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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Desenvolvimento da função perturbadora e aplicações em dinâmica de exoplanetas

Casteletti, Juliana Rodrigues [UNESP] 06 November 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-11-06Bitstream added on 2014-06-13T18:30:57Z : No. of bitstreams: 1 casteletti_jr_me_rcla.pdf: 1198028 bytes, checksum: 64d53c9ad4dac00f0f39d72fc52d6fae (MD5) / Secretaria de Educação do Estado de São Paulo / Realizamos neste trabalho o estudo de tópicos fundamentais de Mecânica Celeste visando a aplicação em problemas de interesse atual, tal como o estudo de ressonâncias de movimentos médios em sistemas planetários extrassolares. Ênfase foi dada nos seguintes tópicos: i) formulação do problema ressonante de dois planetas em interação mútua; ii) desenvolvimento e expansão da função perturbadora; iii) solução numérica de problemas de valor inicial; iv) aplicações ao par de planetas HD10180d,e, os quais estão próximos da ressonância 3:1. A abordagem dos problemas foi realizada analítica e numericamente. Na primeira parte deste trabalho formulamos o problema geral de três corpos e reproduzimos os principais passos do desenvolvimento da função perturbadora. Na segunda parte realizamos simulações dos sistemas em questão utilizando as equações exatas de movimento (Newton) e comparamos os resultados com soluções numéricas das equações de Lagrange, i.e., equações de variação dos elementos orbitais escritas em termos da função perturbadora envolvida. Os resultados das simulações numéricas realizadas neste trabalho poderão ser aplicados para três propostas: i) comparação dos resultados entre as soluções exatas e aproximadas (Lagrange) das equações de movimento para, com isso, obter evidências numéricas do domínio de validade da aplicação da função perturbadora expandida nos problemas ressonantes; ii) estudo de dinâmica ressonante, i.e., caracterização e evolução temporal de ângulos críticos associados às ressonâncias; iii) estabilidade dinâmica de longo período dos sistemas em questão / In this work we study a fundamental Celestial Mechanics in order to apply to problems of current interest, such as dynamics of extrasolar planetary systems. Emphasis is given on the following topics: i) formulation of the problem of two resonant planets in mutual interaction, ii) dedution and expansion of the disturbing function; iii) numerical solution of initial value problems, iv) applications to the pair of planets HD10180d,e which orbits are near to the 3:1 resonance. We adopt both, analytical and numerical approaches. In the first part, we formulate the general three-body problem, and reproduce the main steps of the expansion of the disturbing function. In the second part we show the results of a great deal of numerical simulations of the systems using both the exact equations of motion (Newton) Lagrange equations. The simulations have been done with three main goals: i) comparison of the results of the exact and approximate solutions (Lagrange) equations of motion, in order to obtain numerical evidences of the validity domain of the application of the expanded disturbing function to resonant problems, ii) study of the resonant dynamics, i.e., characterization and evolution of critical angles associated with resonances, iii) investigate long-term dynamic stability of the systems in question
52

Pohyb malých těles sluneční soustavy:od prachových částic k asteroidům / Dynamics of small bodies in the Solar System: from dust particles to asteroid

Pokorný, Petr January 2014 (has links)
In this thesis, we study two different topics: collisional probability between two bodies and dynamics of the sporadic meteoroids in the Solar System. Determination of the collision probabilities in the Solar System is one of the important problems in mod- ern celestial mechanics. Here, we generalize classical theories of the collisions between two bodies by Öpik, Wetherill or Greenberg by including the Kozai-Lidov oscillations, a mechanism that significantly change orbital eccentricity and inclination in the Solar System. Sporadic meteors have been studied for many decades providing a wealthy re- source of data. Here, we build dynamical steady-state models for all known populations observed in the sporadic meteoroid complex based on the latest and most precise data provided by Canadian Meteor Orbit Radar (CMOR). Our models using the latest theo- ries for cometary populations in the Solar System accurately describe observed sporadic background population. Our results are in agreement with observations provided by space probes IRAS and LDEF.
53

Jarkovského a YORP jevy v dynamice těles Sluneční soustavy / Yarkovsky and YORP Effects in Dynamics of Small Bodies of the Solar System

