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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Teste estatístico para contribuição de genótipos e ambientes na matriz de interação GE / Statistical test for contribution in the interaction matrix of genotypes and environments

Araújo, Mirian Fernandes Carvalho 21 July 2008 (has links)
O presente trabalho teve por objetivos propor um método para testar a contribuição de cada genótipo e ambiente para a interação genótipos X ambientes em ensaios multi-ambientais através de um teste F e implementar uma rotina computacional para a realização da análise de dados segundo o teste proposto. O estudo avalia quatro conjuntos de dados, cada um com diferentes números de genótipos dentro de ambientes com quatro blocos. Para um dos conjuntos, simulou-se as somas de quadrados das linhas (genótipos) e colunas (ambientes) da matriz de interação genótipos X ambientes (GE) gerando 500, 5000 e 10000 experimentos para verificar a distribuição empírica. Os resultados indicaram um ajuste à distribuição qui-quadrado não-central para as linhas e colunas da matriz de interação GE, verificados também pelo teste de Kolmogorov-Smirnov e o gráfico QQplot. Na aplicação do teste F proposto aos quatro conjuntos de dados, identificou-se os genótipos e ambientes que contribuiram mais para a interação genótipos X ambientes. Dessa forma, os melhoristas podem selecionar bons genótipos e ambientes nos seus estudos. / The objective of the present work was to propose a method for testing the con- tribution of each element in a genotypes X environments interaction using multi-environment analyses by means of an F test and implementation of a computational routine to analyze the data according to the test proposed. The study evaluated four data sets, each with a di®erent number of genotypes and environments, in a block design with four repetitions. In one group, the sum of squares within rows (genotypes) and columns (environments) of the genotypes X environments (GE) matrix was simulated, generating 500, 5000 and 10000 experiments to verify the empirical distribution. Results indicate a non-central chi-squared distribution for rows and columns of the GE interaction matrix, which was also verified by the Kolmogorov-Smirnov test and QQplot graph. Application of the F test to the four data sets identified the genotypes and environments that contributed the most to the genotypes X environments interaction. In this way, geneticists can select good genotypes and environments in their studies.
2

Teste estatístico para contribuição de genótipos e ambientes na matriz de interação GE / Statistical test for contribution in the interaction matrix of genotypes and environments

Mirian Fernandes Carvalho Araújo 21 July 2008 (has links)
O presente trabalho teve por objetivos propor um método para testar a contribuição de cada genótipo e ambiente para a interação genótipos X ambientes em ensaios multi-ambientais através de um teste F e implementar uma rotina computacional para a realização da análise de dados segundo o teste proposto. O estudo avalia quatro conjuntos de dados, cada um com diferentes números de genótipos dentro de ambientes com quatro blocos. Para um dos conjuntos, simulou-se as somas de quadrados das linhas (genótipos) e colunas (ambientes) da matriz de interação genótipos X ambientes (GE) gerando 500, 5000 e 10000 experimentos para verificar a distribuição empírica. Os resultados indicaram um ajuste à distribuição qui-quadrado não-central para as linhas e colunas da matriz de interação GE, verificados também pelo teste de Kolmogorov-Smirnov e o gráfico QQplot. Na aplicação do teste F proposto aos quatro conjuntos de dados, identificou-se os genótipos e ambientes que contribuiram mais para a interação genótipos X ambientes. Dessa forma, os melhoristas podem selecionar bons genótipos e ambientes nos seus estudos. / The objective of the present work was to propose a method for testing the con- tribution of each element in a genotypes X environments interaction using multi-environment analyses by means of an F test and implementation of a computational routine to analyze the data according to the test proposed. The study evaluated four data sets, each with a di®erent number of genotypes and environments, in a block design with four repetitions. In one group, the sum of squares within rows (genotypes) and columns (environments) of the genotypes X environments (GE) matrix was simulated, generating 500, 5000 and 10000 experiments to verify the empirical distribution. Results indicate a non-central chi-squared distribution for rows and columns of the GE interaction matrix, which was also verified by the Kolmogorov-Smirnov test and QQplot graph. Application of the F test to the four data sets identified the genotypes and environments that contributed the most to the genotypes X environments interaction. In this way, geneticists can select good genotypes and environments in their studies.
3

Acoplamento de interface Iterativo MEF—MEFE para problemas do tipo sólido-fluido no domínio do tempo

