Dinâmica de uma partícula coorbital a um sistema de satélites

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

Estudo numérico da captura gravitacional temporária utilizando o problema de quatro corpos

Pós-graduação em Física - FEG

Universalidade em sistemas de 3 e 4 bósons

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Weakly bound states of two- and three-boson systems in the crossover from two to three dimensions

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

Estrutura de sistemas de três corpos fracamente ligados em duas dimensões

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Dynamics of the 3:1 resonant planetary systems

Many of the discovered exoplanetary systems are involved inside mean-motion resonances. In this work we focus on the dynamics of the 3:1 mean-motion resonant planetary systems. Our main purpose is to understand the dynamics in the vicinity of the apsidal corotation resonance (ACR) which are stationary solutions of the resonant problem. We apply the semi-analytical method (Michtchenko et al., 2006) to construct the averaged three-body Hamiltonian of a planetary system near a 3:1 resonance. Then we obtain the families of ACR, composed of symmetric and asymmetric solutions. Using the symmetric stable solutions we observe the law of structures (Ferraz-Mello,1988), for different mass ratio of the planets. We also study the evolution of the frequencies of σ1, resonant angle, and Δω, the secular angle. The resonant domains outside the immediate vicinity of ACR are studied using dynamical maps techniques. We compared the results obtained to planetary systems near a 3:1 MMR, namely 55 Cnc b-c, HD 60532 b-c and Kepler 20 b-c.

Study of electromagnetic reactions on light nuclei with the Lorentz Integral Transform method

In dieser Arbeit aus dem Bereich der Wenig-Nukleonen-Physik wird die neu entwickelte Methode der Lorentz Integral Transformation (LIT) auf die Untersuchung von Kernphotoabsorption und Elektronenstreuung an leichten Kernen angewendet. Die LIT-Methode ermoeglicht exakte Rechnungen durchzufuehren, ohne explizite Bestimmung der Endzustaende im Kontinuum. Das Problem wird auf die Loesung einer bindungzustandsaehnlichen Gleichung reduziert, bei der die Endzustandswechselwirkung vollstaendig beruecksichtigt wird. Die Loesung der LIT-Gleichung wird mit Hilfe einer Entwicklung nach hypersphaerischen harmonischen Funktionen durchgefuehrt, deren Konvergenz durch Anwendung einer effektiven Wechselwirkung im Rahmem des hypersphaerischen Formalismus (EIHH) beschleunigt wird. In dieser Arbeit wird die erste mikroskopische Berechnung des totalen Wirkungsquerschnittes fuer Photoabsorption unterhalb der Pionproduktionsschwelle an 6Li, 6He und 7Li vorgestellt. Die Rechnungen werden mit zentralen semirealistischen NN-Wechselwirkungen durchgefuehrt, die die Tensor Kraft teilweise simulieren, da die Bindungsenergien von Deuteron und von Drei-Teilchen-Kernen richtig reproduziert werden. Der Wirkungsquerschnitt fur Photoabsorption an 6Li zeigt nur eine Dipol-Riesenresonanz, waehrend 6He zwei unterschiedliche Piks aufweist, die dem Aufbruch vom Halo und vom Alpha-Core entsprechen. Der Vergleich mit experimentellen Daten zeigt, dass die Addition einer P-Wellen-Wechselwirkung die Uebereinstimmung wesentlich verbessert. Bei 7Li wird nur eine Dipol-Riesenresonanz gefunden, die gut mit den verfuegbaren experimentellen Daten uebereinstimmt. Bezueglich der Elektronenstreuung wird die Berechnung der longitudinalen und transversalen Antwortfunktionen von 4He im quasi-elastischen Bereich fuer mittlere Werte des Impulsuebertrages dargestellt. Fuer die Ladungs- und Stromoperatoren wird ein nichtrelativistisches Modell verwendet. Die Rechnungen sind mit semirealistischen Wechselwirkungen durchgefuert und ein eichinvarianter Strom wird durch die Einfuehrung eines Mesonaustauschstroms gewonnen. Die Wirkung des Zweiteilchenstroms auf die transversalen Antwortfunktionen wird untersucht. Vorlaeufige Ergebnisse werden gezeigt und mit den verfuegbaren experimentellen Daten verglichen.

