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21.
In the Abu Rusheid area, Southeastern Desert of Egypt, polymineralized (HREEs, U, Zn and Pb) lam-prophyre dykes are recently recorded. The lamprophyre dykes cut cataclastic rocks along share zones in NNW-SSE trends. The secondary U-minerals are essentially represented by uranophane, kasolite, torbernite and autunite. Ex-perimental work was carried out on the lamprophyre dykes for the recovery of uranium and other valuable elements (e.g. Zn, Pb and Al) from 50 kg of technological sample. The optimum conditions were: 100 g/L sulfuric acid con-centration, 1:5 S/L (solid/liquid) and soaking for 15 days at room temperature. The leaching efficiencies for the re-covery of uranium and other elements like Al, Zn and Pb were 40, 33.6, 98.8 and 78, respectively. 相似文献
22.
Mostafa Rabah Zaki Zedan Essam Ghanem Ahmed Awad Ahmed Sherif 《Arabian Journal of Geosciences》2016,9(13):613
Nowadays many continuously operating reference stations (CORS) network were established in Middle East to improve the surveying tasks. Establishing such geodetic control networks can be a costly business where multiple stations should be occupied simultaneously and post-processed with scientific software. Recently, precise point positioning (PPP) provides precise positioning values that may be an alternative to precise relative processing. The current research aims to investigate that PPP has a potential as a reliable absolute positioning technique operational simplicity as well as to investigate the capability of PPP approach to be a low cost alternative to the conventional positioning methods used in position determination of core networks stations. In comparison with common relative GPS techniques, the costs are reduced; because no base stations and no simultaneous observations are necessary, no need for control network maintenance which could be the most defective factors that Egypt HARN network suffered from. To see the feasibility study of using PPP for precise determination of the CORS, 14 days of GNSS data for the 14 Kuwait integrated with 27 IGS stations were processed by Bernese software to calculate the precise coordinates of Kuwaiti CORS network in the latest terrestrial geodetic frame. Three days of these data were processed by Trimble business center software and using PPP approach to calculate the precise coordinates of Kuwait network. In the current research, a comparable investigation was carried out between the coordinates obtained from Bernese software, Trimble business center, and PPP approach. The comparison proved high level of agreement between the coordinates which confirm that PPP approach can be applied for establishment of CORS network. 相似文献
23.
Naoki Ikegaya Aya Hagishima Jun Tanimoto Yudai Tanaka Ken-ichi Narita Sheikh Ahmad Zaki 《Boundary-Layer Meteorology》2012,143(2):357-377
We performed a series of wind-tunnel experiments under neutral conditions in order to create a comprehensive database of scalar
transfer coefficients for street surfaces using regular block arrays representing an urban environment. The objective is to
clarify the geometric dependence of scalar transfer phenomena on rough surfaces. In addition, the datasets we have obtained
are necessary to improve the modelling of scalar transfer used for computational simulations of urban environments; further,
we can validate the results obtained by numerical simulations. We estimated the scalar transfer coefficients using the salinity
method. The various configurations of the block arrays were designed to be similar to those used in a previous experiment
to determine the total drag force acting on arrays. Our results are summarized as follows: first, the results for cubical
arrays showed that the transfer coefficients for staggered and square layouts varied with the roughness packing density. The
results for the staggered layout showed the possibility that the mixing effect of air can be enhanced for the mid-range values
of the packing density. Secondly, the transfer coefficients for arrays with blocks of non-uniform heights were smaller than
those for arrays with blocks of uniform height under conditions of low packing density; however, as the packing density increased,
the opposite tendency was observed. Thirdly, the randomness of rotation angles of the blocks in the array led to increasing
values of the transfer coefficients under sparse packing density conditions when compared with those for cubical arrays. 相似文献
24.
