Numerical investigation of undrained cavity expansion in fine-grained soils     

Abid Ali  Thomas Meier  Ivo Herle 《Acta Geotechnica》2011,6(1):31-40

Based on the spherical cavity expansion (SCE) problem, Cudmani and Osinov (Can Geotech J 38:622–638, 2001), Osinov and Cudmani (Int J Numer Anal Method Geomech 25:473–495, 2001) developed a semi-empirical method of interpretation of CPT for coarse-grained soils (sand, gravel) using a hypoplastic constitutive model. Using a material-independent shape factor, the cone penetration resistance was related to the limit pressure required to expand a spherical cavity. The shape factor was observed to be a function of the soil state only, in particular the pressure-dependent relative density. This paper presents an analogous interpretation technique for CPT in fine-grained soils using the shape factor concept, Cavity Expansion approach, and a hypoplastic constitutive model. Relations for the shape factor and the limit pressure have been proposed based on the parameters affecting these quantities. A validation of the proposed interpretation technique with experimental results has also been performed.  相似文献   

Planar SAS for Sea Bottom and Subbottom Imaging: Concept Validation in Tank     

Afif Belkacem Kamel Besbes Jacques Chatillon Manell E. Zakharia 《Oceanic Engineering, IEEE Journal of》2006,31(3):614-627

The paper deals with a new concept of imaging technique based on planar synthetic aperture sonar (P-SAS). P-SAS processing takes advantage of the overlap of both ping-to-ping and track to track footprints to improve the imaging resolution in both directions. After describing the method, its implementation is discussed. The exact implementation [three-dimensional (3-D)] is defined and an approximated and faster approach [2timestwo-dimensional (2-D)] is then proposed. The gain in computation time and the possible loss in performances (resolutions, echo amplitude) are investigated by simulating a simple point target. The point spread function is studied in details. The new concept is finally validated by tank experiments (scale about 100) for both proud and buried target imaging  相似文献   

Expansion of the first-order planetary disturbing function by Smart's method     

Osman M. Kamel  Adel S. Soliman 《Earth, Moon, and Planets》1989,47(3):241-263

We expand the principal part of the planetary disturbing function, by Smart's method, using Taylor's theorem. In our expansion we neglect terms of degree higher than the fourth in the eccentricities and tangents of the inclinations.Now at the JPL Pasadena, California.  相似文献   

Removal of Heavy Metals from Synthetic Mixture as well as Pharmaceutical Sample Via Cation Exchange Resin Modified with Rhodamine B: Its Thermodynamic and Kinetic Studies     

Syed A. Nabi  Mohammad Shahadat  Abid H. Shalla  Amjad M. T. Khan 《洁净——土壤、空气、水》2011,39(12):1120-1128

A new sorbent was prepared by loading rhodamine B on Amberlite IR‐120. Various physico‐chemical parameters such as effects of adsorbate concentration, contact time, pH, and temperature on the sorption of the dye have been studied. Thermodynamic parameters (ΔH° and ΔS°) were also evaluated for the sorption of dye. Kinetic studies revealed that the sorption of the dye was best fit for pseudo‐second‐order kinetic. The metal ion uptake in different solvent systems has been explored through column studies. On the basis of distribution coefficient (K_d), some heavy metal ions of analytical interest from binary mixtures have been separated. The limit of detection (LOD) for the Ni²⁺ and Fe³⁺ metal ions was 0.81 and 0.60 µg L^?1, and the limit of quantification (LOQ) was found to be 2.72 and 2.0 µg L^?1. This sorbent has also been successfully applied in the analysis of multivitamin formulation. The applicability of the modified resin in the separation of heavy metals constituting real and synthetic samples has been explored.  相似文献   

Salinisation origin and hydrogeochemical behaviour of the Djerid oasis water table aquifer (southern Tunisia)     

