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Ezzat Rafiee,Narges Nobakht 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1
A desulfurization process for model oil and real oil was investigated based on the chemical oxidation of mixed sulfur containing compounds in the presence of nitrogen compounds (indole and quinoline) using hydrogen peroxide as oxidizing agent and dodecamolibdophosphoric acid (H3PMo12O40) encapsulated in a kind of metal-organic framework (HKUST-1) as PMo@HKUST-1. The effect of isopropanol, ethanol and acetonitrile as extractive solvent and 1-ring (toluene, xylene and mesitylene) and 2-ring (naphthalene) aromatic hydrocarbons in desulfurization of model oil was studied. The desulfurization of sulfur-containing compounds was accelerated in the presence of aromatic hydrocarbons. In fact, a higher desulfurization efficiency of the heterogeneous catalyst could be achieved with system containing a polar solvent in contact with an aromatic hydrocarbon. Quinoline had no effect on oxidative desulfurization (ODS) reaction, whereas indole had a slightly negative effect. Presence of aromatic compounds had slightly positive effect on ODS reaction.
Ezzat H. Fahmy,Yousry B. I. Shaheen,Ahmed Mahdy Abdelnaby,Mohamed N. Abou Zeid 한국콘크리트학회 2014 International Journal of Concrete Structures and M Vol.8 No.1
This paper presents the results of an investigation aimed at developing reinforced concrete beams consisting of precast permanent U-shaped reinforced mortar forms filled with different types of core materials to be used as a viable alternative to the conventional reinforced concrete beam. To accomplish this objective, an experimental program was conducted and theoretical model was adopted. The experimental program comprised casting and testing of thirty beams of total dimensions 300 9 150 9 2,000 mm consisting of permanent precast U-shaped reinforced mortar forms of thickness 25 mm filled with the core material. Three additional typical reinforced concrete beams of the same total dimensions were also cast to serve as contro specimens. Two types of single-layer and double-layers steel meshes were used to reinforce the permanent U-shaped forms; namely welded wire mesh and X8 expanded steel mesh. Three types of core materials were investigated: conventional concrete, autoclaved aerated lightweight concrete brick, and recycled concrete. Two types of shear connections between the precast permanent reinforced mortar form and the core material were investigated namely; adhesive bonding layer between the two surfaces, and mechanical shear connectors. The test specimens were tested as simple beams under three-point loadings on a span of 1,800 mm. The behavior of the beams incorporating the permanent forms was compared to that of the control beams. The experimental results showed that better crack resistance, high serviceability and ultimate loads, and good energy absorption could be achieved by using the proposed beams which verifies the validity of using the proposed system. The theoretical results compared well with the experimental ones.
GENERALIZED THERMOELASTICITY WITH TEMPERATURE DEPENDENT MODULUS OF ELASTICITY UNDER THREE THEORIES
Ezzat, M.,Zakaria, M.,Abdel-Bary, A. 한국전산응용수학회 2004 Journal of applied mathematics & informatics Vol.14 No.1
A new model of generalized thermoelasticity equations for isotropic media with temperature-dependent mechanical properties is established. The modulus of elasticity is taken as a linear function of reference temperature. The present model is described both generalizations, Lord Shulman (L-S) theory with one relaxation time and Green-Lindsay (G-L) with two relaxation times, as well as the coupled theory, instantaneously. The method of the matrix exponential, which constitutes the basis of the state space approach of modern control theory, applied to two-dimensional equations. Laplace and Fourier integral transforms are used. The resulting formulation is applied to a problem of a thick plate subject to heating on parts of the upper and lower surfaces of the plate that varies exponentially with time. Numerical results are given and illustrated graphically for the problem considered. A comparison was made with the results obtained in case of temperature-independent modulus of elasticity in each theory.
