [4]. This hypothesis has been tested with experiments performed at transition zone pressures using the multi-anvil apparatus. At 20 GPa the composition of a low degree melt

  17. Extraction of Crustal Deformation from Seafloor Hydraulic Pressure Gauges: A trial collaboration study

    Science.gov (United States)

    Ariyoshi, Keisuke; Nagano, Akira; Hasegawa, Takuya; Matsumoto, Hiroyuki; Kido, Motoyuki; Igarashi, Toshihiro; Uchida, Naoki; Nakata, Ryoko; Yamashita, Yusuke

    2016-04-01

    It has been well known that megathrust earthquakes such as the 2004 Sumatra-Andaman Earthquake (Mw 9.1) and the 2011 the Pacific Coast of Tohoku Earthquake (Mw 9.0) had devastated the coastal areas in the western of Indonesia and in the north-eastern of Japan, respectively. Some researchers have pointed out that the 2011 Tohoku earthquake may correspond to the recurrence of the 869 Jogan earthquake. In addition, the 887 Nin'na earthquake followed it and ruptured the source regions for both the 1946 Mw 8.1 Nankai and 1944 Mw 7.9 Tonankai earthquakes with probably greater magnitude than the sum of the two earthquakes. These may indicate that megathrust earthquakes like the Nin'na earthquake might occur along the Nankai Trough in the near future. To mitigate the disaster of those forthcoming megathrust earthquakes, the Japanese government has established seafloor networks of cable-linked observatories around Japan: DONET (Dense Oceanfloor Network system for Earthquakes and Tsunamis along the Nankai Trough) and S-net (Seafloor Observation Network for Earthquakes and Tsunamis along the Japan Trench). The advantage of the cable-linked network is to monitor the propagation process of tsunami and seismic waves as well as seismic activity in real time. Before the occurrence of such megathrust earthquakes, monitoring of seismically plate coupling is important to evaluate the disaster risk in advance. Recently, owing to the inland networks of highly sensitive seismic broadband seismogram stations, very low-frequency interplate earthquakes (VLFEs) have been observed near the trench. Since VLFE is thought to be located in the shallower and deeper edge of seismogenic segments occurring megathrust earthquakes and be sensitive to small stress change such as Earth tidal modulation due to low stress drop, monitoring the spatiotemporal change of VLFE activity has been expected to detect the strongly plate coupling regions in advance of megathrust earthquake occurrence. In this study

  18. Reflection Character of the Continental Lithosphere and Crustal Evolution

    Science.gov (United States)

    Brown, L. D.

    2015-12-01

    Reflection images represent the high-frequency end member of the suite of seismological tools commonly used to probe the lithosphere. The global inventory of deep reflection profiles has documented reflection characters as varied as the surface geology that provides the primary boundary condition for the interpretation of reflection images. Past reviews of reflection results have stressed similarities in reflection patterns between various geographic regions and attempted to associate these patterns with specific tectonic processes. Examples include: laminated sequences (shear fabrics formed during extension or collision), reflective Mohos (mafic underplating), bright spots (contemporary and fossil magma bodies), dipping mantle reflections rooted in the lower crust (fossil subduction zones) and subhorizontal mantle reflections (phase changes in the lower lithosphere). Here I focus on relating reflection character to the inversion and/or interpretation of results from broadband techniques such as receiver functions, body wave and surface wave tomography. Among the underappreciated aspects of reflectivity are its dependence upon density as well as velocity, and the limitations of 2D images in a 3D world. A core consideration is the need to meaningfully relate integrated physical properties (e.g. velocity inferred from refraction and surface wave measurements) with the differential physical properties (e.g. reflection coefficients) to which reflection images are primarily sensitive. Examples from Tibet and Eurasia are used to illustrate examples of successful integration of controlled (active) and natural (passive) source observations to constrain models of crustal evolution.

  19. Crustal and tectonic controls on large-explosive volcanic eruptions

    Science.gov (United States)

    Sheldrake, Tom; Caricchi, Luca

    2017-04-01

    Quantifying the frequency-Magnitude (f-M) relationship for volcanic eruptions is important to estimate volcanic hazard. Furthermore, understanding how this relationship varies between different groups of volcanoes can provide insights into the processes that control the size and rate of volcanic events. Using a Bayesian framework, which allows us to conceptualise the volcanic record as a series of individual and unique time series, associated by a common group behaviour, we identify variations in the size and rate of volcanism in different volcanic arcs. These variations in behaviour are linked to key parameters that include the motion of subduction, rate of subduction, age of the slab and thickness of the crust. The effects of these parameters on volcanism are interpreted in terms of variations in mantle productivity and the thermal efficiency of magma transfer in arc crustal systems. Understanding the link between subduction architecture, heat content of magmatic systems, and volcanic activity will serve to improve our capacity to quantify volcanic hazard in regions with limited geological and historical records of volcanic activity.

  20. Investigation of upper crustal structure beneath eastern Java

    Science.gov (United States)

    Martha, Agustya Adi; Widiyantoro, Sri; Cummnins, Phil; Saygin, Erdinc; Masturyono

    2016-05-01

    The complexity of geology structure in eastern Java causes this region has many potential resources as much as the disasters. Therefore, the East Java province represents an interesting area to be explored, especially regarding its upper crustal structure. To investigate this structure, we employ the Ambient Noise Tomography (ANT) method. We have used seismic waveform data from 25 Meteorological, Climatological and Geophysical Agency (BMKG) stationary seismographic stations and 26 portable seismographs installed for 2 to 8 weeks. Inter-station cross-correlation produces more than 800 Rayleigh wave components, which depict the structure beneath eastern Java. Based on the checkerboard resolution test, we found that the optimal grid size is 0.25ox0.25o. Our inversion results for the periods of 1 to 10 s indicate a good agreement with geological and Bouguer anomaly maps. Rembang high depression, most of the southern mountains zone, the northern part of Rembang zone and the central part of the Madura Island, the area of high gravity anomaly and areas dominated with igneous rocks are associated with high velocity zones. On the other hand, Kendeng zone and most of the basin in the Rembang zone are associated with low velocity zones.

  1. Crustal deformation across the Southern Patagonian Icefield observed by GNSS

    Science.gov (United States)

    Richter, A.; Ivins, E.; Lange, H.; Mendoza, L.; Schröder, L.; Hormaechea, J. L.; Casassa, G.; Marderwald, E.; Fritsche, M.; Perdomo, R.; Horwath, M.; Dietrich, R.

    2016-10-01

    Geodetic GNSS observations at 43 sites well distributed over the Southern Patagonian Icefield region yield site velocities with a mean accuracy of 1 mm/a and 6 mm/a for the horizontal and vertical components, respectively. These velocities are analyzed to reveal the magnitudes and patterns of vertical and horizontal present-day crustal deformation as well as their primary driving processes. The observed vertical velocities confirm a rapid uplift, with rates peaking at 41 mm/a, causally related to glacial-isostatic adjustment (GIA). They yield now an unambiguous preference between two competing GIA models. Remaining discrepancies between the preferred model and our observations point toward an effective upper mantle viscosity even lower than 1.6 ṡ1018 Pas and effects of lateral rheological heterogeneities. An analysis of the horizontal strain and strain-rate fields reveals some complex superposition, with compression dominating in the west and extension in the east. This deformation field suggests significant contributions from three processes: GIA, a western interseismic tectonic deformation field related to plate subduction, and an extensional strain-rate field related to active Patagonian slab window tectonics.

  2. Crustal structure between Lake Mead, Nevada, and Mono Lake, California

    Science.gov (United States)

    Johnson, Lane R.

    1964-01-01

    Interpretation of a reversed seismic-refraction profile between Lake Mead, Nevada, and Mono Lake, California, indicates velocities of 6.15 km/sec for the upper layer of the crust, 7.10 km/sec for an intermediate layer, and 7.80 km/sec for the uppermost mantle. Phases interpreted to be reflections from the top of the intermediate layer and the Mohorovicic discontinuity were used with the refraction data to calculate depths. The depth to the Moho increases from about 30 km near Lake Mead to about 40 km near Mono Lake. Variations in arrival times provide evidence for fairly sharp flexures in the Moho. Offsets in the Moho of 4 km at one point and 2 1/2 km at another correspond to large faults at the surface, and it is suggested that fracture zones in the upper crust may displace the Moho and extend into the upper mantle. The phase P appears to be an extension of the reflection from the top of the intermediate layer beyond the critical angle. Bouguer gravity, computed for the seismic model of the crust, is in good agreement with the measured Bouguer gravity. Thus a model of the crustal structure is presented which is consistent with three semi-independent sources of geophysical data: seismic-refraction, seismic-reflection, and gravity.

  3. Crustal kinematics of the Colorado Plateau from GPS geodesy

    Science.gov (United States)

    Holland, A. A.; Broermann, J.; Bennett, R. A.; Kreemer, C.; Blewitt, G.

    2013-12-01

    We present results from new continuous and campaign GPS networks spanning the state of Arizona and the southern portion of Utah. The 33 station continuous GPS network, funded by the NSF EarthScope Program, supplements a sparse distribution of continuous GPS stations that comprise the NSF EarthScope Plate Boundary Observatory network. The campaign network originally established by the National Geodetic survey in the mid-1990's, has been reoccupied two or more times over the past five years with support from the Arizona Geological Survey. The data from the continuous GPS stations are analyzed independently with the GIPSY and GAMIT software. The new horizontal velocity data set provides an improved image of deformation in the transition zone between the Colorado Plateau and the Northern and Southern Basin and Ranges Provinces. Preliminary modeling of the crustal kinematics reveals that only a very limited part of the region can be modeled as a rigid-body rotation. Most of the area is part of a broad zone of diffuse east-west directed extension from the Rio Grande Rift in the East to the Mojave Desert in the west. Only near the transition from the northern Colorado Plateau to the northern Basin and Range Province is the extension more localized. Besides a discussion of the regional kinematics, we will also discuss the affect the 2010 El Mayor-Cucapah earthquake had on the geodetic data in the southern Basin and Range.

  4. Fragmentation of wall rock garnets during deep crustal earthquakes

    Science.gov (United States)

    Austrheim, Håkon; Dunkel, Kristina G.; Plümper, Oliver; Ildefonse, Benoit; Liu, Yang; Jamtveit, Bjørn

    2017-01-01

    Fractures and faults riddle the Earth’s crust on all scales, and the deformation associated with them is presumed to have had significant effects on its petrological and structural evolution. However, despite the abundance of directly observable earthquake activity, unequivocal evidence for seismic slip rates along ancient faults is rare and usually related to frictional melting and the formation of pseudotachylites. We report novel microstructures from garnet crystals in the immediate vicinity of seismic slip planes that transected lower crustal granulites during intermediate-depth earthquakes in the Bergen Arcs area, western Norway, some 420 million years ago. Seismic loading caused massive dislocation formations and fragmentation of wall rock garnets. Microfracturing and the injection of sulfide melts occurred during an early stage of loading. Subsequent dilation caused pervasive transport of fluids into the garnets along a network of microfractures, dislocations, and subgrain and grain boundaries, leading to the growth of abundant mineral inclusions inside the fragmented garnets. Recrystallization by grain boundary migration closed most of the pores and fractures generated by the seismic event. This wall rock alteration represents the initial stages of an earthquake-triggered metamorphic transformation process that ultimately led to reworking of the lower crust on a regional scale.

  5. Decrease in oceanic crustal thickness since the breakup of Pangaea

    Science.gov (United States)

    van Avendonk, Harm J. A.; Davis, Joshua K.; Harding, Jennifer L.; Lawver, Lawrence A.

    2017-01-01

    Earth's mantle has cooled by 6-11 °C every 100 million years since the Archaean, 2.5 billion years ago. In more recent times, the surface heat loss that led to this temperature drop may have been enhanced by plate-tectonic processes, such as continental breakup, the continuous creation of oceanic lithosphere at mid-ocean ridges and subduction at deep-sea trenches. Here we use a compilation of marine seismic refraction data from ocean basins globally to analyse changes in the thickness of oceanic crust over time. We find that oceanic crust formed in the mid-Jurassic, about 170 million years ago, is 1.7 km thicker on average than crust produced along the present-day mid-ocean ridge system. If a higher mantle temperature is the cause of thicker Jurassic ocean crust, the upper mantle may have cooled by 15-20 °C per 100 million years over this time period. The difference between this and the long-term mantle cooling rate indeed suggests that modern plate tectonics coincide with greater mantle heat loss. We also find that the increase of ocean crustal thickness with plate age is stronger in the Indian and Atlantic oceans compared with the Pacific Ocean. This observation supports the idea that upper mantle temperature in the Jurassic was higher in the wake of the fragmented supercontinent Pangaea due to the effect of continental insulation.

  6. Maps of North American crustal stability and geothermal potential

    Energy Technology Data Exchange (ETDEWEB)

    Fairbridge, R.W.

    1977-01-01

    A three-year program of analysis of crustal movements in North America was planned with the objective of preparing a series of 1 = 5 million scale maps depicting relative stability/instability. The part of the proposal completed during the first year is described; much of this first year's work was preparatory. Three time scales were considered for the data analysis: 1 - 10/sup 2/ yr., 10/sup 4/ yr., and 10/sup 8/ yr. Significant differences in sign and rate were suspected between short and long-term motions and these are now confirmed. The first part of the program is now complete. It consisted of two principal activities: (a) data collection for the short and mid-term scales on a U.S.-wide basis, excluding Alaska and Hawaii (all of this material has been reduced to compatible computer language and is stored on tape ready for further study, analysis and final cartography); (b) map and data analysis of the long-term scale with a completed draft map, applied specifically to the Mid-West and eastern U.S.

  7. Estimating gravity changes caused by crustal strain: application to the Tibetan Plateau

    Science.gov (United States)

    Yin, Zhi; Xu, Caijun

    2017-08-01

    Temporal gravimetry is an efficient tool for monitoring mass transfers, but distinguishing the contribution of each process to the measured signals is challenging. Few effective methods have been developed to estimate the changes in gravity caused by crustal strain for large-scale geophysical problems. To fill this research gap, we proposed a formula that describes a negative linear correlation between changes in gravity and crustal dilatational strain. Surface observations of gravity changes and dilatational strains were simulated using PSGRN/PSCMP, which is a numerical code used to calculate the surface response to fault dislocations, and the accuracy of the formula was quantitatively verified. Four parameters are required for this formula: the crustal dilatational strain, the crustal density, the Moho depth, and a coefficient that characterizes the degree of crust-mantle coupling. To illustrate the application of this new method to a natural case study, including specifying the values of the necessary parameters, the crustal strain-caused gravity changes (CSGCs) were calculated at 1° × 1° grid nodes over the Tibetan Plateau (TP). The CSGC model shows that most of the crust of the TP is undergoing extension, which generates negative gravity signals. The magnitude of the Tibetan CSGC model is approximately 0.2 μGal yr-1, which is similar to the results obtained from numerical modelling of the crustal tectonics of the Taiwanese Orogen. To evaluate the reliability of the Tibetan CSGC model, the uncertainties in the crustal dilatational strain, crustal density, Moho depth, and crust-mantle coupling factor were evaluated and then used to estimate the CSGC uncertainty by applying the error propagation law. The CSGC model was used to analyse the mass transfers of the TP. The results suggest that a significant mass accumulation process may be occurring beneath the crust of the northern TP.

  8. Crustal shortening and Eocene extension in the southeastern Canadian Cordillera: Some thermal and rheological considerations

    Science.gov (United States)

    Liu, Mian; Furlong, Kevin P.

    1993-06-01

    Metamorphic core complexes in the southeastern Canadian Cordillera were formed during Eocene crustal extension, shortly (within a few millions of years) after Late Jurassic-Paleocene crustal shortening. Thermal-rheological modeling, constrained by geological and geochronological studies of the Valhalla core complex and other core complexes in this region, is used to investigate two major problems concerning the formation of these core complexes: (1) the dynamic links between crustal shortening and extension and (2) the cooling history and unroofing rates during extension. Thermal-rheological effects associated with crustal shortening are integrated through the history of crustal compression, since crustal shortening in this region was a long and slow process and cannot be treated as an instantaneous event. Our results suggest that crustal shortening may have played an important role in Eocene extension in the southeastern Canadian Cordillera by (1) producing a thickened and therefore unstable crust and (2) thermally weakening the lithosphere. However, heat generated by crustal shortening is not enough to account for the thermal state of the Valhalla complex, and additional heat sources at depth may be necessary. We then investigate thermal evolution during extension in both a simple shear model and a progressive pure stretching model. We show that the geotherm in an extensional region is time-and space-dependent and is affected by many variables including the preextensional thermal history and the mode of extension. Thus caution needs to be exercised when inferring unroofing rates from thermochronologic data. The cooling history of the Valhalla core complex may be explained by unroofing at rates of 1-2 mm/yr.

  9. Crustal architecture across Phanerozoic Australia along the Eromanga-Brisbane Geoscience Transect: evolution and analogues

    Science.gov (United States)

    Finlayson, D. M.

    1993-03-01

    The crustal architecture across Phanerozoic Australia has been established from seismic data along an 1100-km-long east-west transect, the Eromanga-Brisbane Geoscience Transect. This has enabled a better understanding of deep structures and processes that have controlled the development of major sedimentary basin systems. It has shown that crustal dynamics throughout geological history have played an important role in the development of these sedimentary basins and that structures developed during the early Palaeozoic have influenced, and continue to influence, basin systems. The transect crosses three major basement provinces of the Tasman Orogenic System in eastern Australia - the Thomson, northern Lachlan, and New England Orogens. The basement geology in the transect region has, until now, been only poorly understood because it is largely obscured by the Mesozoic cover rocks of the Eromanga, Surat and Clarence-Moreton Basins. The transect interpretation has firmly identified crustal-scale ramp structures, multiple intra-crustal detachment surfaces, strike-slip fault architecture, lower-crustal magmatism/underplating, Mono remobilisation, and intra-crustal terranes in the geological reconstructions of southern Queensland. The boundaries between the orogens, the Foyleview and Burunga—Mooki Geosutures, have been identified as lithospheric-scale structures that have influenced the evolution of the Tasman Orogenic System as a whole.

  10. Crustal model for the Middle East and North Africa region: implications for the isostatic compensation mechanism

    Science.gov (United States)

    Seber, Dogan; Sandvol, Eric; Sandvol, Christine; Brindisi, Carrie; Barazangi, Muawia

    2001-12-01

    We present a new 3-D crustal model for the Middle East and North Africa region that includes detailed topography, sediment thickness, and Moho depth values. The model is obtained by collecting, integrating, and interpolating reliable, published sedimentary rock thickness and Moho depth measurements in the Middle East and North Africa region. To evaluate the accuracy of the model, the 3-D gravity response of the model is calculated and compared with available observed Bouguer gravity anomalies in the region. The gravity modelling shows that the new crustal model predicts large portions of the observed Bouguer anomalies. However, in some regions, such as the Red Sea and Caspian Sea regions, where crustal structure is relatively well-determined, the residual anomalies are of the order of a few hundred milligals. Since the new crustal model results in large residual anomalies in regions where reasonably good constraints exist for the model, these large residuals cannot simply be explained by inaccuracies in the model. To analyse the cause of these residuals further we developed an isostatically compensated (Airy-type) Moho-depth model and calculated its gravity response. Isostatic gravity anomalies are in nearly perfect agreement with the observed gravity values. However, the isostatic model differs significantly from the new (3-D) crustal model. If isostasy is to be maintained, crustal and/or upper mantle lateral density variations are needed to explain the large observed gravity residuals.

  11. Near-axis crustal structure and thickness of the Endeavour Segment, Juan de Fuca Ridge

    Science.gov (United States)

    Soule, Dax; Wilcock, William S. D.; Toomey, Douglas R.; Hooft, Emilie E. E.; Weekly, Robert T.

    2016-06-01

    A model of crustal thickness and lower crustal velocities is obtained for crustal ages of 0.1-1.2 Ma on the Endeavour Segment of the Juan de Fuca Ridge by inverting travel times of crustal paths and non-ridge-crossing wide-angle Moho reflections obtained from a three-dimensional tomographic experiment. The crust is thicker by 0.5-1 km beneath a 200 m high plateau that extends across the segment center. This feature is consistent with the influence of the proposed Heckle melt anomaly on the spreading center. The history of ridge propagation on the Cobb overlapping spreading center may also have influenced the formation of the plateau. The sharp boundaries of the plateau and crustal thickness anomaly suggest that melt transport is predominantly upward in the crust. Lower crustal velocities are lower at the ends of the segment, likely due to increased hydrothermal alteration in regions influenced by overlapping spreading centers, and possibly increased magmatic differentiation.

