Three-dimensional finite element analysis of reinforced concrete slabs strengthened with epoxy-bonded steel plates

Metwally, Ibrahim M. Techno-Press 2014 Advances in concrete construction Vol.2 No.2

This paper presents a nonlinear finite element analysis (FEA) in order to investigate the flexural performance of one-way slabs strengthened by epoxy-bonded steel plates. Four point loading scheme is selectively chosen. A model is developed to implement the material constitutive relationships and non-linearity. Five Slabs were modeled in FEM software using ABAQUS. One slab was unstrengthened control slab and the others were strengthened with steel plates with varying the plate thickness and configuration. In order to verify the accuracy of the numerical model, a comparison was done between the experimental results available in the literature and the proposed equations by ACI 318-11 for the calculation of ultimate load capacities of strengthened slabs, the agreement has proven to be good and FEA attained accurate results compared with ACI code. A parametric study was also carried out to investigate the influence of thickness of steel plate, strength of epoxy layer and type of strengthening plate on the performance of plated slabs. Also, the practical and technical feasibility of splitting the steel plate in strengthening process has been taken into account. For practical use, the author recommended to use bonded steel plate as one unit rather than splitting it to parts, because this saves more effort and reduces the risk of execution errors as in the case of multiple bonded parts. Both techniques have nearly the same effect upon the performance of strengthened slabs.

Synthesis, Tautomeric Structure, Dyeing Characteristics, and Antimicrobial Activity of Novel 4-(2-Arylazophenyl)-3-(2-hydroxyphenyl)-1-phenyl-2-pyrazolin-5-ones

Metwally, M.A.,Bondock, S.A.,El-Desouky, S.I.,Abdou, M.M. Korean Chemical Society 2012 대한화학회지 Vol.56 No.1

Novel azopyrazolin-5-one dyes 4a-f were synthesized by the regioselective reaction of phenylhydrazine with 2,3,4-chromantrione-3-arylhydrazones 2a-f. The acid dissociation constants $pK_a$ for the series prepared were determined and correlated by the Hammett equation. The results of such correlation together with the spectral data indicated that the studied compounds exist predominantly in the hydrazone keto structure, (D) as the Z-configuration. The dyes were applied to polyester fabrics, affording orange-yellow shades and assessments of their dyeing performance are considered. Further, the compounds 4a-f were screened for their antimicrobial activity against various microorganisms.

Synthesis, Structure Investigation and Dyeing Assessment of Novel Bisazo Disperse Dyes Derived from 3-(2'-Hydroxyphenyl)-1-phenyl-2-pyrazolin-5-ones

Metwally, M.A.,Bondock, S.,El-Desouky, S.I.,Abdou, M.M. Korean Chemical Society 2012 대한화학회지 Vol.56 No.3

In an attempt to find a new class of bisazo disperse dyes with better dyeing properties, a series of novel bisazo dyestuffs based on 4-arylhydrazono-3-(2'-hydroxyphenyl)-1-phenyl-2-pyrazolin-5-ones $\mathbf{3a-f}$ were prepared by diazocoupling of p-nitrophenyl diazonium chloride with 4-arylhydrazono-3-(2'-hydroxyphenyl)-1-phenyl-2-pyrazolin-5-ones $\mathbf{2a-f}$. Compounds $\mathbf{3a-f}$ were subsequently reacted with acetic anhydride in the presence of p-toluenesulfonic acid afford the corresponding O-acetyl derivatives $\mathbf{4a-f}$. The latter products as well as spectral data indicated that compounds $\mathbf{3a-f}$ exist predominantly in the azo-hydrazone tautomeric form (H) as the ZE-configuration. Additionally, two series of the synthesized dyes $\mathbf{3a-f}$ and $\mathbf{4a-f}$ were applied as disperse dyes for dyeing polyester fabrics and their fastness properties were evaluated. Also the position of color in CIELAB coordinates ($L^*$, $a^*$, $b^*$, $H^*$, $C^*$*) was assessed.