Compilation between the previous studies about the river systems evolution and integrating them with the remotely sensed data-based landscape analysis provide a new vision to the river systems evolution in Egypt during the Cenozoic Era. Relics of geomorphologic features left in the old basins related to these rivers suggest the existence of a natural dam between Nag Hammadi City and Wadi El-Assuiti. This barrier was separating two river systems during Late Miocene time: (1) the Qena River System and (2) the newly suggested North Egypt River System. The North Egypt River is supposed to be started by the Wadi El-Assuiti drainage basin, which flowed first in a westward direction, from its source in the Eastern Limestone Plateau to continue in a northward direction across the Nile Canyon (along the course of the Nile) to join the drainage system of Wadi Tarfa and Wadi Sannur and to end, finally, in the depression of Wadi El-Natrun to constitute the Wadi El-Natrun Miocene Delta. The present interpretation on the existence of a North Egypt River System, with the presence of an old natural dam to the south of Nag Hammadi City, necessitates a revision of the concepts used for groundwater exploration in Upper Egypt. 相似文献
25.
S. Zaki Ph.D. S. Farag Ph.D. G. Abu Elreesh Ph.D. M. Elkady Ph.D. M. Nosier D. El Abd Ph.D. 《International Journal of Environmental Science and Technology》2011,8(4):831-840
The aim of this study was to look for high efficient bioflocculant-producing microorganisms. Among 36 bacterial colonies isolated from a crude petroleum oil sample, three of them as Bacillus subtilis and Pseudomonas spp. exhibited flocculation activity exceeding 90 % after 3 days of cultivation. They were identified by 16 S rDNA sequence analysis as Bacillus subtilis and Pseudomonas sp. Spectroscopic analysis of the polymers by nuclear magnetic resonance and fourier-transform infrared revealed that the polymers were glycoproteins. These polymers were soluble in water and insoluble in any organic solvents tested. The effects of bioflocculant dosage, temperature and pH on the flocculation activity were evaluated. The maximum bioflocculation activities were observed at an optimum bioflocculant dosage of 3.5 mg/L (strains Bacillus subtilis and Pseudomonas) and 5.0 mg/L (strain CPO14), respectively. In addition, these biopolymers were able to flocculate kaolin suspension (5 g/L) over a wide range of pH (pH 3–9) and temperature (5–50 °C) tested in the presence of CaCl2. The highest flocculation activities of strains CPO8, CPO13 and CPO14 were 96.03 %, 92.17 % and 97.59 %, respectively in the early stationary phase (at 24 h), while the cell production reached its maximum in the stationary phase (at 72 h). Their efficient flocculation capabilities suggest potential applications in industries. 相似文献
26.
D. Abd-El-haleem A. Amara S. Zaki A. Abulhamd G. Abulreesh 《International Journal of Environmental Science and Technology》2007,4(4):513-520
In the recent decade, biosynthesis of the degradable biopolymers polyhydroxyalkanotes in transgenic yeasts became an important research task. Most research strategies depend on either metabolic engineering or molecular approaches. In the present work, research compared PHA biosynthesis in two types of yeasts; Saccharomyces cerevisiae and a non-convenient Kloeckera spp. Yeast strains were equipped in their cytoplasm with the phaABCRe operon containing genes phbA, phbB and phbC of the PHA biosynthetic pathway of Ralstonia eutropha, which encode β-ketothiolase, NADPH-linked acetoacetyl-CoA reductase and PHA synthase, respectively. The transgenic strains Saccharomyces cerevisiae and Kloeckera sp. were able to produce PHA. The maximum content of the polymer detected in the recombinant strain INVSc1/PHA1 was 2.68 % and only poly-3-hydroxybutyrate (PHB) accumulated. However, the non-conventional transgenic strain KY1/PHA was able to accumulate as maximum of 7.06 % of the copolymer poly-(3-hydroxybutyrate-co-poly-3-hydroxyvalerate) (PHV). Western blot analysis confirmed expression of the phaABCRe operon in the transgenic yeast strains. The nature of the PHA thus produced by all tested strains was analyzed by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. 相似文献
27.