RAPID SPACE TRAJECTORY GENERATION USING A FOURIER SERIES SHAPE-BASED APPROACH

With the insatiable curiosity of human beings to explore the universe and our solar system, it is essential to benefit from larger propulsion capabilities to execute efficient transfers and carry more scientific equipment. In the field of space trajectory optimization the fundamental advances in using low-thrust propulsion and exploiting the multi-body dynamics has played pivotal role in designing efficient space mission trajectories. The former provides larger cumulative momentum change in comparison with the conventional chemical propulsion whereas the latter results in almost ballistic trajectories with negligible amount of propellant. However, the problem of space trajectory design translates into an optimal control problem which is, in general, time-consuming and very difficult to solve. Therefore, the goal of the thesis is to address the above problem by developing a methodology to simplify and facilitate the process of finding initial low-thrust trajectories in both two-body and multi-body environments. This initial solution will not only provide mission designers with a better understanding of the problem and solution but also serves as a good initial guess for high-fidelity optimal control solvers and increases their convergence rate. Almost all of the high-fidelity solvers enjoy the existence of an initial guess that already satisfies the equations of motion and some of the most important constraints. Despite the nonlinear nature of the problem, it is sought to find a robust technique for a wide range of typical low-thrust transfers with reduced computational intensity. Another important aspect of our developed methodology is the representation of low-thrust trajectories by Fourier series with which the number of design variables reduces significantly. Emphasis is given on simplifying the equations of motion to the possible extent and avoid approximating the controls. These facts contribute to speeding up the solution finding procedure. Several example applications of two and three-dimensional two-body low-thrust transfers are considered. In addition, in the multi-body dynamic, and in particular the restricted-three-body dynamic, several Earth-to-Moon low-thrust transfers are investigated.

Edge Detection by Adaptive Splitting II. The Three-Dimensional Case

In Llanas and Lantarón, J. Sci. Comput. 46, 485–518 (2011) we proposed an algorithm (EDAS-d) to approximate the jump discontinuity set of functions defined on subsets of ℝ d . This procedure is based on adaptive splitting of the domain of the function guided by the value of an average integral. The above study was limited to the 1D and 2D versions of the algorithm. In this paper we address the three-dimensional problem. We prove an integral inequality (in the case d=3) which constitutes the basis of EDAS-3. We have performed detailed computational experiments demonstrating effective edge detection in 3D function models with different interface topologies. EDAS-1 and EDAS-2 appealing properties are extensible to the 3D case

Relativistic many-body bound systems : electromagnetic properties /

Mode of access: Internet.

Many-body quantum dynamics of polarization squeezing in optical fibers

We report new experiments that test quantum dynamical predictions of polarization squeezing for ultrashort photonic pulses in a birefringent fiber, including all relevant dissipative effects. This exponentially complex many-body problem is solved by means of a stochastic phase-space method. The squeezing is calculated and compared to experimental data, resulting in excellent quantitative agreement. From the simulations, we identify the physical limits to quantum noise reduction in optical fibers. The research represents a significant experimental test of first-principles time-domain quantum dynamics in a one-dimensional interacting Bose gas coupled to dissipative reservoirs.

O problema mente-corpo na psicologia fenomenológica de Edith Stein : implicações para uma fundamentação da ciência psicológica