Influence of Skull Anisotropic Mechanical Properties in Low-Intensity Focused Ultrasound

Metwally, M. K.,Han, H.-S.,Jeon, H. J.,Nam, S. B.,Han, S. M.,Kim, T.-S. WORLD SCIENTIFIC PUBLISHING 2016 Vol.24 No.1

<P>Low-intensity focused ultrasound (LIFU) is a new noninvasive brain stimulation technique where ultrasound is applied with low frequency and intensity to focus at a target region within the brain in order to exhibit or inhibit neuronal activity. In applying LIFU to the human brain, the skull is the main barrier due to its well-known high anisotropic mechanical properties which will affect the ultrasound focusing thereby affecting the neuromodulation or brain stimulation. This study aims at investigating the influence of the anisotropic mechanical properties of the skull on ultrasound propagation and focusing in LIFU. In this study, we used 2D finite element (FE) head models incorporating the isotropic and anisotropic properties of the skull. Three kinds of stresses were examined and shown within the skull: namely the normal stress in the direction of wave propagation (x-stress), normal stress in the transverse direction to the wave propagation (y-stress), and shear stress. Our analysis show that although most of the pressure that reaches to the brain is due to the longitudinal wave propagation through the skull, the stress in the transverse direction to the wave propagation direction (y-stress) has the main influence on the pressure profile inside the brain. The results also show that the anisotropic properties of the skull broaden the focal size about 19% and 13% in the longitudinal and transverse directions, respectively more than the case of considering the isotropic properties in the realistic 2D FE head model. The results indicate the importance of considering the anisotropic properties of the skull in practicing LIFU to achieve accurate targeting within the brain.</P>

Synthesis of 2,5Bis(2'-piperidymethyl)piperidine and Related Compounds

Hammouda, Metwally,Kandeel, Ex-el-Din,Hamama, Wafaa,Afsah, Elsayed The Pharmaceutical Society of Korea 1993 Archives of Pharmacal Research Vol.16 No.1

The triketones 3-6 were obtained by alkylation of cyclopentanone or cyclohexanone with the appropriate cycloalkanone bis-mannich base (1) or (2). Schmidt reaction of the tricketones 3-6 afforded the corresponding trcyclic lactames 7-10 respectively. reduction of 7 and 9 gave compounds 11 and 12 respectively.

Poster Session : PS 0353 ; Epidemiology and Public Health : National Survey for Assessment of Level of Behavioral Development of the General Public about Hepatitis C Virus

( Ammal Mokhtar Metwally ),( Amany T Abdel Hameed ),( Dalia M Elmosalami ),( Amira Mohsen ),( Sherif El Deeb ),( Walaa A Fouad ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Scientifi c research clearly showed that personal health behaviors played a major role in endemicity of Hepatitis, mainly Hepatitis C (HCV) in Egypt. The study was a national survey that focused on identifying the level of behavioral development concerning different aspects of HCV and assessing the dominance of risk practices associated with infection by HCV for deciding which practices can be altered and targeted. Methods: This study was conducted through a project that was supported fi nancially by the Science and Technology Development Fund (STDF), Egypt, Grant No1774, during a period of one year started from November 2012 till November 2013. The national survey was directed to 1200 sampled families with 3780 individuals. The sample was selected from six governorates as representative to the six major subdivisions of Egypt; Urban Governorates, rural and urban Lower Egypt, urban and rural Upper Egypt and the Frontier Governorates Results: Only one fourth of the surveyed groups irrespective to their age group and sex could identify why HCV is considered dangerous reporting that it is a cause of Liver cirrhosis and liver failure. Generally speaking, participants who personally feel at risk were those who developed positive attitudes, those who tried and adopted the recommended safe practices that can prevent HCV infection (50 %), indicating that around half of individuals could participate in behaviors that increase the spread of HCV. Awareness was high (= 75%) as regard to only using previously used syringes, sharing shaving equipment, nail cutter or through needle stick injury as responsible methods for transmission of HCV. Conclusions: finding of the survey will put the corner stone for the development of appropriate and culture sensitive educational and multimedia materials to limit the endemicity of HCV in Egypt.