  12. Só Jesus Na Causa: Fé E Percepção de Crowding em Evento Religioso

    Directory of Open Access Journals (Sweden)

    Izabelle Quezado

    2016-12-01

    Full Text Available Journal of Retailing and Consumer Services, 21 + (2013 54-60. doi:10.1016/j.jretconser.2013.09.004 Frank Pons Crowding; Density; Expectations; Dissatisfaction; Scarcity 12.00 Mediante a forte representatividade cultural e econômica do turismo motivado pela religião, este estudo tem como objetivo analisar as relações entre percepção de crowding, emoções e satisfação do consumidor em situação de alta densidade em evento religioso, testando a moderação da variável fé. A pesquisa empírica tem abordagem quantitativa e apresenta uma amostra de 201 casos, com dados analisados por meio da técnica de Modelagem de Equações Estruturais. Os resultados indicaram influência positiva da percepção de crowding na satisfação em evento religioso. No entanto, ao contrário do esperado, as emoções negativas não mediaram essa relação, exclusivamente as positivas. Com relação à moderação da variável fé, esta foi atestada na pesquisa empírica, fortalecendo reações positivas e enfraquecendo reações negativas à aglomeração. Normal 0 21 false false false PT-BR X-NONE X-NONE MicrosoftInternetExplorer4

  13. Modelagem da adsorção de compostos orgânicos voláteis sobre nanotubos de carbono cup-stacked usando o modelo da força motriz linear = Modeling volatile organic compounds (voc’s adsorption onto cupstacked carbon nanotubes (cscnt using the linear driving force model

    Directory of Open Access Journals (Sweden)

    Waldir Nagel Schirmer

    2010-07-01

    Full Text Available Os compostos orgânicos voláteis (COV são importante classe de poluentes do ar, e a adsorção tem sido largamente empregada no seu tratamento há vários anos. O presente trabalho utilizou metodologias analíticas convencionais para avaliar o nanotubo cup-stacked (CSCNT na purificação de correntes gasosas contaminadas com COV. O CSCNT é constituído de múltiplas camadas de grafeno em formato cônico, apresentando extremidades abertas em sua superfície externa e canais centrais vazios. Foi adotado o Carbotrap como suporte do cup-stacked. O adsorvente-parâmetro de comparação do desempenho desse compósito foi o próprio Carbotrap (sem o nanotubo. Foi avaliada a capacidade de adsorção de cada adsorvente, bem como suas capacidades de saturação para cada uma das concentrações trabalhadas com os dois adsorbatos utilizados (1, 5, 20 e 35 ppm de tolueno e fenol. Na modelagem das curvas massaxtempo, utilizou-se o modelo da força motriz linear (LDF – linear driving force. A metodologia proposta para determinação das curvas massa.tempo mostrou-se aplicável a análises desta natureza. Em relação ao desempenho dos adsorventes, o compósito obteve clara vantagem em relação ao Carbotrap; os valores das capacidades de saturação para o compósito foram, em média, 67% superiores aos obtidos para o Carbotrap.Volatile organic compounds (VOC’s are an important category of air pollutants and adsorption has been employed in the treatment (or simply concentration of these compounds. The current study used an ordinary analytical methodology to evaluate the properties of a cupstacked nanotube (CSCNT, a stacking morphology of truncated conical graphene, with large amounts of open edges on the outer surface and empty central channels. This work used a Carbotrap bearing a cup-stacked structure (composite; for comparison, Carbotrapwas used as reference (without the nanotube. The retention and saturation capacities of both adsorbents to each

  14. An application of PIXE technique to Proto Crustal Rocks: Geo chemical evaluation of Granulitic Charnockites of Eastern Ghats, Andhrapradesh, India

    Directory of Open Access Journals (Sweden)

    A.V.S. SATYANARAYANA

    2016-02-01

    Full Text Available In this work, PIXE has been used for a variety of Precambrian proto crustal rocks in the form of granulitic charnockites,Eastern Ghats AP,India. In previous study of exterior part of the charnockite hill elemental analysis using electron microprobe analysis, the elements in host charnockites no Na, traces of Mn,Ca and high Ti,Cl,F (Biotite, no Mn, low Na,and high K,Cl (Hastingsite, and Cl, Fe (Apatite were only detected, but by using PIXE technique in addition to the above twenty two trace elements are identified. PIXE is highly sensitive and non-destructive method for multi elemental analysis in a variety of Precambrian charnockite rocks down to levels of a few parts per million. The samples chosen for analysis from the central portion of a charnockite hill near Visakhapatnam airport. A big reticular mass of relict litho logical body which is compositionally and physically different from host chatnockite was observed in the central portion of the hill. These experiments are carried out using a 3MV pelletron accelerator facility at the Institute of physics, Bhubaneswar. A collimated proton beam of 2mm diameter is made to fall on to the sample, and the beam current is kept at 20na. A high resolution Si(Li detector(160ev FWHM at 5.9kev energy is employed in the present experiments and the Guelph PIXE (GUPIX software package is used to analyze the spectra. The elements identified in this Precambrian charnockite rock are Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Ru, Ag, Pb..From this study these rocks are early crust(proto crust rocks. These samples are to belong to a very important geological phase and further work on petrography and REE (Rare Earth Elements in Geologyof the rock is indeed to firmly establish its exact parentage.

  15. Modelagem metamórfica e geocronologia de xistos e anfibolitos do grupo Nova Lima, Supergrupo Rio das Velhas, Quadrilátero Ferrífero.

    OpenAIRE

    Coelho, Viviane Viana

    2015-01-01

    Programa de Pós-Graduação em Evolução Crustal e Recursos Naturais. Departamento de Geologia. Escola de Minas, Universidade Federal de Ouro Preto. Para entender a evolução metamórfica da província domos e quilhas do Quadrilátero Ferrífero foi realizado um modelamento metamórfico em granada xistos e granada anfibolitos, rochas supracrustais do Grupo Nova Lima, que encontram-se em contato tectônico com os domos do Bação e Belo Horizonte. Interpretação de dados obtidos através de desc...

  16. Crustal strain-dependent serpentinisation in the Porcupine Basin, offshore Ireland

    Science.gov (United States)

    Prada, Manel; Watremez, Louise; Chen, Chen; O'Reilly, Brian M.; Minshull, Timothy A.; Reston, Tim J.; Shannon, Patrick M.; Klaeschen, Dirk; Wagner, Gerlind; Gaw, Viola

    2017-09-01

    Mantle hydration (serpentinisation) at magma-poor rifted margins is thought to play a key role in controlling the kinematics of low-angle faults and thus, hyperextension and crustal breakup. However, because geophysical data principally provide observations of the final structure of a margin, little is known about the evolution of serpentinisation and how this governs tectonics during hyperextension. Here we present new observational evidence on how crustal strain-dependent serpentinisation influences hyperextension from rifting to possible crustal breakup along the axis of the Porcupine Basin, offshore Ireland. We present three new P-wave seismic velocity models that show the seismic structure of the uppermost lithosphere and the geometry of the Moho across and along the basin axis. We use neighbouring seismic reflection lines to our tomographic models to estimate crustal stretching (βc) of ∼2.5 in the north at 52.5° N and >10 in the south at 51.7° N. These values suggest that no crustal embrittlement occurred in the northernmost region, and that rifting may have progressed to crustal breakup in the southern part of the study area. We observed a decrease in mantle velocities across the basin axis from east to west. These variations occur in a region where βc is within the range at which crustal embrittlement and serpentinisation are possible (βc 3-4). Across the basin axis, the lowest seismic velocity in the mantle spatially coincides with the maximum amount of crustal faulting, indicating fault-controlled mantle hydration. Mantle velocities also suggest that the degree of serpentinisation, together with the amount of crustal faulting, increases southwards along the basin axis. Seismic reflection lines show a major detachment fault surface that grows southwards along the basin axis and is only visible where the inferred degree of serpentinisation is >15%. This observation is consistent with laboratory measurements that show that at this degree of

  17. Rates, Mechanisms, and Implications of Crustal Assimilation in Continental Arcs

    Science.gov (United States)

    Dungan, M.; Davidson, J.

    2002-12-01

    Contrary to the limiting constraints postulated by Bowen for the coupled thermal and mass balance implicated in assimilation, many studies [1-6] suggest that multi-stage and multi-component assimilation, abetted by magma mixing, may be volumetrically important and have profound consequences for the chemistry of basaltic and evolved magmas in long-lived continental magmatic systems. The probability of a primitive or evolved basalt arriving at the Earth's surface having undergone perfectly closed-system evolution during passage through 25-60 km of continental crust is vanishingly low. A case-by-case demonstration that the intra-crustal chemical overprint is trivial, or that it can be quantified and subtracted, is an essential step in any evaluation of mantle source-region chemistry and processes based on inversion of continental basalt compositions. In magmatic systems characterized by mafic magma recharge the thermal energy and physical dynamism needed for assimilation are not constrained to come uniquely from one magma batch [7, 8]. Equally important is that assimilation is rarely equivalent to bulk melting of ingested blocks followed by reservoir-wide homogenization. The mechanics of crustal assimilation are governed by grain boundary melting, disaggregation, and dispersal of refractory solids (including xenocryst settling) wherein liberated low-density, incompatible element-enriched partial melts have the capacity to render primitive arc magma batches variably modified, as well as heterogeneous on short length-scales. Evidence that basalts thermally erode surface channels and conduit walls, and new observations constraining the maximum time that some extensively melted xenoliths have resided in their host magmas, indicate that the time required to impose an open-system overprint on a hot basaltic magma (days to yrs) is far shorter than typical repose periods at most arc volcanoes (50-500 yrs). Assimilative recycling of broadly gabbroic arc cumulates has had large

  18. Cooperação e Poder na Qualidade do Relacionamento das Cooperativas de Crédito

    Directory of Open Access Journals (Sweden)

    Denise Maria Martins

    2016-06-01

    Full Text Available Este artigo tem como objetivo analisar o nível de influência da cooperação e do poder na qualidade do relacionamento entre cooperativas de crédito singulares e centrais. A pesquisa quantitativa e descritiva, foi desenvolvida em cooperativas de crédito vinculadas ao Banco Central do Brasil – BACEN e a Organização das Cooperativas Brasileiras – OCB. Os dados foram tratados por meio da Modelagem de Equações Estruturais (MEE, com aplicação do método de estimação dos mínimos quadrados parciais (PLS-PM. Os resultados obtidos nos coeficientes de determinação (R2 das variáveis latentes endógenas, confirmaram os pressupostos dos modelos teóricos de Morgan e Hunt (1994 e Hutchinson e Singh (2012. Constatou-se significância estatística nas relações entre poder e cooperação influenciando a Qualidade do Relacionamento entre cooperativas de crédito singulares com suas centrais, bem como o quanto os constructos cooperação e poder evidenciam aspectos relevantes para a qualidade dos relacionamentos entre as cooperativas de créditos singulares e suas centrais. 

  19. INVESTIGATION OF CRUSTAL MOTION IN THE TIEN SHAN USING INSAR

    Energy Technology Data Exchange (ETDEWEB)

    Mellors, R J

    2011-02-25

    The northern Tien Shan of Central Asia is an area of active mid-continent deformation. Although far from a plate boundary, this region has experienced 5 earthquakes larger than magnitude 7 in the past century and includes one event that may as be as large as Mw 8.0. Previous studies based on GPS measurements indicate on the order of 23 mm/yr of shortening across the entire Tien Shan and up to 15 mm/year in the northern Tien Shan (Figure 1). The seismic moment release rate appears comparable with the geodetic measured slip, at least to first order, suggesting that geodetic rates can be considered a proxy for accumulation rates of stress for seismic hazard estimation. Interferometric synthetic aperture radar may provide a means to make detailed spatial measurements and hence in identifying block boundaries and assisting in seismic hazard. Therefore, we hoped to define block boundaries by direct measurement and by identifying and resolving earthquake slip. Due to political instability in Kyrgzystan, the existing seismic network has not performed as well as required to precisely determine earthquake hypocenters in remote areas and hence InSAR is highly useful. In this paper we present the result of three earthquake studies and show that InSAR is useful for refining locations of teleseismically located earthquakes. ALOS PALSAR data is used to investigate crustal motion in the Tien Shan mountains of Central Asia. As part of the work, considerable software development was undertaken to process PALSAR data. This software has been made freely available. Two damaging earthquakes have been imaged in the Tien Shan and the locations provided by ALOS InSAR have helped to refine seismological velocity models. A third earthquake south of Kyrgyzstan was also imaged. The use of InSAR data and especially L band is therefore very useful in providing groundtruth for earthquake locations.

  20. Crustal Structure of Salton Trough using Deformable Layer Tomography

    Science.gov (United States)

    Yuan, F.

    2012-12-01

    Salton Trough is an important geologic structure to understand the active rift between Imperial Fault and San Andreas Fault. To determine the underground geometry of Salton Trough and its nearby faults, we analyzed seismic phase data recorded by Southern California Earthquake Data Center (SCEDC). Both 2-D and 3-D models have been made to refine the velocity model so as to determine the basin and moho geometry beneath Salton Trough region. Here three inline and five cross-line velocity profiles were built by using 2D Deformable Layer Tomography (DLT) method. From these 2D profiles, we can see that the velocity gradient is very small in the low velocity zone. The low velocity anomaly can be detected beneath the axis of the Salton Trough around the depth of 19-21 km, and the relatively high velocity can be seen beneath the San Andreas faults. Within 100*150*40 km3 model volume, 90,180 P-wave and S-wave first arrival picks from 27,663 local events (from 2001 to 2012), which were obtained from 44 stations, were used to build 3D seismic velocity model of the crust. During the iterations of velocity updating, full 3-D ray tracing is implemented. From these 3-D velocity models with different sizes of grids, low velocity anomalies are present under the southwest of Salton Sea, while high velocity zone is present across Southern San Andreas Fault throughout all the depths. Profiles from 2-D velocity models compared to 3-D velocity models show similar geometry. 3-D crustal structure, which is determined from 3-D DLT, helps to better understand the divergent boundary between the North American and the Pacific tectonic plates

  1. Contemporary vertical crustal motion in the Pacific Northwest

    Science.gov (United States)

    Holdahl, Sandford R.; Faucher, Francois; Dragert, Herb

    A map of recent vertical crustal motion has been compiled for coastal Washington and southwest British Columbia. Average velocities over the past 80 years were determined by least squares adjustment of repeated precise levelings and mean sea-level observations from 21 tide gauges. Annual variations in mean sea level were determined directly within the adjustment model under the assumption that they were identical at all tide gauges in a given year. The derived vertical velocities range from -2.0±0.9 mm/yr near Seattle, to 2.5±0.8 mm/yr at the northwest tip of the Olympic Peninsula, and over 3 mm/yr in the region to the north of Campbell River on Vancouver Island. Determination of a constant velocity in this latter region is complicated by about 10 cm of coseismic subsidence associated with a magnitude 7.3 earthquake in 1946, and an apparent increase in uplift rate over the past decade. Qualitatively, the regional velocity pattern is consistent with features of the current plate convergence model: 1) the rapid uplift of the region north of central Vancouver Island is consistent with the overriding of the young (Explorer Plate which may be underplating the coastal margin in this area; and 2) the ridge of uplift extending from the Neah Bay area north across Vancouver Island to Campbell River is consistent with a pattern expected from a locked subduction zone underlying this coastal region. The large-scale subsidence to the southwest of Puget Sound is more difficult to explain in the context of plate convergence.

  2. Deep crustal reflection results from the central Eromanga Basin, Australia

    Science.gov (United States)

    Mathur, S. P.

    1983-12-01

    From 1980 to 1982 deep seismic reflection profiles were recorded across the central Eromanga Basin in eastern Australia to study the regional structure, stratigraphy and geological history of the Eromanga Basin and infra-basins. The reflection data were recorded to 20 s to obtain additional information on the nature and structure of the crust below the sediments and their relationship to the development of the basins. The seismic sections show good quality reflections from the deep crust as well as from the sedimentary layers. Based on the character, strength, coherence, continuity and spatial distribution of the reflections, the sections can be divided into four zones. The tope zone between 0 and 2.5 s shows fairly uniform, coherent and continuous events which correlate with the Mesozoic and Late Palaeozoic sediments. The zone from 2.5 to 8 s (4 to 22 km) does not show any primary reflections and is interpreted as the highly-deformed metasedimentary and metavolcanic rocks of the Early Palaeozoic Thomson Orogen underlying the sediments. Without any recognisable reflection or diffraction patterns in this zone, it is difficult to say whether the faulting and folding observed in the sediments extend into the upper crustal basement. The deeper zone of numerous reflection segments between 8 and 12.5 s (22 to 36 km) is interpreted as thin laminae of alternating low and high velocity (intermediate and basic) rocks, and correlates with the lower crust bounded by refraction velocity discontinuities. The lowest zone of no reflections below 12.5 s corresponds with the upper mantle. The reflection character and thickness as well as the refraction velocity structure of the crust under the central Eromanga Basin area are significantly different from those of the Precambrian crust under the Georgina Basin to the northwest. It is proposed that the crust under the Eromanga Basin is extensionally attenuated crust which had been intruded by sills of basaltic melt from the underlying

  3. Shallow Crustal Thermal Structures of Central Taiwan Foothills Region

    Directory of Open Access Journals (Sweden)

    Shao-Kai Wu

    2013-01-01

    Full Text Available Crustal thermal structures are closely related to metamorphism, rock rheology, exhumation processes, hydrocarbon maturation levels, frictional faulting and other processes. Drilling is the most direct way to access the temperature fields in the shallow crust. However, a regional drilling program for geological investigation is usually very expensive. Recently, a large-scale in-situ investigation program in the Western Foothills of Central Taiwan was carried out, providing a rare opportunity to conduct heat flow measurements in this region where there are debates as to whether previous measured heat flows are representative of the thermal state in this region. We successfully collected 28 geothermal gradients from these wells and converted them into heat flows. The new heat flow dataset is consistent with previous heat flows, which shows that the thermal structures of Central Taiwan are different from that of other subduction accretionary prisms. We then combine all the available heat flow information to analyze the frictional parameters of the Chelungpu fault zone that ruptured during the 1999, Chi-Chi, Taiwan, earthquake. The heat flow dataset gave consistent results compared with the frictional parameters derived from another independent study that used cores recovered from the Chelungpu fault zone at depth. This study also shows that it is suitable for using heat-flow data obtained from shallow subsurface to constrain thrusting faulting parameters, similar to what had been done for the strike-slip San Andreas Fault in California. Additional fieldworks are planned to study heat flows in other mountainous regions of Taiwan for more advanced geodynamic modeling efforts.

  4. Mechanism of crustal extension in the Laxmi Basin, Arabian Sea

    Directory of Open Access Journals (Sweden)

    Anju Pandey

    2015-11-01

    Full Text Available Continental rifting and magmatism has been extensively studied worldwide as it is believed that continental rifting, break up of continents and associated magmatism lead to genesis of new oceanic crust. However, various regions of the world show that these processes may lead to genesis of other types of crust than the oceanic crust. Laxmi Basin in the western continental margin of the India is one such region with an enigmatic crust. Due to its extreme strategic significance for the palaeogeographic reconstruction of continents during Cretaceous continental breakup of India, this basin has attracted various workers for more than two decades. However, still the issue of nature of crust in the basin remains controversial. In this contribution, in order to identify nature of crust, mechanism of continental extension in the Laxmi Basin has been studied for the first time through newly acquired seismic data from the basin. Here, we propose a plausible mechanism of crustal extension in the Laxmi Basin which eventually constrains the nature of crust of the Laxmi Basin. We have demonstrated that the crust in the Laxmi Basin can be categorised in two zones of stretched and transitional crust. In the stretched zone several fault bounded horst and graben structures are identified which preserve syn- and post-rift sediments along with different periods of hiatus in sedimentations as unconformities. These faults are identified as listric faults in the upper crust which sole out in the detachment faults. Detachment faults decouples the upper brittle and lower ductile crust. The transitional crust is identified as heavily intruded by sills and basaltic volcanic which were emplaced due to melting of subcontinental mantle (SCM after hyper-stretching of crust and serpentinisation of the SCM. Panikkar Ridge is proposed to be one such basaltic volcanic body derived from melting of lower part of the SCM.

  5. Experimental determination of liquidus H2O contents of haplogranite at deep-crustal conditions

    Science.gov (United States)

    Makhluf, A. R.; Newton, R. C.; Manning, C. E.

