Search results for "Rodin"
showing 10 items of 101 documents
Angular Pseudomomentum Theory for the Generalized Nonlinear Schr\"{o}dinger Equation in Discrete Rotational Symmetry Media
2009
We develop a complete mathematical theory for the symmetrical solutions of the generalized nonlinear Schr\"odinger equation based on the new concept of angular pseudomomentum. We consider the symmetric solitons of a generalized nonlinear Schr\"odinger equation with a nonlinearity depending on the modulus of the field. We provide a rigorous proof of a set of mathematical results justifying that these solitons can be classified according to the irreducible representations of a discrete group. Then we extend this theory to non-stationary solutions and study the relationship between angular momentum and pseudomomentum. We illustrate these theoretical results with numerical examples. Finally, we…
Minimally implicit Runge-Kutta methods for Resistive Relativistic MHD
2016
The Relativistic Resistive Magnetohydrodynamic (RRMHD) equations are a hyperbolic system of partial differential equations used to describe the dynamics of relativistic magnetized fluids with a finite conductivity. Close to the ideal magnetohydrodynamic regime, the source term proportional to the conductivity becomes potentially stiff and cannot be handled with standard explicit time integration methods. We propose a new class of methods to deal with the stiffness fo the system, which we name Minimally Implicit Runge-Kutta methods. These methods avoid the development of numerical instabilities without increasing the computational costs in comparison with explicit methods, need no iterative …
Spritz: General relativistic magnetohydrodynamics with neutrinos
2020
We here present a new version of the publicly available general relativistic magnetohydrodynamic (GRMHD) code $\texttt{Spritz}$, which now includes an approximate neutrino leakage scheme able to handle neutrino cooling and heating. The leakage scheme is based on the publicly available $\texttt{ZelmaniLeak}$ code, with a few modifications in order to properly work with $\texttt{Spritz}$. We discuss the involved equations, physical assumptions, and implemented numerical methods, along with a large battery of general relativistic tests performed with and without magnetic fields. Our tests demonstrate the correct implementation of the neutrino leakage scheme, paving the way for further improvem…
Non-thermal radiation from a pulsar wind interacting with an inhomogeneous stellar wind
2017
Binaries hosting a massive star and a non-accreting pulsar are powerful non-thermal emitters due to the interaction of the pulsar and the stellar wind. The winds of massive stars are thought to be inhomogeneous, which could have an impact on the non-thermal emission. We study numerically the impact of the presence of inhomogeneities or clumps in the stellar wind on the high-energy non-thermal radiation of high-mass binaries hosting a non-accreting pulsar. We compute the trajectories and physical properties of the streamlines in the shocked pulsar wind without clumps, with a small clump, and with a large one. This information is used to compute the synchrotron and inverse Compton emission fr…
Profesors Juris Miķelsons: biobibliogrāfiskais rādītājs
1997
Saturs: Priekšvārds. Profesors Juris Miķelsons / prof.Gunārs Sermons. Profesora Jura Miķelsona publicētie darbi (1964.-1997.) Profesore Jura Miķelsone sastādītie, rediģētie un recenzētie darbi. Profesora Jura Miķelsona autorapliecības. Profesora Jura Miķelsone recenzētās un oponētās disertācijas. Raksti par profesoru Juri Miķelsonu. Profesora Jura Miķelsona darbu alfabētiskais rādītājs. Personu rādītājs.
Collective hydrodynamic transport of magnetic microrollers
2021
We investigate the collective transport properties of microscopic magnetic rollers that propel close to a surface due to a circularly polarized, rotating magnetic field. The applied field exerts a torque to the particles, which induces a net rolling motion close to a surface. The collective dynamics of the particles result from the balance between magnetic dipolar interactions and hydrodynamic ones. We show that, when hydrodynamics dominate, i.e. for high particle spinning, the collective mean velocity linearly increases with the particle density. In this regime we analyse the clustering kinetics, and find that hydrodynamic interactions between the anisotropic, elongated particles, induce p…
Du Toit Memorial Lecture 1999: The Mozambique belt of East Africa and Madagascar: significance of zircon and Nd model ages for Rodinia and Gondwana s…
2001
This paper discusses the question as to whether or not the high-grade metamorphic rocks exposed in the Mozambique belt (MB) of East Africa and Madagascar have played any role in the formation and dispersal of the supercontinent Rodinia, believed to have existed between ~1000 and ~750 Ma. First, there is little evidence for the production of significant volumes of ~1300 to ~1000 Ma (Kibaran- or Grenvillian-age) continental crust in the MB, except, perhaps, in parts of northern Mozambique. This crust cannot be related conclusively to either magmatic accretion processes along the active margin(s) of Rodinia, or to a collision event during continental collision and accretion leading to amalgama…
Vestiges of the Mesoproterozoic Events in the Neoproterozoic Mozambique Belt: the East African Perspective in the Rodinia Puzzle
2003
Abstract Most of the geological and palaeogeographical models consider the Neoproterozoic supercontinent Gondwana (∼650-550 Ma) as the direct offspring of the disintegrated Mesoproterozoic supercontinent Rodinia (∼1300-750 Ma). One of the main classical sutures along which the dispersing Rodinia fragments were fused into a new supercontinent (Godwana) is identified as the Mozambique belt of East Africa. The calc-alkaline magmatism (∼1200-950 Ma) in northern Mozambique, southern Malawi and southern Tanzania is regarded as the sole evidence for fragmentation of Rodinia, which is traced within this Neoproterozoic orogenic belt. There are no unequivocal Mesoproterozoic (Kibaran) sediments in th…
Ca. 750–1100 Ma magmatic events and Grenville-age deformation in Sri Lanka: relevance for Rodinia supercontinent formation and dispersal, and Gondwan…
2003
Abstract Large volumes of ∼880–1100 Ma calc-alkaline granitoid rocks in the Wanni and Vijayan crustal provinces of Sri Lanka make it likely that these domains were produced in active margin settings, probably Grenville-age magmatic arcs. We report new single zircon evaporation ages and Nd isotopic systematics for dioritic to granodioritic gneisses of the Kadugannawa Complex of central Sri Lanka which record a period of magmatic arc activity between 1006 and 881 Ma and show this complex to be part of the Wanni domain. Both provinces were probably generated in arc-related settings at the outer margin of Rodinia, but this cannot be ultimately proven on the basis of the currently available data…
Obstrucción primaria del cuello vesical en el varón
2006
Objetivo: Presentar nuestra experiencia en el diagnóstico y tratamiento de esta infrecuente modalidad de obstrucción funcional infravesical. Método: Durante los últimos 10 años hemos diagnosticado y tratado a 32 varones afectos de esta entidad. Se evalúan los diversos tratamientos previos recibidos así como el tiempo transcurrido hasta la realización del diagnóstico. Se valoran las manifestaciones clínicas, radiológicas, endoscópicas y urodinámicas así como los resultados obtenidos con la administración de bloqueadores alfa-adrenérgicos y con la incisión transuretral endoscópica del cuello vesical. Resultados: La edad de los pacientes osciló entre 26 y 48 años (media 38,2). Todos ellos pres…