An overview on a nonideal system with three and a half degrees of freedom

The present paper studies a system comprised of two blocks connected by springs and dampers, and a DC motor with limited power supply fixed on a block, characterizing a non-ideal problem. This DC motor exciting the system causes interactions between the motor and the structure supporting it. Because of that, the non-ideal mathematical formulation of the problem has one and a half extra degree of freedom than the ideal one. A suitable choice of physical parameters leads to internal resonance conditions, that is, its natural frequencies are multiple of each other, by a known integer quantity. The purpose here is to study the dynamic behavior of the system using an analytical method based on perturbation techniques. The literature shows that the averaging method is the more flexible method concerning non-ideal problems. Summarizing, an steady state solution in amplitude and phase coordinates was obtained with averaging method showing the dependence of the structure amplitudes with the rotation frequency of the motor. Moreover, this solution shows that on of the amplitude coordinates has influence in the determination of the stationary rotation frequency. The analytical solution obtained shows the presence of the rotation frequency in expressions representing the oscillations of the structure, and the presence of amplitude coordinates in expressions describing the dynamic motion of the DC motor. These characteristics show the influence not only of the motor on structure but also of the response of the structure on dynamical behavior of the motor. Copyright © 2005 by ASME.

On the dynamic behaviour of a nonlinear system weakly connected to a linear single degree-of-freedom system

This paper discusses the dynamic behaviour of a nonlinear two degree-of-freedom system consisting of a harmonically excited linear oscillator weakly connected to a nonlinear attachment that behaves as a hardening Duffing oscillator. A system which behaves in this way could be a shaker (linear system) driving a nonlinear isolator. The mass of the nonlinear system is taken to be much less than that in the linear system and thus the nonlinear system has little effect on the dynamics of the linear system. Of particular interest is the situation when the linear natural frequency of the nonlinear system is less than the natural frequency of the linear system such that the frequency response curve of the nonlinear system bends to higher frequencies and thus interacts with the resonance frequency of the linear system. It is shown that for some values of the system parameters a complicated frequency response curve for the nonlinear system can occur; closed detached curves can appear as a part of the overall amplitude-frequency response. The reason why these detached curves appear is presented and approximate analytical expressions for the jump-up and jump-down frequencies of the system under investigation are given.

Estimates of mortality among members of religious orders in Chile in XVIII and XIX centuries

Includes bibliography

A Pilot Study Addressing the Impact of Religious Practice on Quality of Life of Breast Cancer Patients During Chemotherapy

The aim of this preliminary study was to investigate whether religious practice can modify quality of life (QoL) in BC patients during chemotherapy. QoL and religion practice questionnaire (RPQ) scores were evaluated in a sample of BC patients in different moments. Before chemotherapy initiation, women with lower physical and social functional scores displayed higher RPQ scores. On the other hand, low RPQ patients worsened some QoL scores over time. Body image acceptance was positively correlated with religious practice and specifically praying activity. This preliminary study suggests the importance of religion in coping with cancer chemotherapy. © 2011 Springer Science+Business Media, LLC.

Frei Agostinho de Jesus e as tradições da imaginária colonial brasileira: séculos XVI-XVII

Pós-graduação em Artes - IA

Questões preliminares sobre aspectos do vazio na arte contemporânea

Pós-graduação em Artes - IA

The fifth freedom and the Southern Cone: a new perspective

An ECLAC document to be published in the near future examines a subject that has become a frequent topic of discussion in recent years, particularly in the Southern Cone of Latin America (Argentina, Bolivia, Brazil, Chile, Paraguay, Peru and Uruguay), where the greatest volume of land transport in South America is concentrated. Against a background of economic liberalization and integration in the region, and at a time when the development of regional transport infrastructures is growing in importance, the ECLAC Transport Unit analyses the Southern Cone Agreement on International Land Transport (Valparaíso, 1989) in an effort to give it fresh relevance and to determine whether its provisions can cope with the new challenges thrown up by more open international transport markets and management.

Deus abençoe a América: religião, política e relações internacionais dos Estados Unidos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Poder e memória: o autoritarismo na igreja presbiteriana do Brasil no período da ditadura militar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Control of Limit Cycle Oscillation in a Three Degrees of Freedom Airfoil Section Using Fuzzy Takagi-Sugeno Modeling

This work presents a strategy to control nonlinear responses of aeroelastic systems with control surface freeplay. The proposed methodology is developed for the three degrees of freedom typical section airfoil considering aerodynamic forces from Theodorsen's theory. The mathematical model is written in the state space representation using rational function approximation to write the aerodynamic forces in time domain. The control system is designed using the fuzzy Takagi-Sugeno modeling to compute a feedback control gain. It useds Lyapunov's stability function and linear matrix inequalities (LMIs) to solve a convex optimization problem. Time simulations with different initial conditions are performed using a modified Runge-Kutta algorithm to compare the system with and without control forces. It is shown that this approach can compute linear control gain able to stabilize aeroelastic systems with discontinuous nonlinearities.

Nonlinear dynamical analysis of an aeroelastic system with multi-segmented moment in the pitch degree-of-freedom

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

Importance of asymptotic freedom for the pseudocritical temperature in magnetized quark matter

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Algumas reflexões sobre a condição da mulher brasileira da colônia às primeiras décadas do século XX

This article, about reflections on the condition of Brazilian women from the Colony to the first decades of the twentieth century, reveals the historical position of them and the attitudes and behaviors related to gender and sexuality. Subdued, it was treated as a sexual object, arousing all sorts of misogyny by men. Rebel, veiled or ostensibly, could serve their own desires. Throughout history, the Church and medical institutions which jointly accounted for, significantly, established the meaning and place of women. In Colony period, the woman is a ward from the Catholic ideology, but from the nineteenth century, after Independence, this power control arises to Medicine. The physician submits the religious discourse, naturalizing the status of women as one that breeds, namely the insertion of the medical issues of family scientifically legitimate colonial patriarchy. This is accentuated in the early twentieth century, when medicine consolidated setting standards and rules for marriage, to motherhood and family life. We note how the feminine universe was (and it is nowadays) ambivalent, with "one foot" in virtue and another in sin, with a tendency to contain and another to trespass. On the one hand we have the home and motherhood, validated in marriage, in which the woman is cared for and dependent on her husband. Reflecting on the motherhood of Virgin Mary, comes to the sacred dimension of the idealized woman saint by the Church. At the same time, however, feels the need for freedom, identity and independence, needing to give a voice to the desire to have their sexuality and all that it is due in full. The manifestation of the desire and the call for sexual satisfaction, and put in permanent conflict personal, psychological and social split between moral entrenched across generations and cultural transformations resulting from decades of the 20th Century.