Dinâmica de rotação de exoplanetas tipo terrestre com perturbação de terceiro corpo

In this work we study some topics of Celestial Mechanics, namely the problem of rigid body rotation and “spin-orbit” resonances. Emphasis is placed on the problem formulation and applications to some exoplanets with physical parameters (e.g. mass and radius) compatible with a terrestrial type constitution (e.g. rock) belonging to multiple planetary systems. The approach is both analytical and numerical. The analytical part consists of: i) the deduction of the equation of motion for the rotation problem of a spherical body with no symmetry, disturbed by a central body; ii) modeling the same problem by including a third-body in the planet-star system; iii) formulation of the concept of “spin-orbit” resonance in which the orbital period of the planet is an integer multiple of the rotation’s period. Topics of dynamical systems (e.g. equilibrium points, chaos, surface sections, etc.) will be included at this stage. In the numerical part simulations are performed with numerical models developed in the previous analytical section. As a first step we consider the orbit of the planet not perturbed by a third-body in the star-planet system. In this case the eccentricity and orbital semi-major axis of the planet are constants. Here the technique of surface sections, widely used in dynamical systems are applied. Next, we consider the action of a third body, developing a more realistic model for planetary rotation. The results in both cases are compared. Since the technique of disturbed surface sections is no longer applicable, we quantitatively evaluate the evolution of the characteristic angles of rotation (e.g. physical libration) by studying the evolution of individual orbits in the dynamically important regions of phase space, the latter obtained in the undisturbed case

Análise dos efeitos das deformações estruturais sobre a transferência transversal de carga em um veículo do tipo fórmula SAE submetido a uma aceleração lateral constante

This paper studies the frame deformations on a formula SAE vehicle in steady-state cornering and its influence on the lateral load transfers and, consequently, on the tires normal loads due to the applied lateral load. For a vehicle with a perfect rigid frame, the vehicle mass, the position of the center of gravity and the suspensions are the only factors responsible for the load distribution between the tires. When the frame deformations are no longer negligible, the frame deformations affect the loaddistribution between the tires. The frame flexibility turns it able to behave as an additional set of springs to the suspension system, thus changing the behavior of the set. This paper describes howit happens and suggests ways to minimize this phenomenon

Análise da estabilidade do movimento rotacional de satélites artificiais com quatérnions e sob a influência de torques externos

The aim of this work is to analyze the stability of the rotational motion’s artificial satellite using the Routh Hurwitz Algorithm (CRH) and the quaternions to describe the satellite’s attitude. This algorithm allows the investigation of the stability of the motion using the coefficients of the characteristic equation associated with the equation of the rotational motion in the linear form. The equations of the rotational motion are given by the four cinematic equations for the quaternion and the three equations of Euler for the spin velocity’s components. In the Euler equations are included the components of the gravity gradient torque (TGG) and the solar radiation torque (TRS). The TGG is generated by the difference of the Earth gravity force direction and intensity actuating on each satellite mass element and it depends on the mass distribution and the form of the satellite. The TRS is created by changing of the linear momentum, which happens due to the interactions of solar photons with the satellite surface. The equilibrium points are gotten by the equation of rotational motion and the CRH is applied in the linear form of these equations. Simulations are developed for small and medium satellites, but the gotten equilibrium points are not stable by CRH. However, when some of the eigenvalues of the characteristic equation are analyzed, it is found some equilibrium points which can be pointed out as stables for an interval of the time, due to small magnitude of the real part of these eigenvalue

Determinação da freqüência natural de eixos utilizando o software excel

This work aims to determine the first natural frequency of rotation shaft by using a basic software, Excel, and to compare it to the values obtained in laboratory. When an axle is submitted to a rotation, depending on the rotational frequency used, the axle can enter a state of resonance, in which the amplitude of vibration becomes rather high. The frequencies in which the resonance is observed depends on several parameters of the axle, including the number of concentrated masses associated to the axle. Thus, to obtain a computer program of easy use and access, which can preview the frequency of resonance of an axle in rotation with ‘n’ numbers of concentrated masses it has been studied how the frequency varies with each of these parameters. The computer program and the analyses have been made using the Rayleigh Method, which allowed the transformation of a continuous system to discrete through the theory of finite elements, which has proved that, the bigger the number of divisions of the shaft taken into consideration in the calculus of the natural frequency, the more this value gets close to the real value. The results obtained have been considered satisfactory once these have gotten close to the theoretical results expected

Estudo da interação não-nativa no enovelamento de proteínas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Prospecção de novos peptídeos com ação leishmanicida por dinâmica molecular

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo das interações de peptídeos antimicrobianos e sistemas miméticos de membrana por dinâmica molecular

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Novos peptídeos sintéticos e estudo da interação com membranas modelo: efeito de modificações no N-terminal na atividade lítica e antimicrobiana

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise de geradores piezelétricos acoplados com circuitos retificadores operando em regime caótico

Pós-graduação em Engenharia Mecânica - FEIS

A ideologia dos meios de comunicação social na formação da consciência familiar

Pós-graduação em Serviço Social - FCHS

Expansão térmica de nanotubos de carbono de duas camadas

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Dinâmica e controle de um sistema Maglev simplificado

Pós-graduação em Engenharia Mecânica - FEIS

Mecenato no Brasil democrático

This paper analyzes the dynamics of Brazilian cultural policy between 1995 and 2010. Studies related defend the existence of a "contrast" between the results obtained by the government of Fernando Henrique Cardoso (1995-2002) and Luiz Inácio Lula da Silva (2003- 2010), that divide it between a model "neo-liberal" and a "democratic" model of cultural policy. Our main achievement is to produce empirical knowledge that can verify these claims. The build of indicators was guided by the theoretical assumption of the historical new institutionalism, discussed by Pierson (2006), and the observed universe comprises the totality of cultural producers who have submitted projects to “Mecenato”, registered in SALICNET - Ministry of Culture.

Estudo dos efeitos do tamanho e comensurabilidade nas correntes críticas em fitas supercondutoras do tipo II com redes periódicas de pinnings à temperatura finita

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Estudo da Estrutura da Proteína SH do Vírus Sincicial Respiratório Humano: análise funcional da estrutura pentamérica por ferramentas de bioinformática

Pós-graduação em Biofísica Molecular - IBILCE