    2017-09-01

    The liquidus water content of a haplogranite melt at high pressure ( P) and temperature ( T) is important, because it is a key parameter for constraining the volume of granite that could be produced by melting of the deep crust. Previous estimates based on melting experiments at low P (≤0.5 GPa) show substantial scatter when extrapolated to deep crustal P and T (700-1000 °C, 0.6-1.5 GPa). To improve the high-P constraints on H2O concentration at the granite liquidus, we performed experiments in a piston-cylinder apparatus at 1.0 GPa using a range of haplogranite compositions in the albite (Ab: NaAlSi3O8)—orthoclase (Or: KAlSi3O8)—quartz (Qz: SiO2)—H2O system. We used equal weight fractions of the feldspar components and varied the Qz between 20 and 30 wt%. In each experiment, synthetic granitic composition glass + H2O was homogenized well above the liquidus T, and T was lowered by increments until quartz and alkali feldspar crystalized from the liquid. To establish reversed equilibrium, we crystallized the homogenized melt at the lower T and then raised T until we found that the crystalline phases were completely resorbed into the liquid. The reversed liquidus minimum temperatures at 3.0, 4.1, 5.8, 8.0, and 12.0 wt% H2O are 935-985, 875-900, 775-800, 725-775, and 650-675 °C, respectively. Quenched charges were analyzed by petrographic microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), and electron microprobe analysis (EMPA). The equation for the reversed haplogranite liquidus minimum curve for Ab36.25Or36.25Qz27.5 (wt% basis) at 1.0 GPa is T = - 0.0995 w_{{{H}_{ 2} {O}}}^{ 3} + 5.0242w_{{{H}_{ 2} {O}}}^{ 2} - 88.183 w_{{{H}_{ 2} {O}}} + 1171.0 for 0 \\le w_{{{H}_{ 2} {O}}} \\le 17 wt% and T is in °C. We present a revised P - T diagram of liquidus minimum H2O isopleths which integrates data from previous determinations of vapor-saturated melting and the lower pressure vapor-undersaturated melting studies conducted by other workers on

  6. Distribuição espacial da erosão potencial e atual do solo na Bacia Hidrográfica do Rio Sapucaí, MG

    Directory of Open Access Journals (Sweden)

    Matheus Fonseca Durães

    Full Text Available RESUMO Este estudo avalia a distribuição espacial do potencial natural e atual do solo à erosão hídrica na Bacia do Rio Sapucaí, sul de Minas Gerais, utilizando a equação universal de perda de solos revisada, através de modelagem cartográfica, para a obtenção da erosão potencial (EP e da erosão atual (EA. Os resultados indicaram que a EP para a Bacia do Rio Sapucaí variou de "Muito forte", na sua região de cabeceira (Serra da Mantiqueira, a "Fraca", nas áreas com topografia mais suavizada e menor erosividade da chuva. Em relação à EA, mais de 55,17 % da Bacia do Rio Sapucaí apresenta perdas de solo abaixo de 10 t.ha-1.ano-1, significando baixo potencial atual de erosão. A identificação de áreas de risco associadas à erosão acelerada, realizadas neste estudo, fornecem subsídios fundamentais para medidas associadas ao manejo, conservação e planejamento do uso do solo.

  7. A Prática Relacional Existente entre um Fabricante e seus Distribuidores e a Percepção de Valor do Relacionamento na Díade

    Directory of Open Access Journals (Sweden)

    Deonir De Toni

    2015-01-01

    Full Text Available Os relacionamentos interorganizacionais têm despertado inúmeros estudos na área do marketing de relacionamento. Assim sendo, o objetivo central deste trabalho foi o de verificar qual o impacto da prática relacional na díade fabricante e distribuidor sobre a percepção de valor do relacionamento. A partir da utilização de escalas validadas foi realizada uma survey envolvendo o pessoal de linha de frente (PLF do fabricante e seus clientes (distribuidores, sendo que a análise de dados se deu, basicamente, pela técnica da Modelagem de Equações Estr uturais. Os resultados encontrados confirmaram as hipóteses de pesquisa relativas ao modelo teórico testado, contribuindo para a avaliação dos relacionamentos no contexto da díade. A avaliação sobre os dois tipos de agente (PLF do fabricante e clientes in dicou diferenças de percepção no relacionamento, o que pode direcionar estratégias e ações mais assertivas.

  8. Angelite: Paziteli na vhoda

    Directory of Open Access Journals (Sweden)

    Gerov Georgi

    2009-01-01

    Full Text Available (bugarski Statijata prosledjava ikonografskata evoljucija na izobraženijata na arhangelite Mihail i Gavriil, pomesteni pri vhoda na pravoslavnija hram. Povraten moment v neja e 13 vek. Togava arhangel Mihail započva da se izobrazjava kato voin. S tova apotropejnite mu funkcii namirat adekvaten vizualen izraz. K'm kraja na stoletieto arhangel Gavriil započva da se izobrazjava kato pisar - ikonografija, kojato šče b'de dorazvita i utv'rdena prez 14 vek. Prez postvizantijskata epoha v obraza na Mihail se pojavjavat elementi, koito akcentirat v'rhu roljata mu na psihopomp.

  9. Bulk arc strain, crustal thickening, magma emplacement, and mass balances in the Mesozoic Sierra Nevada arc

    Science.gov (United States)

    Cao, Wenrong; Paterson, Scott; Saleeby, Jason; Zalunardo, Sean

    2016-03-01

    Quantifying crustal deformation is important for evaluating mass balance, material transfer, and the interplay between tectonism and magmatism in continental arcs. We present a dataset of >650 finite strain analyses compiled from published works and our own studies with associated structural, geochronologic, and geobarometric information in central and southern Sierra Nevada, California, to quantify the arc crust deformation. Our results show that Mesozoic tectonism results in 65% arc-perpendicular bulk crust shortening under a more or less plane strain condition. Mesozoic arc magmatism replaced ∼80% of this actively deforming arc crust with plutons requiring significantly greater crustal thickening. We suggest that by ∼85 Ma, the arc crust thickness was ∼80 km with a 30-km-thick arc root, resulting in a ∼5 km elevation. Most tectonic shortening and magma emplacement must be accommodated by downward displacements of crustal materials into growing crustal roots at the estimated downward transfer rate of 2-13 km/Myr. The downward transfer of crustal materials must occur in active magma channels, or in "escape channels" in between solidified plutons that decrease in size with time and depth resulting in an increase in the intensity of constrictional strain with depth. We argue that both tectonism and magmatism control the thickness of the crust and surface elevation with slight modification by surface erosion. The downward transported crustal materials initially fertilize the MASH zone thus enhancing to the generation of additional magmas. As the crustal root grows it may potentially pinch out and cool the mantle wedge and thus cause reduction of arc magmatism.

  10. Mercury's Crustal Magnetic Field from Low-Altitude Measurements by MESSENGER.

    Science.gov (United States)

    Johnson, C. L.; Phillips, R. J.; Purucker, M. E.; Anderson, B. J.; Byrne, P. K.; Denevi, B. W.; Fan, K. A.; Feinberg, J. M.; Hauck, S. A., II; Head, J. W., III; Korth, H.; James, P. B.; Mazarico, E.; Neumann, G. A.; Philpott, L. C.; Siegler, M. A.; Strauss, B. E.; Tsyganenko, N. A.; Solomon, S. C.

    2015-12-01

    Magnetized rocks can record the history of a planet's magnetic field, a key constraint for understanding interior evolution. From orbital vector magnetic field measurements of Mercury taken by the MESSENGER spacecraft at altitudes below 150 km, we have detected fields indicative of crustal magnetization. Fields from non-crustal sources, which dominate the observations even at low altitudes, were estimated and subtracted from the observations using both magnetospheric models and signal filtering. The resulting high-pass filtered fields have amplitudes of a few to 20 nT. The first low-altitude signals were detected over the Suisei Planitia region and were confirmed by upward continuation to be of crustal origin. At least some contribution from thermoremanent magnetization is required to account for these signals, and we infer a lower bound on the average age of magnetization of 3.7-3.9 Ga on the basis of correlation of crustal magnetic fields with volcanic units of that age range. Ancient field strengths that range from those similar to Mercury's present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury's crust derived from MESSENGER elemental composition data. Here, we extend these initial results with observations obtained at spacecraft altitudes below 60 km at all body-fixed longitudes from ~40°N to ~75°N. The strongest crustal fields occur in the region 120°E to 210°E, and weaker signals characterize the northern volcanic plains. We test the hypothesis that the longest-wavelength crustal field signals in this region reflect magnetization contrasts between the Caloris basin and the surrounding intercrater plains and circum-Caloris plains. We report the spatial distribution of observed crustal fields, together with magnetization models derived from them and the implications of these models, particularly for the depth distribution of sources compatible with the observations.

  11. Crustal-scale magmatism and its control on the longevity of magmatic systems

    Science.gov (United States)

    Karakas, Ozge; Degruyter, Wim; Bachmann, Olivier; Dufek, Josef

    2017-04-01

    Constraining the duration and evolution of crustal magma reservoirs is crucial to our understanding of the eruptive potential of magmatic systems, as well as the volcanic:plutonic ratios in the crust, but estimates of such parameters vary widely in the current literature. Although no consensus has been reached on the lifetime of magma reservoirs, recent studies have revealed about the presence, location, and melt fraction of multi-level (polybaric) storage zones in the crust. If magma accumulates at different crustal levels, it must redistribute significant enthalpy within the crustal column and therefore must influence the lifetime of magma plumbing systems. However, an evaluation of the mass and heat budget of the entire crustal column is lacking. Here, we use a two-dimensional thermal model to determine the thermal conditions under which both lower and upper crustal magma bodies form. We find that large lower crustal mush zones supply heat to the upper crust and reduce the amount of thermal energy necessary to form subvolcanic reservoirs. This indicates that the crust is thermally viable to sustain partially molten magma reservoirs over long timescales (>10^5-106 yr) for a range of magma fluxes (10^-4 to 10^-2 km^3/yr). Our results reconcile physical models of crustal magma evolution and field-based estimates of intrusion rates in numerous magmatic provinces (which include both volcanic and plutonic lithologies). We also show that young magmatic provinces ( 106 yr) can accumulate magma and build reservoirs capable of triggering supereruptions, even with intrusion rates as low as ≤10^-2 km^3/yr. Hence, the total duration of magmatism is critical in determining the size of the magma reservoirs, and should be combined with the magma intrusions rates to assess the capability of volcanic systems to form the largest eruptions on Earth.

  12. Evaluating Crustal Contamination Effects on the Lithophile Trace Element Budget of Shergottites

    Science.gov (United States)

    Brandon, A. D.; Ferdous, J.; Peslier, A. H.

    2017-01-01

    The origin of the incompatible trace element (ITE) enriched compositions of shergottites has been a point of contention for decades [1-2]. Two scenarios have been proposed, the first is that enriched shergottite compositions reflect an ITE-enriched mantle source, whereas in the second, the ITE enrichment reflects crustal contamination of mantle-derived parent magmas. Evidence supporting the first scenario is that the ITE-enriched shergottite compositions are consistent with the outcomes of magma ocean crystallization [3], and that Os-Nd isotope relationships for shergottites cannot be explained by realistic crustal contamination models [4]. In contrast, Cl and S isotopes are consistent with shergottite magmas interacting with Mars crust [5,6], and ITE-enriched olivine-hosted melt inclusions and interstitial glass are found in depleted shergottite Yamato 980459 [7]. These findings indicate that some level of crustal interaction occurred but the question of whether ITE-enrichments in some bulk shergottites reflect crustal contamination remains open. Recently, a Mars crustal breccia meteorite has been found, NWA 7034 and its paired stones, that is our best analogue to an average of Mars ancient crust [8-10]. This allows for better constraints on crustal contamination of shergottite magmas. We modeled magma-crust mixing and assimilation-fractional crystallization (AFC) using ITE-depleted shergottite compositions and bulk NWA 7034 and its clasts as end-members. The results of these models indicate that crustal contamination can only explain the ITE-enriched compositions of some bulk shergottites under unusual circumstances. It is thus likely that the shergottite range of compositions reflects primarily mantle sources.

  13. Crustal shear velocity structure in the Southern Lau Basin constrained by seafloor compliance

    Science.gov (United States)

    Zha, Yang; Webb, Spahr C.

    2016-05-01

    Seafloor morphology and crustal structure vary significantly in the Lau back-arc basin, which contains regions of island arc formation, rifting, and seafloor spreading. We analyze seafloor compliance: deformation under long period ocean wave forcing, at 30 ocean bottom seismometers to constrain crustal shear wave velocity structure along and across the Eastern Lau Spreading Center (ELSC). Velocity models obtained through Monte Carlo inversion of compliance data show systematic variation of crustal structure in the basin. Sediment thicknesses range from zero thickness at the ridge axis to 1400 m near the volcanic arc. Sediment thickness increases faster to the east than to the west of the ELSC, suggesting a more abundant source of sediment near the active arc volcanoes. Along the ELSC, upper crustal velocities increase from the south to the north where the ridge has migrated farther away from the volcanic arc front. Along the axial ELSC, compliance analysis did not detect a crustal low-velocity body, indicating less melt in the ELSC crustal accretion zone compared to the fast spreading East Pacific Rise. Average upper crust shear velocities for the older ELSC crust produced when the ridge was near the volcanic arc are 0.5-0.8 km/s slower than crust produced at the present-day northern ELSC, consistent with a more porous extrusive layer. Crust in the western Lau Basin, which although thought to have been produced through extension and rifting of old arc crust, is found to have upper crustal velocities similar to older oceanic crust produced at the ELSC.

  14. Modelagem etnoecol?gica da percep??o de vulnerabilidades, riscos e impactos socioambientais em comunidades quilombolas da Ba?a de Todos os Santos

    OpenAIRE

    Santos, Andr?a Iridan dos

    2013-01-01

    Esta pesquisa foi desenvolvida nas comunidades Quilombolas de S?o Braz, em Santo Amaro, e na comunidade Salamina Putumuju, em Maragogipe, ambas localizadas no estado da Bahia,com o objetivo de elaborar modelos etnoecol?gicos que descrevam e reflitam como as popula??es quilombolas dessas comunidades percebem, avaliam e respondem aos impactos socioambientais, riscos e as vulnerabilidades existentes na Ba?a de Todos os Santos. Para isso foram realizadas 67 entrevistas semi-estruturas; observa??e...

  15. Upper crustal seismic structure of the Endeavour segment, Juan de Fuca Ridge from traveltime tomography: Implications for oceanic crustal accretion

    Science.gov (United States)

    Weekly, Robert T.; Wilcock, William S. D.; Toomey, Douglas R.; Hooft, Emilie E. E.; Kim, Eunyoung

    2014-04-01

    isotropic and anisotropic P wave velocity structure of the upper oceanic crust on the Endeavour segment of the Juan de Fuca Ridge is studied using refracted traveltime data collected by an active-source, three-dimensional tomography experiment. The isotropic velocity structure is characterized by low crustal velocities in the overlapping spreading centers (OSCs) at the segment ends. These low velocities are indicative of pervasive tectonic fracturing and persist off axis, recording the history of ridge propagation. Near the segment center, velocities within the upper 1 km show ridge-parallel bands with low velocities on the outer flanks of topographic highs. These features are consistent with localized thickening of the volcanic extrusive layer from eruptions extending outside of the axial valley that flow down the fault-tilted blocks that form the abyssal hill topography. On-axis velocities are generally relatively high beneath the hydrothermal vent fields likely due to the infilling of porosity by mineral precipitation. Lower velocities are observed beneath the most vigorous vent fields in a seismically active region above the axial magma chamber and may reflect increased fracturing and higher temperatures. Seismic anisotropy is high on-axis but decreases substantially off axis over 5-10 km (0.2-0.4 Ma). This decrease coincides with an increase in seismic velocities resolved at depths ≥1 km and is attributed to the infilling of cracks by mineral precipitation associated with near-axis hydrothermal circulation. The orientation of the fast-axis of anisotropy is ridge-parallel near the segment center but curves near the segment ends reflecting the tectonic fabric within the OSCs.

  16. The Nature of Crustal Seismic Anisotropy: Constraints From Field and Rock Physics Observations

    Science.gov (United States)

    Christensen, N. I.; Okaya, D.; Meltzer, A.

    2006-12-01

    Compared with mantle seismic anisotropy studies, which have been active for almost five decades, anisotropy of the crystalline crust has been only rarely studied. Seismic anisotropy within continental tectonic provinces is however important because it provides earth scientists with a powerful tool for measuring and quantifying deformation within the crust. Preferred mineral alignment observed in metamorphic terranes produced during metamorphism by recrystallization is associated with planar structures such as slaty cleavage, schistosity, and gneissic layering. These structures are often pervasive for tens to hundreds of kilometers in major collision zones and produce significant compressional wave seismic anisotropy as well as shear wave splitting. Observations of crustal anisotropy within (1) slates of the chlorite subzone of the Haast schist terrane of South Island, New Zealand, (2) prehnite-pumpellite to lower greenschist facies slates and phyllites of the Taiwan Slate Belt, (3) greenschist faces phyllites and metagraywackes of the Valdez Group Chugach terrane in southern Alaska, and (4) amphibolite facies quartzofeldspathic gneisses, approaching granulite grade, within the Nanga Parbat-Haramosh massif demonstrate that crustal anisotropy is not limited to rocks of any particular metamorphic grade and thus can be present at all crustal levels. Laboratory studies of compressional and shear wave velocities provide important constraints on the magnitudes and symmetries of anisotropies at various crustal levels within these orogenic zones. Although compositional layering can produce anisotropy, preferred mineral orientation of highly anisotropic single crystals, resulting from metamorphic recrystallization, is the major contributor. Most metamorphic rocks show significant compressional and shear wave anisotropy. Anisotropy is a particularly important parameter in low grade pelitic rocks such as phyllite and slate and can be as high as 20%. For the medium grade

  17. The Cora Lake Shear Zone, an Exhumed Deep Crustal Lithotectonic Discontinuity, Western Churchill Province, Canada

    Science.gov (United States)

    Regan, S.; Leslie, S.; Holland, M. E.; Williams, M. L.; Mahan, K. H.; Jercinovic, M. J.

    2011-12-01

    Deep crustal flow is a fundamental tectonic process that may serve to reduce topographic gradients, especially in overthickened collisional orogens. Recent studies have utilized numerical models and seismic interpretations, but generally in two dimensions. Although useful, two dimensional models can not fully characterize lower crustal flow or coupling of crustal layers because they cannot fully incorporate lateral heterogeneity in the flow field. The Athabasca Granulite terrane, in northern Saskatchewan, is an exposed deep crustal terrane that underwent granulite grade deformation during the Neoarchean (ca. 2.55), then cooled isobarically for 600 m.y., and then was reactivated during the Paleoproterozoic (ca. 1.9 Ga). Regional exhumation occurred at roughly 1.85 Ga. This exposure, is a field laboratory for studying lower crustal flow, stabilization, and reactivation. Recent work suggests that the northwestern domain, dominated by the multiphase, opx-bearing, Mary batholith, underwent top-to-the-east lower crustal flow during the Neoarchean. The Chipman domain, to the SE , is primarily underlain by the 3.2 Ga, Chipman tonalite straight gneiss, which was likely restitic, and rheologically strong during the 2.6 Ga flow event. The Cora Lake shear zone (CLsz), which divides the two domains, is interpreted to represent a lithotectonic, compositional, and rheologic boundary within the deep crust. Recent mapping of the western gradient of the CLsz has provided insight into the role and evolution of the rheologic discontinuity and its relationship to crustal flow. The Mary granite (gneiss) contains excellent assemblages for P-T and pseudosection analysis. Interlayered felsic granulite contain abundant monazite for in-situ geochronology. An intense subhorizontal tectonic fabric (S1), interpreted to be the product of crustal flow, is present in both units. This early fabric was locally crenulated, folded, and transposed, by a sub-vertical S2 fabric. Current work involves

  18. Crustal Structure and Extension from Slope to Deepsea Basin in the Northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    Hu Dengke; Zhou Di; Wu Xiangjie; He Min; Pang Xiong; Wang Yuwei

    2009-01-01

    The newly acquired long-cable multi-channel seismic (MCS) lines were used to study the crustal structure and extension in an NW-SE elongated 150 km by 260 Van strip from the slope to the deepsea basin in the northern South China Sea (SCS).These profdes are of good penetration that Moho is recognizable in ~70% length of the lines.Seismostrattgraphic interpretation and time-depth conversion were conducted.A power function D = atb+ c was used in the time-depth conversion,which avoided the under-or over-estimation of the depths of deep-seated interfaces by cubic or quadratic polynomial functions.Contour maps of basement depth,Moho depth,crustal thickness,and crustal stretching factor were obtained for the study area.In the dip direction,the Moho depth decreases stepwisely from 28 km in the outer shelf southwards to 19,15,and 12 km in the deepsea basin,with ramps at the shelf break,lower slope,and the continent ocean boundary (COB),respectively.Accordingly,the crustal thickness decreased southwards from 3,and 7 km spectively.Under the center of the Balynn (白云) sag,the crust thins significantly to < 7 kin.The crustal stretching factor βc was calculated by assuming the original crust thickness of 30 km.In the centers of the Baiyun sag,βc exceeds 5.Tertiary and Quaternary volcanic activities show a general trend of intensifying towards the COB.An important finding of this study is the along-strike variation of the crustal structure.A Moho rise extends from the COB NW-ward until the shelf break,about 170 km long and 50-100 km wide,with Moho depth < 20 kin.This is called the Balyun Moho Nose,which is bounded to the east,west,and north by belts of high Moho gradients indicative of crustal or even lithospheric faults.The doming of Moho in the nose area might he the cause of the W-E segmentation of the crustal and geological structures along the slope of the northern South China Sea,and the cause of the strong crustal

  19. A Disequilibrium Melting Spectrum: Partially Melted Crustal Xenoliths from the Wudalianchi Volcanic Field, NE China.

    Science.gov (United States)

    McLeod, C. L.; McGee, L. E.

