O futebol e sua encenação como um campo de batalha

O presente artigo versa sobre o futebol destacando seus componentes essenciais: o campo, o jogador e o jogo e como a combinação destes elementos dá forma ao esporte mais popular do planeta

Nonlinear modeling of slewing flexible structures: ideal and non ideal approaches

The mathematical modelling of rotating nonlinear flexible beam-like wing, driven by a DC motor, with rectangular cross section is investigated here. The structure is mathematically modeled considering linear curvature and clamped-free boundary conditions. The flexible wing has an angle of attack which is considered constant. Nonlinearities resulting from the coupling between the angular velocity of the rotating axis and the transversal vibration of the beam are considered. A drag force and a lift force acting along the beam length are also included in the mathematical model. These forces are velocity dependent nonlinear excitations acting on the bean-like wing

Nonlinear modeling of slewing flexible structures: ideal and non ideal approaches

The mathematical modelling of rotating nonlinear flexible beam-like wing, driven by a DC motor, with rectangular cross section is investigated here. The structure is mathematically modeled considering linear curvature and clamped-free boundary conditions. The flexible wing has an angle of attack which is considered constant. Nonlinearities resulting from the coupling between the angular velocity of the rotating axis and the transversal vibration of the beam are considered. A drag force and a lift force acting along the beam length are also included in the mathematical model. These forces are velocity dependent nonlinear excitations acting on the bean-like wing

Nonlinear modeling of slewing flexible structures: ideal and non ideal approaches

The mathematical modelling of rotating nonlinear flexible beam-like wing, driven by a DC motor, with rectangular cross section is investigated here. The structure is mathematically modeled considering linear curvature and clamped-free boundary conditions. The flexible wing has an angle of attack which is considered constant. Nonlinearities resulting from the coupling between the angular velocity of the rotating axis and the transversal vibration of the beam are considered. A drag force and a lift force acting along the beam length are also included in the mathematical model. These forces are velocity dependent nonlinear excitations acting on the bean-like wing

O escoamento atmosférico no Centro de Lançamento de Alcântara

The atmospheric flow at Alcântara Launch Center (CLA) was studied using Computational Fluid Dynamics (CFD) techniques. To characterize the region were considered the coastal cliff and the Integration Mobile Tower, called TMI, both within the launching and preparation area (SPL). In this study, the cliff was represented by a step of 90° with 40 meters of height. The inlet velocity profile was elaborate according to the power law, with exponent of 0.11, freestream velocity of 20 m/s and Reynolds number of 4.3 x 105, adopting neutral atmosphere. Three wind directions were considered, 90º, 125º and 135°. The numerical model used was the Reynolds Stress Model (RSM), based on the Reynolds-Averaged Navier-Stokes (RANS) equations. The solution of the equations was obtained by ANSYS FLUENT 19, which uses the finite volume method. The results showed good agreement with the wind tunnel tests especially for wind direction perpendicular to the cliff. The incident wind direction strongly influences the flow dynamics in the SPL forming a helicoidal vortex over the coastal cliff the higher the wind slope.O escoamento atmosférico no Centro de Lançamento de Alcântara (CLA) foi estudado utilizando técnicas de Dinâmica dos Fluidos Computacional (CFD). Para caracterizar a região foi considerada a presença da falésia e da Torre Móvel de Integração (TMI), ambas dentro do Setor de Preparação e Lançamento (SPL). Nesse estudo, a falésia de 40 metros de altura foi representada por um degrau de 90°. O perfil de velocidade de entrada foi elaborado de acordo com a lei de potência, com expoente de 0,11, velocidade média de 20 m/s e número de Reynolds de 4,3 x 105, considerando a atmosfera com estabilidade neutra. Três direções de vento foram testadas, 90º, 125º e 135°. O modelo numérico utilizado foi o Reynolds Stress Model (RSM), baseado nas equações de Reynolds-Averaged Navier-Stokes (RANS). A solução das equações foi obtida pelo software ANSYS FLUENT 19, que utiliza o método dos volumes finitos. Os resultados apresentaram boa concordância com os experimentos de túnel de vento especialmente para direção do vento perpendicular à falésia. A direção predominante do vento influencia fortemente a dinâmica do escoamento atmosférico no SPL, formando um vórtice helicoidal sobre a falésia associado à rotação do vento

The baroclinic structure of the Brazil Current System in the São Paulo Bight

The Brazil Current System is formed by two western boundary currents that flow along the Southeast Brazil continental margin from surface to 1800 m deep. These two currents are the southward-flowing Brazil Current (BC) and the northward-flowing Intermediate Western Boundary Current (IWBC). The investigation of the dynamics of the baroclinic vorticity waves superimposed to the BC System is conducted solely from hydrographic data analysis from two oceanographic mesoscale surveys from the COROAS Project, as part of the World Ocean Circulation Experiment. These two cruises sampled the central portion of the São Paulo Bight (23.5o 27o S) in the summer and winter of 1993. To apply the classical dynamical method to calculate the geostrophic velocities, a quantitative estimate of the reference level is conducted through the comparison of two different and independent methodologies. The first uses the previous knowledge that the BC transports Tropical Water (TW) and South Atlantic Central Water (SACW), and IWBC transports mainly Antarctic Intermediate Water (AAIW). This method, referred here as the Thermodynamical Criterion, applies the Shtokman theorems to estimate the interface depth between SACW and AAIW. The second methodology, designated here as the Dynamical Criterion, consists of modeling absolute baroclinic velocities for all 14 hydrographic transects using the sectional version of the Princeton Ocean Model (POM). The results of those two methods differ only by 7 dbar and reference level 480 dbar is adopted to represent the average interface isobaric level between BC and IWBC, in the geostrophic calculations. Horizontal distributions of geostrophic stream function are generated using objective mapping. These distributions present unequivocal evidences of cyclonic and anticyclonic structures in both summer and winter 1993 cruises. These features are associated to meanders of the BC System. They are depicted in opposing sides of the current core. The cyclone is seen in the BC coastal side as the anticyclone is placed in its oceanic side. The single vertical inversion of these horizontal flows confirms that these vortex-like features are part of a first baroclinic mode wave, which corroborates previous speculations found in the literature..Pages: 1265-126

Preliminary development plan of the ALR, the laser rangefinder for the ASTER deep space mission to the 2001 SN263 asteroid

The Brazilian deep space mission ASTER, as temporarily named, plans to send a small spacecraft to encounter and investigate the triple asteroid 2001-SN263. The launch is scheduled (initially) to occur in 2015, arriving in 2018. The main motivation of the mission is the development of technology and expertise to leverage the national space sector. Within the scientific goals, the investigation of the still unknown asteroid 2001-SN263. The main project guideline is to aggregate the widest possible Brazilian involvement in the platform, the development and operation of subsystems, integration, payload, as well as in the tracking, navigation, guidance and control of the probe. To meet this guideline, among others, the decision for the development of a laser altimeter in Brazil to fly in the mission was taken. This effort is currently coordinated by a group of researchers from the aerospace engineering personnel of UFABC. This article presents the preliminary development plan for the design of this instrument, which was called ALR (ASTER Laser Rangefinder)