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181.
Zeid Abdullah ALOthman Mohamed Abdelaty Habila Nora H. Al-Shalan Sulaiman M. Alfadul Rahmat Ali Ibrahim Gar Al alm Rashed Bader Alfarhan 《Arabian Journal of Geosciences》2016,9(4):315
This work aimed to investigate the adsorption characteristics, both kinetically and thermodynamically, of Cu(II) and Pb(II) removal from aqueous solutions onto mixed-waste activated carbon, as well as to study the competitive behavior found in mixed heavy metal solution systems. This study shows that activated carbon prepared from mixed waste is an effective adsorbent for the removal of Cu(II) and Pb(II) from aqueous solutions, with the aim of detoxifying industrial effluents before their safe disposal onto water surfaces. The adsorption process was characterized in terms of kinetic and thermodynamic studies. In addition, the influence of presence of Cu(II) and Pb(II) in a competitive system was investigated. The results showed that the maximum adsorption capacities were gained at a pH of 6 with a contact time of 180 min, a metal solution concentration of 300 ppm, and an adsorbent dose of 0.3 g/L. The adsorption process was found to follow a pseudo-first-order kinetic model. Thermodynamic parameters such as ΔG o, ΔH o, and ΔS o showed that the sorption process was spontaneous and endothermic in nature. A competitive study demonstrated the applicability of mixed-waste activated carbon to adsorb Cu(II) and Pb(II) from a solution of mixed metals. In addition, the adsorption capacity was found to be as effective as other adsorbents reported in the literature. The developed adsorptive removal procedure was applied for treatment of real wastewater samples and showed high removal efficiency. 相似文献
182.
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184.
Improving the level of seismic hazard parameters in Saudi Arabia using earthquake location 总被引:1,自引:0,他引:1
Abdullah M. Al-Amri Arthur J. Rodgers Tariq A. Al-Khalifah 《Arabian Journal of Geosciences》2008,1(1):1-15
Saudi Arabia is characterized as largely aseismic; however, the tectonic plate boundaries that surround it are very active.
To improve characterization of seismicity and ground motion hazard, the Saudi Arabian Digital Seismic Network (SANDSN) was
installed in 1998 and continues to be operated by the Saudi Geological Survey (SGS) and King Abdulaziz City for Science and
Technology (KACST). This article describes research performed to improve seismic hazard parameters using earthquake location
and magnitude calibration of the high-quality SANDSN data. The SANDSN consists of 38 seismic stations, 27 broadband, and 11
short period. All data are telemetered in real time to a central facility at KACST in Riyadh. The SANDSN stations show low
background noise levels and have good signal detection capabilities; however, some stations show cultural noise at frequencies
above 1.0 Hz. We assessed the SANDSN event location capabilities by comparing KACST locations with well-determined locations
derived from ground truth or global observations. While a clear location bias exists when using the global average iasp91 earth model, the locations can be improved by using regional models optimized for different tectonic source regions. The
article presents detailed analysis of some events and Dead Sea explosions where we found gross errors in estimated locations.
New velocity models we calculated that should improve estimated locations of regional events in three specific regions include
(1) Gulf of Aqabah—Dead Sea region, (2) Arabian Shield, and (3) Arabian Platform. Recently, these models were applied to the
SANDSN to improve local and teleseismic event locations and to develop an accurate magnitude scale for Saudi Arabia. The Zagros
Thrust presents the most seismic hazard to eastern Saudi Arabia because of the frequent occurrence of earthquakes. Although
these events are 200 km or further from the Arabian coast, wave propagation through sedimentary structure of the Gulf causes
long-duration ground motions for periods between 3 and 10 s. Such ground motions could excite response in large engineered
structures (e.g., tall buildings and long bridges) such as was experienced after the November 22, 2005 Qeshm Island earthquake
off the southern coast of Iran. 相似文献
185.
Damien Closson Najib Abou Karaki Musa Jad Hussein Hassan Al-Fugha André Ozer Abdullah Mubarak 《Comptes Rendus Geoscience》2003,335(12):869-879
The Dead Sea shore is affected by major subsidence and sinkholes hazards due to the decrease of the sea level. The frequency of resulting accidents increased during the last four decades. Those phenomena could be at the origin of the catastrophic destruction of a major salt evaporation pond on 22 March 2000. In this paper, we show the main results of eight years of research in gravimetry and radar interferometry devoted to identify potentially hazardous areas, at different scales along the Jordanian Dead Sea coast, from the metric scale (gravimetric approach) to the kilometric one (interferometric approach). To cite this article: D. Closson et al., C. R. Geoscience 335 (2003). 相似文献
186.
Past fisheries development policies in Malaysia are assessed and new grounds for managing the Malaysian fisheries are explored. Some incompatibility in the goals for fishery development are discerned, especially those of increasing domestic landings through mechanization and resource conservation. Future management efforts should be based on a fuller understanding of the fishery stock and regional management of fish stocks. Aquaculture is often seen as a plausible alternative in order to augment supplies from the capture fisheries. A comprehensive multidisciplinary approach is needed to transform and commercialize traditional, experience-dependent culture systems into technology-packaged systems based on scientific methods. There is also substantial potential for the development of recreational fisheries. 相似文献
187.
