The influence of carbonate textures and rock composition on durability cycles and geomechanical aspects of carbonate rocks     

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   

Smoothed Particle Hydrodynamics for modelling landslide–water interaction problems     

Mahallem  Abderrahmane  Roudane  Mohamed  Krimi  Abdelkader  Gouri  Sid Ahmed 《Landslides》2022,19(5):1249-1263

Landslides - This work aims to develop a Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) in-house code for modelling landslide–water interaction problems. While we consider the...  相似文献   

印度河扇水道堤岸外侧更新世沉积物波发育特征与形成过程分析^*          下载免费PDF全文

浩克  纪友亮  张胜久  刘炎鑫  Khurram Shahzad  Saad Ahmed Mashwani  刘笑语  姜燕 《古地理学报》2022,24(2):389-404

印度河扇更新世发育的沉积物波结构复杂、形态多样,其形成过程的认识程度低。本次研究通过高分辨率地震数据和地震解释技术,研究了印度河扇沉积物波的波长、形态、波峰变化等形态特征;阐述了沉积物波与沉积物变形特征的差异、识别了两者的区分标志;总结了水道堤岸斜坡和区域斜坡上沉积物波的分布规律;在此基础上,讨论了沉积物波的形成机理和控制因素,分析了沉积物波的形成过程,并建立了印度河扇沉积物波的形成模式。研究表明: (1)研究区沉积物波波长平均为486.84 m,最大1473 m;波高在10~60 m之间,平均30 m。(2)沉积物波的形态有对称型和非对称型,其迁移方式有上坡迁移型、加积型和下坡迁移型;沉积物波主要发育在水道堤岸的斜坡上,在区域斜坡上也发育少量的沉积物波,这2种沉积物波波脊的走向差异很大,水道堤岸斜坡上的沉积物波主要分布于水道凹岸堤岸的外侧,距离水道越远其规模(波长、波高)越小,波脊走向近于NE-SW方向,与水道的走向平行或斜交;区域斜坡上的沉积物波波脊的走向多为NW-SE向,平行于区域斜坡的走向,离源区越远规模越大。(3)水道堤岸斜坡上的沉积物波是由水道型浊流在离心力的作用下,溢出水道的凹岸,在堤岸外侧的斜坡上沉积形成的,堤岸斜坡的角度对沉积物波的发育规模影响不大,浊流的强度和输沙量对其规模影响大;区域斜坡上发育的沉积物波是由顺坡而下的非水道化的浊流沉积形成;滑塌变形造成的起伏地貌以及早期沉积物波的存在,也都影响了后期沉积物波的发育。  相似文献   

Extraction and analysis of geological lineaments by combining ASTER-GDEM and Landsat 8 image data in the central high atlas of Morocco     

Abdelouhed  Farah  Ahmed  Algouti  Abdellah  Algouti  Mohammed  Ifkirne  Zouhair  Ourhzif 《Natural Hazards》2022,111(2):1907-1929

Natural Hazards - The present work focuses on using remote sensing techniques and geographical information system (GIS) to automatically extract lineaments in the southeast of Morocco, which is one...  相似文献   

Compression Behaviour of Chlef Sand and Transition of Fines Content Using Pressure-Dependent Maximum Void Ratios of Sand     

Bouri  Djamel Eddine  Brahimi  Abdelkader  Krim  Abdallah  Arab  Ahmed  Najser  Jan  Mašín  David 《Geotechnical and Geological Engineering》2022,40(4):1675-1692

Geotechnical and Geological Engineering - This paper presents a study on Chlef sand to examine the effect of fines content (Fc), relative density (RD) and initial conditions on the compressibility...  相似文献   

Uncertainty analysis for extreme flood events in a semi-arid region   总被引：2，自引：0，他引：2  

Majid Mirzaei  Yuk Feng Huang  Ahmed El-Shafie  Tayebeh Chimeh  Juneseok Lee  Nariman Vaizadeh  Jan Adamowski 《Natural Hazards》2015,78(3):1947-1960

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Exploratory experiments to determine the effect of alternative operations on the efficiency of subsurface arsenic removal in rural Bangladesh     

M. M. Rahman  M. Bakker  S. C. Borges Freitas  D. van Halem  B. M. van Breukelen  K. M. Ahmed  A. B. M. Badruzzaman 《Hydrogeology Journal》2015,23(1):19-34

