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11.
Abdullah Gamil M. S. El Aal Ahmed Abd Radwan Ahmed E. Qadri Talha Aly Nevin 《Acta Geotechnica》2023,18(1):105-125
Acta Geotechnica - One of the most important geotechnical parameters in studying the engineering behavior of a rock mass is slake durability. The major goal of this research is to test how a series... 相似文献
12.
Okuhata Brytne K. El-Kadi Aly I. Dulai Henrietta Lee Jonghyun Wada Christopher A. Bremer Leah L. Burnett Kimberly M. Delevaux Jade M. S. Shuler Christopher K. 《Hydrogeology Journal》2022,30(1):231-250
Hydrogeology Journal - Fresh groundwater is a critical resource supporting coastal ecosystems that rely on low-salinity, nutrient-rich groundwater discharge. This resource, however, is subject to... 相似文献
13.
Ahmed Aly Kamel 《Celestial Mechanics and Dynamical Astronomy》1971,4(3-4):397-405
To develop the perturbation solution of the non-Hamiltonian system of differential equationsy=g(y, t; ), it is sufficient to obtain the perturbation solution of a Hamiltonian system represented by the HamiltonianK=Y·g(y, t; ) which is linear in the adjoint vectorY. This Hamiltonization allows the direct use of the perturbation methods already established for Hamiltonian systems. To demonstrate this fact, a Hamiltonian algorithm developed by this author and based on the Lie-Deprit transform is applied to the Hamiltonized system and is shown to be equivalent to the application of the non-Hamiltonian form of this same algorithm to the original non-Hamiltonian system. 相似文献
14.
Stefano Urbini Iacopo Nicolosi Antonio Zeoli Sami El Khrepy Ahmed Lethy Mahfooz Hafez Mohamed El Gabry Ahmed El Barkooky Aly Barakat Mahomoud GOMAA Ali M. Radwan Mohamed El Sharkawi Massimo D’orazio Luigi Folco 《Meteoritics & planetary science》2012,47(11):1842-1868
Abstract– We detail the Kamil crater (Egypt) structure and refine the impact scenario, based on the geological and geophysical data collected during our first expedition in February 2010. Kamil Crater is a model for terrestrial small‐scale hypervelocity impact craters. It is an exceptionally well‐preserved, simple crater with a diameter of 45 m, depth of 10 m, and rayed pattern of bright ejecta. It occurs in a simple geological context: flat, rocky desert surface, and target rocks comprising subhorizontally layered sandstones. The high depth‐to‐diameter ratio of the transient crater, its concave, yet asymmetric, bottom, and the fact that Kamil Crater is not part of a crater field confirm that it formed by the impact of a single iron mass (or a tight cluster of fragments) that fragmented upon hypervelocity impact with the ground. The circular crater shape and asymmetries in ejecta and shrapnel distributions coherently indicate a direction of incidence from the NW and an impact angle of approximately 30 to 45°. Newly identified asymmetries, including the off‐center bottom of the transient crater floor downrange, maximum overturning of target rocks along the impact direction, and lower crater rim elevation downrange, may be diagnostic of oblique impacts in well‐preserved craters. Geomagnetic data reveal no buried individual impactor masses >100 kg and suggest that the total mass of the buried shrapnel >100 g is approximately 1050–1700 kg. Based on this mass value plus that of shrapnel >10 g identified earlier on the surface during systematic search, the new estimate of the minimum projectile mass is approximately 5 t. 相似文献
15.
We present some preliminary results on different mathematical problems encountered in attempts to reconstruct the coronal magnetic field, assumed to be in a force-free state, from its values in the photosphere. We discuss the formulations associated with these problems, and some new numerical methods that can be used to get their approximate solutions. Both the linear constant- and the nonlinear cases are considered. We also discuss the possible use of dynamical 3D MHD codes to construct approximate solutions of the equilibrium force-free equations, which are needed for testing numerical extrapolation schemes. 相似文献
16.
Fahad N. Al-Barakah Aly Anwar A. Abaakhel Emad H. S. Al-Rizkid Abdulwahid M. Alghamdi Abdulaziz G. Al-Sewailem Mohammad S. 《Water Resources》2020,47(5):877-891
Water Resources - The objective of this study was to compare and assess the quality and study the hydrochemistry of groundwater in the Al-Baha and Al-Qassim areas, representing the Arabian Shield... 相似文献
17.
