Radiation transfer for an inhomogeneous half-space with an internal source     

E. A. Saad  A. A. Hendi  S. A. El Wakil 《Astrophysics and Space Science》1984,100(1-2):381-389

The emergent flux for radiation transfer in an inhomogeneous half-space with internal source is obtained in terms of the source-function of the diffuse reflection problem. Modified Eddington method is used to calculate the diffuse problem and, hence, the emergent flux. Numerical result are given and compared with previous work.On leave of absence from the Nuclear Research Centre, Cairo, Egypt.  相似文献   

Enhancement of edges of Sidi Chennane phosphate “disturbances” using sunshading responses of resistivity data     

Saad Bakkali   《Russian Geology and Geophysics》2007,48(9):775-781

Sunshading is a powerful tool for the enhancement of edges in images. Given the azimuth and elevation of a source illumination, it calculates the reflectance from a surface which is composed of the data to be interpreted. It is a standard tool used in the interpretation of geophysical potential field data. In the great Oulad Abdoun phosphate basin, inclusions of sterile hardpan — so-called “disturbances” — are hard to detect as they interfere with phosphates. Their resistivity is above 200 Ohmm against 80 to 150 Ohmm for a phosphate-rich mineral. A Schlumberger resistivity survey over an area of 50 hectares was carried out. The geologic setting was successfully modeled on the basis of sunshaded maps of disturbances. A new field procedure was tested to deal with the extended edges of anomalous zones of phosphate deposit disturbances. Phosphate reserves were estimated more reliably.  相似文献   

An efficient computational algorithm for the initial value problem associated with the universal Y functions     

M. A. Sharaf  A. S. Saad  M. A. Fadak 《Astronomische Nachrichten》2016,337(3):235-238

In the present paper, an efficient iterative method of arbitrary integer order of convergent ≥2 based on the homotopy continuation techniques for the solution of the initial value problem of space dynamics using the universal Y functions is presented. The method is of dynamic nature in the sense that, ongoing from one iterative scheme to the subsequent one, only additional instruction is needed. Most importantly, the method does not need any prior knowledge of the initial guess. This is a property which avoids the critical situations between divergent to very slow convergent solutions that may exist in other numerical methods which depend on initial guesses. A computational package for digital implementation of the method is given, together with numerical applications for elliptic, hyperbolic, and parabolic orbits. The accuracy of the results for all orbits is O(10^–16). (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

A numerical comparison of enhancing horizontal resolution (EHR) technique utilizing 2D resistivity imaging     

M. M. Nordiana  S. Rosli  M. N. M. Nawawi 《Arabian Journal of Geosciences》2014,7(1):299-309

The effectiveness of inversion apparent resistivity data to determine accurately the true resistivity distribution over 2D structures has been investigated using a common inversion scheme based on smoothness-constrained nonlinear least-squares optimization with enhancing horizontal resolution (EHR) technique by numerical simulation. The theoretical model generates in RES2DMOD software at specific distance and depth using Wenner, Wenner–Schlumberger, and pole–dipole arrays were inverted. The inversion model was compared with the original 2D model in RES2DINV software. The study model includes horizontal layering, vertical resolution, and horizontal two layers with different resistivity. Also, the response to variations in data density of these arrays was investigated. The study shows the best array suitable to be used in the survey was chosen for real data acquisition at the actual site. Subsequently, the results from borehole were used to verify the results of 2D resistivity imaging method with and without EHR technique. Saturated zone (0–40 Ω-m) was found scattered at the depth of 10–20 m. The borehole is located at 63 m at 2D resistivity imaging survey which shows at depth 10–20 m is sandy silt. Highly weathered sandstone was found at 6 m depth with resistivity value of 800 Ω-m and SPT N value of 20. The bedrock was found at 27 m depth with resistivity value of 3,000 Ω-m and SPT N value of 50. The application of 2D resistivity imaging with EHR technique indicate the ability of the proposed approach in terms of density, depth, and resistivity value of anomalous and layer in a computationally and numerically efficient manner and to exhibit good performance in the data inversion.  相似文献   

Comparison of Early Succession and Scleractinian Recruitment Between Artificial Live Rocks and Terracotta Tiles     

Hamizan  Yusof Muhammad  Saad  Shahbudin  Naim  Mohd Azrul  Khodzori  Mohd Fikri Akmal  Hanapiah  Muhammad Faiz Mohd 《Ocean Science Journal》2021,56(3):317-325