Silva, Jonathan Esteban Arroyo 27 March 2018 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2018-06-29T15:51:42Z No. of bitstreams: 0 / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-07-03T15:49:10Z (GMT) No. of bitstreams: 0 / Made available in DSpace on 2018-07-03T15:49:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-03-27 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho será proposto um método de acoplamento iterativo de interface com um esquema de subcycling no tempo eficiente e preciso. Este será aplicado a pro-blemas do tipo sólido-fluido discretizados, respectivamente, pelos métodos dos elementos finitos clássico (MEF) e espectral (MEFE). Adicionalmente, será proposta uma melhoria no esquema de subcycling, de modo que para convergir não sejam necessários métodos de relaxação. Aplicando o MEFE em subdomínios com geometrias pouco distorcidas, pode-se usufruir da alta precisão numérica com baixo custo de armazenamento oferecidos pelo método ao mesmo tempo em que é possível aplicar o MEF aos subdomínios com geometrias complexas, acrescentando versatilidade ao método. Diferentes exemplos nu-méricos são apresentados e analisados para demonstrar a precisão e a potencialidade das formulações numéricas propostas. / In this work, an iterative interface coupling method with an efficient and precise time subcycling scheme is proposed. It is applied to solid-fluid type problems discretized respectively by classical finite element method (FEM) and spectral finite element method (SFEM), additionally, an improvement in the subcycling scheme is proposed so as not to require relaxation methods to converge. Applying the SFEM in subdomains with low distorted geometries one can take advantage of the high numerical precision with low cost of storage offered by the method, while it is possible to apply the FEM in subdomains with complex geometries, adding versatility to the method. Many numerical examples are presented and analyzed here to show the accuracy and potentiality of the proposed numerical formulations.
4

Comportement d'une discontinuit?? dans un g??omat??riau sous sollicitation chemo-m??canique : exp??rimentations et mod??lisations

Nouailletas, Olivier January 2014 (has links)
R??sum?? : Ces travaux de th??se s'int??ressent ?? l'??tude du comportement d'une discontinuit?? dans un g??omat??riau sous sollicitations chemo-m??caniques ?? l'??chelle du laboratoire. Des essais de traction-compression cyclique ??tudient la refermeture d'une fissure. Ils indiquent que les d??formations in??lastiques seraient gouvern??es en partie par les frottements g??n??r??s lors du r??-embo??tement des l??vres de la discontinuit??, non correspondantes du fait des contraintes internes. Des joints rocheux alt??r??s chimiquement sous sollicitation tangentielle sont ??tudi??s au travers d'essais de cisaillement direct : le comportement des joints d??grad??s est profond??ment modifi?? du fait de la diminution des propri??t??s m??caniques du mat??riau de part et d'autre de la discontinuit?? et de l'accentuation de la non-correspondance des profils rugueux. Le comportement d'une discontinuit?? est mod??lis??e par le couplage d'un mod??le ??lasto-plastique endommageable continu avec une r??solution discr??te du probl??me de contact/frottement (code calcul aux ??l??ments finis Cast3M). Les r??sultats num??riques confirment les ph??nom??nes constat??s exp??rimentalement.//Abstract: To probate the technology of CO[indice inf??rieur 2] geological storage, the integrity of the site must be assure over time. This industruial problematic involves the study of the mechanical properties alteration of geomaterials in the presence of CO[indice inf??rieur 2]. The scenario at the origin of this thesis illustrates the possibility of a CO[indice inf??rieur 2] leakage on a fault located in the caprock. This geological problem is complicated by the many parameters to consider: in situ temperature and pressure, scale effect, heterogeneities of the geomaterial, geofluide composition, chemical reactions ... These works focus on the behavior of a discontinuity in a geomaterial solicited chemomechanically at the laboratory scale. They were realised in cotutelle between SIAME laboratory at the University of Pau and Pays de l'Adour (France) and the laboratory of rock mechanics and engineering geology from the University of Sherbrooke (Quebec, Canada). The first part of the experimental program was defined to characterize the reclosing of a crack under cyclic uniaxial stress. The second experimental campaign has studied the shear behavior of a rock joint chemically degraded. The data obtained were used to model the behavior of a discontinuity by the finite element method. The mechanical behavior of a crack under normal stress is assessed with cyclic tension-compression tests. Stress curve showed hysteresis during opening and closing cycles of a discontinuity in concrete, it indicated inelastic deformations The analysis of displacement field by image correlation indicated that theses deformations were partially governed by the friction generated during the closing of the discontinuity lips. Frictional phenomena are due to asperities mismatching induced by the internal stresses in the concrete. The shear behavior of a rock joint chemically damaged was studied through direct shear tests. Rough surfaces were immersed in acid solution during 6 hours at constant pH. Digitalization of these surfaces befor and after immesion, with a lase profilometer, indicates little modifications of the geometry induced by dissolution of material. Results of tests pointed out significant modifications for altered joints illustred by a of the peak shear strength and an increased of contractancy. They are induced by: 1) the mismatch enhancement of the rough profiles of the discontinuity and, 2) the degradation of the mechanical properties of the material on both sides of the discontinuity due to the chemical attack. Numerical contribution of the thesis lies in modeling the behavior of a discontinuity by the coupling of an continuous elastic-plastic damaged model with a discrete resolution of the contact/friction problem. The model is developed with the finite element code Cast3M. Geometries lips discontinuities are modeled directly from the roughness profiles from experimental scans. The numerical results correctly represent the friction phenomena observed experimentally. Finally, a model of the shear test altered joints is performed by coupling the mechanical model with chemical damage model.

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