205 research outputs found
Nonlinear Dynamic Phenomena in Macroscopic Tunneling
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
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
[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
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
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
Workshop REDS: el agua y el desarrollo sostenible : retos y oportunidades para la investigación
Workshop RED
Large Scale Structure of the Universe
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
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
Bee-flower association in the Neotropics: implications to bee conservation and plant pollination
Isolation and characterization of putative functional long terminal repeat retrotransposons in the Pyrus genome
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