979 resultados para Secular perturbation


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Introducción: El Papa Benedicto XVI en la Carta Apostólica en forma de Motu proprio Porta Fidei invitó a toda la Iglesia a celebrar un Año de la Fe, con motivo de los 50 años de la apertura del Concilio Vaticano II. Esta celebración ofreció una buena ocasión para reflexionar sobre la aplicación de las enseñanzas conciliares en la vida eclesial. Ellas pueden llegar a ser, según el Santo Padre, una gran fuerza para la renovación siempre necesaria de la Iglesia... Uno de los temas fundamentales que propicio esta renovación conciliar es la nueva mirada sobre la Iglesia, vista ahora como misterio. Si bien el Concilio utiliza la categoria de Pueblo de Dios para definirla, en la eclesiología conciliar está implicita la categoría communio. La Iglesia es un misterio de comunión, como la definiera más adelante el Sínodo extraordinario de los Obispos de 1985, con motivo de la celebración de los veinte años de la clausura del Concilio. A partir de esta eclesiología se desprende una nueva concepción teologíca o reflexión sobre la identidad y ministerio de los presbíteros. Un tema importante de la vida presbiteral que debió afrontar el Concilio fue el de su sostenimiento y remuneración. Por ello, el presente trabajo de investigación tiene dos polos bien definidos: el sostenimiento de los presbíteros y la eclesiología de comunión. Se trata de establecer la relación que hay entre ellos. Es útil pensar que si hay una nueva visión de la Iglesia y de la vida presbiteral, en la dinámica que actualiza la secular evolución, también se ha de renovar la forma en que se debe proveer al sostenimiento de la vida de los presbíteros y a su seguridad previsional...

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In this experimental and numerical study, two types of round jet are examined under acoustic forcing. The first is a non-reacting low density jet (density ratio 0.14). The second is a buoyant jet diffusion flame at a Reynolds number of 1100 (density ratio of unburnt fluids 0.5). Both jets have regions of strong absolute instability at their base and this causes them to exhibit strong self-excited bulging oscillations at welldefined natural frequencies. This study particularly focuses on the heat release of the jet diffusion flame, which oscillates at the same natural frequency as the bulging mode, due to the absolutely unstable shear layer just outside the flame. The jets are forced at several amplitudes around their natural frequencies. In the non-reacting jet, the frequency of the bulging oscillation locks into the forcing frequency relatively easily. In the jet diffusion flame, however, very large forcing amplitudes are required to make the heat release lock into the forcing frequency. Even at these high forcing amplitudes, the natural mode takes over again from the forced mode in the downstream region of the flow, where the perturbation is beginning to saturate non-linearly and where the heat release is high. This raises the possibility that, in a flame with large regions of absolute instability, the strong natural mode could saturate before the forced mode, weakening the coupling between heat release and incident pressure perturbations, hence weakening the feedback loop that causes combustion instability. © 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

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In this paper, effect of strain gradient on adiabatic shear instability in particle reinforced metal matrix composites is investigated by making use of the strain gradient dependent constitutive equation developed by Dai et al. [9] and the linear perturbation analysis presented by Bai [10]. The results have shown that the onset of adiabatic shear instability in metal matrix composites reinforced with small particles is more prone to occur than in the composites reinforced with large particles. This means that the strain gradient provides a strong deriving force for onset of adiabatic shear instability in metal matrix composites.

