Interaction of surface water and groundwater in the Nile River basin: isotopic and piezometric evidence     

Kebede  Seifu  Abdalla  Osman  Sefelnasr  Ahmed  Tindimugaya  Callist  Mustafa  Osman 《Hydrogeology Journal》2017,25(3):707-726

Hydrogeology Journal - Past discussions around water-resources management and development in the River Nile basin disregard groundwater resources from the equation. There is an increasing interest...  相似文献   

Heterogeneity analysis of reservoir porosity and permeability in the Late Ordovician glacio-fluvial Sarah Formation paleovalleys,central Saudi Arabia     

Islam El-Deek  Osman Abdullatif  Gabor Korvin 《Arabian Journal of Geosciences》2017,10(18):400

The Late Ordovician glacio-fluvial Sarah Formation is an important tight gas reservoir target in Saudi Arabia. This study uses statistical methods to characterize the petrophysical heterogeneity of the paleovalleys of the Sarah Formation that crop out in central Saudi Arabia. Four paleovalleys were studied: Bukayriyah, Hanadir, Sarah, and Khanasir Sarah. Several lithofacies were identified in each that vary in texture, porosity, permeability, and facies abundance that reflect periods of ice advance and retreat. The heterogeneity analysis is based on three statistical measures, namely, the coefficient of variation, the Dykstra-Parsons coefficient, and the Lorenz coefficient. The coefficient of variation values is in the 0.62–1.94 range, indicating an extremely heterogeneous distribution. The Dykstra-Parsons coefficient values are in the 0.56–0.88 range, suggesting very high to extremely high heterogeneity in the reservoirs. The Lorenz coefficient correlates well with the Dykstra-Parsons coefficient for paleovalleys of the Sarah Formation. The heterogeneity parameters studied here indicate that the outcrops of Sarah Formation paleovalleys represent heterogeneous to very heterogeneous reservoirs, which may be attributed to complex depositional and diagenetic variations that have affected the porosity and permeability distribution.  相似文献   

Groundwater recharge/discharge in semi-arid regions interpreted from isotope and chloride concentrations in north White Nile Rift, Sudan   总被引：1，自引：0，他引：1  

Osman A. E. Abdalla 《Hydrogeology Journal》2009,17(3):679-692

Deuterium, oxygen-18 and chloride were analyzed for 84 samples from deep and shallow wells, precipitation and the river White Nile to investigate groundwater recharge/discharge relations in the semi-arid central Sudan. Spatial and vertical variation in isotopic signature and chloride concentration in the groundwater show similar patterns and indicate local recharge and evaporative discharge. Progressive decrease in isotopic composition along the regional groundwater flow path demonstrates aquifer continuity down the NW–SE recharge-discharge path. Isotope-heavy recharged water progressively mixes with lighter older groundwater formed during cooler and humid conditions in the late Pleistocene. However, evaporative fractionation in the flow path’s final reach in the southeast re-enriches the isotopic composition and suggests evaporative loss of groundwater as the plausible discharge mechanism. Chloride concentration increases down the gradient from the recharge area and reaches its peak in the discharge zones indicating: lack of recharge from direct infiltration down the gradient, evaporation and prolonged rock/water interaction. Head differences and increased isotopic concentration in the vicinity of the White Nile suggest recharge from the river from subsurface flow. Reduced chloride content and relatively heavier isotopic composition in the deep groundwater beneath the wadi of Khor Abu Habil indicate recharge from the streambed into the deep aquifer.  相似文献   

Sr–Nd isotopes and geochemistry of the infrastructural rocks in the Meatiq and Hafafit core complexes, Eastern Desert, Egypt: Evidence for involvement of pre-Neoproterozoic crust in the growth of Arabian–Nubian Shield     

Ali A.  Khudeir  Mohamed A.  Abu El-Rus  Samir  El-Gaby  Osman  El-Nady  Wagih W.  Bishara 《Island Arc》2008,17(1):90-108

Abstract Meatiq and Hafafit core complexes are large swells in the Eastern Desert of Egypt, comprising two major tectono‐stratigraphic units or tiers. The lower (infrastructure) unit is composed of variably cataclased gneissose granites and high‐grade gneisses and schists. It is structurally overlain by Pan–African ophiolitic mélange nappes (the higher unit). The two units are separated by a low‐angle sole thrust, along which mylonites are developed. Major and trace element data indicate formation of the gneissose granites in both volcanic arc and within‐plate settings. Nevertheless, all analyzed gneissose granites and other infrastructural rocks, exhibit low initial ratios (Sr_i) (<0.7027), positive ε_Nd(t) (+4.9 to +10.3) and Neoproterozoic Nd model age (T_DM) (592–831 Ma for the gneissose granite samples). Although these values are compatible with other parts of the Arabian– Nubian Shield considered to be juvenile, the ε_Nd(t) values and several incompatible element ratios of the gneissose granites are too low to be derived from a mantle source without contribution from an older continental crust. Our geological, Sr–Nd isotopic and chemical data combined with the published zircon ages indicate the existence of a pre‐Neoproterozoic continent in the Eastern Desert that started to break up at ca 800 Ma. Rifting and subsequent events caused the formation of oceanic crust and emplacement within‐plate alkali basalts in the hinterland domains of the old continent. The emplacement of basaltic magma might have triggered melting of lower crust in the old continent and resulted in emplacement of the within‐plate granite masses between 700 Ma and 626 Ma. The granite masses and other rocks in the old continent have been subjected to deformation during the over‐thrusting of Pan–African nappes, probably because of the oblique convergence between East and West Gondwanaland. Rb–Sr isotopes of the gneissose granites in both Meatiq and Hafafit core complexes defines an isochron age of 619 ± 25 Ma with Sr_i of 0.7009 ± 0.0017 and mean squares of weighted deviates = 2.0. We interpret this age as the date of thrusting of the Pan–African nappes in the Eastern Desert. Continued oblique convergence between East and West Gondwanaland could have resulted in the formation northwest–southeast‐trending Meatiq and Hafafit anticlinoriums.  相似文献   

