Impacts of Water Quality on the Spatiotemporal Susceptibility of Water Distribution Systems     

Md Maruf Mortula  Tarig A. Ali  Rehan Sadiq  AlaEldin Idris  Asam Al Mulla 《洁净——土壤、空气、水》2019,47(5)

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Efficient and accurate edge‐preserving smoothing for 3D hexagonally sampled seismic data          下载免费PDF全文

Haroon Ashraf  Wail A. Mousa  Saleh Al‐Dossary 《Geophysical Prospecting》2017,65(3):696-710

The automatic detection of geological features such as faults and channels is a challenging problem in today's seismic exploration industry. Edge detection filters are generally applied to locate features. It is desirable to reduce noise in the data before edge detection. The application of smoothing or low‐pass filters results in noise suppression, but this causes edge blurring as well. Edge‐preserving smoothing is a technique that results in simultaneous edge preservation and noise suppression. Until now, edge‐preserving smoothing has been carried out on rectangular sampled seismic data. In this paper, an attempt has been made to detect edges by applying edge‐preserving smoothing as a pre‐processing step in the hexagonally sampled seismic‐data spatial domain. A hexagonal approach is an efficient method of sampling and has greater symmetry than a rectangular approach. Here, spiral architecture has been employed to handle the hexagonally sampled seismic data. A comparison of edge‐preserving smoothing on both rectangular and hexagonally sampled seismic data is carried out. The data used were provided by Saudi Aramco. It is shown that hexagonal processing results in well‐defined edges with fewer computations.  相似文献   

Estimating Groundwater Mounding in Sloping Aquifers for Managed Aquifer Recharge          下载免费PDF全文

Vitaly A. Zlotnik  Anvar Kacimov  Ali Al‐Maktoumi 《Ground water》2017,55(6):797-810

Design of managed aquifer recharge (MAR) for augmentation of groundwater resources often lacks detailed data, and simple diagnostic tools for evaluation of the water table in a broad range of parameters are needed. In many large‐scale MAR projects, the effect of a regional aquifer base dip cannot be ignored due to the scale of recharge sources (e.g., wadis, streams, reservoirs). However, Hantush's (1967) solution for a horizontal aquifer base is commonly used. To address sloping aquifers, a new closed‐form analytical solution for water table mound accounts for the geometry and orientation of recharge sources at the land surface with respect to the aquifer base dip. The solution, based on the Dupiuit‐Forchheimer approximation, Green's function method, and coordinate transformations is convenient for computing. This solution reveals important MAR traits in variance with Hantush's solution: mounding is limited in time and space; elevation of the mound is strongly affected by the dip angle; and the peak of the mound moves over time. These findings have important practical implications for assessment of various MAR scenarios, including waterlogging potential and determining proper rates of recharge. Computations are illustrated for several characteristic MAR settings.  相似文献   

Seismic behavior and zoning of the sabkha soils in Jubail industrial city,Saudi Arabia     

H. R. Ahmed  N. A. Al Shayea 《Journal of Seismology》2017,21(5):1145-1169

This study aimed at the micro-level seismic behavior and zoning of the saline sabkha strata in Jubail industrial area in Eastern Saudi Arabia. It encompasses the evaluation of the site-specific seismic response parameters and the liquefaction potential for various possible subsurface conditions under the probable seismic event(s). The approach to achieve the objectives of this study included the following: analysis of geologic, hydrologic, and geotechnical data of the area; performance of field and laboratory dynamic testing; and dynamic modeling and analysis of the subsurface profiles. The results of the simulation have been used to develop liquefaction potential maps and site-specific spectra of the study area, consisting of ten seismic zones under a range of probable peak horizontal ground acceleration (PHA). Results do not show significant probability of liquefaction of the loose soil layers in the study area at the maximum possible design PHA of 0.035 g; however, liquefaction is anticipated at higher PHA values. Site-specific spectral response resulted in values of S _s and S ₁ spectral accelerations to be different as compared to those suggested by local standards. The resulting seismic micro-zonation maps and the corresponding parameters are very useful for the stability analysis of the existing and planned structures in the Jubail area.  相似文献   

Rare Earth Elements Around the Barakah Nuclear Power Plant,UAE     

Al Rashdi  Mouza Rashid  El Tokhi  Mohamed  Alaabed  Sulaiman  El Mowafi  Walid  Arabi  Alya A. 《Natural Resources Research》2020,29(6):4149-4160

Natural Resources Research - Rare earth element (REE) contamination has major consequences for the environment and humans. Some forms of REEs have more serious environmental impacts than others. It...  相似文献   

