M. Amer

Al-Azhar University

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Papers

Citation

H-Index

i-10 index

Research Field

Interferometric studies on fibres with irregular transverse sections

Polymer Testing (1993)

A.A. Hamza M. Amer H.I. Abd El-Kader A.M. Nasr

Abstract Multiple-beam Fizeau fringes in transmission and at reflection were applied to the study of the optical properties of fibres with irregular cross-section (Orlon 42 and nylon fibres). The mathematical expressions used for the application of multiple-beam Fizeau fringes to determine the refractive indices and birefringence of fibres are given. The experimental techniques used for producing multiple-beam Fizeau fringes in transmission and at reflection are also given. Interferometric methods were applied to study the variation of refractive indices with wavelength of light and along the fibre axis. Values of refractive indices were used to calculate Cauchy's dispersion constants. The value of thermal coefficient of refractive index has been calculated. Illustrations are given using multiple-beam interferograms.

10.1016/0142-9418(93)90037-p

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Citations (1)

Multiple-beam interferometric determination of the coherence length of spectral sources

Optics & Laser Technology (1993)

F. Sharaf M. Amer

Visibility

Voigt profile

Optical path length

Path length

Coherence time

Interferometric visibility

Degree of coherence

10.1016/0030-3992(93)90107-q

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Citations (0)

Cardioprotective and antioxidant effects of oleogum resin “Olibanum” from Bos Boswellia carteri Birdw. (Bursearceae)

Chinese Journal of Natural Medicines (2014)

Ahmed A. Zaki Nadia E. Hashish M. Amer M. Lahloub

Boswellia serrata

Burseraceae

ABTS

10.1016/s1875-5364(14)60042-x

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Citations (27)

Analytical Study for Chlorpyrifos Breakdown Derivatives Qualification After Silver Vanadate (Agvo3) Nanoparticles Fragmentation Reaction

Research Square (Research Square) (2021)

Islam R. Ghoniem Ashraf M. Elmarsafy M. Amer Hassan A. El- Gammal M.M. Aly

Abstract The use of pesticides in agriculture has become one of the basic necessities to meet the world's food requirements as a result of the continuous population increase. But sometimes the use of some of these pesticides in large quantities and in high concentrations poses a great danger to the environment and then to humans. Through weather factors, pesticides are transferred to the water and then harm aquatic organisms, which leads to a direct impact and harm to the fish wealth. Monitoring these compounds in the environment requires a large cost of time and money to ensure food safety. Therefore, a new method was used in this study in an attempt to get rid of these compounds in water. The silver vanadate nanoparticles (AgVO3) were synthesized using a novel method in an attempt to eliminate different groups of pesticides that had been detected in Egyptian agricultural crops and water. The effect of 0.1 g of AgVO3 nanoparticles were found on three compounds: chlorpyrifos, dimethoate and malathion. Where a concentration of these compounds, which is 0.5 mg / kg, was used and it was estimated using Exion HPLC coupled with Sciex Qtrap API 6500 + LC-MS/MS System. After 15 minutes of treatment with 0.1 g of AgVO3 nanoparticles, these compounds were undetectable on the device's chromatogram, which is regarded a short period in Affecting these compounds and changing their nature in an attempt to get rid of them. Determination of chlorpyrifos breakdown products by using mass scan of Qtrap API 6500 + LC-MS/MS System and Thermo Scientific Q Exactive Focus Orbitrap LC-MS/MS System was investigated. Supported AgVO3 NPs, according to the study, could be used in long-term environmental remediation because they can be used in aqueous solutions at room temperature without the need for additional stimulus such as UV light.

Vanadate

10.21203/rs.3.rs-653522/v1

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STUDY OF THE MAJOR CONDITIONS INFLUENCING STEP HEIGHT MEASUREMENT USING INTERFERENCE MICROSCOPE

Al-Azhar Bulletin of Science (2013)

EZZAT ORABY M. Amer T.Z.A. Abou-Elnasr M. M. El-Okr

Step height measurements in micro and nano scale are essential to the micro-technology.The interferometric measurement is carried out using two main techniques: white light scanning interferometry (WLI) and phase stepping interferometry (PSI).A step height standard sample of nominal step height value h of 90.1 nm has been studied using the PSI mode with an optical filter light of λ = 633.4nm against three parameters: vertical distance (z) between objective and sample, intensity of the incident light and the inclination angles of the sample to the incident light.The effect of numerical aperture of objectives has been referenced to some literature.The total budget of studied parameters for the sample 90.1 nm leads to expanded uncertainty of 0.46 nm.