A finite element analysis of a reinforced embankment-foundation system has been conducted using a coupled formulation and elastoplasticity theory. Such important factors as type of reinforcement, the type of clay, depth of foundation and drainage condition affecting the system have been systematically investigated using appropriate constitutive models to depict various components of the system and material parameters of two typical soft clay deposits found in India. The displacements, reinforcement force and maximum heights of the embankments are among the aspects presented and discussed. It is shown that the effectiveness of the reinforcement is dependent on its stiffness and the shear strength of the clay deposit. The foundation depth has significant effect on the nature and magnitude of displacement, the reinforcement force and the height of embankment. Drainage conditions are shown to markedly influence the effectiveness of reinforcement. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
18.
Christopher K. Shuler Aly I. El-Kadi Henrietta Dulai Craig R. Glenn Joseph Fackrell 《Hydrogeology Journal》2017,25(8):2419-2434
This study presents a modeling framework for quantifying human impacts and for partitioning the sources of contamination related to water quality in the mixed-use landscape of a small tropical volcanic island. On Tutuila, the main island of American Samoa, production wells in the most populated region (the Tafuna-Leone Plain) produce most of the island’s drinking water. However, much of this water has been deemed unsafe to drink since 2009. Tutuila has three predominant anthropogenic non-point-groundwater-pollution sources of concern: on-site disposal systems (OSDS), agricultural chemicals, and pig manure. These sources are broadly distributed throughout the landscape and are located near many drinking-water wells. Water quality analyses show a link between elevated levels of total dissolved groundwater nitrogen (TN) and areas with high non-point-source pollution density, suggesting that TN can be used as a tracer of groundwater contamination from these sources. The modeling framework used in this study integrates land-use information, hydrological data, and water quality analyses with nitrogen loading and transport models. The approach utilizes a numerical groundwater flow model, a nitrogen-loading model, and a multi-species contaminant transport model. Nitrogen from each source is modeled as an independent component in order to trace the impact from individual land-use activities. Model results are calibrated and validated with dissolved groundwater TN concentrations and inorganic δ15N values, respectively. Results indicate that OSDS contribute significantly more TN to Tutuila’s aquifers than other sources, and thus should be prioritized in future water-quality management efforts. 相似文献
19.
In this study, the spatio-temporal evolution of Yellowstone deformation between 1992 and 2009 is monitored using interferometric
synthetic aperture radar (InSAR) data acquired by the European Remote-Sensing Satellites (ERS-1 and ERS-2) and the Environmental
Satellite (ENVISAT). These data are combined with continuous global positioning system (GPS) measurements to identify four
discrete episodes of caldera subsidence and uplift, these episodes are: 1992–1995 (subsidence of 2.7 cm/year), 1996–2000 (subsidence
of 0.5 cm/year, with local uplift of 1.7 cm/year at Norris), 2000–2004 (subsidence of 0.7 cm/year, with local uplift of 0.6 cm/year
at Norris), and 2004–2009 (uplift of 3–8 cm/year, with local subsidence of 1–4 cm/year at Norris). We construct the full three-dimensional
velocity field of Yellowstone deformation for 2005–2006 from ascending and descending ENVISAT orbits. The InSAR three-dimensional
velocity field and three-component GPS measurements indicate that the majority of the observed deformation (3–8 cm/year) across
the Yellowstone caldera and near Norris Geyser Basin (NGB) occurred in the vertical direction between the summers of 2005
and 2006. During this time, significant lateral displacements of 3–7 cm/year also occurred in the east–west direction at the
southeastern and western rims of the Yellowstone caldera and in the area between Hebgen Lake and NGB. Minor north–south displacements
of about 0.2 cm/year also occurred, however, in the southwestern section of the caldera and near Yellowstone Lake during the
same period. The calculated three-dimensional velocity field for 2005–2006 implies the existence of two pressure-point sources,
beneath the two structural resurgent domes in the Yellowstone caldera, connected by a planar conduit, rather than a single,
large sill as proposed in previous studies. Furthermore, no measurable displacements occurred along any fault zone across
the caldera during the entire period of observation (1992–2009). Therefore, we infer that magmatic and hydrothermal processes
beneath the Yellowstone caldera and NGB were the main sources of deformation. 相似文献
20.
Aly I. El-Kadi 《Advances in water resources》1985,8(3):148-153
A new empirical equation to estimate hydraulic conductivity is proposed, based on a large set of measured data for hydraulic properties of soil. The equation is simpler and more accurate than the series-parallel model. Under conditions of insufficient data, the new equation provides a good estimation of hydraulic conductivity for sands. For the same class of soils, another empirical equation is proposed to estimate the power N in the Averjanov-Irmay function. 相似文献