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Nota del Director. Nuestra brújula segura -- La crisis de los cuarenta / María Josefina Llach -- Hacia una nueva imaginación. Sobre el laicado y las mujeres en la Iglesia / Virginia R. Azcuy -- Logros y tareas a 40 años de la promulgación de la Constitución Dogmática sobre la Divina Revelación / Claudia Mendoza -- La Constitución Pastoral Gaudium et Spes como “acontecimiento”. Un ingreso desde las “redes” / Marcelo González -- De una cultura ritual a una cultura secular. Críticas a la reforma litúrgica conciliar / Osvaldo Santagada -- El misterio de la Iglesia, pueblo de Dios en comunión / José Carlos Caamaño -- El movimiento ecuménico a 40 años del Concilio Vaticano II / Jorge A. Scampini -- Una articulación del binomio Iglesia universal/ Iglesia particular-local / Antonio Fidalgo -- Nuestra facultad de teología en perspectiva histórica: desde su origen (1915) y hacia su centenario (2015) / Carlos M. Galli -- En torno al misterio de Dios. El pensamiento de Ricardo Ferrara / Carlos A. Castro -- Notas Bibliográficas -- Instrucciones para los colaboradores

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In the cylindrical coordinate system, a singular perturbation theory of multiple-scale asymptotic expansions was developed to study single standing water wave mode by solving potential equations of water waves in a rigid circular cylinder, which is subjec

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Plasma instabilities with charged particle production processes in non-equilibrium plasma are analysed. A criterion on plasma instabilities is deduced by 6rst-order perturbation theory. The relationship between plasma instabilities and certain factors (degree of non-equilibrium in Plasma, the electron attachment rate coefficient and electron temperature) are described.

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We use vibration localization as a sensitive means of detecting small perturbations in stiffness in a pair of weakly coupled micromechanical resonators. For the first time, the variation in the eigenstates is studied by electrostatically coupling nearly identical resonators to allow for stronger localization of vibrational energy due to perturbations in stiffness. Eigenstate variations that are orders of magnitude greater than corresponding shifts in resonant frequency for an induced stiffness perturbation are experimentally demonstrated. Such high, voltagetunable parametric sensitivities together with the added advantage of intrinsic common mode rejection pave the way to a new paradigm of mechanical sensing. ©2009 IEEE.

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We investigate the morphological stability of epitaxial thin elastic films on a substrate by the Casimir force between the film surface and a flat plate. Critical undulation wavelengths are derived for two different limit conditions. Consideration of the Casimir force in both limit cases decreases the critical wavelength of the surface perturbation.

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Casimir effect on the critical pull-in gap and pull-in voltage of nanoelectromechanical switches is studied. An approximate analytical expression of the critical pull-in gap with Casimir force is presented by the perturbation theory. The corresponding pull-in parameters are computed numerically, from which one can notice the nonlinear effect of Casimir force on the pull-in parameters. The detachment length has been presented, which increases with increasing thickness of the beam.

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The assumption of constant rock properties in pressure-transient analysis of stress-sensitive reservoirs can cause significant errors in the estimation of temporal and spatial variation of pressure. In this article, the pressure transient response of the fractal medium in stress-sensitive reservoirs was studied by using the self-similarity solution method and the regular perturbation method. The dependence of permeability on pore pressure makes the flow equation strongly nonlinear. The nonlinearities associated with the governing equation become weaker by using the logarithm transformation. The perturbation solutions for a constant pressure production and a constant rate production of a linear-source well were obtained by using the self-similarity solution method and the regular perturbation method in an infinitely large system, and inquire into the changing rule of pressure when the fractal and deformation parameters change. The plots of typical pressure curves were given in a few cases, and the results can be applied to well test analysis.

