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Mohammad Mokammel Haque Hussien Abdulrahman Al Attas Mutaz Ali Hassan 《Arabian Journal of Geosciences》2016,9(6):464
The concentrations of 16 trace elements (Ag, Al, As, B, Ba, Cd, Cr, Cu, Hg, Mn, Ni, Pb, Se, Ti, U, and Zn) in drinking water from Najran City, Saudi Arabia, were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and compared with local, regional, and international guidelines. Water samples from 22 water treatment plants and 13 commercial bottled water brands were analyzed. Except for B and U, the trace element concentrations were below the permitted limits defined in SASO, GSO, and WHO drinking water quality guidelines. The B concentrations in three brands of bottled water were 533.19, 602.29, and 1471.96 μg/L, which were all higher than the GSO and SASO limit (500 μg/L). The U concentrations were higher than the SASO limits for drinking water in two samples; one in treatment plant (2.39 μg/L) and another in foreign bottled water (2.17 μg/L). The median As, Ba, Cu, Ni, U, and Zn concentrations were statistically significantly higher in the treatment plant water samples than those in the bottled water samples, and conversely, the B concentrations were higher in the bottled water samples. The Cd, Hg, and Ti concentrations were below the detection limits of ICP-MS in all of the water samples. Apart from few exceptions, trace element concentrations in drinking water of Najran City were all within limits permitted in the national, regional, and international drinking water quality guideline values. 相似文献
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The Penman?CMonteith (PM) method is the most recommended method for estimating reference evapotranspiration (ETo). The PM equation requires several parameters to be available, either measured or computed. Some of these parameters are conventionally calculated by some slightly sophisticated formulas, especially for handy calculations. This paper aimed to derive some simpler statistical equivalents to these formulas. Simplifications were performed to the formulas of the saturation vapor pressure e o[T], slope of vapor pressure (?), atmospheric pressure (P), the psychrometric constant (??), wind speed correction, the long-wave radiation, R nl; the sunset hour angle, ?? s; and the extraterrestrial radiation, R a. For the first five parameters, the parameter-independent factor was analyzed for its extremes, then fitted by interpolation to a simpler equivalent formula. The last three parameters were fitted to simpler form through data from the FAO-CLIMWAT database. Each of the simplified formulas was compared to the conventional one; some correlation indices were applied to validate the new formulas. The ETo was calculated for all stations in the CLIMWAT database by both simplified and conventional formulas. All the correlation results were excellent, with a minimum correlation coefficient of 0.9966. The simplified formulas were proven to be equivalent in performance, with almost no loss in accuracy but simpler in form and faster in execution in the online database applications. 相似文献
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Abdulrahman A. Malawi 《Earth, Moon, and Planets》2013,110(3-4):175-183
We present here a detailed explanation of the reduction method that we use to determine the angular diameters of the stars occulted by the dark limb of the moon. This is a main part of the lunar occultation observation program running at King Abdul Aziz University observatory since late 1993. The process is based on the least square model fitting method of analyzing occultation data, first introduced by Nather et al. (Astron. J. 75:963, 1970). 相似文献
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Omar A. Almisned Abdulrahman A. Alquraishi Khalaf A. Al-Otaibi 《Arabian Journal of Geosciences》2018,11(10):235
The spontaneous imbibition phenomenon is an important process in hydrocarbon recovery. Laboratory study of imbibition is affected by many parameters including, rock characteristics, boundary conditions, length of the sample, variable interfacial tension, and sample heterogeneity. Investigating spontaneous imbibition enhances our understanding of the imbibition mechanism and, hence, helps improve waterflooding used in the oil industry. A simple apparatus has been developed to resemble naturally fractured reservoirs. Using the developed apparatus, the effects of lithology, permeability, and wettability on spontaneous imbibition have been experimentally investigated. Some encountered unexpected technical problems during the experiments are overcome and reported in this paper. Details of the developed apparatus are shown and spontaneous imbibition results are presented. First, the effect of permeability on the oil recovery rate is presented. In addition, obtained curves of oil recovery by water spontaneous imbibition using different lithology are presented. Finally, results of oil recovery from Berea sandstone core sample before and after wettability alteration are shown. 相似文献
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Wimpy Karnanda M. S. Benzagouta Abdulrahman AlQuraishi M. M. Amro 《Arabian Journal of Geosciences》2013,6(9):3535-3544
In this research, effect of temperature, pressure, salinity, surfactant concentration, and surfactant type on interfacial tension (IFT) and critical micelle concentration of Saudi Arabian crude oil and various aqueous phases were investigated. The temperature ranged from ambient condition to 90°C, and the pressures were varied from atmospheric to 4,000 psi (27.58 MPa). Surfactant solutions were prepared using several aqueous phases, i.e., purified water, 10% brine consisting of 100% NaCl, 10% brine consisting of 95% NaCl and 5% CaCl2, and 10% brine consisting of 83% NaCl and 17% CaCl2. Out of 13 commercial surfactants, only three surfactants showed good solubility in pure water and brine. Those are Zonyl FSE Fluorosurfactant®, Triton X-100®, and Triton X-405®. Therefore, they were investigated thoroughly by measuring their efficiency in reducing the crude oil-aqueous phase IFT. Based on this screening process, laboratory surfactant flooding experiments for crude oil recovery were conducted using Triton X-405 and Triton X-100. The chemical flood was made at both original oil in place and at residual oil in place subsequent to conventional water flooding. Based on the obtained results, both surfactants were efficient, and more oil was recovered than that obtained through water flooding. Comparing both surfactant solutions, it was observed that Triton X-405 was more efficient than Triton X-100 at the same surfactant concentration and reservoir conditions. 相似文献
