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1.
Mohamed H. Taha Samir A. Abdel Maksoud Mohsen M. Ali Ahmed M. A. El Naggar Asmaa S. Morshedy Amir A. Elzoghby 《International journal of environmental analytical chemistry》2013,93(12):1211-1234
ABSTRACTThis study reports the removal of organic matters from phosphoric acid using waste-produced bio-charcoal structures. Particularly, the freshly made bio-char species via pyrolysis and two sub-driven acids activated charcoals were applied during the removal process. The treated charcoal with hydrochloric and nitric acids had attained a higher adsorption rate for organic matters than that of the non-treated one. Removal percentages of 70% and 60% were, respectively, attained by acid-modified chars. The kinetics of the adsorption process was fitted via pseudo-first/second-order and Morris–Weber models. The thermodynamic parameters of the presented sorption process indicate that organic matter removal has been endothermic, physical and spontaneous. 相似文献
2.
The growth rate of pearlite during isothermal transformation of an aluminium-zinc eutectoid has been determined experimentally.
Different theoretical models, assuming either volume or boundary diffusion of zinc to be a rate controlling mechanism for
the eutectoid transformation, have been applied. With volume diffusion models, the calculated growth rates were lower than
the experimental growth rates by a factor of three orders of magnitude. Reasonable agreement between the calculated and experimental
growth rates has been obtained on applying the boundary diffusion models. The activation energy for boundary diffusion of
zinc in the aluminium-zinc alloy was estimated to be ≅11.6 kcals/mole. 相似文献
3.
A. A. Taha A. M. Ahmed H. H. Abdel Rahman M. O. Abdel Maksoud 《Journal of Dispersion Science and Technology》2017,38(5):757-767
Nano-bentonite was used as an adsorbent to remove nickel ions from aqueous solutions. Experimental investigation was carried out to identify the effect of pH, contact time, initial concentration, and adsorbent dose of Ni(II). Equilibrium data were described by and fitted to Langmuir, Freundlich, and Dubinin–Radushkevich models. Results showed that the optimum conditions for the removal of the Ni(II) are initial concentration 100 mg/L, adsorbent dose 0.5 g, and pH 6. Surface morphology and functionality of nano-bentonite were characterized by SEM and FTIR. The kinetics data were more accurately described by pseudo-second-order model. The intra-particle diffusion model gave multi-linear curves, so more than one step controlled the adsorption process. Nano-bentonite removed nickel with maximum adsorption capacity of 39.06 mg/g (30°C, pH) and thermodynamic data indicated that adsorption reaction is spontaneous and of an endothermic nature. 相似文献
4.
Chemistry of Phosphorus Ylides. Part 40. Synthesis of Pyrazoles by the [3 + 2] Cycloaddition of Diazo Compounds with Wittig Reagents as Antimicrobial Compounds 下载免费PDF全文
Soher S. Maigali Mansoura A. Abd‐El‐Maksoud Fouad M. Soliman Mysa E. Moharam 《Journal of heterocyclic chemistry》2015,52(3):834-840
A comparative study between the reactions of active phosphacumulenes and stabilized phosphonium ylides on some diazo compounds have been performed. A number of substituted phosphanylidene spiro pyrazoles have been synthesized from the reaction of the active phosphacumulenes and the diazo derivatives. On the other hand, treatment of the diazo substrates with the stabilized phosphonium ylides led to the formation of the corresponding ylidenes and diazenyl phosphanylidenes. The antimicrobial activities for the new compounds are also reported. 相似文献
5.
Mohamed Aly Mohamed Abdou Abdel‐Maksoud Abdel‐Kader Soliman 《Mathematical Methods in the Applied Sciences》2012,35(10):1117-1125
In this paper, the study the momentum and heat transfer characteristics in an incompressible electrically conducting non‐Newtonian boundary layer flow of a viscoelastic fluid over a stretching sheet. The partial differential equations governing the flow and heat transfer characteristics are converted into highly nonlinear coupled ordinary differential equations by similarity transformations. The resultant coupled highly nonlinear ordinary differential equations are solved by means of, homotopy analysis method (HAM) for constructing an approximate solution of heat transfer in magnetohydrodynamic (MHD) viscoelastic boundary layer flow over a stretching sheet with non‐uniform heat source. The proposed method is a strong and easy to use analytic tool for nonlinear problems and does not need small parameters in the equations. The HAM solutions contain an auxiry parameter, which provides a convenient way of controlling the convergence region of series solutions. The results obtained here reveal that the proposed method is very effective and simple for solving nonlinear evolution equations. The method is straightforward and concise, and it can also be applied to other nonlinear evolution equations in physics. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
6.
El Naggar Ahmed M. A. Ali Mohsen M. Abdel Maksoud Samir A. Taha Mohamed H. Morshedy Asmaa S. Elzoghby Amir A. 《Journal of Radioanalytical and Nuclear Chemistry》2019,320(3):741-755
Journal of Radioanalytical and Nuclear Chemistry - The ultimate usage of phosphoric acid is declared in food and fertilizers industries. Therefore, purification of commercial phosphoric from their... 相似文献
7.
