Curvature and wrinkling of premixed flame Kernels comparison between planar laser induced fluorescence (PLIF) and 3D direct numerical simulations (DNS)

A direct comparison between time resolved PLIF measurements of OH and two dimensional slices from a full three dimensional DNS data set of turbulent premixed flame kernels in lean methane/air mixture was presented. The local flame structure and the degree of flame wrinkling were examined in response to differing turbulence intensities and turbulent Reynolds numbers. Simulations were performed using the SEGA DNS code, which is based on the solution of the compressible Navier Stokes, species, and energy equations for a lean hydrocarbon mixture. For the OH PLIF measurements, a cluster of four Nd:YAG laser was fired sequentially at high repetition rates and used to pump a dye laser. The frequency doubled laser beam was formed into a sheet of 40 mm height using a cylindrical telescope. The combination of PLIF and DNS has been demonstrated as a powerful tool for flame analysis. This research will form the basis for the development of sub-grid-scale (SGS) models for LES of lean-premixed combustion systems such as gas turbines. This is an abstract of a paper presented at the 30th International Symposium on Combustion (Chicago, IL 7/25-30/2004).

Phase transitions in planar magnetic nanostructures

Using numerical micromagnetics we have studied the ground state magnetization distribution of square planar ferromagnetic elements ("nanostructures"). As the element size is reduced from 250 to 2 nm at constant thickness (2-35 nm), we find that the magnetization distribution undergoes up to three phase transitions involving as many as three different near single domain states. One of these phase transitions is analogous to the reorientation phase transition observed in continuous ultrathin magnetic films. © 1998 American Institute of Physics.

Un caso de auto-reescritura : El astrólogo fingido de Calderón

Resumen: La pulcra edición de la Segunda parte de comedias de Pedro Calderón de la Barca por Santiago Fernández Mosquera (Biblioteca Castro, 2007) y la reciente tesis de Fernando Rodríguez-Gallego (2009) sobre las dos versiones de El astrólogo fingido (Zaragoza, 1632 y Madrid, 1637) obligan hoy a una revisión de uno de los casos, tan frecuentes en la producción del dramaturgo madrileño, de reescritura —con miras esta vez a la publicación impresa— de una de sus obras. El examen se centrará, más allá de consideraciones formales y estéticas, en la valoración del alcance ético de las profundas transformaciones sufridas por el personaje del primer protagonista, el falso astrólogo, don Diego de Luna, así como en el análisis de las dos versiones del desenlace.