Salih Muhammad Awadh Heba S. Al-Mimar Abdullah A. Al-Yaseri 《Arabian Journal of Geosciences》2018,11(18):552
Cation and anion concentrations and boron isotopic ratio of brines in the Mishrif Formation (U. Campanian-Tuoronian) from North Rumaila, South Rumaila, Majnoon, Zubair, and West Qurna oilfields southern Iraq were investigated. The aims of this study are to define the type, origin of the oilfield waters, and its flow model in the subsurface oil traps. Mishrif brines are characterized by having higher concentrations of sodium (50,500–84,200 ppm), chlorine (102,100–161,500 ppm), and boron (21.9–31.1 ppm) with lower sulfate contents (187–1350 ppm) relative to the modern seawater. Samples have slightly depleted in δ 11B (35.4‰) relative to seawater fall near the seawater intrusion of the diagram Cl/Br Vs δ 11B and occupied the field of evaporated seawater on the diagrams of Cl vs B and 1/Br vs δ 11B. The brine of Na-chloride type is characteristics of the Mishrif reservoir in all oilfields except WQ which defined by facies of Na-Ca-chloride type. A weak acidic brine of a salinity six-time greater than seawater plays a role in generating the formation pressure and controlling the fluid flow. The reservoir rock-fluid interactions were interpreted using boron isotopes which eventually reveal an ongoing dilution process by the present seawater intrusion and injection water used for the secondary production under conditions of high-temperature digenetic reactions. The 11B in the oilfield water is resulted from uptake of the tetrahedral borate after precipitation of calcium carbonate, while 10B is sourced from the thermal maturation of organic matters. 相似文献
188.
Ali Mutar Fanos Biswajeet Pradhan Shattri Mansor Zainuddin Md Yusoff Ahmad Fikri bin Abdullah 《Landslides》2018,15(9):1833-1850
The main objectives of this paper are to design and evaluate a hybrid approach based on Gaussian mixture model (GMM) and random forest (RF) for detecting rockfall source areas using airborne laser scanning data. The former model was used to calculate automatically slope angle thresholds for different type of landslides such as shallow, translational, rotational, rotational-translational, complex, debris flow, and rockfalls. After calculating the slope angle thresholds, a homogenous morphometric land use area (HMLA) was constructed to improve the performance of the model computations and reduce the sensitivity of the model to the variations in different conditioning factors. After that, the support vector machine (SVM) was applied in addition to backward elimination (BE) to select and rank the conditioning factors considering the type of landslides. Then, different machine learning methods [artificial neural network (ANN), logistic regression (LR), and random forest (RF) were trained with the selected best factors and previously prepared inventory datasets. The best fit method (RF) was then used to generate the probability maps and then the source areas were detected by combining the slope raster (reclassified according to the thresholds found by the GMM model) and the probability maps. The accuracy assessment shows that the proposed hybrid model could detect the potential rockfalls with an accuracy of 0.92 based on training data and 0.96 on validation data. Overall, the proposed model is an efficient model for identifying rockfall source areas in the presence of other types of landslides with an accepted generalization performance. 相似文献
189.
Osman A. E. Abdalla Talal Al-Hosni Abdullah Al-Rawahi Anvar Kacimov Ian Clark 《Hydrogeology Journal》2018,26(8):2561-2573
Hydrochemistry and well hydrographs are coupled to assess groundwater recharge in the regional catchment of Samail, Oman. The complex geology comprises three aquifers: limestones of the Hajar Supergroup (HSG) at the highlands of North Oman Mountains (NOM); fractured/weathered ophiolites; and Quaternary alluvium. Groundwater flows south–north from the NOM to the coast. Samples from groundwater wells and springs (38) were analyzed for isotopes and major ions. Corrected 14C dating reveals modern groundwater across the entire catchment, while 87Sr/86Sr (0.70810–0.70895) shows greater homogeneity. Groundwater in the upper catchment is depleted in 2H and 18O, indicating a high-altitude recharge source (NOM), and becomes enriched downstream, with a slope indicating an evaporation effect. The hydrographs of nested piezometers located in the upper, middle and lower catchment show different recharge responses between deep and shallower depths. Head difference in response to recharge is observed upstream, suggesting a lateral recharge mechanism, contrary to vertical recharge downstream reflected in identical recharge responses. The homogeneous 87Sr/86Sr ratio, head changes, downstream enrichment of 2H and 18O, and the presence of modern groundwater throughout the catchment suggest that groundwater recharge takes place across the entire catchment and that the three aquifers are hydraulically connected. The recharge estimated using the chloride mass balance method is in the range of 0–43% of the mean annual rainfall. 相似文献
190.
Habes A. Ghrefat Abdullah A. Al Zahrani Mahmoud A. Galmed 《Journal of the Indian Society of Remote Sensing》2018,46(9):1399-1411
Mapping the surficial extent of oolitic iron ore deposits hosted in the Oligo–Miocene sedimentary rocks of the Ashumaysi Formation, western Saudi Arabia, was carried out using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data. Ore samples were collected from four various locations in the study area, and were studied in the laboratory using the GER 3700 Spectroradiometer (0.4–2.5 µm) and X-ray diffraction (XRD). Principal component analysis (PCA), minimum noise fraction (MNF), and minimum distance classification were used and assessed to map mineralization zones in the study area. Good correspondences were observed between the results obtained from the above mentioned techniques, spectral reflectance analyses, and XRD. The confusion matrix results revealed that mapping of iron ores using MNF is better and more accurate than using PCA. Good matching was also observed between the spectral reflectance curves of the collected samples and the corresponding pixels from Landsat 7 ETM+. The results demonstrated the usefulness of the image processing and interpretation of Landsat 7 ETM+ data for the detection and delineation iron ore deposits in arid and semi-arid areas. 相似文献