Impacts of human activities and natural inputs on heavy metal contents of many coral reef environments along the Egyptian Red Sea coast     

Hashem Abbas Madkour 《Arabian Journal of Geosciences》2013,6(6):1739-1752

In order to monitor the heavy metals effect coming from both human activities and natural inputs on coral reef environments of the Egyptian Red Sea coast, metal concentrations in thirty- eight coral reef species and nearby sediment samples collected from seven studied sites were analyzed. Four sites represent impacted areas; included from south to north Hamrawein, Safaga and Hurghada Harbours and Ras El-Behar Area. Wadi El-Gemal represents natural input area while Qola'an and Kalawye Reefs are the control areas. Heavy metal contents were measured in both coral skeletons and nearby marine sediments. Both impact areas as well as natural inputs area recorded the highest values of metals compared with the control ones. However, heavy metal contents recorded high values in sediments of Hamrawein Harbour, while coral species recorded high values in Wadi El-Gemal area. Generally, metal variations in coral reef species reflect natural conditions and human activity. On the other hand, there are no clear relationships between concentrations of heavy metals in coral reef species and those in sediments.  相似文献   

Deforestation Trends and Spatial Modelling of its Drivers in the Dry Temperate Forests of Northern Pakistan–A Case Study of Chitral   总被引：2，自引：2，他引：0  

Khuram Shehzad  Faisal M. Qamer  M. S. R. Murthy  Sawaid Abbas  Laxmi D. Bhatta 《山地科学学报》2014,11(5):1192-1207

Deforestation is a major environmental challenge in the mountain areas of Pakistan. The study assessed trends in the forest cover in Chitral tehsil over the last two decades using supervised land cover classification of Landsat TM satellite images from 1992, 2000, and 2009, with a maximum likelihood algorithm. In 2009, the forest cover was 10.3% of the land area of Chitral(60,000 ha). The deforestation rate increased from 0.14% per annum in 1992–2000 to 0.54% per annum in 2000–2009, with 3,759 ha forest lost over the 17 years. The spatial drivers of deforestation were investigated using a cellular automaton modelling technique to project future forest conditions. Accessibility(elevation, slope), population density, distance to settlements, and distance to administrative boundary were strongly associated with neighbourhood deforestation. A model projection showed a further loss of 23% of existing forest in Chitral tehsil by 2030, and degradation of 8%, if deforestation continues at the present rate. Arandu Union Council, with 2212 households, will lose 85% of its forest. Local communities have limited income resources and high poverty and are heavily dependent on non-timber forest products for their livelihoods. Continued deforestation will further worsen their livelihood conditions, thus improved conservation efforts are essential.  相似文献   

Integrated risk assessment of urban water supply systems from source to tap   总被引：1，自引：1，他引：0  

Abbas Roozbahani  Banafsheh Zahraie  Massoud Tabesh 《Stochastic Environmental Research and Risk Assessment (SERRA)》2013,27(4):923-944

Urban water supply systems (UWSS) are generally composed of water sources, transmission pipes, treatment plants, and distribution networks from source to tap and usually are exposed to variety of uncertain threatening hazards. These threats can be divided to three main groups of natural, human-made, and operational hazards which affect either water quantity or water quality. In order to evaluate the reliability of water supply systems, risk assessment tools must be used to identify threats, their probability, and consequences and vulnerabilities of each element of these systems against the hazards. Due to the complexity and uncertainties affecting water supply systems and threatening hazards, a comprehensive and effective risk assessment method is required. In this study, an integrated fuzzy hierarchical risk assessment model for water supply systems (IFHRA-WSS) is proposed to assess hazards in a complex UWSS using a systematic approach incorporating both water quantity and quality issues. This model uses a hierarchical framework for breaking down the UWSS infrastructures to their interrelated elements to reduce the overall complexity of the system. It also considers uncertainties using Fuzzy Logic approach. Effects of functional interdependencies between different components of the system have also been considered in the vulnerability analysis. IFHRA-WSS incorporates the contributions of urban water experts in a group risk assessment procedure in a way that they can be easily expressed in terms of the qualitative and quantitative risk measures. Efficiency of this model has been examined in a case study which includes a large part of a drinking water supply system in a major city in Iran. This system includes all the elements of the UWSS from the delivery point to the consumption point. In the case study, different components and subcomponents of this system have been ranked based on their estimated risk values. It is envisaged that the results of the proposed model can help the decision makers to plan for effective risk mitigation measures.  相似文献   