Screening thirty soybean genotypes under solid and intercropping plantings in Egypt

Abd El-Alim A. Metwally,Sayed A. Safina,Eman I. Abdel-Wahab,Sherif I. Abdel-Wahab,Tamer I. Abdel-Wahab 한국작물학회 2021 Journal of crop science and biotechnology Vol.24 No.2

Cropping systems are relatively more important for testing soybean genotypes under Egyptian conditions. A field experiment was carried out at the Agricultural Experiments and Research Station, Faculty of Agriculture, Cairo University, Giza, Egypt, during the 2016 and 2017 seasons to evaluate the productivity of thirty soybean genotypes collected from four countries in intercropping with corn. Intercropping two soybean ridges alternating with another two of corn (2:2) was used in a split plot distributed in randomized complete block design. Intercropping and solid systems were randomly assigned to the main plots, and the soybean genotypes were allocated in sub-plots. All over the genotypes, intercropping caused significant increases in maturity date, root length, and plant height; meanwhile, the reverse was true for each of total leaf chlorophyll content, numbers of branches and pods, as well as seed yield per plant. Soybean genotypes Giza 111, C1, Woodworth, C34, Hill, Hutcheson, and Holladay gave higher seed yield than the others. Allover cropping systems, soybean genotypes Giza 111, Woodworth, Hutcheson, and C1 had higher seed yield than the others under intercropping. A significant positive correlation was detected between pod number and seed yield under cropping systems. Early maturing genotypes under intercropping were correlated positively with a higher yield of plants, as well as relative values. Determinate soybean variety Woodworth was matured under intercropping and solid planting at the same time. Soybean genotypes Woodworth, C1, C34, Giza 35, Giza 82, and Giza 111 were tolerant than the others to intercropping. The six soybean genotypes off er useful genetic materials for soybean breeding programs to improve yield under intercropping.

Gaussian process approach for dose mapping in radiation fields

Khuwaileh Bassam A.,Metwally Walid A. 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.8

In this work, a Gaussian Process (Kriging) approach is proposed to provide efficient dose mapping for complex radiation fields using limited number of responses. Given a few response measurements (or simulation data points), the proposed approach can help the analyst in completing a map of the radiation dose field with a 95% confidence interval, efficiently. Two case studies are used to validate the proposed approach. The First case study is based on experimental dose measurements to build the dose map in a radiation field induced by a D-D neutron generator. The second, is a simulation case study where the proposed approach is used to mimic Monte Carlo dose predictions in the radiation field using a limited number of MCNP simulations. Given the low computational cost of constructing Gaussian Process (GP) models, results indicate that the GP model can reasonably map the dose in the radiation field given a limited number of data measurements. Both case studies are performed on the nuclear engineering radiation laboratories at the University of Sharjah

Spectrophotometric Determination of Some Fluoroquinolone Antibacterials through Charge-transfer and Ion-pair Complexation Reactions

El-Brashy, Amina Mohamed,Metwally, Mohamed El-Sayed,El-Sepai, Fawzi Abdallah Korean Chemical Society 2004 Bulletin of the Korean Chemical Society Vol.25 No.3

