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Josep Mas‐Pla Agustí Rodríguez‐Florit Manel Zamorano Carles Roqué Anna Menció David Brusi 《水文研究》2013,27(16):2352-2366
Intensive pumping in urban coastal areas is a common threat to water resource quality due to seawater intrusion. In those areas where subsurface water resources are not usually used for human consumption or irrigation, intensive pumping is associated with other activities like the lowering of the water table necessary to support underground structures and building foundations. This activity also increases the likelihood of soil settlement that affects building stability and the corrosion of concrete structures due to groundwater salinity. Under these circumstances, the awareness of a certain municipality (Calonge, NE Spain) of the potential effects of groundwater withdrawal upon foundations has led to an integrated approach to anticipate seawater intrusion related to urban development. Geological mapping and correlation of borehole logs, electrical resistivity tomography, and hydrochemical data provide comprehensive knowledge of the geology and hydrogeology of the area and act as screening tools necessary to discern the influence of hydrological processes in coastal areas. Developing Strack's analytical solution, new comprehensive, dimensionless expressions are herein derived to determine the critical pumping rate necessary to prevent seawater intrusion, as well as to reproduce the evolution of the wedge toe and the water table stagnation point under different withdrawal rates. Furthermore, the Dupuit–Forchheimer well discharge formula allows the estimation of the effects of the water table lowering due to such critical pumping in the surrounding building foundations. Field data from the Calonge coastal plain illustrate this approach and provide assessment criteria for future urban development and planning. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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We have studied the velocity field of the Blue Compact Dwarf galaxy Mrk86 using an Hα Fabry-Perot image and 14 long-slit optical
spectra. From the ionized gas velocities measured we have found that Mrk86 follows a solid-body rotation law with a central
angular velocity of 34 ± 5 km s-1 kpc-1. The comparison of the modeled rotation curve with our velocity data indicates a clear dominance of the stellar mass component
over the dark matter. Related with the galaxy most intense star forming knot, a very strong gradient steeping is observed.
Finally, we give kinematic evidence for the Mrk86-C expanding bubble.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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A. Gil de Paz A. Aragón-Salamanca J. Gallego A. Alonso-Herrero J. Zamorano G. Kauffmann 《Monthly notices of the Royal Astronomical Society》2000,316(2):357-373
We present new near-infrared J and K imaging data for 67 galaxies from the Universidad Complutense de Madrid (UCM) survey used in the determination of the SFR density of the local Universe by Gallego et al. This is a sample of local star-forming galaxies with redshift lower than 0.045, and they constitute a representative subsample of the galaxies in the complete UCM survey. From the new data, complemented with our own Gunn- r images and long-slit optical spectroscopy, we have measured integrated K -band luminosities, r − J and J − K colours, and H α luminosities and equivalent widths. Using a maximum likelihood estimator and a complete set of evolutionary synthesis models, these observations allow us to estimate the strength of the current (or most recent) burst of star formation, its age, the star formation rate and the total stellar mass of the galaxies. An average galaxy in the sample has a stellar mass of 5×1010 M⊙ and is undergoing (or has recently completed) a burst of star formation involving about 2 per cent of its total stellar mass. We identify two separate classes of star-forming galaxies in the UCM sample: low-luminosity, high-excitation galaxies (H ii like ) and relatively luminous spiral galaxies (starburst disc- like ). The former show higher specific star formation rates (SFRs per unit mass) and burst strengths, and lower stellar masses than the latter. With regard to their specific star formation rates, the UCM galaxies are intermediate objects between normal quiescent spirals and the most extreme H ii galaxies. 相似文献
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A. Gil de Paz J. Zamorano J. Gallego 《Monthly notices of the Royal Astronomical Society》1999,306(4):975-987
We have studied the velocity field of the blue compact dwarf galaxy Mrk 86 (NGC 2537) using data provided by 14 long-slit optical spectra obtained in 10 different orientations and positions. This kinematical information is complemented with narrow-band ([O iii ]5007 Å and H α ) and broad-band ( B , V , Gunn r and K ) imaging. The analysis of the galaxy global velocity field suggests that the ionized gas could be distributed in a rotating inclined disc, with projected central angular velocity of Ω=34 km s−1 kpc−1 . The comparison between the stellar, H i and modelled dark matter density profile indicates that the total mass within its optical radius is dominated by the stellar component. Peculiarities observed in its velocity field can be explained by irregularities in the ionized gas distribution or local motions induced by star formation.
Kinematical evidences for two expanding bubbles, Mrk 86–B and Mrk 86–C, are given. They show expanding velocities of 34 and 17 km s−1 , H α luminosities of 3×1038 and 1.7×1039 erg s−1 , and physical radii of 374 and 120 pc, respectively. The change in the [S ii ]/H α , [N ii ]/H α , [O ii ]/[O iii ] and [O iii ]/H β line ratios with the distance to the bubble precursor suggests a diminution in the ionization parameter and, in the case of Mrk 86–B, an enhancement of the shock-excited gas emission. The optical–near-infrared colours of the bubble precursors are characteristic of low‐metallicity star‐forming regions (∼0.2 Z⊙ ) with burst strengths of about 1 per cent in mass. 相似文献
Kinematical evidences for two expanding bubbles, Mrk 86–B and Mrk 86–C, are given. They show expanding velocities of 34 and 17 km s
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The mass-radius relation is determined for Main-Sequence stars from observational data of well-detached binary systems. The results are compared to previous empirical relations and we discuss their application to the study of the light curves of eclipsing binaries. A comparison with theoretical Main-Sequence models has been carried out. 相似文献
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A. Gil de Paz J. Gallego J. Zamorano A. Alonso-Herrero A. Argón-Salamanca 《Astrophysics and Space Science》1998,261(1-4):147-150
We present results from a spectroscopic survey of Paβ & Brγ emission in a sample of T Tauri stars, mostly in the Taurus-Auriga
complex. Velocity resolved spectra (Δv ∼ 15 km s-1) show that, of the 41 stars observed in Paβ emission, 34% display IPC redshifted absorptions, while, of the 29 stars observed
in Brγ emission, 21% display IPC redshifted absorptions. The lines are broad (FWHM ∼ 200 km s-1) and lack blueshifted absorptions. These observations are consistent with the near infrared hydrogen lines forming predominantly
in infalling material, as suggested by magnetospheric accretion column models. Radiative transfer calculations of the Paβ
and Brγ line profiles in a very simplified, spherically symmetric situation are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献