956 resultados para Integral turbulent time scales


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Pós-graduação em Educação - FFC

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Tendo como foco as múltiplas escalas de tempo que atuam na Amazônia, este trabalho foi desenvolvido com o objetivo de investigar a possível influencia da Oscilação Madden – Julian (OMJ) em elementos turbulentos da CLP. A OMJ foi identificada a partir de 30 anos de dados de reanálise de radiação de onda longa (ROL) e componente zonal do vento (u). As grandezas turbulentas foram estudadas a partir da variância, covariância e coeficiente de correlação de um conjunto de dados de resposta rápida coletado na torre micrometeorológica de Caxiuanã (PA), e tratados com a Transformada em Ondeletas (TO) para se obter a contribuição de cada escala para estes momentos estatísticos. A análise dos 30 anos de dados de ROL e u mostrou que a ocorrência da OMJ está ligada com o fenômeno do El Niño/Oscilação Sul (ENOS), bem como influência do ENOS no tempo da região amazônica pode estar associado a presença ou não da OMJ. Foi observado que anos de El Niño tendem a desfavorecer a ocorrência da OMJ e anos de La Niña tendem a favorecer o desenvolvimento da oscilação. Caso uma OMJ se desenvolva durante um episodio de El Niño, a oscilação pode influenciar a temperatura, a velocidade do vento e a precipitação de forma diferente ao do El Niño. A análise por fase da OMJ mostrou que, em Belém, há diferença significativa na temperatura máxima e na precipitação entre cada fase, porém, a temperatura mínima e o módulo do vento apresentaram pouca diferença. Os fluxos cinemáticos turbulentos analisados, por escala, em três horários distintos, foram mais diferentes durante o período diurno, principalmente w’T’ e w’q’. A diferença entre fase ativa e fase inativa foi reduzindo com passar do dia, durante o período de transição dia – noite, poucas escalas tiveram diferença significativa, e durante a noite, nenhuma escala teve nível de confiança acima ou igual a 95%. Estes resultados indicam que a convecção diurna é o mecanismo responsável por esta diferença e como a OMJ atua como uma grande célula convectiva, a convecção local é amplificada, explicando a grande diferença observada entre as fases durante o período diurno.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This work presents a framework for full-time education in Brazil, analyzing the levels of proximity and distance of the Brazilian regions in relation to achieving target paragraph 06 of the bill of the new National Education Plan, which establishes the offer of full-time education in at least fifty percent of public schools, and at least twenty-five percent of students in basic education. It aims to determine the contribution of the “Mais Educação” (More Education) Program of the federal government in fulfilling this goal.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Studies show that the disciplines of differential and integral calculus have high failure rates in all schools where they are present and, although this problem has been accentuated in recent years, it is not a local phenomenon. It's observed since 1970s in various Institutions of higher education in Brazil. These studies seek to understand the causes of failures and proposals for teaching methodology that aims to help reduce these rates. However, there is a large contingent of students who are successful at the first time that they perform these disciplines. And these cases, although they have not been studied, can contribute greatly to the understanding the aspects that are related to learning of them. And this understanding can lead to attitudes and learning and teaching methodologies that promote the expansion of this success. The fact that these subjects also have high failure rates in the Degree in Chemistry of this Institute, this study aimed to investigate the factors that were relevant to the cases for approval of the students performed for the first time. For this we constructed a questionnaire containing objective questions and open answers. The objective sought to diagnose the profile of these students with regard to age, gender, basic education (elementary and middle school), study habits, concurrent activities, among others. These questions were analyzed using simple statistics. The open-ended questions asked students to indicate that they attribute the success obtained in the disciplines and to suggest modes of study. These questions were analyzed using thematic categorization, a method of content analysis. This questionnaire was completed, voluntarily and without identification, by students who have passed the first time attended the courses Calculus I and/ or Calculus II and had never started another college prior to this. The results indicate that the most relevant factors in this process were dedication and correct habits...