Interference microscopy

10.21608/absb.2013.6583

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Sodium hypochlorite as dentin pretreatment for etch-and-rinse single-bottle and two-step self-etching adhesives: atomic force microscope and tensile bond strength evaluation.

Journal of adhesive dentistry/The journal of adhesive dentistry (2008)

Amr Fawzy M. Amer Farid Sabry El-Askary

Purpose The aim of this study was to evaluate the effect of using 5.25% commercial sodium hypochlorite treatment prior to the application of etch-and-rinse and self-etching adhesives on dentin surface microtopography and tensile bond strength. Materials and methods Thirty-two noncarious, nonrestored human third molars were collected. The occlusal enamel of all teeth was removed using diamond disks to expose flat dentin surfaces. The exposed dentin surfaces were abraded using 600-grit SiC disks, to create a uniform dentin smear layer. For AFM characterization, 12 teeth were equally divided into 4 groups according to the proposed dentin surface treatment. Three dentin disks, 2 mm thick, were evaluated per group using tapping mode assessment. Twenty teeth were used for TBS and SEM evaluation and were equally divided into 4 groups, according to the proposed dentin surface treatment. For TBS, 8 dentin/composite slabs, 2 mm thick, were used in each group, while for SEM evaluation 2 slabs were used. Each slab was tested in tension at a crosshead speed of 0.5 mm/min until failure occurred. The samples were examined using SEM operated at 30 kv to evaluate the hybrid layer photographically at 1500X. Statistical analysis was carried out using StatsDirect 2.5.7. One-way ANOVA followed by Tukey-Kramer multiple-comparison post-hoc tests were performed to test the difference between roughness parameters and TBS between groups. Results Sodium hypochlorite followed by the application of 37% phosphoric acid significantly increased the arithmetic average of the absolute values of surface height deviations (Sa), the surface area ratio which expresses the ratio between the surface area (taking the z height into account) and the area of the flat x,y plane (Sdr), and the surface bearing index (Sbi) parameters, while the application of sodium hypochlorite prior to the application of the self-etching primer significantly increased the valley fluid retention index (Svi) parameter. Self-etching primer without sodium hypochlorite pretreatment significantly increased the core fluid retention index (Sci) parameter. Sodium hypochlorite/AdheSE (7.42 +/- 2.16 MPa) significantly increased TBS value compared to other groups. However, no statistically significant difference was found between sodium hypochlorite/Excite (4.68 +/- 1.26 MPa), AdheSE (4.42 +/- 1.36), and Excite (4.06 +/- 1.35). Remnants of smear layer were detected with areas devoid of resin tags in SEM images of samples bonded with AdheSE self-etching adhesive, in contrast to samples bonded with sodium hypochlorite followed by AdheSE self-etching adhesive. Conclusion The application of 5.25% commercial sodium hypochlorite with rubbing action for 60 s (total application time 120 s) seems to positively influence the TBS of the self-etching adhesive; however, it has no significant effect on TBS of etch-and-rinse single-bottle adhesive to dentin. The addition of functional roughness parameters to study the dentin surface was shown to be of importance in evaluating the relationship between bond strength and surface topography of conditioned dentin.

Sodium hypochlorite

Smear layer

Crosshead

Dental bonding

Source

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Citations (43)

Elucidating the Role of Prickly Pear Fruits (Opuntia littoralis) in Mitigation of Cadmium Toxicity in Oreochromis niloticus: Impacts on Haemato-Biochemical and Immunological Responses

Research Square (Research Square) (2024)

Mahmoud Mahrous M. Abbas M. Amer Jamila S. Al Malki Amaal Mohammadein Metwally G. Metwally