Žižka, Jindřich January 2018 (has links)
In this thesis, we study the influence of non-gravitational perturbations induced by the Yarkovsky/YORP effect and solar radiation pressure (SRP) on the orbital evolution of selected asteroids, asteroid families and pairs. These perturbations are of great importance if one wants to perform precise and long-term propagation of meter-sized and kilometer-sized bodies. Although they have found many applications in the Solar System, here, we particularly investigated how they influence the orbit of near-Earth asteroid (99942) Apophis and what is their role in the age determination of asteroid families and pairs. Our numerical simulations showed that the perturbations of Apophis' orbit caused by the SRP are orders of magnitude smaller than those produced by the Yarkovsky effect. The age determination of asteroid families and pairs was another pillar of this work. Over the past decade it turned out that the Yarkovsky effect must be taken into account for backward propagation of pair/family members. We modified the current method for estimating the age of asteroid pairs to be suitable for weakly convergent cases and discovered 7 young pairs with similar-sized components, which is in contradiction with the current theory of pair formation. In addition, we focused on an interesting pair of asteroids -...
54

Rebirth of a Lineage: The Hereditary Household of the Han Celestial Master and Celestial Masters Daoism at Dragon and Tiger Mountain

January 2016 (has links)
abstract: This dissertation is a study and translation of the Hereditary Household of the Han Celestial Master (Han tianshi shijia 漢天師世家), a hagiographical account of successive generations of the Zhang family patriarchs of Celestial Masters Daoism (Tianshi dao 天師道) at Dragon and Tiger Mountain (Longhu shan 龍虎山) in Jiangxi province that was compiled in stages between the late fourteenth and early seventeenth centuries. The Zhang family emerged in the late Tang or early Five dynasties period and rose to great prominence and power through the Song, Yuan, and Ming dynasties on the basis of the claim of direct and unbroken lineal descent from Zhang Daoling 張道陵 the ancestral Celestial Master whose covenant with the deified Laozi in 142 C.E. is a founding event of the Daoist religion. In this study I trace the lineal history of the Zhang family as presented in the Hereditary Household in chronological parallel to contrasting narratives found in official histories, epigraphy, and the literary record. This approach affords insight into the polemical nature of the text as an assertion of legitimacy and allows for a demonstration of how the work represents an attempt to create in writing an idealized past in order to win prestige in the present. It also affords the opportunity to scour the historical record in an attempt to ascertain a plausible timeframe for the origin of the movement and to explore the relationship of the Hereditary Household to earlier hagiographic works that may have informed it. This study also contextualizes the Hereditary Household in the post-Tang religious climate of China. In that period the establishment of lineal authenticity and institutional charisma through narratives of descent became a widespread tool of legitimation employed by Buddhists, Daoists, and Confucians in hopes of obtaining imperial recognition and patronage. / Dissertation/Thesis / Doctoral Dissertation Religious Studies 2016
55

Observation of celestial phenomena in the Gospel of Matthew

Um, Hongsuk January 2016 (has links)
A close reading of the gospel of Matthew highlights the striking reports of the observation of distinct celestial phenomena in the narrative (e.g. 2.1-12; 3.16-17; 17.5; 24.29-31). However, the motif of celestial phenomena in Matthew lacks a full or even comprehensive investigation. These have been addressed only in part both in journal articles and in individual chapters of various books. Looking at these celestial phenomena as interrelated parts of the evangelist’s wide theological perspective in the gospel, this study explores Matthew’s description of these occurrences in relation to the contemporary perspective on celestial phenomena and astrological application. It seeks to assess what meaning and significance the Matthean representation of celestial phenomena was designed to have in the process of the gospel narrative and for the readership. In so doing, this study discusses the conception of heaven and the attitude towards celestial phenomena in the Graeco-Roman world in the Second Temple period, the Sitz im Leben of the Matthean community, and the significance of the heaven motif in the gospel narrative, as preliminaries to the investigation of Matthew’s portrayal of celestial phenomena. This study will show that the motif of celestial phenomena in Matthew carefully crafted and thoughtfully arranged plays a significant role in authenticating the identity of Jesus.
56

