Vol. 58 No. 2 Jul-Dec (2012): Revista Mexicana de Física E
Published:
2012-01-01
Artículos
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Revisiting spherically symmetric relativistic hydrodynamics
Abstract:In this paper we revise two classical examples of Relativistic Hydrodynamics in order to illustrate in detail the numerical methods commonly used in fluid dynamics, specifically those designed to deal with shocks, which are based on a finite volume approximation. The two cases we consider are the relativistic blast wave problem and the evolution of a Tolman-Oppenheimer-Volkoff star model, in spherical symmetry. In the first case we illustrate the implementation of relativistic Euler's equations on a fixed background space-time, whereas in the second case we also show how to couple the evolution of the fluid to the evolution of the space-time.⬇️ Scroll down to see the full summary -
Caracterización de la regla de colisión de Huygens-Newton mediante una cantidad vectorial invariante Galileo
Abstract:We restate the collision rule Huygens - Newton in terms of a vector quantity we call the collision vector $\vec{A}(\epsilon)$. The collision vector is invariant and covariant Galileo. It contains information about the process of interaction and scattering of the particles. The geometric and energetic sense of the collision rule Huygens-Newton in terms of the collision vector is shown.⬇️ Scroll down to see the full summary -
Control para estabilizar y atenuar las perturbaciones en un péndulo invertido rotatorio
Abstract:This paper presents the combination of the following two methods to stabilize and to attenuate the disturbances of a rotatory inverted pendulum: 1) The disturbance is rejected using the structure at infinity method if there exist a control function such that, the transfer function of the outputs and the disturbances is null, forcing the system to have a behavior free of disturbances. 2) It is guaranteed that the controlled system is stable by equating the polynomial of the controlled system and a desired stable polynomial, forcing the system to follow a stable behavior.⬇️ Scroll down to see the full summary -
Descripción del modelo eléctrico del memristor
Abstract:The physical realization of memristor, achieved by the Hewlett Packard Laboratories in 2008, has become this novel device into an important topic under study in the Electronics Engineering area. However, in spide of the existence of several papers, theses, book chapters, and technical reports about this topic found in databases, it is unfortunate the lack of references written in spanish and furthermore references that approach it under a perspective which let an easy understanding with the only academic background requirement of basic concepts of electromagnetism. Taking in account this fact as motivation, this paper emerges with the objective of being an introductory reference for undergraduate students in Physics, Electrical Engineering or Electronics Engineering that could be interested in beginning a study about the memristor electrical model. The model proposed by Hewlett-Packart has been taken as reference and its verification has been performed through Maple Realease 13.0 and PSpice simulations.⬇️ Scroll down to see the full summary -
Quantum echoes in classical and semiclassical statistical treatments
Abstract:Some quantal systems require only a small part of the full quantum theory for their analysis in classical terms. In such understanding we discuss some recent literature on semiclassical treatments and add some results of our own. This analysis allows one to see that some important quantum features of the harmonic oscillator, a system of great didactic value, can indeed be already encountered at the classical or semiclassical statistical levels.⬇️ Scroll down to see the full summary -
Cosmología en México. Datos para su historia más temprana
Abstract:We present data on the first mexican paper on Cosmology, understood this discipline as the study of the physical structure of the universe, showing that it was written at the end of the eighteenth century. The text in question had the explicit intention to make young Newhispanics aware of what was being done in the field in Europe and to help them in the acquisition of a modern view of the universe, of the physical laws that apply to it and of the movement and distribution of the stars. At the time this project was very ambitious and novel in the New Spain, as students of middle and upper levels of our country were mostly studying the traditional aristotelian natural philosophy.⬇️ Scroll down to see the full summary -
Entre vórtices cartesianos y gravitación newtoniana: la Cosmología de Andrés de Guevara y Basoasabal S. J. (1748-1801)
Abstract:This work reviews the content of the Cartesian vortex theory and Newton's gravitation in the only books that Andrés de Guevara Basoasabal wrote: Pasatiempos de Cosmologia (1789) and Institutionum Elementarium Philosophi{\ae} (1796). For this purpose we discuss the origin and development of the rivalry between the two theories by analyzing two Jesuit encyclopedic journals published during the Age of Enlightenment. It is shown that on the one hand a group of Jesuits championed the Cartesian theory while scientists that of Newton. Despite being Guevara a Jesuit we show his penchant for Newtonian gravitation in both of his works.⬇️ Scroll down to see the full summary -
Experimental study of the dynamics of a diode-pumped Nd:YVO$_{4}$ laser under periodic modulation of losses
Abstract:With the aim of developing experiments for teaching dynamics of complex systems and stabilization methods in lasers, we study the dynamics of a diode-pumped Nd:YVO$_{4}$ laser under periodic loss modulation produced with an acousto-optic modulator and a function generator. Our goal is stabilization of the laser oscillations in a chosen dynamical state. The results obtained with the rate-equation model for different modulation schemes are in a good agreement with the experiments.⬇️ Scroll down to see the full summary