    2015-12-01

    Disequilibrium melting has been established as a common process occurring during crustal anatexis and thus demonstrates that crustal assimilation by ascending mantle-derived magmas is likley not a closed system. Observations of extreme compositional heterogeneity within partial melts derived from crustal xenoliths have been documented in several recent examples, however, the retention or transfer of elements to and from residues and glasses, and their relative contributions to potential crustal contaminants warrants further investigation. Sampled lavas from the Huoshaoshan volcano in the Holocene Wudalianchi volcanic field of Northeast China contain crustal xenoliths which preserve a spectrum of partial melting both petrographically and geochemically, thus providing an excellent, natural example of crustal anatexis. Correlations exist between the volume of silicic glass preserved within the xenoliths and bulk rock SiO2 (70-83 wt%), Al2O3 (16-8 wt%), glass 87Sr/86Sr (0.715-0.908), abundances of elements common in feldspars and micas (Sr, Ba, Rb) and elements common in accessory minerals (Y, Zr, Nb). These correlations are likely associated with the consumption of feldspars and micas and the varying retention of accessory phases during partial melting. The xenoliths which contain the greater volumes of silicic glass and residual quartz (interpreted as being the most melted) were found within pahoehoe lava, whilst the least melted xenoliths were found within scoria of the summit cone of Huoshaoshan; thus it is interpreted that the extent of melting is linked to the immersion time in the lava. Small-scale (mm) mingling and transfer of material from the enclosing lava to the xenolith is observed, however, modelling of potential contaminant compositions is inconsistent with crustal contamination during lava petrogenesis. It is inferred that crustal contamination in sampled lavas is localized within the open magmatic system and most likely occurs at the contact zone

  20. Flash Heating of Crustal Rocks at Seismic Slip Rates

    Science.gov (United States)

    Goldsby, D. L.; Spagnuolo, E.; Smith, S. A.; Beeler, N. M.; Tullis, T. E.; Di Toro, G.; Nielsen, S. B.

    2012-12-01

    Recent experiments have demonstrated that rocks undergo extreme frictional weakening at near-earthquake slip rates due to the thermal degradation of the strength, or even melting, of microscopic asperity contacts on their sliding surfaces (Goldsby and Tullis, 2012). These previous experiments, conducted at constant normal stress and slip rates of up to ~0.4 m/s, revealed a 1/V dependence of friction on slip rate above a characteristic weakening velocity, Vw, in accord with theories of flash heating (e.g., Rice, 2006). The weakening velocity obtains values of ~0.1 m/s for many crustal silicate rocks (Goldsby and Tullis, 2012). Here we test two further predictions of flash-heating theory - that the degree of weakening saturates at slip rates approaching 1 m/s, and that the weakening behavior due to flash heating is independent of normal stress - by testing samples at slip rates of up to 1 m/s at different normal stresses. Experiments were conducted in a 1-atm, high-velocity friction apparatus at the Istituto Nazionale di Geofisica e Vulcanologia in Rome. A sample consisted of a pair of hollow cylinders of Westerly granite or Frederick diabase subjected to a nominally constant normal stress of from 1 to 30 MPa and subjected to a variety of rate-stepping sequences. Data were acquired at rates of up to 1 MHz. As predicted, the experiments demonstrate that the degree of weakening due to flash heating saturates at slip rates approaching 1 m/s; in a few cases, friction even increases slightly with increasing slip rate near 1 m/s. The experiments also demonstrate that, within the scatter of the data, the value of Vw and the friction coefficient in the weakened state is independent of normal stress, the expected result if average contact sizes and contact stresses are independent of normal stress. The data thus further corroborate existing theories and experimental data for flash heating, allowing for a more reliable determination of the conditions under which flash heating

  1. Millennia of magmatism recorded in crustal xenoliths from Southwest Greenland

    Science.gov (United States)

    Smit, Matthijs; Waight, Tod; Nielsen, Troels

    2016-04-01

    Eruption of CO2-rich ultramafic magma involves rapid ascent of mantle-derived magmas loaded with mantle xenoliths and xenocrysts (>30 vol%). The dynamics and duration of such eruptions are increasingly well constrained; the causes are nevertheless largely unclear. To address this issue, we performed a petrological and speedometric analysis of well-preserved crustal xenoliths from aillikite dikes at Sisimiut and Sarfartôq alkaline provinces, W Greenland. The xenoliths represent mafic granulites, scavenged from c. 25-36 km depth within the mid-to-lower crust. The rocks are infiltrated by various types of melt in grain boundaries, cracks and veins. Zirconium-in rutile thermometry and Fe-in-rutile speedometry indicate melt temperature of c. 1,015 °C and melt exposure time of a few hours for the host aillikite, implying an average ascent rate of c. 2 m/s. This is slower than average ascent rates of mantle cargo (4-40 m/s [1]), suggesting a slowing-down of transport at shallow levels. Local diffusive zoning in garnet indicates up to several millenia of melt-assisted mass transport. This demonstrates a two-stage magmatic process of rapid melt ascent preceded by a previously unrecognized long magmatic episode. Melt infiltration at Sismiut lasted 10 times longer than at Sarfartôq, and unlike at Sarfartôq was initially associated with carbonate- and sulfide-rich melt. This contrast reflects a fundamental difference in the devolatilization efficiency of parental carbonatite magma. The rapid development of the Sarfartôq system is ascribed to the local lithospheric mantle being highly depleted [2] and rich in the decarbonation reactant orthopyroxene [3]. A link is also proposed between this feature, and the occurrence of REE-carbonatite and diamond-bearing mantle cargo at that particular location. References [1] Sparks, R.S.J. et al., 2006. J. Volcanol. Geotherm. Res. 155, 8-48. [2] Bizzarro, M. and Stevenson, R.K., 2003. Contrib. Mineral. Petrol. 146, 223-240. [3] Russell

  2. Crustal structure of the western Indian shield: Model based on regional gravity and magnetic data

    Directory of Open Access Journals (Sweden)

    Suman Kilaru

    2013-11-01

    This study probes the geometry of the different crustal units in terms of density and susceptibility variations in order to decipher the imprints of the major tectonic processes the region has undergone. In order to decipher the crustal geometry of the Gadra–Fatehpur profile, two NW–SE gravity and magnetic profile vertical sections (A–A′ in the south and B–B′ in the north are modelled on the basis of the constraints provided from previous seismic models. The crustal model of the Gadra–Fatehpur profile is composed of alluvium, Tertiary sediments, MIS, Marwar Supergroup, low-density layers (LDLs and the middle–lower crustal layers, with a distinct change in configuration from the southwest to northeast. The Moho dips from SW to NE, the MIS in the SW gives way to the thick pile of the Marwar Supergroup to the NE. The evolution of MIS has been suggested to have occurred as a consequence of delamination of the upper mantle. LDLs are incorporated in Gadra–Fatehpur model. In the SW, LDL (2550 kg/m3 lies below the MIS in the NE, another LDL (2604 kg/m3 is depicted below the mid-crustal layer.

  3. Seismotectonics of Taiwan Shoal region in northeastern SCS: Insights from crustal structure

    Science.gov (United States)

    Kuiyuan, Wan; Jinlong, Sun; Shaohong, Xia; Xiaoling, Xie; Xiang, Zhang; Huilong, Xu; Jinghe, Cao

    2017-04-01

    A seismicity cluster and a great 16 September 1994 earthquake occur in the Taiwan Shoal region, outer rise of the Manila subduction zone. To understand what mechanisms control and generate the earthquake cluster, it is important to investigate the deep crustal structure of the Taiwan Shoal region. We present a 2-D seismic tomographic image of the crustal structure along the OBS2012 profile based on ocean bottom seismographic (OBS) data. The structure exhibits that a high velocity anomaly in the upper crust beneath the Taiwan Shoal is flanked by lower velocity anomalies. Based on the crustal structure, we study the 765 earthquakes, which occurred in the period 1991-2015. These epicenters, combined with the regional faults, and crustal structure, allow us to better understand the nature of the active tectonics in this region. The high velocity area is interpreted as representing stronger, defining major asperities where stress is concentrated corresponding to the location of the earthquake cluster. The earthquake cluster is influenced by the fault interactions. However, the 16 September 1994 earthquake is independents of the seismic activities but associated with the reactivation of the preexisting fault. In Taiwan region, the slab-pull was resisted by the exposed pre-collision accretionary prism and the resistive force caused the in-plane compressive stress accumulation. This condition may favor the triggering of future damaging earthquakes in this region. Key words: earthquake cluster; crustal structure; fault interactions; outer rise; Taiwan Shoal

  4. Lifetime and size of shallow magma bodies controlled by crustal-scale magmatism

    Science.gov (United States)

    Karakas, Ozge; Degruyter, Wim; Bachmann, Olivier; Dufek, Josef

    2017-06-01

    Magmatic processes on Earth govern the mass, energy and chemical transfer between the mantle, crust and atmosphere. To understand magma storage conditions in the crust that ultimately control volcanic activity and growth of continents, an evaluation of the mass and heat budget of the entire crustal column during magmatic episodes is essential. Here we use a numerical model to constrain the physical conditions under which both lower and upper crustal magma bodies form. We find that over long durations of intrusions (greater than 105 to 106 yr), extensive lower crustal mush zones develop, which modify the thermal budget of the upper crust and reduce the flux of magma required to sustain upper crustal magma reservoirs. Our results reconcile physical models of magma reservoir construction and field-based estimates of intrusion rates in numerous volcanic and plutonic localities. Young igneous provinces (less than a few hundred thousand years old) are unlikely to support large upper crustal reservoirs, whereas longer-lived systems (active for longer than 1 million years) can accumulate magma and build reservoirs capable of producing super-eruptions, even with intrusion rates smaller than 10-3 to 10-2 km3 yr-1. Hence, total duration of magmatism should be combined with the magma intrusion rates to assess the capability of volcanic systems to form the largest explosive eruptions on Earth.

  5. Heat flow, heat production, and crustal dynamics in the Central Alps, Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Rybach, L. (Inst. of Geophysics, Zurich); Werner, D.; Mueller, S.; Berset, G.

    1977-08-03

    Interrelations between temperature field, crustal structure, and crustal dynamics (vertical crustal movements) were investigated along a selected profile: the Swiss Geotraverse which cross-sects in a NW--SE direction the following tectonic units: Rhine-Graben, Jura Mountains, Molasse Basin, Helvetic Nappes, Central Massifs with autochthonous cover, Penninic units, basement and sedimentary units of the Southern Alps (total length: 220 km). The corrected heat flow is slightly elevated along or close to the traverse (approximately equal to 75 mW/m/sup 2/). Thermal effects of Alpine overthrusting and metamorphism on the surface gradient are negligible today. For steady-state calculations of the temperature field heat production was determined experimentally for surface samples; for deep crustal rocks it was inferred from an empirical relationship between heat production and seismic compressional wave velocity or density. The temperature field shows downwarped isotherms where a pronounced inversion of seismic velocity and density occurs in the upper crust. The same area of the Central Alps (Lepontine gneiss region) exhibits the strongest recent crustal movements (vertical uplift approximately equal to 1 mm/yr). The Mohorovicic discontinuity is clearly not an isothermal surface; its asymmetric shape found by seismic and gravimetric measurements is likely to be a result of the early Alpine subduction tectonics.

  6. The role of rheology, crustal structures and lithology in the seismicity distribution of the northern Apennines

    Science.gov (United States)

    Chiaraluce, L.; Barchi, M. R.; Carannante, S.; Collettini, C.; Mirabella, F.; Pauselli, C.; Valoroso, L.

    2017-01-01

    The Northern Apennines of Italy is a unique area to study active crustal processes due to the availability of high-resolution subsurface geology (deep borehole and seismic profiles) and seismicity (back-ground and seismic sequences) data. In this work we have investigated the relationship between crustal structures and lithologies, rheological profiles and seismicity cut-off by constructing three integrated profiles across the Umbria-Marche Apennines. At first approximation we observe a good correspondence between the background seismicity cut-off and the modelled brittle ductile transition (BDT): 90% of the seismic activity is located above the transition. In the area characterized by active extension, where the majority of the seismicity is occurring, most of the crustal earthquakes are confined within the brittle layer at depth rheology and therefore the position of the brittle ductile transition exerts a role at regional scale for the occurrence of crustal seismicity, however crustal structures and lithology play the major role at a more local scale and therefore they need to be considered for a better understanding of earthquake distribution within the seismogenic layer.

  7. Calibration of the Regional Crustal Waveguide and the Retrieval of Source Parameters Using Waveform Modeling

    Science.gov (United States)

    Saikia, C. K.; Woods, B. B.; Thio, H. K.

    - Regional crustal waveguide calibration is essential to the retrieval of source parameters and the location of smaller (MPnl waves to the surface waves and the interaction of regional sPmP and pPmP phases being good indicators of event depths. We also found that for deep events a seismic phase which follows an S-wave path to the surface and becomes critical, developing a head wave by S to P conversion is also indicative of depth. The detailed characteristic of this phase is controlled by the crustal waveguide. The key to calibrating regionalized crustal velocity structure is to determine depths for a set of master events by applying the above methods and then by modeling characteristic features that are recorded on the regional waveforms. The regionalization scheme can also incorporate mixed-path crustal waveguide models for cases in which seismic waves traverse two or more distinctly different crustal structures. We also demonstrate that once depths are established, we need only two-stations travel-time data to obtain reliable epicentral locations using a new adaptive grid-search technique which yields locations similar to those determined using travel-time data from local seismic networks with better azimuthal coverage.

  8. Qinghai-Tibet Plateau crustal thickness derived from EGM2008 and CRSUT2.0

    Directory of Open Access Journals (Sweden)

    Zhou Hao

    2014-11-01

    Full Text Available Qinghai-Tibet Plateau is the most complex region for crustal thickness inversion, while high-resolution earth gravity model (EGM makes it possible to obtain high precision gravity anomaly, which is a key parameter to depict the Earth’s inner structure in geodesy domain. On the basis of this principle, we calculated the Bouguer gravity anomalies in Qinghai-Tibet Plateau with EGM2008 and SRTM6. 0 by efficient high-degree spherical harmonic synthesis algorithm. In order to obtain the gravity anomaly caused by Moho density mutant, the noises caused by the topography was removed by wavelet details. Then, the crustal thickness was corrected on the basis of CRUST 2. 0 with the deep-large-scale single density interface formula. The inversion result indicates that the crustal thickness in Qinghai-Tibet Plateau is between 50 km and 75 km, which is in correspondence with the recent science research result. Compared with the 2 degree CRUST 2. 0 model, the spatial resolution of crustal thickness in our research can reach 40 arc minutes. In addition, there is a positive relationship between the inversed crustal thickness and topography, which can prove the effectiveness of Airy-Heiskanen isostatic model in gravity reduction.

  9. Seismological constraints on the crustal structures generated by continental rejuvenation in northeastern China.

    Science.gov (United States)

    Zheng, Tian-Yu; He, Yu-Mei; Yang, Jin-Hui; Zhao, Liang

    2015-10-07

    Crustal rejuvenation is a key process that has shaped the characteristics of current continental structures and components in tectonic active continental regions. Geological and geochemical observations have provided insights into crustal rejuvenation, although the crustal structural fabrics have not been well constrained. Here, we present a seismic image across the North China Craton (NCC) and Central Asian Orogenic Belt (CAOB) using a velocity structure imaging technique for receiver functions from a dense array. The crustal evolution of the eastern NCC was delineated during the Mesozoic by a dominant low seismic wave velocity with velocity inversion, a relatively shallow Moho discontinuity, and a Moho offset beneath the Tanlu Fault Zone. The imaged structures and geochemical evidence, including changes in the components and ages of continental crusts and significant continental crustal growth during the Mesozoic, provide insight into the rejuvenation processes of the evolving crust in the eastern NCC caused by structural, magmatic and metamorphic processes in an extensional setting. The fossil structural fabric of the convergent boundary in the eastern CAOB indicates that the back-arc action of the Paleo-Pacific Plate subduction did not reach the hinterland of Asia.

  10. Crustal radial anisotropy in Northeast China and its implications for the regional tectonic extension

    Science.gov (United States)

    Guo, Zhen; Yang, Yingjie; Chen, Y. John

    2016-10-01

    We obtain high-resolution Rayleigh and Love wave phase velocity maps from ambient noise tomography using data recorded by NECESSArray in Northeast China. The resulting radial anisotropic model from the joint inversion of Rayleigh and Love wave dispersion curves reveals strong relationship between the crustal radial anisotropy and tectonic provinces, that is, strong positive anisotropy (Vsh > Vsv) beneath the Songliao Basin and weak radial anisotropy beneath the Xinmeng Belt and Changbaishan Region. The Songliao Basin experienced widespread crustal extension during the late Mesozoic. We interpret the lower crustal anisotropy beneath the Songliao Basin as a result of ductile deformation during the rifting stage, which may lead to the alignment of anisotropic minerals and the observed strong radial anisotropy at present. In the northern Songliao Basin, where thick syn-rift and post-rift sediments (≥4 km) are believed to be present, we observe a broader lateral distribution of anisotropy with stronger amplitude compared with the southern basin. We suggest that the broader distribution of crustal radial anisotropy in the northern basin could be the consequence of outward lower crustal flow driven by the sedimentary loading during the post-rift stage, which is also proposed by previous numerical modeling.

  11. Crustal CO2 liberation during the 2006 eruption and earthquake events at Merapi volcano, Indonesia

    Science.gov (United States)

    Troll, Valentin R.; Hilton, David R.; Jolis, Ester M.; Chadwick, Jane P.; Blythe, Lara S.; Deegan, Frances M.; Schwarzkopf, Lothar M.; Zimmer, Martin

    2012-06-01

    High-temperature volcanic gas is widely considered to originate from ascending, mantle-derived magma. In volcanic arc systems, crustal inputs to magmatic gases mainly occur via subducted sediments in the mantle source region. Our data from Merapi volcano, Indonesia imply, however, that during the April-October 2006 eruption significant quantities of CO2 were added from shallow crustal sources. We show that prior to the 2006 events, summit fumarole gas δ13C(CO2) is virtually constant (δ13C1994-2005 = -4.1 ± 0.3‰), but during the 2006 eruption and after the shallow Yogyakarta earthquake of late May, 2006 (M6.4; hypocentres at 10-15 km depth), carbon isotope ratios increased to -2.4 ± 0.2‰. This rise in δ13C is consistent with considerable addition of crustal CO2 and coincided with an increase in eruptive intensity by a factor of ˜3 to 5. We postulate that this shallow crustal volatile input supplemented the mantle-derived volatile flux at Merapi, intensifying and sustaining the 2006 eruption. Late-stage volatile additions from crustal contamination may thus provide a trigger for explosive eruptions independently of conventional magmatic processes.

  12. Discussão de premissas básicas para a modelagem do problema de planejamento da expansão da geração de longo prazo

    Directory of Open Access Journals (Sweden)

    Maria Luiza.V.Lisboa

    2014-08-01

    Full Text Available Para sistemas hidrotérmicos, a modelagem do subproblema de operação impõe umgrande desafio no que diz respeito à representação matemática das incertezashidrológicas. Uma representação simplificada, porém adequada, é necessária paraviabilizar computacionalmente a solução do problema. No modelo MELP, desenvolvidopelo CEPEL para estudos de planejamento da expansão da geração de longo prazo,estas incertezas são representadas através de apenas dois cenários hidrológicos. Amodelagem proposta requer o conceito de energias firme e média de usinashidrelétricas e de fatores de participação crítico e médio de usinas termelétricas. Esteartigo tem por objetivo descrever a formulação matemática do modelo MELP,analisando, de forma detalhada, as premissas e conceitos utilizados.