Desenvolvimento da função perturbadora e aplicações em dinâmica de exoplanetas /

Casteletti, Juliana Rodrigues. January 2013 (has links)
Orientador: Nelson Callegari Júnior / Banca: Marcos Tadeu dos Santos / Banca: Renata Zotin Gomes de Oliveira / Resumo: Realizamos neste trabalho o estudo de tópicos fundamentais de Mecânica Celeste visando a aplicação em problemas de interesse atual, tal como o estudo de ressonâncias de movimentos médios em sistemas planetários extrassolares. Ênfase foi dada nos seguintes tópicos: i) formulação do problema ressonante de dois planetas em interação mútua; ii) desenvolvimento e expansão da função perturbadora; iii) solução numérica de problemas de valor inicial; iv) aplicações ao par de planetas HD10180d,e, os quais estão próximos da ressonância 3:1. A abordagem dos problemas foi realizada analítica e numericamente. Na primeira parte deste trabalho formulamos o problema geral de três corpos e reproduzimos os principais passos do desenvolvimento da função perturbadora. Na segunda parte realizamos simulações dos sistemas em questão utilizando as equações exatas de movimento (Newton) e comparamos os resultados com soluções numéricas das equações de Lagrange, i.e., equações de variação dos elementos orbitais escritas em termos da função perturbadora envolvida. Os resultados das simulações numéricas realizadas neste trabalho poderão ser aplicados para três propostas: i) comparação dos resultados entre as soluções exatas e aproximadas (Lagrange) das equações de movimento para, com isso, obter evidências numéricas do domínio de validade da aplicação da função perturbadora expandida nos problemas ressonantes; ii) estudo de dinâmica ressonante, i.e., caracterização e evolução temporal de ângulos críticos associados às ressonâncias; iii) estabilidade dinâmica de longo período dos sistemas em questão / Abstract: In this work we study a fundamental Celestial Mechanics in order to apply to problems of current interest, such as dynamics of extrasolar planetary systems. Emphasis is given on the following topics: i) formulation of the problem of two resonant planets in mutual interaction, ii) dedution and expansion of the disturbing function; iii) numerical solution of initial value problems, iv) applications to the pair of planets HD10180d,e which orbits are near to the 3:1 resonance. We adopt both, analytical and numerical approaches. In the first part, we formulate the general three-body problem, and reproduce the main steps of the expansion of the disturbing function. In the second part we show the results of a great deal of numerical simulations of the systems using both the exact equations of motion (Newton) Lagrange equations. The simulations have been done with three main goals: i) comparison of the results of the exact and approximate solutions (Lagrange) equations of motion, in order to obtain numerical evidences of the validity domain of the application of the expanded disturbing function to resonant problems, ii) study of the resonant dynamics, i.e., characterization and evolution of critical angles associated with resonances, iii) investigate long-term dynamic stability of the systems in question / Mestre
57

Central configurations of the curved N-body problem

Zhu, Shuqiang 14 July 2017 (has links)
We extend the concept of central configurations to the N-body problem in spaces of nonzero constant curvature. Based on the work of Florin Diacu on relative equilib- ria of the curved N-body problem and the work of Smale on general relative equilibria, we find a natural way to define the concept of central configurations with the effective potentials. We characterize the ordinary central configurations as constrained critical points of the cotangent potential, which helps us to establish the existence of ordi- nary central configurations for any given masses. After these fundamental results, we study central configurations on H2, ordinary central configurations in S3, and special central configurations in S3 in three separate chapters. For central configurations on H2, we generalize the theorem of Moulton on geodesic central configurations, the theorem of Shub on the compactness of central configurations, the theorem of Conley on the index of geodesic central configurations, and the theorem of Palmore on the lower bound for the number of central configurations. We show that all three-body central configurations that form equilateral triangles must have three equal masses. For ordinary central configurations in S3, we construct a class of S3 ordinary central configurations. We study the geodesic central configurations of two and three bodies. Three-body non-geodesic ordinary central configurations that form equilateral trian- gles must have three equal masses. We also put into the evidence some other classes of central configurations. For special central configurations, we show that for any N ≥ 3, there are masses that admit at least one special central configuration. We then consider the Dziobek special central configurations and obtain the central con- figuration equation in terms of mutual distances and volumes formed by the position vectors. We end the thesis with results concerning the stability of relative equilibria associated with 3-body special central configurations. We find that these relative equilibria are Lyapunov stable when confined to S1, and that they are linearly stable on S2 if and only if the angular momentum is bigger than a certain value determined by the configuration. / Graduate
58

