Uranium and rare earth elements in Hazm El-Jalamid phosphate,Saudi Arabia: concentrations and geochemical patterns comparison     

Ashraf E. M. Khater  Mahmoud A. Galmed  Mahmoud M. Nasr  Atef El-Taher 《Environmental Earth Sciences》2016,75(18):1261

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Influence of size of granulated rubber on bearing capacity of fine-grained sand     

Seyed Mahmoud Anvari  Issa Shooshpasha 《Arabian Journal of Geosciences》2016,9(18):707

Nowadays, in most of the advanced and developing countries, waste tires have caused serious environmental problems such as fire and environmental contamination. For reusing them in an appropriate and beneficial way, waste tires have been utilized as a lightweight fill material in geotechnical engineering applications such as highway embankments. In this study, Babolsar fine-grained sand and granulated rubber with sizes in the ranges of 1 to 4, 1 to 9, and 4 to 9 mm were used. A series of model footing tests on reinforced sand with different sizes of granulated rubber were carried out. According to the results, 4- to 9-mm granulated rubber had the highest effect on enhancement of bearing capacity and reduction of fine-grained sand settlement. The results showed that sand-granulated rubber mixtures with granulated rubber in the range of 4 to 9 mm and content of 10% by weight of mixture can increase the bearing capacity of sand up to 50%. In addition, for this mixture, a series of laboratory tests were conducted to determine the optimum width and depth of the reinforcement layer consisting of sand-granulated rubber mixture. The results indicate that the optimum width and the most effective depth of this mixture are 5B and 1B, respectively (where B is the footing width).  相似文献   

Hindcasting community-level building damage for the 2011 Joplin EF5 tornado     

Navid Attary  John W. van de Lindt  Hussam Mahmoud  Steve Smith  Christopher M. Navarro  Yong Wook Kim  Jong Sung Lee 《Natural Hazards》2018,93(3):1295-1316

Resiliency of communities prone to natural hazards can be enhanced through the use of risk-informed decision-making tools. These tools can provide community decision makers key information, thereby providing them the ability to consider an array of mitigation and/or recovery strategies. The Center for Risk-Based Community Resilience Planning, headquartered at Colorado State University in Fort Collins, Colorado, developed an Interdependent Networked Community Resilience (IN-CORE) computational environment. The purpose of developing this computational environment is to build a decision-support system, for professional risk planners and emergency responders, but even more focused on allowing researchers to explore community resilience science. The eventual goal was being to integrate a broad range of scientific, engineering and observational data to produce a detailed assessment of the potential impact of natural and man-made hazards for risk mitigation, planning and recovery purposes. The developing computational environment will be capable of simulating the effects from different natural hazards on the physical and socioeconomic sectors of a community, accounting for interdependencies between the sectors. However, in order to validate this computational tool, hindcasting of a real event was deemed necessary. Therefore, in this study, the community of Joplin, Missouri in the USA, which was hit by an EF-5 tornado on May 22, 2011, is modeled in the IN-CORE v1.0 computational environment. An explanation of the algorithm used within IN-CORE is also provided. This tornado was the costliest and deadliest single tornado in the USA in the last half century. Using IN-CORE, by uploading a detailed topological dataset of the community and the estimated tornado path combined with recently developed physics-based tornado fragilities, the damage caused by the tornado to all buildings in the city of Joplin was estimated. The results were compared with the damage reported from field studies following the event. This damage assessment was done using three hypothetical idealized tornado scenarios, and results show very good correlation with observed damage which will provide useful information to decision makers for community resilience planning.  相似文献   

Stability analysis and optimization of the support system of an underground powerhouse cavern considering rock mass variability     

Mahmoud Behnia  Masoud Cheraghi Seifabad 《Environmental Earth Sciences》2018,77(18):645

Input parameters, such as rock mass strength parameters and deformation modulus, considered in the design of underground openings involve some uncertainty. The current uncertainty in these parameters is due to the inherent variability of these parameters. To quantify these parameters and design underground openings, the statistical methods must be utilized. In this research, a statistical method was used to define the GSI of rock mass (Geological Strength Index), block volume (V_b), and joint conditions (J_c). Using the GSI distribution function obtained from field data and intact rock strength characteristics, the statistical distribution functions of rock mass parameters were defined using the Monte Carlo method. The statistical analysis of the stability in Azad-pumped storage powerhouse cavern was carried out through the point estimate method. The appropriate support system was suggested according to the support pressure and the plastic zone around the cavern. This study showed the application of the statistical method, by combining the uncertainties of the intact rock strength and discontinuity parameters, in the assessment of the strength and deformability of rock masses and the support selection process in comparison with the deterministic methods.  相似文献   

Campanian-Lower Paleogene gastropods from the Kharga Oasis,south Western Desert,Egypt     

Abdel Galil A. Hewaidy  Gamal M. El Qot  El Sayed M. Moneer 《Arabian Journal of Geosciences》2018,11(24):781