Bearing capacity of strip footings on spatially random soils using sparse polynomial chaos expansion     

Tamara Al‐Bittar  Abdul‐Hamid Soubra 《国际地质力学数值与分析法杂志》2013,37(13):2039-2060

A probabilistic model is presented to compute the probability density function (PDF) of the ultimate bearing capacity of a strip footing resting on a spatially varying soil. The soil cohesion and friction angle were considered as two anisotropic cross‐correlated non‐Gaussian random fields. The deterministic model was based on numerical simulations. An efficient uncertainty propagation methodology that makes use of a non‐intrusive approach to build up a sparse polynomial chaos expansion for the system response was employed. The probabilistic numerical results were presented in the case of a weightless soil. Sobol indices have shown that the variability of the ultimate bearing capacity is mainly due to the soil cohesion. An increase in the coefficient of variation of a soil parameter (c or φ) increases its Sobol index, this increase being more significant for the friction angle. The negative correlation between the soil shear strength parameters decreases the response variability. The variability of the ultimate bearing capacity increases with the increase in the coefficients of variation of the random fields, the increase being more significant for the cohesion parameter. The decrease in the autocorrelation distances may lead to a smaller variability of the ultimate bearing capacity. Finally, the probabilistic mean value of the ultimate bearing capacity presents a minimum. This minimum is obtained in the isotropic case when the autocorrelation distance is nearly equal to the footing breadth. However, for the anisotropic case, this minimum is obtained at a given value of the ratio between the horizontal and vertical autocorrelation distances. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Efficient sparse polynomial chaos expansion methodology for the probabilistic analysis of computationally‐expensive deterministic models     

T. Al‐Bittar  A.‐H. Soubra 《国际地质力学数值与分析法杂志》2014,38(12):1211-1230

The sparse polynomial chaos expansion (SPCE) methodology is an efficient approach that deals with uncertainties propagation in case of high‐dimensional problems (i.e., when a large number of random variables is involved). This methodology significantly reduces the computational cost with respect to the classical full PCE methodology. Notice however that when dealing with computationally‐expensive deterministic models, the time cost remains important even with the use of the SPCE. In this paper, an efficient combined use of the SPCE methodology and the Global Sensitivity Analysis is proposed to solve such problem. The proposed methodology is firstly validated using a relatively non‐expensive deterministic model that involves the computation of the PDF of the ultimate bearing capacity of a strip footing resting on a weightless spatially varying soil where the soil cohesion and angle of internal friction are modeled by two anisotropic non‐Gaussian cross‐correlated random fields. This methodology is then applied to an expensive model that considers the case of a ponderable soil. A brief parametric study is presented in this case to show the efficiency of the proposed methodology. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Correlations between SPT,CPT, and Vs for Reclaimed Lands near Dubai     

Khan  Zahid  Yamin  Mohammad  Attom  Mousa  Al Hai  Nasser 《Geotechnical and Geological Engineering》2022,40(8):4109-4120

Geotechnical and Geological Engineering - Artificial islands near Dubai were constructed with geomaterials of significant gravel content from other areas of the United Arab Emirates (UAE). The...  相似文献   

Primordial magnetic fields in the f2FF model in large field inflation under de Sitter and power law expansion     

A. S. Al Muhammad  R. Lopez‐Mobiia 《Astronomische Nachrichten》2016,337(3):318-328

We use the f²FF model to study the generation of primordial magnetic fields (PMF) in the context of large field inflation (LFI), described by the potential, V ∼ Mϕ^p. We compute the magnetic and electric spectra for all possible values of the model parameters under de Sitter and power law expansion. We show that scale invariant PMF are not obtained in LFI to first order in the slow roll approximation, if we impose the constraint V (ϕ = 0) ∼ 0. Alternatively, if these constraints are relaxed, the scale invariant PMF can be generated. The associated electric field energy can fall below the energy density of inflation, ρ_Inf for the ranges of comoving wavenumbers, k > 8 × 10^–7 Mpc^–1 and k > 4 × 10^–6 Mpc^–1 in de Sitter and power law (PL) expansion. Further, it can drop below ρ_Inf on the ranges, e‐foldings N > 51, p < 1.66, p > 2.03, l₀ > 3 × 10⁵ M_Pl^–1(H_i < 3.3 × 10^–6 M_Pl), and M > 2.8 × 10^–3 M_Pl. All of the above ranges fit with the observational constraints. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

Cosmic acceleration in non-canonical scalar field model: an interacting scenario     

Sudipta Das  Abdulla Al Mamon 《Astrophysics and Space Science》2015,355(2):371-380

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