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Iftikhar Ahmed Abbasi Osman Salad Hersi Abdulrahman Al-Harthy Iman Al-Rashdi 《Arabian Journal of Geosciences》2013,6(12):4931-4945
Over 70 m thick interbedded sandstone, siltstone and claystone of the upper member of the Gharif Formation are exposed in western Huqf area in Oman Interior Sedimentary Basin. The Gharif Formation, particularly its upper member hosts major hydrocarbon reservoir in the subsurface of the Oman Interior Sedimentary Basin. The upper member of the Gharif Formation is comprised of interbedded thick sandstone, siltstone, carbonaceous clays and intraformational conglomerates. The sandstone lithofacies, on average, constitute 10 m thick multistoreyed sequences, which are composed internally of 2–3 m thick and 100 s of metres across vertically and laterally amalgamated sandstone bodies. Two major types of sandstones (types 1 and 2) are identified on the basis of their lithofacies association and internal architecture. The type 1 sandstone constitutes the lower part of the member and is comprised of pebbly to coarse-grained, planar and trough cross-bedded sandstone, plane bedded sandstone and pebble lags at the base of major sandstone bodies. The cross-beds are, on average, 30 cm thick exhibiting a dominant paleoflow direction towards NW (280–300° N). It is interpreted to be deposited by low sinuosity braided streams. The type 2 sandstone constitutes the upper part of the member and is comprised of medium-grained sandstone, trough to low angle plane bedding associated with lateral accretion surfaces. It is commonly interbedded with carbonaceous clays. Silicified plant fragments are commonly distributed in the upper part of the sandstone. Interbedded clays and siltstones are red, mottled and extensively bioturbated due to root burrows. It is interpreted to be deposited by high sinuosity meandering streams. In the uppermost part of the section, several dark grey to black carbonaceous clay/coal beds with plant matter are interbedded with sandstone and red clay indicating development of swampy conditions during onset of the coastal setting in the uppermost part of the formation. About 30 cm thick bioclastic sandstone deposited by the marine coastal bars mark transition from the Gharif Formation to carbonate dominated Khuff Formation. The sandstone of the Gharif Formation is arkosic in composition. Very small amount of cement and negligible compaction of constituent grains in sandstone indicates shallow burial before uplift. 相似文献
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Mineralogical and geochemical characterization of listwaenite from the Semail Ophiolite, Oman 总被引：2，自引：0，他引：2
Sobhi Nasir Abdul Razak Al Sayigh Abdulrahman Al Harthy Salah Al-Khirbash Omar Al-Jaaidi Abdullah Musllam Ali Al-Mishwat Salim Al-Bu'saidi 《Chemie der Erde / Geochemistry》2007,67(3):213-228
The late Cretaceous-lower Tertiary hydrothermal alteration of serpentinized peridotite in the Semail ophiolite has formed two distinct types of listwaenite. Type I is characterized by the presence of calcite (Type IA) or dolomite (Type IB)+fuchsite±spinel. Type II is dominated by silicate minerals (quartz, chlorite, fuchsite)±calcite+dolomite±magnetite±apatite±plagioclase. Most listwaenites occur as veins along thrust fault zones within the ophiolite mélange. High Cr and Ni contents, abundant occurrence of Cr-spinel within a matrix of red-brown ferruginous carbonates within a micro-vein network of goethite, and the relics of mesh texture indicate an ultramafic protolith. Type I and II listwaenites represent different stages of hydrothermal alteration. The mineralogical and chemical distinctions of both types are the response to the extent of the reactions between the protoliths and the solutions leading to different stages of metasomatic replacement. The hydrothermal fluids involved in the formation of Type I listwaenite were enriched in Ca, Mg, and CO2, whereas Type II listwaenite bodies were formed from a hydrothermal fluid enriched in SiO2. REE and trace elements in both listwaenite types were extracted in part from adjoining peridotite. No Au anomaly in the study areas has been detected. 相似文献
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Acacia nilotica was used for the adsorption of Reactive Black 5 (RB5) dye from an aqueous solution. Both the raw and activated (with H3PO4) carbon forms of Acacia nilotica (RAN and ANAC, respectively) were used for comparison. Various parameters (including dye concentration, contact time, temperature, and pH) were optimized to obtain the maximum adsorption capacity. RAN and ANAC were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The maximum experimental adsorption capacities for RAN and ANAC were 34.79 and 41.01 mg g?1, respectively, which agreed with the maximum adsorption capacities predicted by the Langmuir, Freundlich, and Dubinin–Radushkevich equilibrium isotherm models. The adsorption data of ANAC showed a good fit to the isotherm models based on the coefficient of determination (R 2): Langmuir type II (R 2 = 0.99) > Freundlich (R 2 = 0.9853) > Dubinin–Radushkevich (R 2 = 0.9659). This result suggested monolayer adsorption of RB5 dye. The adsorption of RB5 dye followed pseudo-second-order kinetics. The RAN adsorbent reflected an exothermic reaction (enthalpy change, ΔH = ?0.006 kJ mol?1) and increased randomness (standard entropy change, ΔS = 0.038 kJ mol?1) at the solid–solution interface. In contrast, ANAC reflected both exothermic [?0.011 kJ mol?1 (303–313 K)] and endothermic [0.003 kJ mol?1 (313–323 K)] reactions. However, the ΔS value of ANAC was lower when the RB5 adsorption increased from 313 to 323 K. The negative values for the Gibbs free energy change at all temperatures indicated that the adsorption of RB5 dye onto RAN and ANAC was spontaneous in the forward direction. 相似文献