Robustness and uncertainties of seismic damage estimates at urban scale: a methodological comparison on the example of the city of Oran (Algeria)     

Abbas Senouci  Pierre Yves Bard  Mohamed Naboussi Farsi  Elise Beck  Stéphane Cartier 《Bulletin of Earthquake Engineering》2013,11(4):1191-1215

The city of Oran is exposed to a significant seismic hazard, as almost all the northern Algeria territory, where numerous casualties and severe damage occurred in the last decades due to several moderate to large earthquakes. A mitigation policy should include the establishment of priorities to reduce the vulnerability of existing buildings based on the knowledge of the actual urban fabrics. The complexity of vulnerability assessment requires a gradual approach from the urban scale to the building scale. The study reported in this paper corresponds to the first step of such an approach, i.e., a preliminary study of the seismic vulnerability and expected damage within an urban district of the city of Oran, based on a non-dedicated data base from a building survey previously performed for other purposes. The main goals of this study are twofold: (1) an assessment of the degree of uncertainty and robustness of such results through a comparison of the results derived from different urban vulnerability methods (GNDT 2; RISK-UE LM1; and VULNERALP 2.0) and (2) an assessment of the actual level of seismic risk in the city of Oran. Cross-method comparisons and correlations highlight a satisfactory agreement between mean damage estimates at the urban scale, despite significant scattering at the single building scale, and uncertainty levels which vary significantly from one method to the other. For a given scenario, the three methods provide damage estimates lying within half an EMS damage degree of one another, with some systematic positive bias for VULNERALP and negative bias for RISK-UE LM1, especially for masonry buildings. The expected mean damage is very important for intensities 9 and 10, with an average damage grade around 3–4 for intensity 9 and 4–5 for intensity 10. The spatial distribution of damage systematically exhibits larger values in the northern, older, commercial area, than in the southern, more recent and more residential area, in relation to the building typology and the existence of several aggravating factors. Some areas of higher vulnerability / damage can be distinguished, which should receive particular attention for retrofitting priorities or urban planning decisions, also taking into account their cultural heritage value.  相似文献   

Environmental and Health Impacts of Successive Mineral Fertilization in Egypt     

Ahmed A. Abdelhafez  Hassan H. Abbas  Rafat S. Abd‐El‐Aal  Nabil F. Kandil  Jianhua Li  Wahballah Mahmoud 《洁净——土壤、空气、水》2012,40(4):356-363

Excessive amounts of mineral fertilizers are unnecessarily applied to agricultural soils in Egypt to increase crop yield. The current study aims at assessing the impacts of fertilization with different mineral fertilizers for different cultivation periods on the accumulation of heavy metals in soils and plants grown thereon. In addition, human risks resulted due to the exposure to these metal ions through ingestion, and dermal routes were evaluated. Soil and plant samples were collected from several locations in El‐Behira Governorate, Egypt and their heavy metal contents were measured. The result indicated that there is a continuous accumulation of heavy metals in the soils and the plants grown thereon. Calculation of the hazard index (HI) revealed that humans, especially children, have a potential health risk for both Pb and Cd, which have levels greater than the safe level (1). Finally, the obtained results showed that the continuous application of mineral fertilizers containing high levels of heavy metals pose a potential health threat.  相似文献   

Ground-roll attenuation using modified common-offset–common-reflection-surface stacking     

Seyyed Ali Fa’al Rastegar  Abdolrahim Javaherian  Naser Keshavarz Farajkhah  Mehrdad Soleimani Monfared  Abbas Zarei 《应用地球物理》2016,13(2):353-363