Generalized thermoelasticity with temperature dependent modulus of elasticity under three theories
M. Ezzat,M. Zakaria,A. Abdel-Bary 한국전산응용수학회 2004 Journal of applied mathematics & informatics Vol.14 No.-
A new model of generalized thermoelasticity equations for isotropic media with temperature-dependent mechanical properties is established. The modulus of elasticity is taken as a linear function of reference temperature. The present model is described both generalizations, Lord- Shulman (L-S) theory with one relaxation time and Green-Lindsay (G-L) with two relaxation times, as well as the coupled theory, instantaneously. The method of the matrix exponential, which constitutes the basis of the state space approach of modern control theory, applied to two-dimensional equations. Laplace and Fourier integral transforms are used. The resulting formulation is applied to a problem of a thick plate subject to heating on parts of the upper and lower surfaces of the plate that varies exponentially with time. Numerical results are given and illustrated graphically for the problem considered. A comparison was made with the results obtained in case of temperature-independent modulus of elasticity in each theory.
Shahira M. Ezzat,Maha M. Salama,Aliaa N. ElMeshad,Mahmoud H. Teaima,Laila A. Rashad 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.7
The anti-wrinkle activity of defatted rosemaryextract (DER) was assessed, and its effect was optimized byencapsulation in transferosomes (TFs). DER was standardizedto a rosmarinic acid content of 4.58 ± 0.023 mg%using reversed-phase high performance liquid chromatography(Rp-HPLC), and its components were identified byHPLC-diode array detection-tandem mass spectrometry. In vitro free radical scavenging assays showed DER hadhigh free radical scavenging activity against 2,2-diphenyl-2-picryl hydrazyl, 2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and superoxide radicals. DER also inhibitedbleaching of b-carotene with high Fe(III) and Fe(II)chelating ability. In vivo anti-wrinkle activities of topicallyapplied DER (20, 50, and 100 mg) and a TF formulation(TF4, 20 mg of DER) were evaluated in UVB-irradiatedmice using a wrinkle scoring method, metalloproteinase(MMP) expression, and histopathology. Among thenanovesicles, TF4 was the most deformable, and had anacceptable size and encapsulation efficiency and enhancedpermeation of DER through rat skin compared with unencapsulatedDER. DER (50 and 100 mg) and TF4 significantlyinhibited MMP-2 and MMP-9 expression andimproved wrinkle scores. DER and TF4 moderatelydecreased epidermal thickness without pigmentation. DERis a potent natural antioxidant for combating skin aging. Moreover, encapsulation of DER in TFs will enhance itsskin permeation and anti-wrinkle activity.
A novel model of fractional thermal and plasma transfer within a non-metallic plate
Magdy A. Ezzat 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.1
While in several publications the thermo-viscoelastic properties of solids have been documented, no attempt has been made to examine the action of coupled thermal and plasma wave in viscoelastic materials. In this paper, a new mathematical model for thermal and plasma transfer in an organic semiconductor was constructed with a time-fractional derivative of order <i>α</i> (0 < <i>α</i> ≤ 1) and a time-fractional integral of order <i>β</i> (0 < <i>β</i> ≤ 2), respectively. A two-dimensional problem is viewed for a half-space of viscoelastic thin-walled semiconductor whose surface is traction free and subjected to a heat flux with an exponentially decaying pulse. Laplace and Fourier's integral transforms are utilized. The carrier density, temperature, thermal stress, and viscoelastic displacement distributions have been obtained through the use of the theoretical model together with plasma and thermo-viscoelastic effects. The inversion technique for Fourier and Laplace transforms is carried out using a numerical technique based on Fourier series expansions. Comparisons are made with the results anticipated thru the coupled idea and generalized theory. The influence of the fractional-order parameter on all the regarded fields is examined.
Thermoelectric viscoelastic materials with memory-dependent derivative
Magdy A. Ezzat,Ahmed S. El Karamany,A.A. El-Bary 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.19 No.5
A mathematical model of electro-thermoelasticity has been constructed in the context of a new consideration of heat conduction with memory-dependent derivative. The governing coupled equations with time-delay and kernel function, which can be chosen freely according to the necessity of applications, are applied to several concrete problems. The exact solutions for all fields are obtained in the Laplace transform domain for each problem. According to the numerical results and its graphs, conclusion about the proposed model has been constructed. The predictions of the theory are discussed and compared with dynamic classical coupled theory. The result provides a motivation to investigate conducting thermoelectric viscoelastic materials as a new class of applicable materials.