Padé approximant calculations for dispersive,isotropic scattering,homogeneous media     

E. A. Saad  M. S. Abdel Krim  A. A. El-Dimerdash 《Astrophysics and Space Science》1988,149(2):187-195

Exact relations for radiation heat flux at the boundaries of a slab with diffusely reflecting boundary conditions and internal source are obtained in terms of the reflection and transmission coefficients of a source free slab with isotropic boundary conditions. The integral equation defining the radiation heat flux contains explicitly the internal source. So, the particular solution for radiative transfer equation is not required. Available exact values for albedos give exact values of radiation heat flux. Padé approximant technique is used to obtain numerical values for homogenous media.  相似文献   

Angular radiation transfer in inhomogeneous dispersive media     

E. A. Saad  M. S. Abdel Krim  A. A. El Ghazaly 《Astrophysics and Space Science》1988,148(2):363-372

The equation of radiative transfer for an inhomogenous dispersive finite medium subject to general boundary conditions is solved. The Padé approximation technique is used to calculate the angular distribution of radiation. Numerical results for the [0/1] Padé approximant lead to numerical results that compared with the exact results.  相似文献   

Manganese deposits in a Carboniferous paleokarst profile,Um Bogma region,west-central Sinai,Egypt     

M. A. El Sharkawi  M. M. El Aref  A. Abdel Motelib 《Mineralium Deposita》1990,25(1):34-43

The Carboniferous carbonates of the Um Bogma Formation of the west-central Sinai include two rock successions. The lower succesion consists of karstic carbonates, intrakarstic products, weathering varieties, manganese deposits, and soil cover. The lower karstic rocks and the associated soil cover are preserved under a rhythmic alternation of dolostone and shale forming the upper rock succession of the Um Bogma Formation. The all over congruent relations between the manganese deposits and the fossilized karst profile, karst products, and the associated pedogenesis demonstrate the role of weathering in the accumulation of these deposits during Carboniferous karstification. It is clear that the manganese oxides were deposited during the mature stage of Carboniferous karstification, i.e., during the soil formation, preceeding initial diagenetic change of the karstic rocks and final deposition of the related late-diagenetic caliche cement. The geochemical behavior of Mn during the karstification and the microbiological processes involved in pedogenesis played an essential role in the concentration of the manganese ore in the subsoil horizon of the paleokarst profile. The Um Bogma Formation has been subjected to another episode of karstification during the Quaternary and resulted in lowering of the landforms of the Carboniferous carbonates and destruction of the Carboniferous karst and the associated manganese deposits in some localities.  相似文献   

Styles of salt tectonics in the Sab’atayn basin,onshore Yemen     

Gabor Tari  Rudi Dellmour  Emma Rodgers  Chloe Asmar  Peter Hagedorn  Adel Salman 《Arabian Journal of Geosciences》2016,9(10):570

A variety of distinct salt tectonic features are present in the Sab’atayn Basin of western Yemen. Based on the interpretation of regional 2D seismic reflection data and exploration wells in the central part of the basin, an Upper Jurassic evaporite formation produced numerous salt rollers, salt pillows, reactive, flip-flop, and falling diapirs. Due to regional extension, halokinetics began as soon as the early Cretaceous, within just a few million years after the deposition of the Tithonian Sab’atayn evaporite sequence, by formation of salt rollers. The salt locally formed salt pillows which evolved to reactive and active salt diapirs and diapiric salt walls as the result of renewed, but low-strain extension in the basin. Some of the diapiric walls further evolved into falling diapirs due to ongoing extension. As the result of a prominent extensional episode at the end of the Cretaceous, many of the diapiric walls in the basin are controlled by large normal faults on their updip flanks. As the post-Cretaceous sedimentary cover is largely missing in the study area, the assumed reactivation of salt structures during the Cenozoic remains poorly constrained. The interpreted changes in the style of salt tectonics in the Sab’atayn Basin offer a better understanding of the regional-scale tectonic development of the Arabian plate during the late Jurassic and Cretaceous.  相似文献   

Assessment of hot groundwater in an arid area in Tunisia using geochemical and fuzzy logic approaches     

Belgacem Agoubi  Faiza Souid  Adel Kharroubi  Abdelaziz Abdallaoui 《Environmental Earth Sciences》2016,75(24):1497