The roadway tunnel is considered a good solution for the success of modern roadway networks. It can help to overcome possible traffic congestion and considerably reduce journey time. The continuous growth of traffic volumes leads to increase congestion and decrease safety. This leads to the need for extra tunnel space. The extra tunnel space can be achieved either by the widening of the existing tunnel or by adding a new one. The choice of the suitable method is dependent on many factors like tunnels alignment, site conditions, construction method, tunnel operation, risk assessment…etc. The current research investigates the second alternative through a specific case study as an example. The method comprises adding two new tunnels to an existing twin roadway tunnels. The investigated problem considers the new tunnels to be added vertically or horizontally. The influence of the new tunnel construction on the existing tunnels is investigated considering both the variation of relative position and spacing distance in a parametric study context. Several numerical models are employed to check the construction sequence and the tunnelling safety. These models are used to evaluate the induced stresses in surrounding ground for two different soil types, straining actions in tunnels’ liner and deformations of both ground and liner. The result demonstration shows how to find out the minimum practical and safe spacing distance between the driven new tunnels and the existing ones without the need for the relatively expensive soil strengthening techniques. 相似文献
28.
S. Zaki Ph.D. S. Farag Ph.D. 《International Journal of Environmental Science and Technology》2010,7(3):553-560
The biosorption of copper (II) from aqueous solution using different bacterial strains was studied. Copper-biosorbing bacteria were isolated from tannery effluent collected from Borg Al-Arab, Alexandria, Egypt. These isolates displayed different degrees of copper biosorption under aerobic conditions. Based on 16S rDNA gene sequence analysis, three of them (S2, S5 and S7) were identified as Chryseobacterium sp., Enterobacter sp. and Stenotrophomonas sp., respectively. Initial copper (II) ion concentrations from 25–250 mg/L at constant temperature 30 °C were studied. The residual copper (II) concentration and its toxicity effect in solution were determined using atomic absorption spectrophotometer and bioluminescent bioreporter. The bioluminescence inhibition of strain (S5) reached to 91.4 % as compared with the strain (S7) reached to 83.3 % at 225 mg/L of copper ion where the maximum biosorption efficiency for S5 and S7 were 71 % and 70.1 % correspondingly using atomic absorption. The bioluminescent bioreporter was proved to be fast and accurate technique for measurement the toxicity effect of residual copper (II) in solution. 相似文献
29.
30.
Ahmed Zaki Ahmed Hamdi Mansi Mohamed Selim Mostafa Rabah Gamal El-Fiky 《Marine Geodesy》2018,41(3):258-269
The determination of high-resolution geoid for marine regions requires the integration of gravity data provided by different sources, e.g. global geopotential models, satellite altimetry, and shipborne gravimetric observations. Shipborne gravity data, acquired over a long time, comprises the short-wavelengths gravitation signal. This paper aims to produce a consistent gravity field over the Red Sea region to be used for geoid modelling. Both, the leave-one-out cross-validation and Kriging prediction techniques were chosen to ensure that the observed shipborne gravity data are consistent as well as free of gross-errors. A confidence level equivalent to 95.4% was decided to filter the observed shipborne data, while the cross-validation algorithm was repeatedly applied until the standard deviation of the residuals between the observed and estimated values are less than 1.5 mGal, which led to the elimination of about 17.7% of the shipborne gravity dataset. A comparison between the shipborne gravity data with DTU13 and SSv23.1 satellite altimetry-derived gravity models is done and reported. The corresponding results revealed that altimetry models almost have identical data content when compared one another, where the DTU13 gave better results with a mean and standard deviation of ?2.40 and 8.71 mGal, respectively. A statistical comparison has been made between different global geopotential models (GGMs) and shipborne gravity data. The Spectral Enhancement Method was applied to overcome the existing spectral gap between the GGMs and shipborne gravity data. EGM2008 manifested the best results with differences characterised with a mean of 1.35 mGal and a standard deviation of 11.11 mGal. Finally, the least-squares collocation (LSC) was implemented to combine the shipborne gravity data with DTU13 in order to create a unique and consistent gravity field over the Red Sea with no data voids. The combined data were independently tested using a total number of 95 randomly chosen shipborne gravity stations. The comparison between the extracted shipborne gravity data and DTU13 altimetry anomalies before and after applying the LSC revealed that a significant improvement is procurable from the combined dataset, in which the mean and standard deviation of the differences dropped from ?3.60 and 9.31 mGal to ?0.39 and 2.04 mGal, respectively. 相似文献