Groundwater recharge dams in arid areas as tools for aquifer replenishment and mitigating seawater intrusion: example of AlKhod, Oman   总被引：1，自引：1，他引：0  

Osman A. E. Abdalla  Abdullah S. Al-Rawahi 《Environmental Earth Sciences》2013,69(6):1951-1962

Groundwater depletion and seawater intrusion constitute major challenges along coastal aquifers in arid areas. This paper assesses the role of groundwater recharge dams constructed to replenish aquifers and fight seawater intrusion with reference to AlKhod dam, Oman, sited 7 km from the coast on a gravely unconfined aquifer. Water table rise in piezometers located downstream from the dam shows regular patterns correlating with magnitude of wadi flow, whereas upstream piezometers show irregular patterns. Controlled release of water captured by the dam optimizes water percolation and enhances artificial recharge which was estimated in the wet years 1997, 2003 and 2005 as 15, 22 and 27 Mm³, respectively, using water table fluctuation method. Recharge contributed 40–60 % of the total annual abstraction. Groundwater salinity increased in the 1980s and 1990s and the saline/freshwater interface advanced inland, but has receded partially after 1997 (highest rainfall) and completely after 2005 indicated by reduction in electrical conductivity and thickening of freshwater lens. The recession is attributed to the dam’s induced recharge and reduction of pumping in 2004 following the commissioning of Barka desalination plant. Integrating artificial recharge with groundwater resources management is therefore an effective measure to replenish aquifers in arid areas and mitigate seawater intrusion along the coasts.  相似文献   

The porosity of saturated shallow sediments from seismic compressional and shear wave velocities     

Osman Uyanık 《Journal of Applied Geophysics》2011,73(1):16-24

This study devises a new analytical relationship to determine the porosity of water-saturated soils at shallow depth using seismic compressional and shear wave velocities. Seismic refraction surveys together with soil sample collection were performed in selected areas containing water-saturated clay–silt, sand and gravely soils. Classification of clay–silt, sand and gravel dense soils provided the coefficient of experimental equation between the data sets, namely, Poisson's ratio, shear modulus and porosity values. This study presents a new analytical relationship between Poisson's ratio and shear modulus values, which are obtained from seismic velocities and porosity values of water-saturated material computed from water content and grain densities, which are determined by laboratory analysis of disturbed samples. The analytical relationship between data sets indicates that when the shear modulus of water-saturated loose soil increases, porosity decreases logarithmically. If shear modulus increases in dense or solid saturated soils, porosity decreases linearly.  相似文献   

Fourier techniques for an analysis of eclipsing binary light curves,VII     

Osman Demircan 《Astrophysics and Space Science》1980,72(2):287-291

A Laplace and a Hankel transform of the light curves of eclipsing binary star systems have been expressed in terms of the eclipse elements (L ₁,r _1,2 andi) of the spherical basic model. These general expressions can be used for the solution of the eclipse elements of the systems in terms of the observed quantities.  相似文献   

The elimination of short-periodic terms in a Uranus-Neptune general planetary theory by von Zeipel's method     

Osman M. Kamel  Abdel A. Bakry 《Astrophysics and Space Science》1979,62(1):79-116

We eliminate by the method of von Zeipel the short-period terms in a first order-with respect to planetary masses—general planetary Uranus-Neptune theory. We exclude in the expansion terms of eccentricities and sines of inclinations higher than the third power.Our variables are the Poincaré canonical variables. We use the Jacobi-Radau set of origins, and we refer the planes of the osculating ellipses to a common fixed plane, the longitudes to a common origin. The short-periodic terms arising from the indirect and principal parts of the disturbing functions, are eliminated separately. The Fourier series of the principal part of the disturbing function, is reduced to the sum of only the first three terms.  相似文献   

Fourier techniques for an analysis of eclipsing binary light curves: IV     

Osman Demircan 《Astrophysics and Space Science》1979,62(1):235-240

The aim of the present paper is to establish two further series expansions (alternative to those given in Demircan, 1979a, b, c), for the observed light changes of eclipsing binary system. The coefficients of these expansions have also been expressed in the form of general series expansions in terms of the eclipse elementsr _1.2,i andL ₁ of the spherical model on which all other distorted models may be based (Kopal, 1975, 1976) in an analysis in the frequency-domain.  相似文献   

Astrometry of the Open Cluster M25     

A.L. Tadross  M.A. Marie  A.I. Osman  S.M. Hassan 《Astrophysics and Space Science》2002,282(4):607-623