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The instability of the crack tip in brittle Mg-based bulk metallic glass (BMG) is studied. The formation of various fractographic surfaces of the BMG is associated with the instability of the fluid meniscus, which is due to viscous fluid matter being present on the fracture process zone. Depending on the values of the wavelength of the initial perturbation of the fluid meniscus and the local stress intensity factor, different fracture surface profiles, i.e. a dimple-like structure, a periodic corrugation pattern and a pure mirror zone are formed. The fractographic evolution is significantly affected by the applied stress. A decreased fracture Surface roughness is observed under a low applied stress. An increased fracture surface roughness, which has frequently been reported by other researchers, is also observed in the present studies under a high applied stress. Unique fractographic features are attributed to the non-linear hyperelastic stiffening for less softening) mechanism. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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Direct numerical simulation of transition How over a blunt cone with a freestream Mach number of 6, Reynolds number of 10,000 based on the nose radius, and a 1-deg angle of attack is performed by using a seventh-order weighted essentially nonoscillatory scheme for the convection terms of the Navier-Stokes equations, together with an eighth-order central finite difference scheme for the viscous terms. The wall blow-and-suction perturbations, including random perturbation and multifrequency perturbation, are used to trigger the transition. The maximum amplitude of the wall-normal velocity disturbance is set to 1% of the freestream velocity. The obtained transition locations on the cone surface agree well with each other far both cases. Transition onset is located at about 500 times the nose radius in the leeward section and 750 times the nose radius in the windward section. The frequency spectrum of velocity and pressure fluctuations at different streamwise locations are analyzed and compared with the linear stability theory. The second-mode disturbance wave is deemed to be the dominating disturbance because the growth rate of the second mode is much higher than the first mode. The reason why transition in the leeward section occurs earlier than that in the windward section is analyzed. It is not because of higher local growth rate of disturbance waves in the leeward section, but because the growth start location of the dominating second-mode wave in the leeward section is much earlier than that in the windward section.

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Rossby waves are the most important waves in the atmosphere and ocean, and are parts of a large-scale system in fluid. The theory and observation show that, they satisfy quasi-geostrophic and quasi-static equilibrium approximations. In this paper, solitary Rossby waves induced by linear topography in barotropic fluids with a shear flow are studied. In order to simplify the problem, the topography is taken as a linear function of latitude variable y, then employing a weakly nonlinear method and a perturbation method, a KdV (Korteweg-de Vries) equation describing evolution of the amplitude of solitary Rossby waves induced by linear topography is derived. The results show that the variation of linear topography can induce the solitary Rossby waves in barotropic fluids with a shear flow, and extend the classical geophysical theory of fluid dynamics.

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Resumen: Esta ponencia forma parte del primer Panel Inaugural del II Congreso de Teólogas latinoamericanas y alemanas “Espacios de Paz”, realizado del 28 al 31 de marzo de 2016. Se aborda el tema de la paz como signo de estos tiempos desde tres claves: el contexto latinoamericano, la centralidad de la violencia en los estudios sobre la paz y su relación con las mujeres como constructoras de paz y víctimas de violencia. La reflexión se organiza en dos partes: primero, se analiza el discernimiento teológicopastoral sobre la paz realizado por la Conferencia de Medellín, en un contexto de subdesarrollo e injusticia caracterizados como violencia institucional y pecado estructural; además, se mencionan en forma breve los desafíos de reconciliación que plantearon los procesos de transición que siguieron a los gobiernos militares y a los conflictos armados internos. En la segunda parte, se enfocan algunos valores y esferas de la paz y la violencia –personal, estructural y cultural–, para considerar el concepto secular y cristiano de “pacificación” (peacebuilding) y los aportes teóricos y prácticos de las mujeres en la construcción de la paz en contextos de violencia.

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Vamos a detenernos en los siguientes temas: imputabilidad, atenuantes, eximentes y agravantes, y en su aplicación a los delitos sexuales de clérigos contra menores. Queremos ver en qué medida los clérigos acusados de abuso de menores son imputables en el Derecho Canónico, para lo cual estudiaremos la figura misma de la imputabilidad y su posible relación con las enfermedades mentales, y con los trastornos de la personalidad. Para una mejor comprensión, haremos algunas consideraciones sobre cómo es tratado el tema de los abusos de menores en la legislación secular, en relación a la imputabilidad de los mismos, y bajo qué sistema se suelen regir para declarar inimputable o no a un delincuente que padece trastornos mentales o psicológicos. El concepto de imputabilidad es especialmente controvertido, pudiendo contemplarse desde toda una variedad de perspectivas y desde una multiplicidad de posicionamientos dogmáticos, penales, médicos, psicológicos y psiquiátricos...