205 research outputs found

    Nonlinear Dynamic Phenomena in Macroscopic Tunneling

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    Numerical simulations of the NLSE (or GPE) are presented demonstrating emission of short pulses of the matter (light) density formed in the course of tunneling in wave-guided light and/or trapped BEC. The phenomenon is observed under various conditions, for nonlinearities of different signs, zero nonlinearity included. We study, both numerically and analytically, pulsations of matter (light) remaining within the trap and use the results in order to induce emission of sequential pulses by properly narrowing the trap. This allows us to propose a mechanism for a realization of Atom Pulse Laser.Comment: 14 pages, 6 figure

    Luces en una crisis global

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    El segundo semestre de 2008 fue especialmente difícil, en donde destacaron diversos puntos que se recogen en este número de Análisis Plural, como: los secuestros y el “ya basta”; los efectos de la crisis en México; el narcotráfico, terrorismo y corrupción; la “inacabada” reforma energética; el “avionazo” de Mouriño; la crisis en el Partido de la Revolución Democrática; el estallido bursátil estadounidense, de resonancia mundial, y los problemas energéticos agudizados por la globalización

    Performance evaluation of a waste-heat driven adsorption system for automotive air-conditioning: Part II - Performance optimization under different real driving conditions

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    [EN] In this part, Part 11, of a two-part study, the validated model of part I is integrated into a general vehicle model in order to predict the performance of the system under real driving conditions. The overall model takes into account all the system components to simulate the dynamic performance of the entire system and predict the cabin temperature at the available waste heat. The system was implemented in a Fiat Grande Punto vehicle and the experimental tests were performed at the Centro Ricerche Fiat (CRF), Italy laboratories. Different design configurations were investigated to explore further improvements of the performance. Results showed that the model was able to well predict the transient performance of the system under different start-up and ambient conditions as well as the normal operating conditions. Using two radiators instead of one radiator increases the cooling capacity by 7.0% and decreases the cabin temperature by 9.1%. At the warming up period, the adsorption system faces serious difficulties to start producing the required cooling. Possible strategies to avoid this problem were studied and compared. In general, it has been proved that the amount of engine waste heat available is sufficient to produce enough cooling to keep reasonably comfortable temperatures in the cabin. (C) 2016 Elsevier Ltd. All rights reserved.This work has been partially supported by the Thermally Operated Mobile Air Conditioning Systems (TOPMACS). The authors are very grateful to the Energy Research Center of Netherlands (ECN) for their support with the experimental work.This work has been partially supported by the Thermally Operated Mobile Air Conditioning Systems (TOPMACS). The authors are very grateful to the Energy Research Center of Netherlands (ECN) for their support in the experimental work.Verde Trindade, M.; Harby Mohamed Abd Alaal, K.; De Boer, R.; Corberán, JM. (2016). Performance evaluation of a waste-heat driven adsorption system for automotive air-conditioning: Part II - Performance optimization under different real driving conditions. Energy. 115:996-1009. doi:10.1016/j.energy.2016.09.086S996100911

    The central slope of dark matter cores in dwarf galaxies: Simulations vs. THINGS

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    We make a direct comparison of the derived dark matter (DM) distributions between hydrodynamical simulations of dwarf galaxies assuming a LCDM cosmology and the observed dwarf galaxies sample from the THINGS survey in terms of (1) the rotation curve shape and (2) the logarithmic inner density slope alpha of mass density profiles. The simulations, which include the effect of baryonic feedback processes, such as gas cooling, star formation, cosmic UV background heating and most importantly physically motivated gas outflows driven by supernovae (SNe), form bulgeless galaxies with DM cores. We show that the stellar and baryonic mass is similar to that inferred from photometric and kinematic methods for galaxies of similar circular velocity. Analyzing the simulations in exactly the same way as the observational sample allows us to address directly the so-called "cusp/core" problem in the LCDM model. We show that the rotation curves of the simulated dwarf galaxies rise less steeply than CDM rotation curves and are consistent with those of the THINGS dwarf galaxies. The mean value of the logarithmic inner density slopes alpha of the simulated galaxies' dark matter density profiles is ~ -0.4 +- 0.1, which shows good agreement with \alpha = -0.29 +- 0.07 of the THINGS dwarf galaxies. The effect of non-circular motions is not significant enough to affect the results. This confirms that the baryonic feedback processes included in the simulations are efficiently able to make the initial cusps with \alpha ~ -1.0 to -1.5 predicted by dark-matter-only simulations shallower, and induce DM halos with a central mass distribution similar to that observed in nearby dwarf galaxies.Comment: 13 pages, 7 figures; Accepted for publication in AJ; minor correction

    Los Foros Regionales - gestión ambiental y competitividad regional

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    Esta publicación busca sistematizar las visiones y percepciones desde las Regiones y de esta manera ilustrar los avances significativos y las experiencias valiosas ya generadas; así como las esperanzas y las necesidades para lograr un desarrollo sostenible basado en el uso racional de los recursos naturales y la conservación de la diversidad biológica,Glosario de término

    Large Scale Structure of the Universe

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    Galaxies are not uniformly distributed in space. On large scales the Universe displays coherent structure, with galaxies residing in groups and clusters on scales of ~1-3 Mpc/h, which lie at the intersections of long filaments of galaxies that are >10 Mpc/h in length. Vast regions of relatively empty space, known as voids, contain very few galaxies and span the volume in between these structures. This observed large scale structure depends both on cosmological parameters and on the formation and evolution of galaxies. Using the two-point correlation function, one can trace the dependence of large scale structure on galaxy properties such as luminosity, color, stellar mass, and track its evolution with redshift. Comparison of the observed galaxy clustering signatures with dark matter simulations allows one to model and understand the clustering of galaxies and their formation and evolution within their parent dark matter halos. Clustering measurements can determine the parent dark matter halo mass of a given galaxy population, connect observed galaxy populations at different epochs, and constrain cosmological parameters and galaxy evolution models. This chapter describes the methods used to measure the two-point correlation function in both redshift and real space, presents the current results of how the clustering amplitude depends on various galaxy properties, and discusses quantitative measurements of the structures of voids and filaments. The interpretation of these results with current theoretical models is also presented.Comment: Invited contribution to be published in Vol. 8 of book "Planets, Stars, and Stellar Systems", Springer, series editor T. D. Oswalt, volume editor W. C. Keel, v2 includes additional references, updated to match published versio

    Constraining CMB-consistent primordial voids with cluster evolution

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    Using cosmological simulations, we make predictions for the distribution of clusters in a plausible non-gaussian model where primordial voids nucleated during inflation act together with scale-invariant adiabatic gaussian fluctuations as seeds for the formation of large-scale structure. This model agrees with most recent observations of the anisotropies of the cosmic microwave background (CMB) and can account for the excess of power measured on cluster scales by the Cosmic Background Imager (CBI), the large empty regions apparent in nearby galaxy redshift surveys and the number of giant arcs measured in deep cluster lensing surveys. We show that the z=0 cluster mass function differs from predictions for a standard LCDM cosmology with the same sigma_8. Moreover, as massive clusters also form much earlier in the "void" scenario, we show that integrated number counts of SZ sources and simple statistics of strong lensing can easily falsify this model.Comment: 12 pages, 9 figures, figure 1 and 2 available as .gif file. Matches accepted version (significant improvements but main conclusions unchanged
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