  13. Avaliação da dispersão atmosférica de compostos odorantes emitidos na indústria papeleira

    Directory of Open Access Journals (Sweden)

    Waldir Nagel Schirmer

    2009-01-01

    Full Text Available O caráter odorante de compostos reduzidos de enxofre (TRS, tipicamente emitidos na indústria papeleira, tem geradogrande interesse por parte dessas indústrias em predizer a qualidade do ar nas proximidades de suas fontes emissoras. Desse modo,o presente trabalho tem por objetivo avaliar o impacto na atmosfera resultante das emissões de TRS de uma fabricante de papel ecelulose de grande porte, por meio da modelagem dos compostos gasosos emitidos a partir de duas fontes pontuais (tomadas comoas maiores contribuidoras: caldeira de recuperação e tanque de dissolução. Para tanto, foi utilizado o “software” AID (AvaliaçãoInstantânea de Dispersão baseado no modelo de Gauss para determinação das concentrações (no ar resultantes dessas emissões.Nessa determinação, foram abordados os principais parâmetros meteorológicos (dos últimos 3 anos e cinéticos de emissãonecessários à modelagem. A máxima concentração de TRS obtida após a modelagem foi de 3,84 ppb (somatório das duas fontesavaliadas, ficando bem abaixo dos limites de percepção odorífera (LPO recomendado por órgãos internacionais (o Brasil nãopossui leis específicas para esse caso. Como os limites de toxicidade quase sempre estão bem acima dos LPO, é seguro afirmarque, no caso avaliado, a concentração máxima estimada não apresenta riscos de toxicidade à população exposta, uma vez, pelovalor obtido, nem o odor pode ser percebido.Abstract The odorant character of total reduced sulfur(TRS has been generated interest by some of the paperindustries in predicting the quality of the air around theirissuing sources. This way, the present paper focus onevaluating the impact on the atmosphere resulting from theTRS emissions from a great paper and cellulosemanufacturer by the modeling of the gaseous compositionsemitted from two points of sources (considered as the largestcontributed: boiler of recuperation and dissolution tank. So,it was used the "software" AID

  14. Modelagem da formação e propagação de trincas em misturas asfálticas

    Directory of Open Access Journals (Sweden)

    Jorge Barbosa Soares

    2009-12-01

    Full Text Available

    O trincamento da camada asfáltica em pavimentos é apontado como o principal defeito das rodovias brasileiras. Estudos experimentais e numéricos sobre este fenômeno vêm sendo realizados considerando o material como homogêneo. Este artigo apresenta uma abordagem numérica baseada na Teoria da Mecânica da Fratura na qual considera-se a heterogeneidade do material, sendo o ligante e os agregados tratados separadamente. As simulações realizadas são verificadas e calibradas através de ensaios laboratoriais simples e convencionais. O estudo trata da formação e propagação de trincas sob carregamentos monotônicos e aponta para uma nova forma de simulação do fenômeno de fadiga de misturas. É ainda discutida a utilização de uma abordagem multi-escala, na qual o dano observado na forma da propagação de trincas na escala local pode ser considerado numa escala global compatível com o pavimento real.

  15. S-wave crustal and upper mantle’s velocity structure in the eastern Tibetan Plateau——Deep environment of lower crustal flow

    Institute of Scientific and Technical Information of China (English)

    Paul; SILVER

    2008-01-01

    A teleseismic profile consisting of 26 stations was deployed along 30°N latitude in the eastern Tibetan Plateau. By use of the inversion of P-wave receiver function, the S-wave velocity structures at depth from surface to 80 km beneath the profile have been determined. The inversion results reveal that there is significant lateral variation of the crustal structure between the tectonic blocks on the profile. From Linzhi north of the eastern Himalayan Syntaxis, the crust is gradually thickened in NE direction; the crustal thickness reaches to the maximum value (~72 km) at the Bangong-Nujiang suture, and then decreased to 65 km in the Qiangtang block, to 57―64 km in the Bayan Har block, and to 40―45 km in the Sichuan Basin. The eastern segment of the teleseismic profile (to the east of Batang) coincides geographically with the Zhubalong-Zizhong deep seismic sounding profile carried out in 2000, and the S-wave velocity structure determined from receiver functions is consistent with the P-wave velocity structure obtained by deep seismic sounding in respect of the depths of Moho and major crustal interfaces. In the Qiangtang and the Bayan Har blocks, the lower velocity layer is widespread in the lower crust (at depth of 30―60 km) along the profile, while there is a normal velocity distribution in lower crust in the Sichuan Basin. On an average, the crustal velocity ratio (Poisson ratio) in tectonic blocks on the profile is 1.73 (σ = 0.247) in the Lhasa block, 1.78 (σ = 0.269) in the Banggong-Nujiang suture, 1.80 (σ = 0.275) in the Qiangtang block, 1.86 (σ = 0.294) in the Bayan Har blocks, and 1.77 (σ = 0.265) in the Yangtze block, respectively. The Qiangtang and the Bayan Har blocks are characterized by lower S-wave velocity anomaly in lower crust, complicated Moho transition, and higher crustal Poisson ratio, indicating that there is a hot and weak medium in lower crust. These are considered as the deep environment of lower crustal flow in the eastern

  16. S-wave crustal and upper mantle's velocity structure in the eastern Tibetan Plateau-Deep environment of lower crustal flow

    Institute of Scientific and Technical Information of China (English)

    WANG ChunYong; Paul SILVER; L(U) Hai; LOU ZhiYong; WU JianPing; CHANG LiJun; DAI ShiGui; YOU HuiChuan; TANG FangTou; ZHU LuPei

    2008-01-01

    A teleseismic profile consisting of 26 stations was deployed along 30°N latitude in the eastern Tibetan Plateau. By use of the inversion of P-wave receiver function, the S-wave velocity structures at depth from surface to 80 km beneath the profile have been determined. The inversion results reveal that there is significant lateral variation of the crustal structure between the tectonic blocks on the profile. From Linzhi north of the eastern Himalayan Syntaxis, the crust is gradually thickened in NE direction; the crustal thickness reaches to the maximum value (~72 km) at the Bangong-Nujiang suture, and then decreased to 65 km in the Qiangtang block, to 57-64 km in the Bayan Har block, and to 40-45 km in the Sichuan Basin. The eastern segment of the teleseismic profile (to the east of Batang) coincides geographically with the Zhubalong-Zizhong deep seismic sounding profile carried out in 2000, and the S-wave velocity structure determined from receiver functions is consistent with the P-wave velocity structure obtained by deep seismic sounding in respect of the depths of Mono and major crustal interfaces. In the Qiangtang and the Bayan Har blocks, the lower velocity layer is widespread in the lower crust (at depth of 30-60 km) along the profile, while there is a normal velocity distribution in lower crust in the Sichuan Basin. On an average, the crustal velocity ratio (Poisson ratio) in tectonic blocks on the profile is 1.73 (σ= 0.247) in the Lhasa block, 1.78 (σ= 0.269) in the Banggong-Nujiang suture, 1.80 (σ = 0.275) in the Qiangtang block, 1.86 (σ= 0.294) in the Bayan Har blocks, and 1.77 (σ=0.265) in the Yangtze block, respectively. The Qiangtang and the Bayan Har blocks are characterized by lower S-wave velocity anomaly in lower crust, complicated Moho transition, and higher crustal Poisson ratio,indicating that there is a hot and weak medium in lower crust. These are considered as the deep environment of lower crustal flow in the eastern Tibetan Plateau

  17. Crustal thickening in an active margin setting (Philippines): The whys and the hows

    Institute of Scientific and Technical Information of China (English)

    C.B.Dimalanta; G.P.Yumul,Jr.

    2004-01-01

    A synthesis of crustal thickness estimates was made recently utilizing available field, geochemical, seismicity, shear wave velocity and gravity data in the Philippines. The results show that a significant portion of the Philippine archipelago is generally characterized by crust with a thickness of around 25 to 30 kilometers. However, two zones, which are made up of a thicker crust (from 30 to 65 km) have also been delineated. The Luzon Central Cordillera region is characterized by thick crust. Another belt of thickened crust is observed in the Bicol-Negros-Panay-Central Mindanao region. This paper examines the interplay of tectonic and magmatic processes and their role in modifying Philippine arc crust. The processes, which could account for the observed crustal thicknesses, are presented. The contributions of magmatic arcs as compared to the contribution of the emplacement and accretion of ophiolite complexes to crustal thickness are also discussed.

  18. Crustal Flows beneath the Eastern Tibetan Plateau Revealed by Magnetotelluric Observations

    Institute of Scientific and Technical Information of China (English)

    BAI Denghai; TENG Jiwen; MA Xiaobing; KONG Xiangru

    2011-01-01

    @@ The ongoing collision of the Indian and Asian continents has created the Himalayan and Tibetan plateau through a range of deformation processes that include crustal thickening, delamination, lateral extrusion and crustal flow.A debate continues as to which of these processes are most significant in terms of the overall mass balance of this continent-continent collision.In eastern Tibet GPS data show large-scale motion of the surface has been occurring around the eastern Himalayan syntaxis (EHS), but the nature of deformation at depth remains unresolved.A large-scale crustal flow has been proposed as an explanation for regional uplift in eastern Tibet, but existing geophysical data do not constrain the pattern of flow.

  19. Anisotropic Solar Wind Sputtering of the Lunar Surface Induced by Crustal Magnetic Anomalies

    Science.gov (United States)

    Poppe, A. R.; Sarantos, M.; Halekas, J. S.; Delory, G. T.; Saito, Y.; Nishino, M.

    2014-01-01

    The lunar exosphere is generated by several processes each of which generates neutral distributions with different spatial and temporal variability. Solar wind sputtering of the lunar surface is a major process for many regolith-derived species and typically generates neutral distributions with a cosine dependence on solar zenith angle. Complicating this picture are remanent crustal magnetic anomalies on the lunar surface, which decelerate and partially reflect the solar wind before it strikes the surface. We use Kaguya maps of solar wind reflection efficiencies, Lunar Prospector maps of crustal field strengths, and published neutral sputtering yields to calculate anisotropic solar wind sputtering maps. We feed these maps to a Monte Carlo neutral exospheric model to explore three-dimensional exospheric anisotropies and find that significant anisotropies should be present in the neutral exosphere depending on selenographic location and solar wind conditions. Better understanding of solar wind/crustal anomaly interactions could potentially improve our results.

  20. Surface effects of Rayleigh-Taylor instability: Feedback between drip dynamics and crustal deformation

    Science.gov (United States)

    Wang, H.; Currie, C. A.

    2013-12-01

    For many continental plates, significant vertical motion of Earth's surface has occurred within the plate interior which can not be clearly linked to plate tectonic processes. For example, several craton areas exhibit anomalous basins, e.g., the Williston basin, Illinois basin and Michigan basin in North America. In orogenic belts, there are examples of local areas (~100 km wide) where the surface has undergone subsidence and then uplift of >1 km, such as the Arizaro basin (central Andes) and Wallowa Mountains (northeast Oregon). Given the near-circular shape of the surface deflection, it has been suggested that they may be related to gravitational foundering of dense lower lithosphere, i.e., Rayleigh-Taylor instability (or 'RT drip'). In order to investigate the surface effects of an RT drip, we use two methods: (1) 2D thermal-mechanical numerical models to study links between drip dynamics and crustal deformation and (2) a theoretical analysis of the crustal deformation induced by stresses from the RT drip. The numerical models consist of a continental lithosphere overlying a sublithospheric mantle. A high-density material is placed in the mantle lithosphere or lower crust to initiate a drip event, and a stress-free boundary condition allows the development of surface topography during model evolution. A reasonable range of crustal viscosity and thickness is tested to study the RT drip in different tectonic settings, from a cold craton to a hot orogen with thick crust. Four types of surface deflection are observed: (1) subsidence; (2) subsidence followed by uplift; (3) uplift; and (4) little deflection. When the crust is relatively strong or thin, the surface has a negative elevation, forming a basin. For a weak or thick crust, the RT drip induces crustal flow, leading to crustal thickening that can uplift the surface; an extremely weak crust decouples the surface and RT drip and the surface is unperturbed. Our theoretical analysis considers the surface

  1. Fast crustal deformation computing method for multiple computations accelerated by a graphics processing unit cluster

    Science.gov (United States)

    Yamaguchi, Takuma; Ichimura, Tsuyoshi; Yagi, Yuji; Agata, Ryoichiro; Hori, Takane; Hori, Muneo

    2017-08-01

    As high-resolution observational data become more common, the demand for numerical simulations of crustal deformation using 3-D high-fidelity modelling is increasing. To increase the efficiency of performing numerical simulations with high computation costs, we developed a fast solver using heterogeneous computing, with graphics processing units (GPUs) and central processing units, and then used the solver in crustal deformation computations. The solver was based on an iterative solver and was devised so that a large proportion of the computation was calculated more quickly using GPUs. To confirm the utility of the proposed solver, we demonstrated a numerical simulation of the coseismic slip distribution estimation, which requires 360 000 crustal deformation computations with 82 196 106 degrees of freedom.

  2. Isotopic disequilibrium and lower crustal contamination in slowly ascending magmas: Insights from Proterozoic anorthosites

    Science.gov (United States)

    Bybee, G. M.; Ashwal, L. D.

    2015-10-01

    Many Proterozoic anorthosite massifs show crustal isotopic signatures that have, for decades, fuelled debate regarding the source of these temporally-restricted magmas. Are these signatures indicative of lower crustal melting or of significant assimilation of crustal material into mantle-derived magmas? Traditional whole rock isotopic tracers (Sr, Nd, Pb and Os), like other geochemical, petrological and experimental tools, have failed to identify unambiguously the origins of the crust-like signature and resolve the source controversies for these feldspathic, cumulate intrusives. We make use of high precision Sr, Nd and Pb isotopic compositions of mineral phases (plag, opx, mag) and comagmatic, high-pressure orthopyroxene megacrysts as well as whole rock anorthosites/leuconorites from the Mealy Mountains Intrusive Suite (MMIS) and the Nain Plutonic Suite (NPS) to probe the origin of the crustal isotopic signatures and assess the importance of differentiation at lower crustal depths. This selection of samples represents fragments from various stages of the polybaric ascent of the magmas, while the study of the Mealy Mountains Intrusive Suite and the Nain Plutonic Suite is instructive as each is intruded into crust of significantly different age and isotopic composition. We observe marked differences in the whole-rock isotopic composition of Proterozoic anorthosites and high-pressure megacrysts (e.g. εNd;T = +2 to -10) intruded into crustal terranes of different ages and isotopic compositions. Evidence for varying degrees of internal isotopic disequilibrium (ΔNd, ΔSr, ΔPb) in anorthosites from these different terranes reinforces the notion that crustal contamination, and more importantly, the nature of the crustal assimilant, has a profound influence on the chemical signature of Proterozoic anorthosites. While most samples from the MMIS and NPS show significant and measurable ΔNd and ΔPb disequilibrium, ΔSr compositions cluster around zero. This decoupling in

  3. Variations of the crustal thickness in Nepal Himalayas based on tomographic inversion of regional earthquake data

    Directory of Open Access Journals (Sweden)

    I. Koulakov

    2014-10-01

    Full Text Available We estimate variations of the crustal thickness beneath the Nepal Himalayas based on tomographic inversion of regional earthquake data. We have obtained a low-velocity anomaly in the upper part of the model down to depths of 40 to 80 km and proposed that the lower limit of this anomaly represents variations of the Moho depth. This statement was supported by results of synthetic modeling. The obtained variations of crustal thickness match fairly well with the free-air gravity anomalies: thinner crust patterns correspond to lower gravity values and vice versa. There is also some correlation with magnetic field: higher magnetic values correspond to the major areas of thicker crust. We propose that elevated magnetic values can be associated with more rigid segments of the incoming Indian crust which cause more compression in the thrust zone and leads to stronger crustal thickening.

  4. The crustal structure beneath Mauritius from teleseismic P-receiver functions - oceanic or continental?

    Science.gov (United States)

    Singh, Manvendra; Kaviani, Ayoub; Rümpker, Georg

    2016-09-01

    It has recently been suggested that the volcanic island of Mauritius may be underlain by a remnant of continental origin termed "Mauritia". To constrain the crustal thickness beneath Mauritius, we analyzed data from 11 land stations, 10 of which were deployed recently by the RHUM-RUM project. From the recordings, we obtained 382 P-receiver functions (RFs). By applying the H-κ stacking technique, we derive crustal thicknesses of approximately 10-15 km. We observe a considerable variation in the Vp/Vs-ratio caused by a lack of clear multiples. Using forward modeling of RFs, we show that the lack of clear multiples can be explained by a transitional Moho, where the velocity increases gradually. The modeling further indicates that the thickness of this gradient zone is estimated to be approximately 10 km. We argue that our findings suggest oceanic crust thickened by crustal underplating due the mantle plume currently located beneath the La Réunion.

  5. Do crustal deformations observed by GPS in Tierra del Fuego (Argentina reflect glacial-isostatic adjustment?

    Directory of Open Access Journals (Sweden)

    L. Mendoza

    2010-09-01

    Full Text Available Vertical site velocities determined by geodetic GPS observations in the Lago Fagnano area, Tierra del Fuego main island, are interpreted with respect to their potential relation with the glacial-isostatic crustal response to ice mass changes. The spatial pattern of the uplift rates, in combination with the horizontal crustal deformation pattern, point towards a fault-tectonic rather than glacial-isostatic origin of the determined vertical crustal deformations. This implies rather small GIA effects pointing towards relatively small Holocene ice-mass changes in Tierra del Fuego. However, these findings are considered to be preliminary. They should be confirmed by additional observations covering an extended area with GPS sites.

  6. Contemporary velocity field of crustal movement of Chinese mainland from Global Positioning System measurements

    Institute of Scientific and Technical Information of China (English)

    NIU Zhijun; WANG Yongqing; WANG Yongxiang; LI Bai; WANG Min; SUN Hanrong; SUN Jianzhong; YOU Xinzhao; GAN Weijun; XUE Guijiang; HAO Jinxin; XIN Shaohua

    2005-01-01

    @@ Significant advancement for the monitoring of crustal deformation in the Chinese mainland was accomplished in 1998 when the Crustal Movement Observation Network of China (CMONOC) was established. This National Key Scientific Infrastructural Project provides important information on present-day crustal deformation that can be used for many aspects of earth sciences such as navigation, positioning, and surveying. The principal GPS data used for this study come from the CMONOC collected from 1998 to 2004, including 27 fiducial stations which operate continuously since 1988, 56 basic stations observed annually with an occupation of at least 7 days (~168 hours' data collection) in each survey, and 961 regional stations observed in 1999, 2001, and 2004 with an occupation of at least 3 days (~72 hours' data collection) in each survey[1,2].

  7. Solar wind interaction with the Reiner Gamma crustal magnetic anomaly: Connecting source magnetization to surface weathering

    Science.gov (United States)

    Poppe, Andrew R.; Fatemi, Shahab; Garrick-Bethell, Ian; Hemingway, Doug; Holmström, Mats

    2016-03-01

    Remanent magnetization has long been known to exist in the lunar crust, yet both the detailed topology and ultimate origin(s) of these fields remains uncertain. Some crustal magnetic fields coincide with surface albedo anomalies, known as lunar swirls, which are thought to be formed by differential surface weathering of the regolith underlying crustal fields due to deflection of incident solar wind protons. Here, we present results from a three-dimensional, self-consistent, plasma hybrid model of the solar wind interaction with two different possible source magnetizations for the Reiner Gamma anomaly. We characterize the plasma interaction with these fields and the resulting spatial distribution of charged-particle weathering of the surface and compare these results to optical albedo measurements of Reiner Gamma. The model results constrain the proposed source magnetizations for Reiner Gamma and suggest that vertical crustal magnetic fields are required to produce the observed "dark lanes."