The Campanian-Lower Paleogene successions exposed at the Kharga Oasis contain well-preserved gastropods. Nineteen gastropod species are identified and described in detail. Two new species are established: Gisortia khargaensis from the lower Eocene El Rufuf Formation and Ornopsis? barisensis from the lower Paleocene Kurkur Formation. In addition to, Turritella (Torquesia) derbesi Coquand is recorded herein for the first time from Egypt. The studied gastropods belonging to four clades: Sorbeoconcha (Metacerithium abictiforme (Wanner), Mesalia hofana Mayer-Eymar, Mesalia sp., Turritella (Torquesia) derbesi Coquand, Turritella (Torquesia) forgemoli Coquand, Turritella kaserensis Hewaidy and Azab, Turritella sp.), Littorinimorpha (Cypraedia bullina Oppenheim, Gisortia khargaensis nov. sp., Natica farafrensis Wanner, Aporrhais schweinfurthi (Quaas), Drepanocheilus bicarinatus Abbass, Drepanocheilus? sp., Anchura? unicarinatus (Abbass), Epitonium sp.), Neogastropoda (Ornopsis? barisensis nov. sp., Rostellana daniensis (Quaas), Vouta sp.), and Heterobranchia (Avellana cretacea Quaas).  相似文献   

Cyclostratigraphy across a Mississippian carbonate ramp in the Esfahan–Sirjan Basin,Iran: implications for the amplitudes and frequencies of sea-level fluctuations along the southern margin of the Paleotethys     

Bayet-Goll  Aram  Esfahani  Fariba Shirezadeh  Daraei  Mehdi  Monaco  Paolo  Sharafi  Mahmoud  Mohammadi  Amir Akbari 《International Journal of Earth Sciences》2018,107(6):2233-2263

International Journal of Earth Sciences - The Tournaisian–Visean carbonate successions of the Esfahan–Sirjan Basin (ESB) from Sanandaj–Sirjan Zone, Iran, have been used to...  相似文献   

Evidence of Quaternary active folding near Utique (Northeast Tunisia) from tectonic observations and a seismic profile     

Lassaad Mejri  Vincent Regard  Sébastien Carretier  Stéphane Brusset  Mahmoud Dlala 《Comptes Rendus Geoscience》2010,342(11):864-872

The present-day seismicity in northeastern Tunisia reported from permanent networks is of low to moderate magnitude. However, earthquakes are mentioned in the literature, specially a destructive one in the antique city of Utique. Geologic, seismic, and neotectonic investigations in this area show that the Utique fold is closely related to the recent tectonic activity in this region. Data show that the Utique fold is built on an east-west fault, and we found evidence of activity of this fault in the past 20 kyr. A seismic section and balanced cross-section show that the slip rate is of the order of 0.38 mm.yr⁻¹. Our data show definitively the Late Pleistocene–Holocene activity of the Utique Fault; and we can predict the earthquake recurrence interval which should be of ∼10³–10⁴ yr. This high seismic risk zone deserves to be taken into account during the establishment of important regional development programs and in the application of seismic building codes.  相似文献   

Effect of nonthermality of ions on the nature of dust acoustic waves in two temperatures charged dusty grains     

S. A. Elwakil  A. Elgarayhi  E. K. El-Shewy  Abeer A. Mahmoud  M. A. El-Attafi 《Astrophysics and Space Science》2013,343(2):661-666

Effect of nonthermality of ions on the propagation of dust-acoustic waves (DAWs) in unmagnetized plasma having electrons, singly charged ions, hot and cold dust grains have been investigated. The reductive perturbation method is employed to reduce the basic set of fluid equations to the Korteweg-de Vries (KdV) equation. Moreover, the energy of two temperatures charged dusty grains were computed. The present investigation can be of relevance to the electrostatic solitary structures observed in various space plasma environments.  相似文献   

Isotopic composition of rainfall and ground-water recharge in the western province of Saudi Arabia   总被引：1，自引：0，他引：1  

Mahmoud S. Alyamani 《Journal of Arid Environments》2001,49(4):751

The oxygen-18 and deuterium isotopic compositions of rainfall from eight meteorological stations are discussed. The results show that the stable isotope distribution of the rainfall over the western province display a difference in isotopic ratios, which can be attributed to the altitude effect and water vapour sources, and to some extent, to rainfall amount. The changes of δ¹⁸O and δ D contents with altitude are −0·08 and −0·38‰ per 100 m respectively. Comparison of the isotopic analyses of rainfall and local ground-water and springs indicates that the monsoon derived rainfall that prevails during the autumn season plays a crucial role in alluvial aquifer recharge. Although Atlantic water vapour can arrive virtually throughout the area in winter months, its influence seems to be of minor importance to the water balance in the study area.  相似文献   

Pt/十六烷基三甲基溴化铵纳米聚集体修饰玻碳电极促进析氢(英文)     

Jahan-Bakhsh Raoof  Sayed Reza Hosseini  Seyedeh Zeinab Mousavi-Sani 《甘肃地质》1997,(1):216-220

A novel, cost-effective, and simple electrocatalyst based on a Pt-modified glassy carbon electrode(GCE), using cetyltrimethylammonium bromide(CTAB) as a cationic surfactant, is reported. Amphiphilic CTAB molecules were adsorbed on GCE by immersion in a CTAB solution. The positively charged hydrophilic layer, which consisted of small aggregates of average size less than 100 nm,was used for accumulation and complexation of [PtCl2. anions by immersing the electrode in Ksolution. The modified electrode was characterized using scanning electron microscopy,energy-dispersive X-ray spectroscopy, impedance spectroscopy, and electrochemical methods. The electrocatalytic activity of the Pt particles in the hydrogen evolution reaction(HER) was investigated.The results show that the CTAB surfactant enhances the electrocatalytic activity of the Pt particles in the HER in acidic solution.  相似文献