Psychology is a relatively new scientific branch and still lacks consistent methodological foundation to support its investigations. Given its immaturity, this science finds difficulties to delimit its ontological status, which spawnes several epistemological and methodological misconceptions. Given this, Psychology failed to demarcate precisely its object of study, leading, thus, the emergence of numerous conceptions about the psychic, which resulted in the fragmentation of this science. In its constitution, psychological science inherited a complex philosophical problem: the mind-body issue. Therefore, to define their status, Psychology must still face this problem, seeking to elucidate what is the mind, the body and how they relate. In light of the importance of this issue to a strict demarcation of psychological object, it was sought in this research, to investigate the mind-body problem in the Phenomenological Psychology of Edith Stein (1891-1942), phenomenologist philosopher who undertook efforts for a foundation of Psychology. For that, the discussion was subsidized from the contributions of the Philosophy of Mind and the support of the phenomenological method to the mind-body problem. From there, by a qualitative bibliographical methodology, it sought to examine the problem of research through the analysis of some philosophical-psychological philosopher's works, named: "Psychic Causality” (Kausalität Psychische, 1922) and “Introduction to Philosophy" (Einführung in die Philosophie, 1920). For this investigation, it was made, without prejudice to the discussion, a terminological equivalence between the terms mind and psyche, as the philosopher used the latter to refer to the object of Psychology. It sought to examine, therefore, how Stein conceived the psyche, the body and the relationship between them. Although it wasn't the focus of the investigation, it also took into account the spiritual dimension, as the philosopher conceived the human person as consisting of three dimensions: body, psyche and spirit. Given this, Stein highlighted the causal mechanism of the psyche, which is based on the variations of the vital force that emerges from the vital sphere. In relation to the corporeal dimension, the philosopher, following the analysis of Edmund Husserl (1859-1938), highlighted the dual aspect of the body, because it is at the same time something material (Körper) and also a linving body (Leib). On the face of it, it is understood that the psyche and the body are closely connected, so that it constitutes a dual-unit which is manifested in the Leib. This understanding of the problem psyche-mind/body provides a rich analysis of this issue, enabling the overcoming of some inconsistencies of the monistic and dualistic positions. Given this, it allows a strict elucidation of the Psychology object, contributing to the foundation of this science.

Secular and tidal evolution of circumbinary systems

We investigate the secular dynamics of three-body circumbinary systems under the effect of tides. We use the octupolar non-restricted approximation for the orbital interactions, general relativity corrections, the quadrupolar approximation for the spins, and the viscous linear model for tides. We derive the averaged equations of motion in a simplified vectorial formalism, which is suitable to model the long-term evolution of a wide variety of circumbinary systems in very eccentric and inclined orbits. In particular, this vectorial approach can be used to derive constraints for tidal migration, capture in Cassini states, and stellar spin–orbit misalignment. We show that circumbinary planets with initial arbitrary orbital inclination can become coplanar through a secular resonance between the precession of the orbit and the precession of the spin of one of the stars. We also show that circumbinary systems for which the pericenter of the inner orbit is initially in libration present chaotic motion for the spins and for the eccentricity of the outer orbit. Because our model is valid for the non-restricted problem, it can also be applied to any three-body hierarchical system such as star–planet–satellite systems and triple stellar systems.

Fat talk and its relationship with body image disturbance

Although past studies have highlighted fat talk as relevant to body image disturbance, the majority of these have only investigated the link between fat talk and body esteem, to the exclusion of other body image constructs. One hundred and ninety-nine women completed an online survey measuring levels of appearance-based comparisons, body surveillance, thin ideal internalization, body esteem, and fat talk (FT-body concerns and FT-body comparisons). Results showed that fat talk made a significant contribution in explaining additional variance in body esteem above the other three body image factors, with FT-body concerns in particular making the highest unique contribution. Hierarchical regression analyses suggest that fat talk should be viewed as an independent psychosocial predictor of body esteem in both theoretical and therapeutic contexts. Future research should explore these relationships from a longitudinal perspective, and also clarify the nuances in the relationships by investigating the nature of women's everyday body image experiences.

Tailoring of ion species composition in complex plasmas with charge exchange collisions

A generic approach towards tailoring of ion species composition in reactive plasmas used for nanofabrication of various functional nanofilms and nanoassemblies, based on a simplified model of a parallel-plate rf discharge, is proposed. The model includes an idealized reactive plasma containing two neutral and two ionic species interacting via charge exchange collisions in the presence of a microdispersed solid component. It is shown that the number densities of the desired ionic species can be efficiently managed by adjusting the dilution of the working gas in a buffer gas, rates of electron impact ionization, losses of plasma species on the discharge walls, and surfaces of fine particles, charge exchange rates, and efficiency of three-body recombination processes in the plasma bulk. The results are relevant to the plasma-aided nanomanufacturing of ordered patterns of carbon nanotip and nanopyramid microemitters.