Halla Mohamed Ragab Nabila Abd El Maksoud Mona A. Amin Mohab H. Halim Nour A. Abdulla Abdelkarim Kamel Shorouk M. Moussa 《Applied biochemistry and biotechnology》2018,184(2):484-499
Fatty acid desaturases (FADs) catalyze the introduction of a double bond into acyl chains. Two FAD groups have been identified in plants: acyl-acyl carrier proteins (ACPs) and acyl-lipid or membrane-bound FAD. The former catalyze the conversion of 18:0 to 18:1 and to date have only been identified in plants. The latter are found in eukaryotes and bacteria and are responsible for multiple desaturations. In this study, we identified 82 desaturase gene and protein sequences from 10 grass species deposited in GenBank that were analyzed using bioinformatic approaches. Subcellular localization predictions of desaturase family revealed their localization in plasma membranes, chloroplasts, endoplasmic reticula, and mitochondria. The in silico mapping showed multiple chromosomal locations in most species. Furthermore, the presence of the characteristic histidine domains, the predicted motifs, and the finding of transmembrane regions strongly support the protein functionality. The identification of putative regulatory sites in the promotor and the expression profiles revealed the wide range of pathways in which fatty acid desaturases are involved. This study is an updated survey on desaturases of grasses that provides a comprehensive insight into diversity and evolution. This characterization is a necessary first step before considering these genes as candidates for new biotechnological approaches. 相似文献
8.
Chemistry of Phosphonium Ylides. Part 39: Facile Synthesis of Aziridine,Pyridine, Pyrolotriazole Chromenones and Azaphosphinin Chromenones as Antitumor Agents 下载免费PDF全文
Mansoura A. Abd‐El‐Maksoud Soher S. Maigali Fouad M. Soliman 《Journal of heterocyclic chemistry》2014,51(6):1830-1837
The reaction of 4‐azido‐2‐oxo‐2H‐chromene‐3‐carbaldehyde with the active nucleophilic phosphacumulenes yielded the corresponding phosphanylidene‐aziridines and chromeno‐pyrolo‐triazoles. On the other hand, the reaction of the allylic phosphonium ylide, hexaphenylcarbodiphosphorane with the azido compound, was also undertaken. In this case, the phosphanylidene‐chromeno‐triazinone was obtained. Further assessment of these new compounds against (breast: MCF‐7 and liver: HPEG2) human solid tumor cell lines is necessary. 相似文献
9.
The heat of hydration of a fresh, locally produced sample of some industrial gypsum (plaster of Paris, CaSO4 · 0.5 H2O) was determined. An adiabatic calorimeter was used for this purpose. The obtained heat of hydration was ?9 cal g?1, which is higher than that for the hemihydrate (?5 cal g?1). The calculated heat of hydration for calcium sulphate hemihydrate from the known heats of formation, and using ordinary thermochemical equations, is ?5 cal g?1. In the same manner, however, the calculated heat of hydration for the anhydrite (CaSO4) is ?29 cal g?1. The higher heat of hydration (?9 cal g?1) for the tested sample than that for the ordinary hemihydrate (?5 cal g?1) was attributed to the presence of a certain percent of anhydrite. The composition of the tested sample was proposed by applying conventional chemical and rational analyses. The present work suggests the use of the heat of hydration as a tool for determining the composition of calcined gypsum. 相似文献
10.
Ibrahim E. El Aassy Mohamed M. El Galy Afaf A. Nada Mohamed G. El Feky Thanaa M. Abd El Maksoud Shadia M. Talaat Eman M. Ibrahim 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(1):173-184
The contents of natural radionuclides in various types of sedimentary rocks in Um Bogma Formation and base of El Hashash Formation
were determined by gamma-ray spectrometry. Three types of lower Carboniferous sedimentary rocks were investigated; sandstone
(El Hashash Formation), dolostone and argillaceous sediments (Um Bogma Formation). The alteration processes are dolomitization,
dedolomitization, karstification and lateritization. The specific radioactivity of 238U, 226Ra, 232Th and 40K determined in different samples, indicate that 238U and its decay products contribute primarily to the high natural radioactivity of rocks. The maximum concentration of 238U reached up to 2129.36 ppm in argillaceous sediments. The average concentrations of determined radionuclides (238U, 226Ra, 232Th and 40K) are 8.34 ppm, 7.88 ppm, 4.68 ppm and 0.3%, respectively in sandstone. In dolostones the average concentrations are 418.69 ppm,
808.75 ppm, 3.14 ppm and 0.29%, respectively. For argillaceous sediments are 276.88 ppm, 419.49 ppm, 11.47 ppm and 0.93%,
respectively. The 238U/226Ra ratio in sandstone ranges between 0.89 and 1.25, while in dolostones and argillaceous sediments are 0.27–2.63 and 0.27–1.83,
respectively. These variations in the concentrations of radioelements and their ratios are due to the action of the alteration
processes affected these different sedimentary rocks in different times. Environmentally, the Raeq in dolostones and argillaceous sediments exceeds the permitted limits, while in the sandstone samples; it is within the permissible
levels. 相似文献