Abstract The purpose of the study was to ascertain the preventative value of dietary supplements with fruits of the prickly pear on the haemato-biochemical and immunological responses of O. niloticus exposed to subacute waterborne cadmium toxicity. Four diets supplemented with different proportions of fruits of 0% (control, OLFE-0% group), 0.5% (OLFE-0.5% group), 1% (OLFE-1% group), and 2% (OLFE-2% group) were administered to tilapia fingerlings for sixty days (pre-cadmium). After the feeding session, the tilapia treatments were subjected to waterborne cadmium toxicity for four days (post-cadmium). Blood samples were captured pre- and post-cadmium exposure to assess the haemato-biochemical and immunological alternations. According to the current findings, nutritional meals fortified with OLFE can enhance tilapia fish's growth performance and digestive enzymes. Nile tilapia fed on OLFE-fortified diets showed a significant reduction in cortisol, alanine transaminase (ALAT), aspartate transaminase (ASAT), glucose, protein, and malondialdehyde (MDA) compared to the control with a basal diet without OLFE (P < 0.05). Additionally, it significantly improves the activities of complement C3, lysozyme, catalase (CAT), total immunoglobulin, superoxide dismutase (SOD), and glutathione peroxidase (GPX). Significant increases in cortisol, leukocytes, glucose, CAT, ALAT, GPX, ASAT, and SOD were observed following exposure to waterborne cadmium. At the same time, there were decreases in erythrocytes, blood indices, hemoglobin, complement C3, packed cell volume, lysozyme, total immunoglobulin, and malondialdehyde (MDA) values. In brief, these findings suggest that supplementing prickly pear fruits to tilapia diets, especially at a level of 2%, can enhance immunological and antioxidant properties and effectively mitigate the harmful effects of Cd exposure in food safety and aquaculture.

Malondialdehyde

Nile tilapia

10.21203/rs.3.rs-4234898/v1

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Uncertainties in small-angle measurement systems used to calibrate angle artifacts

Journal of Research of the National Institute of Standards and Technology (2004)

Jack A. Stone M. Amer B. Faust J. Zimmerman

We have studied a number of effects that can give rise to errors in small-angle measurement systems when they are used to calibrate artifacts such as optical polygons.Of these sources of uncertainty, the most difficult to quantify are errors associated with the measurement of imperfect, non-flat faces of the artifact, causing the instrument to misinterpret the average orientation of the surface.In an attempt to shed some light on these errors, we have compared autocollimator measurements to angle measurements made with a Fizeau phase-shifting interferometer.These two instruments have very different operating principles and implement different definitions of the orientation of a surface, but (surprisingly) we have not yet seen any clear differences between results obtained with the autocollimator and with the interferometer.The interferometer is in some respects an attractive alternative to an autocollimator for small-angle measurement; it implements an unambiguous and robust definition of surface orientation in terms of the tilt of a best-fit plane, and it is easier to quantify likely errors of the interferometer measurements than to evaluate autocollimator uncertainty.

Fizeau interferometer

Artifact (error)

10.6028/jres.109.024

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Citations (21)

Green's function expansion for exponentially graded elasticity

International Journal for Numerical Methods in Engineering (2009)

Omar M. Sallah L. J. Gray M. Amer M. S. Matbuly

Abstract New computational forms are derived for Green's function of an exponentially graded elastic material in three dimensions. By suitably expanding a term in the defining inverse Fourier integral, the displacement tensor can be written as a relatively simple analytic term, plus a single double integral that must be evaluated numerically. The integration is over a fixed finite domain, the integrand involves only elementary functions, and only low‐order Gauss quadrature is required for an accurate answer. Moreover, it is expected that this approach will allow a far simpler procedure for obtaining the first and second‐order derivatives needed in a boundary integral analysis. The new Green's function expressions have been tested by comparing with results from an earlier algorithm. Copyright © 2009 John Wiley & Sons, Ltd.

Quadrature (astronomy)

Exponential integral

10.1002/nme.2786

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Citations (5)

Analysis of Dislocations Nucleated after Nano Indentation Tests at Room Temperature in 4H-SiC

Materials science forum (2012)

Jean Luc Demenet M. Amer C. Tromas Jacques Rabier

4H-SiC intrinsic homoepitaxied single crystals have been nano indented at room temperature using a spherical indentor and the related deformation microstructures have been analyzed by Transmission Electron Microscopy. Dislocations are lying in the basal plane but have been found to be perfect, in contrast with observations made at higher temperature. Although such a change in deformation mechanism has been observed in other semiconductors such as Silicon and Indium Antimonide, it was unexpected in a very low stacking fault material such as SiC.

Indium antimonide

Stacking fault

Indentation

10.4028/www.scientific.net/msf.717-720.339

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Citations (3)