Hydrodynamics of dense granular systems

The properties of dense granular systems are analyzed from a hydrodynamical point of view, based on conservation laws for the particle number density and linear momentum. We discuss averaging problems associated with the nature of such systems and the peculiarities of the sources of noise. We perform a quantitative study by combining analytical methods and numerical results obtained by ensemble-averaging of data on creep during compaction and molecular dynamics simulations of convective flow. We show that numerical integration of the hydrodynamic equations gives the expected evolution for the time-dependent fields.Comment: 10 pages, 7 figure

The dynamic characterisation of disk geometry particle dampers

Particle dampers (PDs) have the advantages of being simple in geometry, small in volume and applicable in extreme temperature environments. Experimental studies have shown that PDs can offer considerable potential for suppressing structural resonant conditions over a wide frequency range. In this paper, the nonlinear characteristics of PDs are studied experimentally in a series of response-level-controlled tests. The effect of the geometry is studied and a method is developed to model the nonlinear damping of PDs as equivalent viscous dampers that can be applied directly to engineering structures at the design stage

A memória educativa e o “fazer" do gestor escolar : uma abordagem psicanalítica

Monografia (especialização)—Universidade de Brasília, Ministério da Educação, Centro de Estudos Avançados Multidisciplinares, Centro de Formação Continuada de Professores, Secretaria de Educação do Distrito Federal, Escola de Aperfeiçoamento de Profissionais da Educação, Curso de Especialização em Gestão Escolar, 2014.A trajetória na construção dessa monografia baseia-se no campo da subjetividade e traz como objetivo geral identificar aspectos da memória educativa que influenciam o “fazer” do gestor escolar (diretor e vice) em uma escola pública do Distrito Federal e como objetivos específicos analisar alguns aspectos da memória educativa dos sujeitos (diretor e vice) e identificar e estabelecer possíveis relações de fatos das memórias educativas com o “fazer” destes profissionais. Nesta perspectiva, a pesquisa apresenta aspectos reflexivos em relação ao “fazer” do gestor escolar numa abordagem psicanalítica. Esse trabalho foi realizado à luz da abordagem qualitativa com natureza exploratória e busca ressaltar saberes e fazeres do gestor e o reflexo disso em sua atuação. Na análise dos dados, os processos subjetivos são ressaltados, pois os mesmos constituem a identidade do sujeito. A base da pesquisa é a apreciação e análise das memórias educativas e também dados obtidos por meio de entrevistas semiestruturadas de duas gestoras de uma escola pública no Distrito Federal. Os resultados indicam que a subjetividade e os processos inconscientes perpassam direta ou indiretamente todas as ações do gestor escolar

A numerical study of the Navier-Stokes transport coefficients for two-dimensional granular hydrodynamics

A numerical study that aims to analyze the thermal mechanisms of unsteady, supersonic granular flow by means of hydrodynamic simulations of the Navier–Stokes granular equation is reported in this paper. For this purpose, a paradigmatic problem in granular dynamics such as the Faraday instability is selected. Two different approaches for the Navier–Stokes transport coefficients for granular materials are considered, namely the traditional Jenkins–Richman theory for moderately dense quasi-elastic grains and the improved Garzó–Dufty–Lutsko theory for arbitrary inelasticity, which we also present here. Both the solutions are compared with event-driven simulations of the same system under the same conditions, by analyzing the density, temperature and velocity field. Important differences are found between the two approaches, leading to interesting implications. In particular, the heat transfer mechanism coupled to the density gradient, which is a distinctive feature of inelastic granular gases, is responsible for a major discrepancy in the temperature field and hence in the diffusion mechanisms