The young open star cluster M25 (IC 4725) is located in the direction of the galactic center, near much irregular absorption features on Sagittarius arm. This system is found to be at a distance of 600 pc, with a median age of 9.45 × 10⁷ years and a distance from the galactic plane of –52.82 pc The mass data available in the literature has been gathered and many statistical methods have been applied for this cluster. Depending only on these methods, the stellar density, the distribution of dark matter, the luminosity and the mass functions have been estimated. The center of the cluster has been defined, it is shifted by 45 arc sec in the northeast direction. The radius of the cluster is found to be 4 pc. More than 220 stars with mean reddening of 0.50 mag and absorption of 1.62mag are found inside this aria. The total mass of the cluster has been estimated with the mass of the interstellar matter (gas and dust). It is found to be 1937 M _⊙, whereas about 24% of the material mass of the cluster has remained as interstellar matter after the processes of formation. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Two orogenies in the Meatiq area of the Central Eastern Desert,Egypt     

Mohamed E. Habib  A.A. Ahmed  Osman M. El Nady 《Precambrian Research》1985,30(2):83-111

The Pan-African basement exposed in the Meatiq area west of Quseir, Egypt, consists of an infracrustal basement overthrusted by a supracrustal cover. The infracrustal rocks were developed as a result of an old orogeny referred to as the Meatiqian orogeny where granite—gneiss, migmatitic gneisses and migmatized amphibolites were formed. The granite—gneiss represents a deformed granite pluton emplaced at 626±2 Ma, whereas the migmatitic gneisses and amphibolites are of mixed igneous and sedimentary parentage. In view of the data so far available, the nature of the Meatiqian orogeny could not be deciphered. In spite of the young isotopic ages, it is suggested that at least the metasedimentary gneisses represent older rocks in the stratigraphic sequence of the infracrustal basement.The supracrustal cover represents a part of an extensive ophiolitic mélange obducted onto the infracrustal basement during the next orogeny (Abu Ziran orogeny) which culminated at 613±2 Ma. An active continental margin-type regime can adequately explain the evolution of such a supracrustal cover. During obduction, the ophiolitic mélange and the upper 2 km thick part of the infracrustal basement were intensely deformed and metamorphosed under PT conditions of the greenschist—epidote amphibolite facies. The deformed infracrustal basement was converted into mylonitic—blastomylonitic rocks and schists composing five thrust sheets, and subsequently intruded by synkinematic granitoid sheets. Later, both the infracrustal basement and the overlying supracrustal cover were isostatically uplifted, subjected to complex shallow folding giving rise to the major Meatiq domal structure, and were intruded by a postkinematic adamellite pluton at 579±6 Ma.  相似文献   

Placing Venus in an orbit similar to that of the Earth     

Osman M. Kamel 《Earth, Moon, and Planets》1993,62(2):131-138

Motivated by the recent proposals of A. Abian, we introduce the physical and dynamical considerations for producing a second Earth-like planet on which life sustaining conditions may exist, and hence we acquire multiplication of the cosmic resources of the human race. We investigate the perturbations in our solar system after alteration, through a third order Hamiltonian planetary theory for the eight principal planets. The Hori-Lie theorem, the Jacobi-Radau coordinates, and the canonical variables of H. Poincaré are adopted.  相似文献   

A note on the Hori-Lie perturbation technique     

Osman M. Kamel 《Earth, Moon, and Planets》1992,56(1):53-56

In this paper we describe how to avoid the introduction of Hori's pseudo time in general planetary theory in the case of two planets.  相似文献   

Mineral chemistry of ultramafic and mafic cumulates as an indicator of the arc-related origin of the Mersin ophiolite (southern Turkey)     

Osman Parlak  Michel Delaloye  Ergüzer Bíngöl 《International Journal of Earth Sciences》1996,85(4):647-661

The Mersin ophiolite, represented by approximately 6-km-thick oceanic lithospheric section on the southern flank of the Taurus calcareous axis, formed in the Mesozoic Neo-Tethyan ocean some time during Late Cretaceous in southern Turkey. The ultramafic and mafic cumulates having over 3 km thickness consist of dunite ± chromite, wehrlite, clinopyroxenite at the bottom and pass into gabbroic cumulates in which leucogabbro, olivine-gabbro and anorthosite are seen. Crystallization order is olivine (Fo₉₁₋₈₀) ± chromian spinel (Cr# 60-80), clinopyroxene (Mg#₉₅₋₇₇), plagioclase (An_95.6−91.6) and orthopyroxene (Mg#₆₈₋₇₇). Mineral chemistry of ultramafic and mafic cumulates suggest that highly magnesian olivines, clinopyroxenes and absence of plagioclase in the basal ultramafic cumulates are in good agreement with products of high-pressure crystal fractionation of primary basaltic melts beneath an island-arc environment. Major, trace element geochemistry of the cumulative rocks also indicate that Mersin ophiolite was formed in an arc environment. Coexisting Ca-rich plagioclase and Forich olivine in the gabbroic cumulates show arc cumulate gabbro characteristics. Field relations as well as the geochemical data support that Mersin ophiolite formed in a supra-subduction zone tectonic setting in the southern branch of the Neo-Tethys in southern Turkey.  相似文献