Samir Kamel 《Arabian Journal of Geosciences》2013,6(6):2103-2117

The shallow Plio-Quaternary (PQ) water table, present over almost the whole Djerid and Chott El Gharsa basins (southern Tunisia), is used as a complement of oases irrigation, especially in summer season. The simplicity of the Plio-Quaternary lithology is confronted to the complexity of the mineralisation mechanisms and the water origin in this aquifer. An approach combining the use of water-dissolved chemical species and isotopic contents has been used to better understand the PQ behaviour under severe increasing exploitation and to determinate the origin of its different water bodies. In southern Tunisia, the aquifer system is composed of the upper unconfined PQ aquifer, the intermediate semi-confined/confined Complexe Terminal (CT) and the deeper confined Continental Intercalaire (CI). Chemical analyses highlighted an origin of mineralisation in close relationship to the dissolution of both sulphated salts (MgSO₄ and Na₂SO₄) and chlorinated salts (NaCl and MgCl) abundant in the surface and subsurface gypsum crust. Positive correlations between gypsum anhydrite, mirabilite, thenardite and halite saturation indexes with respective mineral species, confirm evaporites dissolutions. Isotopic data showed that in addition of sporadic rainfall events, there is a contribution from the CI and the CT Saharan groundwaters, recharging the PQ aquifer in the study area. Return flow irrigation is partly affected by evaporation, before recharging the shallow aquifer, in oases limits.  相似文献   

Fractal variogram-based time–space of aftershock sequences analysis—case study: the May 21, 2003 Boumerdes–Algeria earthquake, M w = 6.8     

Moh-Amokrane Aitouche  Mabrouk Djeddi  Kamel Baddari 《Arabian Journal of Geosciences》2013,6(7):2183-2192

The most of shallow earthquakes are followed, just after the main shock, by increased residual seismicity known as “aftershocks” or “aftershock sequences”. Because of their disparity in time and space, aftershock sequences are more or less obvious and their productivity is spread out in time. Several studies have been regularly proposed to explain or to understand the mechanisms of the occurrence and the behaviour of these small earthquakes. In a theoretical context, many factors can induce the aftershock triggering: residual friction, subcritical crack growth, pore fluid flow etc. Just after the occurrence of the most destructive main shock of the 21 May 2003 Boumerdes (Algeria) earthquake, a wide sequence of aftershocks was recorded at different geographical locations and with various magnitudes. Based on the fact that the region of Boumerdes (40 km east of the capital Algiers) did not develop major earthquakes in the past, a geostatistical investigation of the data for this aftershock sequence is a valuable input for better seismogeological identification of this area. In the present analysis, after an overview of the geological factors in the likely occurrence of the earthquake, fundamental statistical parameters were chosen: the b value from the Gutenberg–Richter law, the p factor of the extracted respectively from the b value and the fractal variogram defined as a graphic tool to describe the continuity or the roughness of data. Jointly to the geostatistical parameters provided by the variogram like the fractal dimension. The main objective of the calculation and interpretation of these parameters is oriented towards a better understanding of the seismicity of the region of Boumerdes (Algeria) now classified as seismogenic zone.  相似文献   

GIS in hospital and healthcare emergency management,edited by Ric Skinner     

Maged N. Kamel Boulos 《International journal of geographical information science》2013,27(11):1906-1907

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Processus de minéralisation de la nappe du Plio-Quaternaire dans la plaine de Segui-Zograta (Sud-Ouest tunisien)     

Zohra Kraiem  Kamel Zouari  Narjess Bencheikh  Aissa Agoun  Brahim Abidi 《水文科学杂志》2013,58(3):534-548

Résumé

La plaine de Segui-Zograta est une cuvette synclinale à remplissage Mio-Plio-Quaternaire où la nappe du Plio-Quaternaire constitue la principale source d’approvisionnement en eau pour l’abreuvement du chaptel et pour l’agriculture. Cette zone présente une hétérogénéité de répartition de la minéralisation des eaux souterraines. L’investigation des outils géochimiques basée sur l’étude des éléments majeurs, des isotopes stables (¹⁸O, ²H) et radioactifs (³H, ¹⁴C) indique la combinaison de différents processus contrôlant la minéralisation de ces eaux. Dans la partie Ouest, les eaux du Plio-Quaternaire présentent un facies de type sulfato-calco-sodique et des salinités élevées. Elles subissent l’effet de la dissolution des minéraux évaporitiques et résultent du mélange par drainance ascendante des eaux fossi des aquifères les plus profonds, à salinité élevée et à faciès chloruro-sulfato-sodique, à travers la faille d’Om Ali où leur contribution peut atteindre 96%. Dans la partie Est, ces eaux sont de type sulfato-calcique, considérées relativement moins minéralisées que celles de la partie Ouest. Elles sont issues de l’infiltration des eaux de pluie récentes et qui ont subi l’effet de l’évaporation.