  8. Crustal thinning between the Ethiopian and East African Plateaus from modeling Rayleigh wave dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Benoit, M H; Nyblade, A A; Pasyanos, M E

    2006-01-17

    The East African and Ethiopian Plateaus have long been recognized to be part of a much larger topographic anomaly on the African Plate called the African Superswell. One of the few places within the African Superswell that exhibit elevations of less than 1 km is southeastern Sudan and northern Kenya, an area containing both Mesozoic and Cenozoic rift basins. Crustal structure and uppermost mantle velocities are investigated in this area by modeling Rayleigh wave dispersion. Modeling results indicate an average crustal thickness of 25 {+-} 5 km, some 10-15 km thinner than the crust beneath the adjacent East African and Ethiopian Plateaus. The low elevations can therefore be readily attributed to an isostatic response from crustal thinning. Low Sn velocities of 4.1-4.3 km/s also characterize this region.

  9. Inferring regional vertical crustal velocities from averaged relative sea level trends: A proof of concept

    Science.gov (United States)

    Bâki Iz, H.; Shum, C. K.; Zhang, C.; Kuo, C. Y.

    2017-02-01

    This study demonstrates that relative sea level trends calculated from long-term tide gauge records can be used to estimate relative vertical crustal velocities in a region with high accuracy. A comparison of the weighted averages of the relative sea level trends estimated at six tide gauge stations in two clusters along the Eastern coast of United States, in Florida and in Maryland, reveals a statistically significant regional vertical crustal motion of Maryland with respect to Florida with a subsidence rate of -1.15±0.15 mm/yr identified predominantly due to the ongoing glacial isostatic adjustment process. The estimate is a consilience value to validate vertical crustal velocities calculated from GPS time series as well as towards constraining predictive GIA models in these regions.

  10. Análise da representatividade de diferentes hipóteses de modelagem matemática para definição de manchas de inundações em áreas urbanas: estudo de caso da cidade de Governador Valadares-MG

    OpenAIRE

    Rubens Gomes Dias Campos

    2011-01-01

    Esta pesquisa objetiva a análise de modelos hidráulicos computacionais para representação de manchas de inundação em meios urbanos,com grande importância para delimitação de zonas naturalmente alagáveis. Visa à fornecer elementos para a ocupação planejada e o suporte asistemas de alerta,em cidades que já se encontram implantadas nos leitos maiores de grandes rios, com risco de inundações frequentes. Procura-se com a pesquisa a identificação das peculiaridades deste tipo de modelagem, utilizan...

  11. Modelagem por redes neurais do sistema biológico do tratamento de efluentes em refinarias de petróleo

    OpenAIRE

    Teixeira, Alexandre Casagrande

    2013-01-01

    Resumo: A necessidade de preservação do meio ambiente tem direcionado atenção do setor industrial às unidades de tratamento de efluentes. Dentre as diversas tecnologias existentes, o tratamento biológico por lodos ativados é uma das mais utilizadas, devido a sua excelente robustez. Na indústria do petróleo, não é diferente, devido principalmente a sua elevada eficiência na remoção de nitrogênio amoniacal. No entanto, a eficiência desta tecnologia está diretamente relacionada com a qualidade d...

  12. Estimation of the Crustal Bulk Properties Beneath Mainland Portugal from P-Wave Teleseismic Receiver Functions

    Science.gov (United States)

    Dündar, Süleyman; Dias, Nuno A.; Silveira, Graça; Kind, Rainer; Vinnik, Lev; Matias, Luís; Bianchi, Marcelo

    2016-06-01

    In this work, we present results from teleseismic P-wave receiver functions (PRFs) obtained in Portugal, Western Iberia. A dense seismic station deployment conducted between 2010 and 2012, in the scope of the WILAS project and covering the entire country, allowed the most spatially extensive probing on the bulk crustal seismic properties of Portugal up to date. The application of the H- κ stacking algorithm to the PRFs enabled us to estimate the crustal thickness ( H) and the average crustal ratio of the P- and S-waves velocities V p/ V s ( κ) for the region. Observations of Moho conversions indicate that this interface is relatively smooth with the crustal thickness ranging between 24 and 34 km, with an average of 30 km. The highest V p/ V s values are found on the Mesozoic-Cenozoic crust beneath the western and southern coastal domain of Portugal, whereas the lowest values correspond to Palaeozoic crust underlying the remaining part of the subject area. An average V p/ V s is found to be 1.72, ranging 1.63-1.86 across the study area, indicating a predominantly felsic composition. Overall, we systematically observe a decrease of V p/ V s with increasing crustal thickness. Taken as a whole, our results indicate a clear distinction between the geological zones of the Variscan Iberian Massif in Portugal, the overall shape of the anomalies conditioned by the shape of the Ibero-Armorican Arc, and associated Late Paleozoic suture zones, and the Meso-Cenozoic basin associated with Atlantic rifting stages. Thickened crust (30-34 km) across the studied region may be inherited from continental collision during the Paleozoic Variscan orogeny. An anomalous crustal thinning to around 28 km is observed beneath the central part of the Central Iberian Zone and the eastern part of South Portuguese Zone.

  13. Mantle melting factors and amagmatic crustal accretion of the Gakkel ridge, Arctic Ocean

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tao; GAO Jinyao; CHEN Mei; YANG Chunguo; SHEN Zhongyan; ZHOU Zhiyuan; WU Zhaocai; SUN Yunfan

    2015-01-01

    Spreading rate is a primary factor of mantle melting and tectonic behavior of the global mid-ocean ridges. The spreading rate of the Gakkel ridge decreases gradually from west to east. However, the Gakkel ridge can be divided into four thick-and-thin zones with varying crustal thicknesses along ridge axis. This phenomenon indicates that mantle melting of the Gakkel ridge is not a simple function of spreading rate. Mantle temperature, water content, mantle composition, and other factors are important in crustal accretion processes. Based on gravity-derived crustal thickness and wet melting model, we estimate that the mantle potential temperatures of the four zones are 1 270, 1 220, 1 280, and 1 280°C (assuming that mantle water content equals to global average value), with corresponding mantle water contents of 210, 0, 340, and 280 mg/kg (assuming that mantle potential temperature is 1 260°C), respectivly. The western thinned crust zone is best modeled with low mantle temperature, whereas the other zones are mainly controlled by the enhanced conduction caused by the slower spreading rate. Along the Gakkel ridge, the crustal thickness is consistent with rock samples types. Predominated serpentinized peridotite and basalt are found in the area with crustal thickness 2.5 km, respectively. The rock samples are including from basalt to peridotite in the area with crustal thickness between 1.5 and 2.5 km. Based on this consistency, the traditional magmatic accretion zone accounted for only 44% and amagmatic accretion accounted for 29% of the Gakkel ridge. The amagmatic accretion is a significant characteristic of the ultra-slow spreading ridge.

  14. A Graphical Approach to Quality Checking Crustal Thickness Point Data Using Isostacy

    Science.gov (United States)

    Wallet, B.; Okure, M. S.; Keller, G. R.

    2009-12-01

    Constructing crustal models requires the aggregation of considerable amounts of data from multiple data sources. Unfortunately, such data often are noisy and outliers within the data may produce large errors in the resulting model. However, despite what are clearly large errors, verification and cleaning of the data is complicated by the fact that true crustal thicknesses can vary greatly over a distances of 10’s of kilometers. Thus, it is impossible to select a single threshold that is capable of filtering outliers. In this work, we were attempting to form an estimate of the crustal thickness for North America using 1845 observations from the USGS Earthquake Hazards Program integrated with the receiver function-based crustal thickness estimates that are an EarthScope data product. Our initial efforts demonstrated that a large number of the observed depths were greater than expected. To improve our data, we employed an Airy-Heiskanen local compensation model to estimate crustal thickness based upon elevation. We then calculate the residuals of the crustal thickness. Examination of these residuals revealed a bimodal structure with a smaller upper tail cluster corresponding to observations we believed to be too thick to be reliable. We then adjusted our estimate of the depth of compensation at sea level such that the lower tail cluster had an approximately zero mean residual, which occurred at a value of 37 km. We then recalculated the residuals and estimated a threshold graphical. By then using this new set of filtered data, we were able to obtain better maps than previously obtainable. Our goal is to set up a database than be expanded and revised via community input and new results.

  15. Broadband regional waveform modeling to investigate crustal structure and tectonics of the central Andes

    Science.gov (United States)

    Swenson, Jennifer Lyn

    We use broadband regional waveform modeling of earthquakes in the central Andes to determine seismic properties of the Altiplano crust. Properties of the shear-coupled P-wavetrain (SPL ) from intermediate-depth events provide particularly important information about the structure of the crust. We utilize broadband seismic data recorded at the BANJO and SEDA stations, and synthetic seismograms computed with a reflectivity technique to study the sensitivity of SPL to crustal and upper mantle parameters at regional distances. We find that the long-period SPL-wavetrain is most sensitive to crustal and mantle Poisson's ratios, average crustal velocity, and crustal thickness. A comprehensive grid search method developed to investigate these four parameters suggests that although trade-offs exist between model parameters, models of the Altiplano which provide the best fit between the data and synthetic seismograms are characterized by low Poisson's ratios, low average crustal velocity and thick crust. We apply our grid search technique and sensitivity analysis results to model the full waveforms from 6 intermediate-depth and 2 shallow-focus earthquakes recorded at regional distances by BANJO and SEDA stations. Results suggest that the Altiplano crust is much thicker (55--65 km) and slower (5.75--6.25 km/s) than global average values. Low crustal and mantle Poisson's ratios together with the lack of evidence for a high-velocity lower crust suggests a bulk felsic crustal composition, resulting in an overall weak crust. Our results favor a model of crustal thickening involving large-scale tectonic shortening of a predominantly felsic crust. To better understand the mechanics of earthquake rupture along the South American subduction zone, we have analyzed broadband teleseismic P-waves and utilize single- and multi-station inversion techniques to constrain source characteristics for the 12 November 1996 Peru subduction zone earthquake. Aftershock locations, intensity reports

  16. Mercury's lithospheric thickness and crustal density, as inferred from MESSENGER observations

    Science.gov (United States)

    James, P. B.; Mazarico, E.; Genova, A.; Smith, D. E.; Neumann, G. A.; Solomon, S. C.

    2015-12-01

    The gravity field and topography of Mercury measured by the MESSENGER spacecraft have provided insights into the thickness of the planet's elastic lithosphere, Te. We localized the HgM006 free-air gravity anomaly and gtmes_125v03 shape datasets to search for theoretical elastic thickness solutions that best fit a variety of localized coherence spectra between Bouguer gravity anomaly and topography. We adopted a crustal density of ρcrust =2700 kg m-3 for the Bouguer gravity correction, but density uncertainty did not markedly affect the elastic thickness estimates. A best-fit solution in the northern smooth plains (NSP) gives an elastic thickness of Te =30-60 km at the time of formation of topography for a range of ratios of top to bottom loading from 1 to 5. For a mechanical lithosphere with a thickness of ~2Te and a temperature of 1600 °C at the base, this solution is consistent with a geothermal gradient of 9-18 K km-1. A similar coherence analysis exterior to the NSP produces an elastic thickness estimate of Te =20-50 km, albeit with a poorer fit. Coherence in the northern hemisphere as a whole does not approach zero at any wavelength, because of the presence of variations in crustal thickness that are unassociated with elastic loading. The ratios and correlations of gravity and topography at intermediate wavelengths (harmonic degree l between 30 and 50) also constrain regional crustal densities. We localized gravity and topography with a moving Slepian taper and calculated regionally averaged crustal densities with the approximation ρcrust=Zl/(2πG), where Zl is the localized admittance and G is the gravitational constant. The only regional density estimates greater than 2000 kg m-3 for l=30 correspond to the NSP. Density estimates outside of the NSP were unreasonably low, even for highly porous crust. We attribute these low densities to the confounding effects of crustal thickness variations and Kaula filtering of the gravity dataset at the highest harmonic

  17. Crustal structure of western Hispaniola (Haiti) from a teleseismic receiver function study

    Science.gov (United States)

    Corbeau, J.; Rolandone, F.; Leroy, S.; Guerrier, K.; Keir, D.; Stuart, G.; Clouard, V.; Gallacher, R.; Ulysse, S.; Boisson, D.; Bien-aimé Momplaisir, R.; Saint Preux, F.; Prépetit, C.; Saurel, J.-M.; Mercier de Lépinay, B.; Meyer, B.

    2017-07-01

    Haiti, located at the northern Caribbean plate boundary, records a geological history of terrane accretion from Cretaceous island arc formations to the Eocene to Recent oblique collision with the Bahamas platform. Little is presently known about the underlying crustal structure of the island. We analyze P-waveforms arriving at 27 temporary broadband seismic stations deployed over a distance of 200 km across the major terrane boundaries in Haiti to determine the crustal structure of western Hispaniola. We compute teleseismic receiver functions using the Extended-Time Multi-Taper method and determine crustal thickness and bulk composition (Vp/Vs) using the H-k stacking method. Three distinctive and fault-bounded crustal domains, defined by their characteristic Moho depth distributions and bulk crustal Vp/Vs, are imaged across Haiti. We relate these domains to three crustal terranes that have been accreted along the plate boundary during the northeastwards displacement of the Caribbean plate and are presently being deformed in a localized fold and thrust belt. In the northern domain, made up of volcanic arc facies, the crust has a thickness of 23 km and Vp/Vs of 1.75 ± 0.1 typical of average continental crust. The crust in the southern domain is part of the Caribbean Large Igneous Province (Caribbean LIP), and is 22 km thick with Vp/Vs of 1.80 ± 0.03 consistent with plume-related rocks of late Cretaceous age. Significantly thicker, the crust in central Haiti has values of Moho depths averaging 41 km and with Vp/Vs of 1.80 ± 0.05. We propose that the central domain is likely constructed of an island arc upper crust with fragments of dense material originating from mafic lavas or LIP material. We produce a crustal profile along a N-S transect across Haiti accounting for the surface geology, shallow structural history, and new seismological constraints provided by variations of crustal thickness and bulk composition.

  18. Effects of crustal thickness on magmatic differentiation in subduction zone volcanism: A global study

    Science.gov (United States)

    Farner, Michael J.; Lee, Cin-Ty A.

    2017-07-01

    The majority of arc magmas are highly evolved due to differentiation within the lithosphere or crust. Some studies have suggested a relationship between crustal thickness and magmatic differentiation, but the exact nature of this relationship is unclear. Here, we examine the interplay of crustal thickness and magmatic differentiation using a global geochemical dataset compiled from active volcanic arcs and elevation as a proxy for crustal thickness. With increasing crustal thickness, average arc magma compositions become more silicic (andesitic) and enriched in incompatible elements, indicating that on average, arc magmas in thick crust are more evolved, which can be easily explained by the longer transit and cooling times of magmas traversing thick arc lithosphere and crust. As crustal thickness increases, arc magmas show higher degrees of iron depletion at a given MgO content, indicating that arc magmas saturate earlier in magnetite when traversing thick crust. This suggests that differentiation within thick crust occurs under more oxidizing conditions and that the origin of oxidation is due to intracrustal processes (contamination or recharge) or the role of thick crust in modulating melting degree in the mantle wedge. We also show that although arc magmas are on average more silicic in thick crust, the most silicic magmas (>70 wt.% SiO2) are paradoxically found in thin crust settings, where average compositions are low in silica (basaltic). We suggest that extreme residual magmas, such as those exceeding 70 wt.% SiO2, are preferentially extracted from shallow crustal magma bodies than from deep-seated magma bodies, the latter more commonly found in regions of thick crust. We suggest that this may be because the convective lifespan of crustal magma bodies is limited by conductive cooling through the overlying crustal lid and that magma bodies in thick crust cool more slowly than in thin crust. When the crust is thin, cooling is rapid, preventing residual magmas

  19. Crustal Structure Across the Three Gorges Dam from Wide-Angle Seismic Data

    Science.gov (United States)

    Zhang, Z.; Bai, Z.; Mooney, W. D.; Wang, C.; Chen, X.; Wang, E.; Teng, J.

    2007-12-01

    The Three Gorges Dam (TGD) is one of the biggest engineering projects in the world. In order to understand the crustal structure across the TGD, a wide-angle seismic profile was acquired from Fengjie, Sichuan Province, to Guanyindang, Hubei Province. The crustal velocity and reflectivity cross-section across the TGD shows lateral velocity variation and a northward-slipping, crustal-scale, strong reflector. The TGD is located at a transition in crustal thickness from about 45 km in the northwest to about 35 km in the southeast. The topography of China is characterized by three terraces. The Qinghai-Tibet Plateau is the first terrace with a surface elevation above sea level of >4500 m; the second terrace lies north and east of the Qinghai-Tibet Plateau at an elevation of 1000-2000 m; the third terrace is in the eastern part of China with an elevation of named after the three gorges of Xiling Xia, Wu Xia, and Qutang Xia (Xia means "gorge" in Chinese), is located at the middle segmentations of the Yangtze River, extending from Fengjie, Sichuan Province, to Yichang, Hubei Province, with a total length of about 200 km. Due to the abrupt relief from the second to third topographic terrace of China, the unstopping, huge amounts of river stream provide the best place for the construction of the largest hydro power plant ever in the world. In order to provide a background of the crustal environment for the dam project, a wide-angle seismic profile along the Yangtze River was carried out. Tectonically, the studied area belongs to the Yangtze block and cut several sub-tectonic units: the Wanxian depression fold belt, the Zigui platform fold belt, the southwestern Hubei province complex fold belt, the Huangling Faulted Dome (HLFD), and the Jiangling Depression (JLD). We present the interpretation results of the crustal structure along the Three Gorges extension which shows: there are strong lateral variations both of crustal thickness and P-wave velocity, the Jiangling

  20. Crustal Structure And Magmatism, Coast Mountains Orogen, Latitude 52-53 degrees North, British Columbia, Canada

    Science.gov (United States)

    Rusmore, M. E.; Gehrels, G.; Woodsworth, G. J.

    2007-12-01

    New geologic data and U-Pb ages reveal complex history of arc accretion, crustal thickening and migration of magmatic fronts during deformation. Plutonic ages define distinct western and eastern Jurassic - mid Cretaceous arcs that share a common history after ~90 Ma. Juxtaposition of these arcs occurred during mid- Cretaceous crustal shortening in a dominantly SW-vergent crustal-scale thrust belt. Significant crustal thickening buried 151 Ma granitic clasts to pressures > 6 kb, and mid-Cretaceous plutons were emplaced at this depth along the axis of the orogen. Thrusting continued after establishment of the 90 Ma arc; a regional SW-verging thrust emplaced high-grade metamorphic rocks of the Yukon-Tanana terrane and deep-seated plutons over low- grade rocks of the Alexander and Wrangellia terranes. The shear zone is coincident with the western boundary of 82-89 Ma plutons and a regionally extensive, late-kinematic, sill-like pluton. Dextral shear zones preserved on the flanks of the orogen suggest a component of Late Cretaceous transpression. By 75 Ma, metamorphism, deformation, and magmatism had migrated central portions of the orogen and there is no evidence of ductile deformation and syn-kinematic metarmorphism younger than ~70 - 65 along the western flank of the orogen. The Coast shear zone localized 62-58 Ma synkinematic plutons during NE-side up displacement, creating a sharp western magmatic front. Sparse cooling ages suggest plutons and metamorphic rocks adjacent to the CSZ cooled through 500-600 deg between 54-58 Ma during exhumation along the shear zone. Voluminous granitic plutons were emplaced from ~55-50 Ma, but significant crustal extension that affected the eastern side of the orogen farther north is not evident along this transect. This history supports previous models of crustal subcretion and the generation of arc magmas in thickened crust. Definition of two pre-90 Ma arcs negates models calling for simple Andean-style orogen prior to mid

  1. Crustal structure across the Colorado Basin, offshore Argentina

    Science.gov (United States)

    Franke, Dieter; Neben, Soenke; Schreckenberger, Bernd; Schulze, Albrecht; Stiller, Manfred; Krawczyk, Charlotte M.