Two simple, rapid and sensitive spectrophotometric methods for the determination of three fluoroquinolones, namely levofloxacin, norfloxacin and ciprofloxacin have been performed either in pure form or in their tablets. In the first method, levofloxacin and norfloxacin are directly treated with bromocresol green (BCG) in dichloromethane while ciprofloxacin is allowed to react with the same dye in aqueous acidic buffer. Highly yellow colored complex species were formed instantaneously in case of levofloxacin and norfloxacin or after extraction into dichloromethane for ciprofloxacin. The formed complexes are quantified spectrophotometrically at their absorption maxima at 411 nm for levofloxacin and 412 nm for norfloxacin and ciprofloxacin. The second method involves the reaction of levofloxacin with ${\rho}$-chloranilic acid ( ${\rho}$-CA) and norfloxacin with tetracyanoethylene (TCNE) in acetonitrile to give complexes with maximum absorbance at 521 and 333 nm for the two drugs, respectively. Adopting the first procedure, calibration graphs were linear over the range 1- 20 ${\mu}g\;mL^{-1}$ with mean percentage recoveries of 100.41 ${\pm}$ 0.72, 99.99 ${\pm}$ 0.54 and 100.23 ${\pm}$ 0.91 for the theree drugs, respectively. For the second procedure, the concentration ranges were 15-250 ${\mu}g\;mL^{-1}$ for levofloxacin using ${\rho}$-CA and 0.8-16 ${\mu}g\;mL^{-1}$ for norfloxacin using TCNE with mean percentage recoveries of 99.88 ${\pm}$ 0.45 and 100.26 ${\pm}$ 0.68 for the two drugs, respectively. The proposed methods were successfully applied to determine these drugs in their tablet formulations and the results compared favorably to that of reference methods. The proposed methods are recommended for quality control and routine analysis.

Investigation of Dynamic-Mechanical-Thermal Analysis of Innovative Hybrid Carbon/Glass Fibers Reinforced by GNPs and Al2O3 for Marine Structures

Mohamed Abu‑Okail,Metwally Abdel Ghafaar,Abou Bakr Elshalakany,Mohamed S. Shiba,Ahmed Abu‑Oqail,Mohammed Gamil 한국섬유공학회 2023 Fibers and polymers Vol.24 No.11

Marine structural applications face numerous challenges related to environmental load, corrosion, and fatigue under varying time and temperature conditions. One of the major challenges faced by marine structural applications is dynamic mechanical thermal analysis (DMTA). In this study, innovative hybrid carbon/glass fibers (CGF) reinforced with different contents (1.5 wt. % and 3 wt. %) of dual nano-powders, including graphene nanoplatelets (GNPs) and aluminium oxide (Al2O3), were developed as reinforcements inside the epoxy matrix. The nanocomposites were fabricated using a hand lay-up technique, resulting in a nanocomposite sheet with dimensions of 300 mm length, 200 mm width, and 2.3 mm thickness. DMTA test specimens were prepared with dimensions of 50 mm length, 10 mm width, and 2.3 mm thickness. To ensure accuracy, three replicates were conducted for each condition, and the average values were calculated for analysis. Before DMTA, the prepared nanocomposites were analyzed using optical microscopy (OM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDAX) to compare the influence of incorporating dual nano-powders. DMTA was carried out at different temperature values (ranging from 10 °C to 105 °C) and times (ranging from 5 to 575 min) at 1 Hz frequency with a heating rate of 4 °C/min and a nitrogen flow rate of 20 ml/min. The main objective of this study was to investigate the influence of incorporating dual nano-powders such as GNPs and Al2O3 on various dynamic mechanical properties including storage modulus, loss modulus, damping factor (DF), and glass transition temperature (Tg) of the hybrid carbon/glass fiber-reinforced epoxy composites. The fabricated hybrid CGF composite with 1.5% wt. GA nanoparticles exhibited higher values for the DF of 0.68 and the Tg of 73.4 °C. However, increasing the nanoparticle content to 3% wt. GA led to a deterioration in the DF (0.54) and a reduction in Tg (27.8 °C) due to decreased bonding between the carbon fibers (CF) and glass fibers (GF) caused by the higher nanoparticle concentration. The complex modulus (E*) values demonstrated expected trends with temperature and time for the CGF-1.5% wt. GA composite, indicating acceptable behaviour. In contrast, the CGF-3% wt. GA composite exhibited lower E* values, indicating a decrease in stiffness and mechanical properties compared to the CGF-1.5% wt. GA composite. Microstructural observations after DMTA revealed a uniform scattering of nanoparticles in the CGF-1.5% wt. GA sample, while the CGF-3% wt. GA sample demonstrated improved scattering of Al2O3 nanoparticles on the surface. The microstructural analysis further indicated a brittle nature with high resistance to crack initiation and propagation in the CGF-1.5% wt. GA composite.