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31.
Existing uses for sulfur are relatively advanced and offer limited opportunities to consume significant new supplies. Currently,
sulfur is in net surplus on a global basis, and with environmental regulations, greater sulfur recovery from petroleum and
gas processing is mandated. The outlook is clear: there will be substantial and growing surpluses in global sulfur supply
in the foreseeable future. Sulfur prices are likely to be under pressure, and producers could face substantial and growing
disposal fees. Therefore, new markets must be found for sulfur to avoid disposal crises. One potential new market is the production
of sulfur-solidified concrete. This is a thermoplastic composite of mineral aggregates bound together with chemically modified
sulfur. The product is more durable than Portland cement. There may be monetizeable benefits in reducing greenhouse gas emissions
that would enhance the attraction of sulfur solidified cement applications. The main objective of this study is to evaluate
experimentally the potential use of sulfur as a solidifying agent for hazardous waste. To achieve this objective, the study
reviewed the sulfur concrete literature, analyzed locally produced sulfur, evaluated a number of sulfur polymer modifiers
and physical stabilizing agents, designed a set of experiments and evaluated the produced product for its hydro-mechanical-chemical
properties. The results indicated that the manufactured sulfur polymer cement is an excellent candidate for: waste management
practices such as solidification/stabilization of hazardous waste; barrier systems for landfilling of hazardous waste; and
waste water treatment plants. 相似文献
32.
Mohamed A. Gamal 《Journal of Seismology》2009,13(1):13-30
In order to determine the fundamental period of soil vibrations in Cairo, 174 microtremors stations, in conjunction with mobile
accelerographs, were used. The result was a collection of long-period microtremors and ambient noise arising from cultural
disturbances. The Nile Valley shows some fixed peaks at 2.5–3.5 Hz at the center of the basin, while the Nile’s surrounding
area shows a fundamental peak of 4–5 Hz, leaving a 5–7-Hz resonance peak for the sand-like, gravelly soil from Abbasiya to
the airport. A frequency-dependent soil amplification map is drawn, which includes seismic microzonation maps for Cairo. Based
on the above, a maximum acceleration map for two important earthquakes affecting Egypt in the last century is produced (Faiyum,
1992, and Aqaba, 1995). 相似文献
33.
P. Pourrezaei A. Alpatova P. Chelme-Ayala L. A. Perez-Estrada M. Jensen-Fontaine X. C. Le M. Gamal El-Din 《International Journal of Environmental Science and Technology》2014,11(7):2037-2050
Petroleum coke (PC) is a waste by-product generated during the oil upgrading processes by the petroleum industry. The continuing accumulation of large quantities of PC requires the development of innovative strategies for the effective utilization of this carbon-rich material. In this study, PC was used for the removal of naphthenic acids (NAs) and acid-extractable fraction (AEF) from oil sands process-affected water (OSPW), generated during the oil refining process. A systematic study on the adsorption of organic fractions, vanadium leaching from PC, adsorption mechanisms, and the effect of physico-chemical characteristics of the PC on adsorption process was performed. Physico-chemical properties of PC were determined by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, and Brunauer–Emmett–Teller surface area analysis. AEF and NAs removals of 60 and 75 %, respectively, were achieved at PC dose of 200 g/L after 16 h of contact. FT-IR and TGA analysis of PC suggested the physisorption of organic compounds onto the surface of PC. The calculated mean free energy of adsorption (E < 8 kJ/mol) also indicated the physisorption of organics to the PC surface. The hydrophobic interactions between the NAs and the PC were suggested as the dominant adsorption mechanisms. The vanadium release occurred when PC was mixed with OSPW and vanadium concentration increased with an increase in the PC dose. Speciation analysis indicated that the vanadium leached was predominantly vanadium (V) and insignificant amount of vanadium (IV) was also detected. 相似文献
34.
Hamed Gamal El Dien Mohamed Hamdy Abdel Salam Abu El-El Adel Hassan Youngwoo Kil 《《地质学报》英文版》2015,89(Z2):22-24
<正>Neoproterozoic ophiolitic Serpentinites are common in the Arabian–Nubian Shield(ANS)of the Eastern Desert(ED)of Egypt,which were formed in arc stage in different tectonic setting.Thus they might subject to exchange with the crustal material derived from recycling subducting oceanic lithosphere.This caused metasomatism enriching 相似文献
35.
Gamal G.L. Nashed 《海洋学报(英文版)》2010,29(11)
A theory of (1+1)-dimensional gravity is constructed on the basis of the teleparallel equivalent of general relativity. The fundamental field variables are the tetrad fields eiμ and the gravity is attributed to the torsion. A dilatonic spherically symmetric exact solution of the gravitational field equations characterized by two parameters M and Q is derived. The energy associated with this solution is calculated using the two-dimensional gravitational energy--momentum formula. 相似文献
36.
Nabil T. Eldabe Mahmoud A. Mahmoud Gamal M. A. El Rahman 《Astrophysics and Space Science》1991,178(2):197-204
In this paper, the nonsteady flow of non-Newtonian power-law conducting fluid through a porous medium past an infinite porous plate is investigated. The system is stressed by a constant transverse magnetic field. The velocity outside the boundary layer depends exponentially on time. The rheological effects are shown and discussed on the shear stress in terms of rheological parameter of power-law fluid. The approximate solution in a closed form were obtained by using the Galerkin method. Also the effect of the magnetic field and permeability parameter are discussed. 相似文献
37.
Gamal G. L. Nashed 《Astrophysics and Space Science》2011,335(2):593-598
We give a class of spherically symmetric-Anti de Sitter (Ads), exact solution in the teleparallel equivalent of general relativity
(TEGR). The solution depends on an arbitrary function F(R)\mathcal{F}(R) and reproduce the metric of Schwarzschild Ads space-time. In the context of the Hamiltonian formulation of the TEGR we compute
the gravitational energy of this class. The calculation is carried out by means of an expression for the energy of the gravitational
field that naturally arises from the integral form of the constraint equations of the formalism. We show that the form of
the energy depends on the arbitrary function. We make a constrain on this arbitrary function to give the correct form of energy. 相似文献
38.
39.
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
40.
Gamal G. L. Nashed 《Astrophysics and Space Science》2010,330(2):367-372
We apply the energy-momentum tensor which is coordinate independent, of the gravitational field established in the Hamiltonian structure of the teleparallel equivalent of general relativity (TEGR), to an axially symmetric tetrad field to calculate energy, momentum and angular momentum. Also the definition of the gravitational energy is used to investigate the energy within the external event horizon of this tetrad. 相似文献