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Pós-graduação em Matemática em Rede Nacional - IBILCE

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This paperaims to determine the velocity profile, in transient state, for a parallel incompressible flow known as Couette flow. The Navier-Stokes equations were applied upon this flow. Analytical solutions, based in Fourier series and integral transforms, were obtained for the one-dimensional transient Couette flow, taking into account constant and time-dependent pressure gradients acting on the fluid since the same instant when the plate starts it´s movement. Taking advantage of the orthogonality and superposition properties solutions were foundfor both considered cases. Considering a time-dependent pressure gradient, it was found a general solution for the Couette flow for a particular time function. It was found that the solution for a time-dependent pressure gradient includes the solutions for a zero pressure gradient and for a constant pressure gradient.

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This study aims to evaluate the quality of life of students aged 7 to 12 years in two municipal schools in the municipality of Minas Gerais. One offers full-time care to their students with extracurricular activities and other school offers only the normal. We used the questionnaire AUQEI, Autoquestionnaire Qualité de Vie Enfant Image. The questionnaire was administered to 232 children. Through this study, we observed that the proportion of children with a good Quality of Life was higher in school full time (81%), compared to the normal school hours (58%). Therefore, it is concluded that the school offers an extended workday, is set in an area rich able to develop the maximum potential of children and their personal skills, which will reflect positively on their quality of life.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Selection of the appropriate management unit is critical to the conservation of animal populations. Defining such units depends upon knowledge of population structure and upon the timescale being considered. Here, we examine the trajectory of eleven subpopulations of five species of baleen whales to investigate temporal and spatial scales in management. These subpopulations were all extirpated by commercial whaling, and no recovery or repopulation has occurred since. In these cases, time elapsed since commercial extinction ranges from four decades to almost four centuries. We propose that these subpopulations did not recover either because cultural memory of the habitat has been lost, because widespread whaling among adjacent stocks eliminated these as sources for repopulation, and/or because segregation following exploitation produced the abandonment of certain areas. Spatial scales associated with the extirpated subpopulations are frequently smaller than those typically employed in management. Overall, the evidence indicates that: (1) the time frame for management should be at most decadal in scope (i.e., <100 yr) and based on both genetic and nongenetic evidence of population substructure, and (2) at least some stocks should be defined on a smaller spatial scale than they currently are.

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We deal with the optimization of the production of branched sheet metal products. New forming techniques for sheet metal give rise to a wide variety of possible profiles and possible ways of production. In particular, we show how the problem of producing a given profile geometry can be modeled as a discrete optimization problem. We provide a theoretical analysis of the model in order to improve its solution time. In this context we give the complete convex hull description of some substructures of the underlying polyhedron. Moreover, we introduce a new class of facet-defining inequalities that represent connectivity constraints for the profile and show how these inequalities can be separated in polynomial time. Finally, we present numerical results for various test instances, both real-world and academic examples.

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In a recent study we demonstrated the emergence of turbulence in a trapped Bose-Einstein condensate of Rb-87 atoms. An intriguing observation in such a system is the behavior of the turbulent cloud during free expansion. The aspect ratio of the cloud size does not change in the way one would expect for an ordinary non-rotating (vortex-free) condensate. Here we show that the anomalous expansion can be understood, at least qualitatively, in terms of the presence of vorticity distributed throughout the cloud, effectively counteracting the usual reversal of the aspect ratio seen in free time-of-flight expansion of non-rotating condensates.

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Electrothermomechanical MEMS are essentially microactuators that operate based on the thermoelastic effect induced by the Joule heating of the structure. They can be easily fabricated and require relatively low excitation voltages. However, the actuation time of an electrothermomechanical microdevice is higher than the actuation times related to electrostatic and piezoelectric actuation principles. Thus, in this research, we propose an optimization framework based on the topology optimization method applied to transient problems, to design electrothermomechanical microactuators for response time reduction. The objective is to maximize the integral of the output displacement of the actuator, which is a function of time. The finite element equations that govern the time response of the actuators are provided. Furthermore, the Solid Isotropic Material with Penalization model and Sequential Linear Programming are employed. Finally, a smoothing filter is implemented to control the solution. Results aiming at two distinct applications suggest the proposed approach can provide more than 50% faster actuators. (C) 2012 Elsevier B.V. All rights reserved.

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Máster Universitario en Sistemas Inteligentes y Aplicaciones Numéricas en Ingeniería (SIANI)