Ocean Science Journal - Previous studies indicated that artificial live rock (ALR) has the potential to be used as a substrate for coral juveniles. The present study reported a potential of ALR as...  相似文献   

Saudi Arabian White Silica as a Good Adsorbent for Pollutants          下载免费PDF全文

Islam Hamdy Abd El Maksod  Hassan M. AlBishri  Abdullah Saad Al‐bogami 《洁净——土壤、空气、水》2014,42(4):480-486

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Effects of anthropogenic activities on the quality of surface water of Seybouse River (northeast of the Algeria)     

Asma Reggam  El-Hadi Bouchelaghem  Saad Hanane  Moussa Houhamdi 《Arabian Journal of Geosciences》2017,10(10):219

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A nested multivariate copula approach to hydrometeorological simulations of spring floods: the case of the Richelieu River (Québec,Canada) record flood   总被引：2，自引：2，他引：0  

Christian Saad  Salaheddine El Adlouni  André St-Hilaire  Philippe Gachon 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(1):275-294

Floods have potentially devastating consequences on populations, industries and environmental systems. They often result from a combination of effects from meteorological, physiographic and anthropogenic natures. The analysis of flood hazards under a multivariate perspective is primordial to evaluate several of the combined factors. This study analyzes spring flood-causing mechanisms in terms of the occurrence, frequency, duration and intensity of precipitation as well as temperature events and their combinations previous to and during floods using frequency analysis as well as a proposed multivariate copula approach along with hydrometeorological indices. This research was initiated over the Richelieu River watershed (Quebec, Canada), with a particular emphasis on the 2011 spring flood, constituting one of the most damaging events over the last century for this region. Although some work has already been conducted to determine certain causes of this record flood, the use of multivariate statistical analysis of hydrologic and meteorological events has not yet been explored. This study proposes a multivariate flood risk model based on fully nested Archimedean Frank and Clayton copulas in a hydrometeorological context. Several combinations of the 2011 Richelieu River flood-causing meteorological factors are determined by estimating joint and conditional return periods with the application of the proposed model in a trivariate case. The effects of the frequency of daily frost/thaw episodes in winter, the cumulative total precipitation fallen between the months of November and March and the 90th percentile of rainfall in spring on peak flow and flood duration are quantified, as these combined factors represent relevant drivers of this 2011 Richelieu River record flood. Multiple plausible and physically founded flood-causing scenarios are also analyzed to quantify various risks of inundation.  相似文献   

Geotectonic significance of the Neoproterozoic ophiolitic metagabbros of Muiswirab area,South Eastern Desert,Egypt: constraints from their mineralogical and geochemical characteristics     

Mogahed  Moustafa M.  Saad  Wlaa Mahmoud 《中国地球化学学报》2020,39(6):887-910

Acta Geochimica - Petrological and geochemical studies of Neoproterozoic metagabbros were carried out in the Muiswirab area, South Eastern Desert of Egypt. The Muiswirab area comprises of...  相似文献   

Near-surface foundation level assessment from seismic measurements: a case study of north Jeddah City,Saudi Arabia     

Mogren  Saad  Aldahri  Maher  Abdelrahman  Kamal  Zahran  Hani 《Arabian Journal of Geosciences》2020,13(5):1-22

In this study, a comprehensive assessment on the generation mechanism, distribution characteristics, and extension rules of structure cracks was conducted by in situ monitoring and field investigation in the Chengchao Iron Mine. Structure cracks are affected by many factors, e.g., surface deformation, structure strength, occurrence position, and machine vibration. They initially occur in a structure when the strength of the structure is not enough to resist the inner strain as surface deformation increases. In contrast, increases in width and length of structure crack exert stress release in the structure and thus decrease structure deformation surrounding the crack. A great ground crack may adversely aggravate structure cracking and release the stress of surrounding rock masses. In addition, micro cracks in rock masses provide favorable conditions for the generation and extension of cracks, resulting that cracks occur in shaft walls more easily and extend towards the deeper. The initial distribution of cracks is generally consistent with such micro cracks. Subsequently, cracks in deep rock masses will extend along the strike of the mined-out area as surface deformation increases. Sensibilities to cracking of structures are changed by their different strain resistances and become stronger from bolt-shotcrete shaft, bolt-shotcrete tunnel, and brick-concrete building to brick wall. Based on distribution characteristics of cracks and wave velocity in rock masses, the overlaying strata affected by underground mining can be divided into four zones: broken zone, broken transition zone, crack generation zone, and micro deformation zone.  相似文献