Improving the Quality of Municipal Solid Waste Compost by Using Expanded Perlite and Natural Zeolite     

N. Gamze Turan  Osman Nuri Ergun 《洁净——土壤、空气、水》2008,36(3):330-334

The scope of this study was to investigate the effects of natural zeolite and expanded perlite on the quality of municipal solid waste compost. Various ratios of the materials were added as supplements to the organic fraction of municipal solid waste. These applications were periodically compared with an untreated control process. The results obtained from experimental studies clearly showed that municipal solid waste collected from the metropolitan city center of Samsun, Turkey could not be composted without any additions due to the very high moisture content, which reached up to 75–80%. In the untreated control process, thermophilic temperatures were not supported during the composting. In this system, ammonia and other odors became a problem because of the high pH levels, and the electrical conductivity was too high for aged compost. However, the addition of natural zeolite and expanded perlite had a positive affect on the quality of the final compost. Natural zeolite trapped ammonium and reduced nitrogen losses from the compost. Expanded perlite held excess moisture and supported improved aeration. The results also indicated that the use of natural zeolite together with expanded perlite in municipal solid waste composting processes produced mature and stable compost.  相似文献   

Health risk profile for terrestrial radionuclides in soil around artisanal gold mining area at Alsopag,Sudan     

Hajo Idriss  Isam Salih  Abdulaziz S. Alaamer  M. A. AL-Rajhi  Alshfia Osman  Tahir Elamin Adreani  M. Y. Abdelgalil  Nagi I. Ali 《Acta Geophysica》2018,66(4):673-681

This study shows the assessment of radiation hazard parameters due to terrestrial radionuclides in the soil around artisanal gold mining for addressing the issue of natural radioactivity in mining areas. Hence, the levels ²³⁸U, ²³²Th, ⁴⁰K and ²²⁶Ra in soil (using gamma spectrometry), ²²²Rn in soil and ²²²Rn in air were determined. Radiation hazard parameters were then computed. These include absorbed dose D, annual effective dose E, radium equivalent activity Ra_eq, external hazard H_ex, annual gonadal dose equivalent hazard index AGDE and excess lifetime cancer risk ELCR due to the inhalation of radon (²²²Rn) and consumption of radium (²²⁶Ra) in vegetation. Uranium (²³⁸U), thorium (²³²Th) and potassium (⁴⁰K) averages were, respectively, 26, 36 and 685 Becquerel per kilogram (Bq kg^?1). Soil radon (4671 Bq m^?3) and radon in air (14.77 Bq m^?3) were found to be less than worldwide data. Nevertheless, the average ⁴⁰K concentration was 685 Bq kg^?1. This is slightly higher than the United Nations Scientific Committee on the Effects of Atomic Radiation average value of 412 Bq kg^?1. The obtained result indicates that some of the radiation hazard parameters seem unsavory. The mean value of absorbed dose rate (62.49 nGy h^?1) was slightly higher than average value of 57 nGy h^?1 (~?45% from ⁴⁰K), and that of AGDE (444 μSv year^?1) was higher than worldwide average reported value (300 μSv year^?1). This study highlights the necessity to launch extensive nationwide radiation protection program in the mining areas for regulatory control.  相似文献   

The construction of a seventh-order Jupiter-Saturn analytical theory     

Osman M. Kamel  Adel S. Soliman 《Earth, Moon, and Planets》1993,60(2):141-175

We extend the construction of the Jupiter-Saturn theory to include all the terms up to the seventh order in the masses. The Hori-Lie transformation technique is employed. The Jacobian coordinates are adopted and the theory is expressed in terms of the canonical non-singular variables of H. Poincaré.  相似文献   

Is there period-activity correlation in RS CVn-type binary systems?     

Osman Demircan 《Astrophysics and Space Science》1987,136(1):201-205

The rotation period-activity luminosity and the rotation period-surface activity flux correlations for the components of RS CVn-type binaries are discussed. It is argued that such correlations, although they are required by dynamo generated magnetic fields, do not represent the dominant parameter in determining the level of activity. Evidences are given that these correlations may essentially be induced by the period-radius dependence for the components of RS CVn-type binaries, and in addition, this result may well be valid for all the late-type stars (single or binary components).  相似文献   

The construction of a third order secular     

Osman M. Kamel  Abdel Aziz Bakry  Salwa M. Waziry 《Earth, Moon, and Planets》1994,65(2):97-117

In this part we find out the 24 equations of secular perturbation equations for the subsystem J-S-U-N. The solution of these equations by the Lagrange-Laplace procedure and the Eigen value Eigen vector is analysed. Also we refer to Hurwitz theorem to test stability.  相似文献   

The construction of a general third-order planetary theory     

Osman M. Kamel 《Earth, Moon, and Planets》1982,26(1):47-60

We review in this part the outline of a third-order general planetary theory established through Von Zeipel's method and in terms of Poincaré's canonical variables We consider our system to consist of the Sun as the primary body, one disturbed planet, and one disturbing planet.  相似文献