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Investigation of seasonal droughts and related large-scale atmospheric dynamics over the Potwar Plateau of Pakistan     

N. U. Ain  M. Latif  K. Ullah  S. Adnan  R. Ahmed  M. Umar  M. Azam 《Theoretical and Applied Climatology》2020,140(1):69-89

As a result of climate change and unsustainable land use management in the recent past, droughts have become one of the most devastating climatic hazards whose impacts may prolong from months to years. This study presents analysis of droughts for two major cropping seasons, i.e., Kharif (May–September) and Rabi (October–April), over the Potwar Plateau of Pakistan. The analysis is performed using various datasets viz. observational, reanalysis, and Regional Climate Models (RCMs), for the past (1981–2010) and future (2011–2100) time periods. The following two methods for the identification of dry and wet years, also referred to as drought and wetness, are applied: (1) the percentile rank approach and (2) the drought indices, Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI). Future projections of droughts are investigated using RCM (RegCM4.4 and RCA4) outputs from CORDEX South Asia domain under two Representative Concentration Pathway (RCP) scenarios, RCP4.5 and RCP8.5. Generally, the indices show non-significant decreasing trends of drought severity in the recent past for all cases; however, significant increasing trends are observed for annual (0.006) and Kharif (0.007) cases under RCP4.5 scenario. The analysis of large-scale atmospheric dynamics suggests the significant role of low-level geopotential height anomalies over Tibetan Plateau (northwest of Pakistan) during Kharif (Rabi) season in controlling drought occurrence by transporting moisture from the Bay of Bengal (Arabian Sea). Moreover, composites of vertically integrated moisture transport, moisture flux convergence/divergence, and precipitable water anomalies show their marked contribution in maintaining the drought/wetness conditions over the Potwar region.  相似文献   

An evaluation of the CORDEX regional climate models in simulating future rainfall and extreme events over Mzingwane catchment,Zimbabwe     

S. Sibanda  S. W. Grab  F. Ahmed 《Theoretical and Applied Climatology》2020,140(1):91-100

The study evaluated CORDEX RCMs’ ability to project future rainfall and extreme events in the Mzingwane catchment using an ensemble average of three RCMs (RCA4, REMO2009 and CRCM5). Model validation employed the statistical mean and Pearson correlation, while trends in projected rainfall and number of rainy days were computed using the Mann-Kendall trend test and the magnitudes of trends were determined by Sen’s slope estimator. Temporal and spatial distribution of future extreme dryness and wetness was established by using the Standard Precipitation Index (SPI). The results show that RCMs adequately represented annual and inter-annual rainfall variability and the ensemble average outperformed individual models. Trend results for the projected rainfall suggest a significant decreasing trend in future rainfall (2016–2100) for all stations at p < 0.05. In addition, a general decreasing trend in the number of rainy days is projected for future climate, although the significance and magnitude varied with station location. Model results suggest an increased occurrence of future extreme events, particularly towards the end of the century. The findings are important for developing proactive sustainable strategies for future climate change adaption and mitigation.  相似文献   

Anticipated economic costs and benefits of ratification of the Kyoto Protocol by the State of Qatar     

Azhari F.M. Ahmed  M. J. Al Maslamani 《Climate Policy》2013,13(1):75-80

Abstract

Further ratification of the Kyoto Protocol by non-Annex 1 countries such as the State of Qatar will not affect the entrance into force of the Treaty; however, ratification remains an important decision due to other considerations, primarily the economic costs and benefits associated with ratification. As a member of the Organization of Petroleum Exporting Countries (OPEC), Qatar's economic position is closely allied with revenue generated from its oil and natural gas resources. Qatar expects adverse impacts from implementing the Kyoto Protocol, though the estimated magnitude varies enormously with different models. Also, the impacts depend significantly on how the implementation is done; for example, the kind of policies that other countries use. Qatar is able to counter adverse impacts by exploiting its greater share of natural gas and developing energy-intensive industries that produce nonenergy goods such as steel, petrochemicals, and chemicals. Furthermore, it is clear that clauses in the Protocol can be developed to protect OPEC interests, and if Qatar does not ratify the Protocol, it will be excluded from the subsequent rule-making processes. On balance, there are benefits to ratifying the Treaty, and there is also a strong need for extensive further research.  相似文献