Simplified Derivation of the Collision Probability of Two Objects in Independent Keplerian Orbits

JeongAhn, Youngmin, Malhotra, Renu 28 April 2017 (has links)
Many topics in planetary studies demand an estimate of the collision probability of two objects moving on nearly Keplerian orbits. In the classic works of Opik and Wetherill, the collision probability was derived by linearizing the motion near the collision points, and there is now a vast amount of literature using their method. We present here a simpler and more physically motivated derivation for non-tangential collisions in Keplerian orbits, as well as for tangential collisions that were not previously considered. Our formulas have the added advantage of being manifestly symmetric in the parameters of the two colliding bodies. In common with the Opik-Wetherill treatments, we linearize the motion of the bodies in the vicinity of the point of orbit intersection (or near the points of minimum distance between the two orbits) and assume a uniform distribution of impact parameter within the collision radius. We point out that the linear approximation leads to singular results for the case of tangential encounters. We regularize this singularity by use of a parabolic approximation of the motion in the vicinity of a tangential encounter.
59

Mean Motion Resonances at High Eccentricities: The 2:1 and the 3:2 Interior Resonances

Wang, Xianyu, Malhotra, Renu 22 June 2017 (has links)
Mean motion resonances (MMRs) play an important role in the formation and evolution of planetary systems and have significantly influenced the orbital properties and distribution of planets and minor planets in the solar system and in. exoplanetary systems. Most previous theoretical analyses have focused on the low- to moderate-eccentricity regime, but with new discoveries of high-eccentricity resonant minor planets and even exoplanets, there is increasing motivation to examine MMRs in the high-eccentricity regime. Here we report on a study of the high-eccentricity regime of MMRs in the circular planar restricted three-body problem. Numerical analyses of the 2: 1 and the 3: 2 interior resonances are carried out for a wide range of planet-to-star mass ratio mu, and for a wide range of eccentricity of the test particle. The surface-of-section technique is used to study the phase space structure near resonances. We find that new stable libration zones appear at higher eccentricity at libration centers that are. shifted from those at low eccentricities. We provide physically intuitive explanations for these transitions in phase space, and we present novel results on the mass and eccentricity dependence of the resonance widths. Our results show that MMRs have sizable libration zones at high eccentricities, comparable to those at lower eccentricities.
60

Kou Qianzhi (365-448) a reforma taoismu za dynastie Severní Wej / Kou Qianzhi (365-448) and the Daoist Reform during the Northern Wei Dynasty

Otčenášek, Jakub January 2011 (has links)
Filozofická fakulta Univerzity Karlovy v Praze Ústav Dálného východu Diplomová práce Jakub Otčenášek Kou Qianzhi (365-448) a reforma taoismu za dynastie Severní Wei Kou Qianzhi (365-448) and the Daoist Reform during the Northern Wei Dynasty Vedoucí práce: Olga Lomová 2011 Konzultant: Jakub Hrubý Poděkování Chtěl bych poděkovat Olze Lomové za vstřícnost, ochotu a cenné rady při vedení mé práce. Můj velký dík patří také mým francouzským pedagogům z École Pratique des Hautes Études (EPHE) v Paříži - Sylvii Hureau za pomoc s rešerší v buddhistických textech, Alainu Arraultovi za další rady a především Johnu Lagerweyovi, který mi pomohl proniknout do jazyka studovaného textu. Pobyt na EPHE mi byl umožněn studijním programem Erasmus. Svým rodičům děkuji za podporu při studiích. Prohlášení Prohlašuji, že jsem diplomovou práci vypracoval samostatně, že jsem řádně citoval všechny použité prameny a literaturu a že práce nebyla využita v rámci jiného vysokoškolského studia či k získání jiného nebo stejného titulu. V Praze dne 5. září 2011 Abstrakt Diplomová práce Kou Qianzhi (365-448) a reforma taoismu za dynastie Severní Wei analyzuje dílo Laojun yinsong jiejing 老君音誦誡經, připisované Kou Qianzhiovi 寇謙之, který v letech 424 až 448 působil na dvoře čínské dynastie Severní Wei jako hlava taoistické tradice nebeských...

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