In this study, thermal groundwater from arid area in southeastern Tunisia was assessed for irrigation use. For this purpose, thirty-one water samples were collected and physiochemical parameters (EC, pH, TDS, major ions) were measured and analyzed. A fuzzy logic model was developed in which six parameters were integrated: electrical conductivity, sodium adsorption ratio, sodium percentage, Kelly ratio, permeability index and temperature. The membership functions for a fuzzy logic model were developed using linguistic terms and trapezoidal shapes. The fuzzy logic model developed was validated with a dataset of chemical analyses from groundwater sampled in the study area. The assessment indicated that 26% of the samples were in the “good” class, 10% in the “good to permissible” class, 55% are in the “permissible” class, 6% are in the “permissible to harmful” class and 3% were considered to be harmful and therefore unsuitable for use in irrigation. The effectiveness, simplicity and robustness of the fuzzy model assessment make this approach a more consistent and reliable way of assessing water quality than conventional methods of assessing water quality data.  相似文献   

Oblique sand ridges in confined tidal channels due to Coriolis and frictional torques     

Hepkema  Tjebbe M.  de Swart  Huib E.  Nnafie  Abdel  Schramkowski  George P.  Schuttelaars  Henk M. 《Ocean Dynamics》2020,70(12):1505-1513

Ocean Dynamics - The role of the Coriolis effect in the initial formation of bottom patterns in a tidal channel is studied by means of a linear stability analysis. The key finding is that the...  相似文献   

Source parameters and ground motion of the Suez-Cairo shear zone earthquakes,Eastern Desert,Egypt   总被引：1，自引：0，他引：1  

K. M. Abou Elenean  Adel M. E. Mohamed  H. M. Hussein 《Natural Hazards》2010,52(2):431-451

Three felt earthquakes with local magnitudes 4.0 (June 29th, 2000), 4.2 (July 07th, 2005) and 3.7 (October 30th, 2007) occurred to the southeast of Cairo along the Suez-Cairo shear zone. Being the most well recorded events by the Egyptian National Seismic Network (ENSN) in this area, they provide us an excellent opportunity to study the tectonics, the stress field, the source parameters, and the expected ground motion at Cairo. The focal mechanisms of the three events based on the first motion P-wave polarities indicate mainly normal faulting with a slight strike-slip component along nodal planes trending nearly EW and NW–SE. The three focal solutions imply a rejuvenation of the pre-existing EW and NW–SE faults due to a partly transfer of rifting deformation from the Red Sea-Gulf of Suez along these trends. Dynamic source parameters of these events are estimated from the P-wave spectra of the closest ENSN stations. The average values of the seismic moment, stress drop, rupture radius, and fault dislocation are estimated from six stations and interpreted in the context of the tectonic setting. These parameters in addition to the effects of site and path are used to synthesize the ground motion seismograms using stochastic modeling technique at the recorded stations and at some strategic sites.  相似文献   

Extended linear-sigma model: transport properties of QCD matter at finite temperature     

Adel Nasser Tawfik  Azzah Elshehri 《Astronomische Nachrichten》2024,345(2-3):e240004

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An Evaluation of Some Geophysical Methods for Water Exploration in the Piedmont Area by T. J. Joiner, J. C. Warman, and W. L. Scarbrough January-February, 1968     

Adel A. R. Zohdy 《Ground water》1968,6(4):38-39

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Biodegradation of municipal refuse and chicken manure in a winter-wheat ecosystem in Saudi Arabia     

H. M. Abdel Magid  R. E. A. Sabrah  R. K. Rabi  A. R. H. El Nadi  S. I. Abdel Aal 《Journal of Arid Environments》1993,25(4)

Addition and incorporation of organic fertilizers is known to improve the properties of agricultural soils. Therefore, during 22 weeks of field incubation we studied the biodegradation (measured by static absorption of CO₂) of two organic manures viz. municipal refuse and chicken manure incorporated into sandy soils, under sprinker irrigation, at the rates of 0, 16·5, 33·0, 49·5 and 66·0, and 0, 4·1, 8·25, 16·5, and 33·0 tonnes/ha, respectively.The results obtained indicated that the cumulative amount of CO₂ respired was linearly correlated with the rate of organic material applied (p < 0.001). Statistical analysis of the data obtained showed that both the intercept (rate of decomposition) and the slope (rate of reaction with time) increased with increasing rate of application of organic manure. The magnitude of increment was highest at the application rates of 33·0 and 8·25 tonnes/ha for municipal refuse and chicken manure, respectively. The rate of increment, generally, declined thereafter thus indicating that these two rates are the optimum levels of incorporation of the appropriate organic manures under the conditions of this study.The maximum organic-carbon mineralized, accounting for 10·5 and approximately 50%, was obtained at the optimum rates for municipal refuse and chicken manure, respectively. Both simple and multiple regression equations describing the relationship between soil temperature and soil-moisture content each separately and in combination, as independent variables, and the cumulative rate of CO₂ production were computed. A substantially strong relationship with soil temperature but inconsistent and contradicting results with soil moisture were obtained. Inclusion of soil temperature and moisture in a single model as an independent variable in relation to cumulative CO₂ as a dependent variable improved the soil moisture-CO₂ production relationship.  相似文献