    2006-06-01

    The geology of the wide shelves surrounding the South Atlantic is closely linked to the kinematics and history of the opening of the ocean. However, several wide sedimentary basins, which developed along the margins show peculiarities that are not yet understood in the context of the evolution of the South Atlantic. The Colorado Basin, a wide sedimentary basin on the broad shelf of Argentina, extends in EW direction. The basin's evolution oblique or orthogonal to the continent-ocean boundary indicates that it is not a product of simple progressive extension and crustal thinning. In addition a basement high, paralleling the continental margin and separating the Colorado Basin from the deep-sea basin is a common interpretation. These findings are hardly in accordance with the idea that the Colorado Basin is an extensional basin that developed in conjunction with the early E-W opening phase of the South Atlantic in the Late Jurassic/Early Cretaceous. The composition, type, and structure of the basement, key points for the evaluation of the basins evolution, are widely speculative. In this context multichannel seismic reflection data from the Argentine Shelf and a 665-km-long onshore-offshore refraction profile, running across the Colorado Basin onto the coast are discussed in combination with gravity data. The stratigraphy for the sedimentary successions was adopted from the literature and the reflection seismic marker horizons formed besides the interval velocities the input for the starting model for refraction seismic traveltime modelling. The modelling strategy was an iterative procedure between refraction seismic traveltime and gravity modelling. The preparation of the density models was coarsely orientated on published velocity-density relations. The modelling results are in favour of a continuation of the main onshore geological features beneath the sedimentary infill of the Colorado Basin. We interpret the basement along the line from west to east as offshore

  2. Laboratory measurements of Vp and Vs in a porosity-developed crustal rock: Experimental investigation into the effects of porosity at deep crustal pressures

    Science.gov (United States)

    Saito, Satoshi; Ishikawa, Masahiro; Arima, Makoto; Tatsumi, Yoshiyuki

    2016-05-01

    In order to evaluate the influence of porosity on the elastic properties of crustal rocks at deep crustal pressures, we performed laboratory measurements of compressional-wave (Vp) and shear-wave (Vs) velocities in a porosity-developed gabbro sample up to 1.0 GPa at room temperature. Based on the measured Vp and Vs data, we evaluated the changes in velocities, Vp/Vs, Poisson's ratio (σ), and total porosity of the rock as a function of pressure. Compared with the 'porosity-free' intrinsic elastic values of the gabbro sample, our results suggest that the development of porosity in crustal rocks lowers their Vp, Vs, Vp/Vs, and Poisson's ratio. Deviations (ΔVp, ΔVs, ΔVp/Vs, and Δσ) of the measured values from the intrinsic values are enhanced with increasing porosity. We evaluated the ΔVp from previous experimental study on the rocks of Tanzawa plutonic complex providing constraints on interpretation of the seismic velocity profiles of the Izu-Bonin-Mariana (IBM) arc and found a large negative ΔVp (up to - 22.7%) at lower pressures. The intrinsic velocity combined with the measured velocity data at in situ pressure conditions suggest that the ranges of Vp (6.0-6.5 km/s) in the middle crust of the IBM arc reflect the presence of considerable porosity and its closure in intermediate rocks and/or the change of composition from felsic to intermediate in mid-crustal rocks.

  3. Sobremortalidade por diarréia simultânea à cólera na região Nordeste do Brasil Excess mortality by diarrhea simultaneous to a cholera epidemic in Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Moacir Gerolomo

    2004-08-01

    Full Text Available OBJETIVO: Avaliar a sobremortalidade por diarréia infecciosa, sem diagnóstico etiológico, simultânea à circulação do Vibrio cholerae. MÉTODOS: Foi aplicada modelagem estatística à série histórica dos óbitos ocorridos por "infecções intestinais mal definidas" (Classificação Internacional de Doenças - CID-9 e "diarréia e gastroenterite de origem infecciosa presumível" (CID-10, entre 1980 e 1998, na região Nordeste. Foi obtida a predição de valores esperados a partir de um ponto de descontinuidade. O excesso de mortalidade foi calculado pela diferença entre o observado e o estimado pelo modelo. RESULTADOS: Entre 1992 e 1994, apenas 19,3% dos óbitos por cólera foram efetivamente registrados. Em 1993, ano em que a epidemia atingiu seu ponto máximo na região, a presente modelagem leva a uma estimativa de sub-registro de 82,2%. CONCLUSÕES: Os resultados apontam um grande sub-registro da mortalidade por cólera durante a epidemia na região Nordeste.OBJECTIVE: To evaluate excess mortality due to infectious diarrhea without etiological diagnosis, occurring simultaneously to Vibrio cholerae circulation. METHODS: Statistical modeling was applied to a time series of deaths ascribed to "poorly defined intestinal infections" (International Classification of Diseases - ICD-9 and "presumably infectious diarrhea and gastroenteritis" (ICD-10, between 1980 and 1998 in the Northeast Region of Brazil. The prediction of expected values was obtained after a discontinuity point. Excess mortality was calculated as the difference between observed figures and those estimated by the model. RESULTS: Between 1992 and 1994, only 19.3% of deaths by cholera were actually notified. In 1993, the year in which the epidemic reached its peak in the area, our modeling estimated underregistration at 82.2%. CONCLUSIONS: Results indicate substantial underregistration of cholera mortality during the epidemic in Northeastern Brazil.

  4. Continuidade espacial da condutividade hidráulica saturada do solo na bacia hidrográfica do Alto Rio Grande, MG

    Directory of Open Access Journals (Sweden)

    Camila Cristina Alvarenga

    2011-10-01

    Full Text Available A distribuição espacial da condutividade hidráulica saturada (k0 é essencial para estudos relacionados a erosão do solo e escoamento superficial. Este trabalho objetivou estudar a continuidade espacial do atributo hidrológico do solo k o na Bacia Hidrográfica do Alto Rio Grande, MG, e realizar seu mapeamento por meio de técnicas geoestatísticas, utilizando dados sem e com transformação logarítmica. Os modelos de semivariograma esférico e exponencial foram ajustados ao semivariograma experimental pelo método dos Mínimos Quadrados Ordinários (MQO e Mínimos Quadrados Ponderados (MQP. Técnicas de validação cruzada e preditiva foram aplicadas para a escolha do melhor modelo. Os resultados indicaram que, ao se trabalhar com o logaritmo dos dados de k o, houve redução de pontos discrepantes e de anisotropia, entretanto os valores mais elevados de grau de dependência espacial foram observados nos dados sem transformação. O ajuste do modelo esférico, por meio do método MQO, foi o que produziu melhor desempenho na modelagem da continuidade espacial de k0. Os mapas gerados a partir dos dados sem e com transformação logarítmica não apresentaram o mesmo comportamento na distribuição espacial dos valores, e o mapa dos dados na forma transformada teve o melhor detalhamento da distribuição espacial.

  5. Kinematic analysis and analogue modelling of the Passeier- and Jaufen faults: Implications for crustal indentation in the Eastern Alps

    NARCIS (Netherlands)

    Luth, S.; Willingshofer, E.; ter Borgh, M.; Sokoutis, D.; van Otterloo, J.; Versteeg, A.

    2013-01-01

    Crustal deformation in front of an indenter is often affected by the indenter's geometry, rheology, and motion path. In this context, the kinematics of the Jaufen- and Passeier faults have been studied by carrying out paleostress analysis in combination with crustal-scale analogue modelling to infer

  6. Mechanism of crustal deformation in the Sichuan-Yunnan region, southeastern Tibetan Plateau: Insights from numerical modeling

    Science.gov (United States)

    Li, Yujiang; Liu, Shaofeng; Chen, Lianwang; Du, Yi; Li, Hong; Liu, Dongying

    2017-09-01

    The characteristics of crustal deformation and its dynamical mechanisms in the Sichuan-Yunnan region are of interest to many researchers because they can help explain the deformation pattern of the eastern Tibetan Plateau. In this paper, we employ a precise three-dimensional viscoelastic finite element model to simulate the crustal deformation in the Sichuan-Yunnan region, southeastern Tibetan Plateau. We investigate the influence of lower crustal flow and rheological variations by comparing the modeled results with GPS observations. The results demonstrate that lower crustal flow plays an important role in crustal deformation in the Sichuan-Yunnan region. The best fitting is achieved when the flow velocity of the lower crust is approximately 10-11 mm/a faster than that of the upper crust. Additionally, crustal rheological properties affect regional crustal deformation. When the viscosity of the middle and lower crust in the South China block reaches 1022 and 1023 Pa·s, respectively, the modeled results match observations well, especially for the magnitude of crustal motion within the South China block. Finally, our dynamic model shows that the maximum principal stress field of the Sichuan-Yunnan region exhibits clear zoning, gradually shifting from an approximately east-west orientation in the northern Bayan Har block to southeast in the South China block, southwest in the western Yunnan block, and a radially divergent distribution in the Middle Yunnan and Southern Yunnan blocks.

  7. Evaluating Crustal Contamination Effects On The Lithophile Trace Element Budget Of Shergottites, NWA 856 As A Test Case

    Science.gov (United States)

    Brandon, A. D.; Ferdous, J.; Peslier, A. H.

    2017-01-01

    The issue of whether crustal contamination has affected the lithophile trace element budget of shergottites has been a point of contention for decades. The evaluation has focused on the enriched shergottite compositions as an outcome of crustal contamination of mantle-derived parent magmas or, alternatively, the compositions of these stones reflect an incompatible trace element (ITE) enriched mantle source.

  8. Regional and global crustal context of soil and rock chemistry from ChemCam and APXS at Gale crater

    Science.gov (United States)

    Newsom, H. E.; Gordon, S.; Jackson, R.; Agee, C. B.; Wiens, R. C.; Clegg, S. M.; Lanza, N.; Cousin, A.; Gasnault, O.; Meslin, P. Y.; Maurice, S.; Forni, O.; McLennan, S. M.; Mangold, N.; Sautter, V.; Clark, B. C.; Anderson, R. B.; Gellert, R.; Schmidt, M. E.; Ollila, A.; Boynton, W. V.; Martín-Torres, J.; Zorzano, M. P.

    2014-12-01

    The chemistry of rocks and soils analyzed by Curiosity represent a diverse population including mafic and felsic compositions. The data from Gale Crater can be compared with the accumulated data for martian materials from other landing sites, the Gamma Ray Spectrometer (GRS) experiment on the Mars Odyssey Spacecraft, and the data for martian meteorites. Variations in the CaO/Al2O3 ratio in primitive igneous rocks can provide a fundamental signature of crustal formation on Mars. Abundances of other elements like Fe in the surface rocks can reflect later differentiation effects. Comparing the chemistry of Gale samples with other martian data must take into account the different geochemical components in the samples. The most important distinction is between the volatile elements including H, C, Cl, S, and the lithophile elements including Al, Si, Fe, Mn, Ca, Na, Mg, etc. The large enrichments of the volatile elements SO3, Cl, and H2O in the soils may represent contributions from volcanic aerosols or other local sources of volatiles. Alteration and transport of fluid mobile major elements by aqueous or hydrothermal processes could complicate the estimation of crustal abundances of elements such as Ca but early results suggest little or no chemical fractionation attributable to alteration. Other clues to the role of fluids can come from the ChemCam data for the highly fluid mobile elements lithium and manganese. Regional comparisons of chemistry only make sense when considering the absolute abundances and elemental ratios within the different component classes. The use of elemental ratios avoids the problem of the correction required to get volatile-free abundance data for comparison of GRS data with meteorites and landing site rocks measured by the ChemCam Laser Induced Breakdown Spectroscopy (LIBS) experiment and Alpha Particle X-ray Spectrometer (APXS). The huge size of the GRS footprint makes it especially difficult to make the required corrections. Eventually data

  9. Arctic and N Atlantic Crustal Thickness and Oceanic Lithosphere Distribution from Gravity Inversion

    Science.gov (United States)

    Kusznir, Nick; Alvey, Andy

    2014-05-01

    The ocean basins of the Arctic and N. Atlantic formed during the Mesozoic and Cenozoic as a series of distinct ocean basins, both small and large, leading to a complex distribution of oceanic crust, thinned continental crust and rifted continental margins. The plate tectonic framework of this region was demonstrated by the pioneering work of Peter Ziegler in AAPG Memoir 43 " Evolution of the Arctic-North Atlantic and the Western Tethys" published in 1988. The spatial evolution of Arctic Ocean and N Atlantic ocean basin geometry and bathymetry are critical not only for hydrocarbon exploration but also for understanding regional palaeo-oceanography and ocean gateway connectivity, and its influence on global climate. Mapping crustal thickness and oceanic lithosphere distribution represents a substantial challenge for the Polar Regions. Using gravity anomaly inversion we have produced comprehensive maps of crustal thickness and oceanic lithosphere distribution for the Arctic and N Atlantic region, We determine Moho depth, crustal basement thickness, continental lithosphere thinning and ocean-continent transition location using a 3D spectral domain gravity inversion method, which incorporates a lithosphere thermal gravity anomaly correction (Chappell & Kusznir 2008). Gravity anomaly and bathymetry data used in the gravity inversion are from the NGA (U) Arctic Gravity Project and IBCAO respectively; sediment thickness is from a new regional compilation. The resulting maps of crustal thickness and continental lithosphere thinning factor are used to determine continent-ocean boundary location and the distribution of oceanic lithosphere. Crustal cross-sections using Moho depth from the gravity inversion allow continent-ocean transition structure to be determined and magmatic type (magma poor, "normal" or magma rich). Our gravity inversion predicts thin crust and high continental lithosphere thinning factors in the Eurasia, Canada, Makarov, Podvodnikov and Baffin Basins

  10. Efektite na prostaciklin vo tretmanot na dijabeticnata nefropatija kaj staorci

    Directory of Open Access Journals (Sweden)

    Jasmina Trojacanec

    2006-06-01

    Full Text Available Mikrovaskularnite komplikacii, a pred se dijabeticnata nefropatija, se edni od najteskite komplikacii na dijabetot, od koi vo golema mera zavisi i prognozata na dijabetot kaj ovie pacienti. Etiopatogenezata na ovaa komplikacija e multifaktorijalna i za sega se uste ne kompletno rasvetlena, a vklucuva morfoloski, patolosko-anatomski i biohemiski metabolni narusuvanja. Se smeta deka narusuvanjeto na modularnata funkcija na endoteliumot moze da bide kriticen i inicijalen faktor vo razvojot na dijabeticnite vaskularni komplikacii. Vrz osnova na farmakodinamskite efekti koi sto gi poseduva prostaciklinot (PGI2 i negovite analozi, se smeta deka istite moze da bidat korisni vo tretmanot na dijabeti~nata nefropatija. Osnovna cel na ovaa studija be{e da se procenat efektite na prostaciklin (PGI2 vo tretmanot na dijabeticnata nefropatija, eksperimentalno predizvikana so streptozocin. Kaj normotenzivni staorci od sojot Wistar, eksperimentalno bese induciran najprvin dijabet so ednokratna i.p. administracija na streptozocin (STZ, a kako komplikacija na dijabetot i jasni znaci i simptomi na dijabeticna nefropatija (proteinurija, zgolemeno serumsko nivo na urea i kreatinin, poliurija, zgolemena aktivnost na NAG vo mockata. Tretman so prostaciklin (p.o. vo doza od 0.1 mg/kg /t.t./den, vo tekot na 4 nedeli, dovede do signifikantno namaluvanje na simptomite i znacite na bubreznite ostetuvanja, vo odnos na grupata zivotni koi ne primaa prostaciklin. Vrz osnova na dobienite rezultati moze da se zakluci deka prostaciklinot moze da ima znacajna uloga vo tretmanot na dijabeticnata nefropatija, eksperimentalno inducirana so streptozocin.

  11. Bayesian spatial modeling applied to environmental monitoring due to the use of different drilling fluids in the maritime exploration activity; Modelagem espacial Bayesiana aplicada ao monitoramento ambiental decorrente do uso de diferentes fluidos de perfuracao na atividade exploratoria maritima

    Energy Technology Data Exchange (ETDEWEB)

    Pulgati, Fernando H. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Modelagem de Bacias (LAB2M); Zouain, Ricardo N.A. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Geociencias. Centro de Estudos de Geologia Costeira e Oceanica; Fachel, Jandyra M.G. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Matematica; Landau, Luiz [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Metodos Computacionais em Engenharia (LAMCE)

    2004-07-01

    Controlling and monitoring environmental researches have accompanied the development of offshore exploration drill activities aimed at finding oil and gas reserves, as there has been an increase in the environmental demands and restrictions. Three stages of the drilling process were isolated and the effects of different fluids were measured using Bayesian spatial models. The probable impact of the use of non-aqueous fluid (NAF) was measured through changes observed in sea sediments in three different occasions: previous to the activity, one (1) month after the end of the activity, and one (1) year after the end of the activity. BACI (Before-After Control Impact) design, which allows the control of temporal and spatial variation components, was chosen. (author)

  12. Modelagem do volume do povoamento para Mimosa scabrella Benth. na regição metropolitana de Curitiba Stand volume modelling of Mimosa scabrella benth. from Curitiba metropolitan region

    Directory of Open Access Journals (Sweden)

    Sebastião do Amaral Machado

    2008-06-01

    Full Text Available O objetivo desta pesquisa foi modelar o volume total com casca do povoamento da bracatinga (Mimosa scabrella Benth.. Coletaram-se dados em bracatingais com regeneração induzida pelo fogo, em 14 municípios da Região Metropolitana de Curitiba (RMC, Estado do Paraná - Brasil. Utilizou-se uma base de dados constituída por 229 unidades amostrais de 100 a 400 m². Em cada parcela, mensurou-se o diâmetro à altura do peito, bem como a altura total de todas as árvores, em bracatingais de 3 a 18 anos de idade. Para a estimativa do volume total com casca, testaram-se vários modelos de regressão selecionados da literatura, o que gerou uma matriz com 58 variáveis independentes, visando construir modelos por meio do método Stepwise. As equações de melhor ajuste foram validadas utilizando-se o teste Qui-quadrado, a análise gráfica de resíduos e o erro-padrão da estimativa. Várias equações tiveram bom desempenho, apresentaram valores de coeficiente de determinação ajustados superiores a 0,995, erro-padrão da estimativa inferior a 3% e adequada distribuição de resíduos. As duas equações de melhor desempenho foram validadas, apresentando erro-padrão da estimativa de 2,37% e 2,13%, valor não-significativo para o teste do Qui-quadrado e equilibrada distribuição dos resíduos.The objective of this research was to model the stand volume outside bark of Mimosa scabrella Benth. stands, from the Curitiba Metropolitan Region (CMR, Parana State - Brazil. To reach this aim, a database of 229 permanent and temporary sample plots measuring from 100 to 400 m² each, from 14 municipalities in the CMR, was used. In each sample plot, the diameter at breast height and the total height of all 3- to 18-year-old bracatinga trees were measured. To estimate the total volume, regression models selected from the literature were tested. A set of 58 independent variables was generated also to construct models by the Stepwise method. The equations of best fitting were validated by the Chi square tests ( 2, residual graphic analysis, and the absolute and relative standard error of estimate. Several equations showed good performance, adjusted coefficient of determination higher than 0.995, relative standard error of estimate lower than 3% and adequate residual distribution. The best two equations presented Syx: 2.37% and Syx: 2.13%, non-significant values for the χ2 test and unbiased distribution of the residuals.

  13. Boundary integral method application in the transportation modeling of radioactive tracers in porous ways; Aplicacao do metodo da integral de contorno na modelagem do transporte de tracadores radioativos em meios porosos

    Energy Technology Data Exchange (ETDEWEB)

    Ferroni, Jose Geraldo

    1996-03-01

    This work describes a method for estimating the effluent concentrations of radioactive tracers in production wells, considering well to well injection tests and piston-like displacements of fluids in the reservoir. The model for tracer transportation takes into account effects of convection and hydrodynamic dispersion. (author)

  14. Bayesian spatial modeling applied to environmental monitoring due to the use of different drilling fluids in the maritime exploration activity; Modelagem espacial Bayesiana aplicada ao monitoramento ambiental decorrente do uso de diferentes fluidos de perfuracao na atividade exploratoria maritima

    Energy Technology Data Exchange (ETDEWEB)

    Pulgati, Fernando H. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Modelagem de Bacias (LAB2M); Zouain, Ricardo N.A. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Geociencias. Centro de Estudos de Geologia Costeira e Oceanica; Fachel, Jandyra M.G. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Inst. de Matematica; Landau, Luiz [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Metodos Computacionais em Engenharia (LAMCE)

    2004-07-01

    Controlling and monitoring environmental researches have accompanied the development of offshore exploration drill activities aimed at finding oil and gas reserves, as there has been an increase in the environmental demands and restrictions. Three stages of the drilling process were isolated and the effects of different fluids were measured using Bayesian spatial models. The probable impact of the use of non-aqueous fluid (NAF) was measured through changes observed in sea sediments in three different occasions: previous to the activity, one (1) month after the end of the activity, and one (1) year after the end of the activity. BACI (Before-After Control Impact) design, which allows the control of temporal and spatial variation components, was chosen. (author)

  15. Modelagem dos processos químicos em plasmas de misturas gasosas usadas na corrosão de silício. Parte 1: CF4 / O2

    Directory of Open Access Journals (Sweden)

    Bauerfeldt G. F.