We modified the common-offset–common-reflection-surface (COCRS) method to attenuate ground roll, the coherent noise typically generated by a low-velocity, low-frequency, and high-amplitude Rayleigh wave. The COCRS operator is based on hyperbolas, thus it fits events with hyperbolic traveltimes such as reflection events in prestack data. Conversely, ground roll is linear in the common-midpoint (CMP) and common-shot gathers and can be distinguished and attenuated by the COCRS operator. Thus, we search for the dip and curvature of the reflections in the common-shot gathers prior to the common-offset section. Because it is desirable to minimize the damage to the reflection amplitudes, we only stack the multicoverage data in the ground-roll areas. Searching the CS gathers before the CO section is another modification of the conventional COCRS stacking. We tested the proposed method using synthetic and real data sets from western Iran. The results of the ground-roll attenuation with the proposed method were compared with results of the f–k filtering and conventional COCRS stacking after f–k filtering. The results show that the proposed method attenuates the aliased and nonaliased ground roll better than the f–k filtering and conventional CRS stacking. However, the computation time was higher than other common methods such as f–k filtering.  相似文献   

New biorthogonal potential–density basis functions     

Alireza Rahmati  Mir Abbas Jalali 《Monthly notices of the Royal Astronomical Society》2009,393(4):1459-1466

We use the weighted integral form of spherical Bessel functions and introduce a new analytical set of complete and biorthogonal potential–density basis functions. The potential and density functions of the new set have finite central values and they fall off, respectively, similar to   r ^{−(1+ l )}  and   r ^{−(4+ l )}  at large radii, where l is the latitudinal quantum number of spherical harmonics. The lowest order term associated with   l = 0  is the perfect sphere of de Zeeuw. Our basis functions are intrinsically suitable for the modelling of three-dimensional, soft-centred stellar systems and they complement the basis sets of Clutton-Brock, Hernquist & Ostriker and Zhao. We test the performance of our functions by expanding the density and potential profiles of some spherical and oblate galaxy models.  相似文献   

Erratum to: Spring rainfall prediction based on remote linkage controlling using adaptive neuro-fuzzy inference system (ANFIS)     

Gholam Abbas Fallah-Ghalhary  Majid Habibi-Nokhandan  Mohammad Mousavi-Baygi  Javad Khoshhal  Akbar Shaemi Barzoki 《Theoretical and Applied Climatology》2010,101(1-2):235-235

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Assessment of Relationship Between Grouted Values and Calculated Values in the Bazoft Dam Site     

Ahmad Rastegarnia  Abdollah Sohrabibidar  Vahid Bagheri  Mehdi Razifard  Abbas Zolfaghari 《Geotechnical and Geological Engineering》2017,35(4):1299-1310

Seepage through foundation and abutments of a dam can potentially result in a waste of the water stored in dam reservoir, erosion of foundation materials, and development of uplift pressure in dam foundation which, consequently, threatens the long-term stability of the dam. In this study, the grout volume is estimated based on parameters such as joint aperture, the maximum penetration length of the grout, and calculated grout take in Bazoft dam site. Bazoft Dam is a hydroelectric supply and double-curvature arch dam with a height of 211 m located in Chaharmahal and Bakhtiari Province of Iran. The bedrock of Bazoft dam site consists of Asemari Formation (limy marl and marly lime), in the middle and upper parts of left abutment, and Jahrom Formation (limestone and dolomite) in the right abutment, river bed, and lower part of left abutment. The joint apertures were calculated based on the permeability and the joint spacing. Next, the maximum penetration length of the grout and grout volume were calculated. Using a statistical analysis, the relationship of the joint aperture, maximum penetration length, and the calculated grout volume with real grout take was also investigated. The results show that the grout take can be predicted with appropriate accuracy based on the calculated grout volume.  相似文献   

A two-dimensional experimental-numerical approach to investigate wave transformation over muddy beds     

Mohsen Soltanpour  S. Abbas Haghshenas  Tomoya Shibayama 《Ocean Dynamics》2015,65(2):295-310

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