    1998-01-01

    Full Text Available The plasma etching of semiconductor surfaces with fluorine-containing compounds has technological interest. Presently, considerable effort is being devoted to understand the chemistry involved. In this work, a numerical modeling analysis of the gas-phase decomposition of CF4/O2 mixtures, in the presence of silicon, was performed. The relative importance of individual processes was determined as well as the effect of the parameters' uncertainties. The results were compared with experimental data. The main etching agent in the system is the fluorine atom. The concentration of the main species, SiF4, CO, CO2 and COF2 depend on the composition of the mixture.

  16. Kriging of proportions using mean kriging.The proportion curves have an important role in petroleum geology; Krigagem das proporcoes utilizando a krigagem da media: uma ferramenta auxiliar na modelagem de reservatorios

    Energy Technology Data Exchange (ETDEWEB)

    Remacre, Armando Zaupa; Sancevero, Sergio Sacani [DGR/IG/UNICAMP, Campinas, SP (Brazil)], Emails: armando@ige.unicamp.br, sacani@gmail.com; Normando, Marcio Nunes [Beicip-Franlab, Rio de Janeiro, RJ (Brazil)], E-mail: marcio.normando@beicip.com

    2008-03-15

    With this tool it is possible to define specific intervals for the dominant facies and, as result we can use the proportion curve as a trend in lithological modeling. However, when the proportion curves are generated they do not consider the well influence and the location of the wells. When we consider those information is possible to generate a more effective proportions curves. So, the main aim of this paper is to present a new technique to generate the proportion curves based in the mean kriging. The main advantage of this methodology is that the well location and his influence zone are considered in the process. This methodology indicated a efficient way to generate the proportion curves that can be used to support in a decisive way the reservoir characterization process linking to the lithological modeling. (author)

  17. Urban index modelling for forecasting of channeled natural gas market: an example in Sao Paulo metropolitan region; Modelagem de indicadores urbanos para previsao do mercado de gas natural canalizado: um exemplo na regiao metropolitana de Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Massara, Vanessa Meloni; Faga, Murilo Tadeu Werneck; Udaeta, Miguel Edgar Morales [Universidade Sao Paulo (USP), SP (Brazil). Programa Interunidades de Pos Graduacao em Energia]. E-mail: vmassara@iee.usp.br; murfaga@iee.usp.br; udaeta@pea.usp.br

    2006-07-01

    This paper aims to present a systemic model for analysis of the expansion and grow up of the natural gas distribution pipeline in a city. This methodology integrates the understanding of the urban dynamics to the strategies of expansion in the natural gas distribution network, through the grouping of information such as family income, demographic density and construction area, percentage of land use, number of households as well as commercial, service and industrial establishments, number of real state as well as indicative information released by the Urban Plan of the city regarding the increments in the peripheral districts. Relating the gas consumption esteemed by each type of land occupation and the cost for expanding the gas distribution network, the model will indicate, for each neighborhood, the viability of implementing a gas network as well as the places with potential for growing density in the existing gas distribution system. The aim is to propose an integration of aspects of city dynamics and new energy source development, taking the advance of natural gas in Sao Paulo Metropolitan area as a specific case study. Through the analysis of highly industrialized, residential and commercial suburbs of the City of Sao Caetano do Sul, the importance of urban parameters in the decision making process for network expansion is identified. (author)

  18. Modeling of thermal and optical effects in dental pulp during the irradiation with neodymium and diode lasers; Modelagem dos efeitos termicos e opticos na polpa dentaria durante a irradiacao com os lasers de diodo de neodimio

    Energy Technology Data Exchange (ETDEWEB)

    Farhat, Patricia Bahls de Almeida

    2003-07-01

    During the development of applications of high intensity lasers in the enamel and dentine, adverse thermal effects into the entire dental structure, including the pulp, must be verified. The measurement of the temperature in the intact pulp, however, is not a solved problem. For this purpose, models have been used frequently, using extracted teeth, with pulpal cavities filled with materials that simulate only thermal properties of the pulp. Current models, however, do not simulate optical properties of the pulp, not taking the remaining radiation in the pulp chamber into account. The aim of this study was to verify if the remaining radiation from neodymium and diode lasers that reach the pulp chamber, at the models using extracted bovine teeth, can cause local thermal effects. For this purpose, two models were developed, using extracted bovine teeth with their pulp chambers filled with water (simulating pulp thermal characteristics) without (model 1) and with (model 2) an optical absorbent. Models were radiated with 1 W. The obtained results show that, for both lasers, the temperature rise in model 2 pulp chamber is: up to 11 % higher than in the model 1 when the enamel is radiated; and up to 37% higher than in the model 1 when dentine is radiated (1 mm from the pulp), indicating that the level of the remaining radiation is relevant for the construction of models excited by the neodymium and diode lasers. (author)

  19. Elastic-acoustic modeling of geopressures in the migration and retention evaluation of petroleum systems fluids; Modelagem acustico-elastica de geopressoes na avaliacao da retencao e migracao de fluidos de sistemas petroliferos

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, Marco A.S.; Rodrigues, Fernando; Coelho, Dimas [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2000-07-01

    The success of a exploratory prospect is closely related to geological risk estimation. 3 D seismic and structural modeling improve reservoir risk and trap geometry estimation; and geothermal models, the evaluation risk of hydrocarbon generation. The objective of this paper is to present geo pressure modeling as a powerful tool for estimating migration and hydrocarbon retention. The method is based on the integration of seismic velocities, sonic logs, pressure data and geomechanical relations in order to build a geo pressure model. After applying this method we were able to predict geo static, fracture, pore pressure and effective stress, which integrated with seismic interpretation consolidate a predictive model of geo pressure potential in the studied area. We show the efficiency of geo pressure modeling in brazilian passive margins, using data from shallow to deep waters in San tos and Sprague/Ageless. From a exploratory point of view, these studies shown the importance of the interface between hydrostatic and geopressured regimes for evaluating migration and retention of fluids in a petroleum system. It was also possible to establish a relation between overburden and rheological properties. (author)

  20. Modelagem de processos de negócios na implementação de ERPs nacionais em PMEs Business processes modeling in the implementation of national ERPs within SMEs

    National Research Council Canada - National Science Library

    Fernanda Pereira Carneiro da Silva; Néocles Alves Pereira

    2006-01-01

    ... implementação para otimizar a integração dos processos internos dos negócios.This article presents evidences found in a research whose objective was to investigate the contribution of using business processes modeling (BPM...

  1. Modelagem da redução do tamanho de partículas na alimentação de ruminantes Modeling of feed particle size reduction in the ruminants nutrition

    Directory of Open Access Journals (Sweden)

    Edgar Alain Collao Saenz

    2005-08-01

    Full Text Available O tamanho de partícula influencia o valor nutricional do alimento porque pode afetar o consumo de matéria seca, a digestão e utilização de nutrientes pelos microorganismos ruminais e, o desempenho animal. Alguns modelos são apresentados para ilustrar a evolução da representação da redução do tamanho de partícula. Em geral, as diferentes propostas se comportam adequadamente e provêem informação útil para produção ou pesquisa. Porém, todos os modelos demonstram inexatidão em certos pontos. Nesta revisão são discutidas as razões para esses problemas e é proposta a inclusão de novas variáveis relacionadas com a cinética de partículas, ingestão descontínua de alimentos e liberação do conteúdo celular com o objetivo de aumentar a precisão de futuros modelos de consumo e digestão.Particle size seems to be an important factor influencing the nutritional value of the feed because it may affect dry matter intake, microbial digestion and utilization of nutrients and animal performance. Some models are described to present different attempts to represent particle size reduction. In general, the diverse approaches behave adequately and provide useful information for production or research. All models, however, demonstrate inaccuracy in some points. The reasons for these failures are discussed and the inclusion of new variables related to particle kinetics, pulses of feed and cell content release to increase accuracy of predictions in future models of feed intake and digestion of ruminants is proposed.

  2. Application of data representation by fuzzy conditional propositions in the modeling of measurement uncertainty; Aplicacao da representacao de dados por proposicoes condicionais difusas na modelagem da incerteza de medicao

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, A.N. de; Lambert-Torres, G.; Rissino, S.; Silva, M.F. da; Silva, L.E. Borges da; Carvalho, L.M.R. de

    2009-07-01

    It is not an easy task to frame uncertainty measurement problems by means of differential equations quickly and satisfactorily. Therefore, it is necessary to adapt the method for data representation by conditional fuzzy propositions for modeling uncertainties measurement and their effect on the propagation. This method provides a parametric adjustment for fuzzy sets of assumptions, and the functions of consequence of each rule in the manner of a parable. The paper introduces concepts of sources of errors in measures, fundamentals of fuzzy logic, description of the algorithm method, application to error detection and representation of global uncertainty.

  3. Modeling and identification of new complementary development opportunities in a Campos Basin offshore giant field; Modelagem e identificacao de novas oportunidades de desenvolvimento complementar de um campo gigante na Bacia de Campos

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Jose Adilson T.; Steagall, Daniel E.; Lorenzatto, Rudimar Andreis [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    The objective of this paper is to present the methodology that has been used for the complementary development of the giant Marlin oil field in the Campos Basin, with the study of the opportunities of new wells and application of new technologies for the enhancement of production, recovery factor and the gain of reserves. This methodology is applied integrating geophysics, geology, engineering, planning and operation, containing: identification of the non drained areas, positioning of new locations, risk analysis, reduction risk analysis actions, production estimation, attractive location selection; conceptual well project with location of the well head, submarine layout, drilling program, multiphase flow curves; drilling schedule, completion, and production commencement; production forecasting with flux simulation using operational reality of the oil, gas, and water treatment production capacity; wells substitution and deviation criteria; project critical resources and preliminary economical evaluation including project risk. The obtained results were the optimization of the project portfolio of new wells considering the identification of new opportunities, schedule and entrance order of wells, helping also in the acquisitions of new data for reservoir risk reduction before project implementation. (author)

  4. Radioisotope and mathematical modeling in the assessment of supplementation of Phytase in diets for growing pigs; Radioisotopo e modelagem matematica na avaliacao da suplementacao de fitase em dietas para suinos em crescimento

    Energy Technology Data Exchange (ETDEWEB)

    Mota, L.C.; Moreira, J.A.; Oliveira, R.L.R., E-mail: japmoreira@bol.com.br [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Vitti, D.M.S.S. [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Patino, R.M. [Universidade de Sucre, Bogota (Colombia)

    2014-02-15

    The purpose of this study was to evaluate the effects of including increasing levels of phytase enzyme in pig diets for growing pigs, using the mathematical model. Data from 20 crossbred male piglets, castrated and weighing 26.80 kg on average was used. The animals were housed in individual metabolic cages to collect feces and urine in a 17 day period. A randomized block experimental design containing five treatments and four repetitions was used. The experimental diet provided to piglets contained corn and soybean and was supplemented with five increasing levels of phytase enzyme (0, 250, 500, 750 and 1000 UF/kg), corresponding to 0.00 %, 0.01 %, 0.02 %, 0.03 % and 0.04 % respectively. The variables evaluated were: intake, excretion, output flow of P in the digestive tract, bloodstream, bones and soft tissues. The phytase enzyme did not affect the P intake (P>0.05 (F{sub 10}), the P excreted in urine (F{sub 02}) and the output flow of P in the bones (F{sub 32} e F{sub 23}) and soft tissue (F{sub 42} e F{sub 24}), however, there was a reduction in P excreted in feces (F{sub 01}) of 8.92 %, 26.76 %, 22.53 % and 28.64 % to the levels 0, 250, 500, 750 e 1000UF/kg, respectively and showed a positive linear effect (P<0.08) for the endogenous P (F{sub 12}). Corn and soybean meal based diets can be used with 50% of P by dicalcium phosphate, adding 250UF/kg diet for growing pigs, and may cause a reduction of 27 % of P excretion in feces. (author)

  5. Perfis de carbono orgânico do solo nas regiões Sul e Serra do Espinhaço Meridional, Minas Gerais: modelagem em profundidade

    Directory of Open Access Journals (Sweden)

    Yuri Lopes Zinn

    2012-11-01

    Full Text Available Apesar de o interesse no comportamento espacial de atributos-chave do solo, só recentemente a variação em profundidade passou a receber mais atenção na literatura. O carbono orgânico do solo (COS é talvez o atributo que mais varie em profundidade, o que dificulta seu estudo. A partir de dados de levantamentos de solos de duas regiões de Minas Gerais (Sul e Serra do Espinhaço Meridional, foram modelados os teores de COS em profundidade, buscando identificar quais fatores mais os influenciam. Os perfis de COS foram mais bem descritos por funções logarítmicas neperianas em ambas as regiões. Houve efeito da classe de solo, uma vez que Latossolos apresentaram menores teores superficiais, mas menor decréscimo no perfil, do que Argissolos, Neossolos, Cambissolos e Nitossolos. Essas tendências podem ser devidas à maior profundidade, permeabilidade e teor de argila+silte dos Latossolos. A variação regular dos parâmetros intercepto (teor médio na superfície e fator logarítmico (taxa de decréscimo das equações obtidas para diferentes faixas de teor de argila+silte permitiu ainda obter funções de pedotransferência em perfil para descrever teores de COS em profundidade em qualquer classe de solo, confirmando a hipótese de que a textura é um controle importante dos teores de COS nessas duas regiões. Na região Sul de MG, os perfis de COS puderam também ser descritos em função de teores de Fe2O3 (ataque sulfúrico, evidenciando controle mineralógico do COS. Ainda na região Sul, solos entre 1.000 e 1.200 m de altitude apresentaram maiores teores de COS do que os de altitudes menores. Latossolos e Nitossolos das duas regiões mostraram perfis muito semelhantes de COS - similaridade atribuída ao efeito positivo de maiores teores de argila na região Sul e maior altitude na Serra do Espinhaço Meridional.

  6. A serendipidade na medicina e na anestesiologia

    OpenAIRE

    Vale,Nilton Bezerra do; Delfino,José; Vale,Lúcio Flávio Bezerra do

    2005-01-01

    JUSTIFICATIVA E OBJETIVOS: Neste trabalho foram examinados mais de uma centena dos mais felizes acoplamentos de uma mente brilhante com a sorte benfazeja (serendipidade), através da releitura das mais relevantes histórias sobre invenções e descobertas relacionadas à ciência (n = 46), à Medicina (n = 46) e à Anestesiologia (n = 16). CONTEÚDO: Conceito de serendipidade; exemplos célebres de serendipidade em Ciência e Tecnologia; serendipidade na pesquisa e prática médicas; serendipidade na Anes...

  7. Magnetic crustal thickness in Greenland from CHAMP and Ørsted data

    DEFF Research Database (Denmark)

    Maule, Cathrine Fox; Purucker, Michael E.; Olsen, Nils

    2005-01-01

    and observatory data. After correcting for the remanent magnetization, we determine the vertically integrated magnetization of the crust. Making some simplifying assumptions about the susceptibility, the thickness of the magnetic crust is determined by iteratively improving an initial crustal thickness model...

  8. Discussion on Characteristics of Crustal Deformation along the Zhangjiakou-Bohai Sea Seismotectonic Zone

    Institute of Scientific and Technical Information of China (English)

    Wang Ruobai; Gu Guohua; Xu Jie; Zhou Wei

    2005-01-01

    The Zhangjiakou-Bohai Sea fault zone located in the northern part of the North China region is a seismotectonic zone controlling the present-day strong earthquake activities. Under the effect of regional principal compressive stress with the direction of NEE-SWW, a series of NEtrending active tectonic zones have developed, which form a group of conjugated shear fracturing systems and control the occurrence of the present-day strong earthquakes. The feature of crustal deformation around this fault zone is studied in the paper. The long-term crustal deformation pattern from GPS measurements exhibits a relatively complete left-lateral strike-slip movement along the active fault zone. However, studies on crustal deformation by stages indicate that a series of NE-trending large-scale anomalous gradient zones have appeared along the Zhangjiakou~Bohai Sea fault zone before moderately strong earthquakes. They are represented respectively by the activities of the Tangshan-Hejian, the Sanhe-Laishui and the Yanhuai-Shanxi seismotectonic zones. This may indicate the occurrence of med-term precursors to moderately strong earthquakes along Zhangjiakou-Bohai Sea zone. The results in the paper show that the crustal deformation pattern before strong earthquake reveals the information of strain status in the deep seismogenic zone, while the chaotic pattern after the occurrence of strong earthquake represents the adjustment of the covering strata.

  9. On the geographical distribution of induced time-varying crustal magnetic fields

    DEFF Research Database (Denmark)

    Thebault, E.; Hemant, K.; Hulot, G.

    2009-01-01

    A long standing question in geomagnetism is whether the time variation of the induced crustal field is a detectable quantity and, if so, at which spatial wavelengths. We tackle this problem with the help of a forward modeling approach using a vertically integrated susceptibility (VIS) grid of the......, and repeat station measurements are available over several decades....

  10. The Crustal Thickness of the Philippine Sea Plate Derived from Gravity Data

    Directory of Open Access Journals (Sweden)

    Horng-Yuan Yen

    2015-01-01

    Full Text Available We constructed a new free-air gravity anomaly map of the Philippine Sea Plate (PSP using ship-tracked gravity data from the National Geophysical Data Center (NGDC. Our results show that the isogals trend correlates well with the tectonic structures in the PSP. After removing the gravity induced by sea water from the free-air gravity data, we obtained the regional Bouguer gravity anomaly, which is later used to compute the Moho geometry in the PSP by applying the Parker-Oldenburg iterative method. Our results indicate that in the southern part of the West Philippine Basin (WPB the crustal thickness is nearly homogeneous with a value of about 5 km, which implies that the WPB is quite stable. The low-amplitude and near-zero free-air gravity anomalies clearly indicate that the whole WPB, except at trenches and island arcs, is nearly in a state of isostatic equilibrium. The average crustal thickness of the Palau Kyushu Ridge (PKR is more than 10 km. In the eastern PSP the crustal thickness gradually increases eastward. Our results also imply that a relatively thin and low density mantle exists beneath the Parece Vela Basin (PVB as a consequence of back-arc spreading and serpentinized upwells of the thin crustal thickness.

  11. Recent progress of deep seismic experiments and studies of crustal structure in northern South China Sea

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The South China Sea (SCS) is one of the largest marginal seas in the western Pacific. Its northern part has the features of a passive continental margin. The studies of deep crustal structure in this area are very important for understanding the tectonic nature, evolution history, basin formation of the northern margin, and the origin of the SCS. In the past decades, the deep seismic experiments of crustal studies in the northern SCS have gone through three stages, namely the sonobuoy, two-ship Expanding Spread Profile (ESP), and Ocean Bottom Hydrophone/Seismometer (OBH/OBS). Along the continental slope, the sonobuoy experiments provided useful information about the velocity structure of the upper crust, while the ESP data recorded for the first time the seismic signals from deep crustal structure and Moho interface. And the OBH/OBS profiles revealed the crustal structure in much greater detail. This paper first gives a brief historical review of these deep seismic experiments and studies, then a summary of the latest progress and important research results. The remaining problems and suggestions for further research work are presented as conclusive remarks.

  12. Fossils as Clues to Ancient Continents. Crustal Evaluation Education Project. Teacher's Guide [and] Student Investigation.

    Science.gov (United States)

    Stoever, Edward C., Jr.

    Crustal Evolution Education Project (CEEP) modules were designed to: (1) provide students with the methods and results of continuing investigations into the composition, history, and processes of the earth's crust and the application of this knowledge to man's activities and (2) to be used by teachers with little or no previous background in the…

  13. Seismological study on the crustal structure of Tengchong volcanic-geothermal area

    Institute of Scientific and Technical Information of China (English)

    王椿镛; 楼海; 吴建平; 白志明; 皇甫岗; 秦嘉政

    2002-01-01

    Based upon the deep seismic sounding profile conducted in the Tengchong volcanic-geothermal area, a two-dimensional crustal P velocity structure is obtained by use of the finite-difference inversion and the forward travel-time fitting method. The crustal model shows that there is a low velocity zone in upper crust in the Tengchong area, which may be related to the volcanic-geothermal activities, and two intracrustal faults (the Longling-Ruili fault and Tengchong fault) exist on the profile, where the Tengchong fault may extend to the Moho discontinuity. Meanwhile, based on teleseismic data recorded by a temporary seismic network, we obtained the S-wave velocity structures beneath the Rehai-Retian region in the Tengchong area, which show the low S-wave velocity anomaly in upper crust. The authors discuss the causes of Tengchong volcanic eruption based on the deep crustal structure. The crustal structure in the Tengchong volcanic-geothermal area is characterized by low P-wave and S-wave velocity, low resistivity, high heat-flow value and low Q value. The P-wave velocity in the upper mantle is also low