Papers by waleed shirbeeny
Surface and Interface Analysis
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Journal of Renewable Materials
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IEEE Photonics Technology Letters, 2012
We present here a measurement of the temperature dependence of the zero dispersion wavelength in ... more We present here a measurement of the temperature dependence of the zero dispersion wavelength in an air/silica photonic crystal fiber. This is done through a simple method based on a fourth-order four-wave mixing process by pumping the fiber in a low normal dispersion regime. The zero dispersion wavelength is found to increase by about 10 nm from room temperature to 250$^{\circ}{\rm C}$ . This result is in good agreement with numerical simulations which demonstrate that it is mainly due to the thermo-optic effect. We found that the zero-dispersion wavelength evolution is not linear with temperature and that the shift rate is continuously increased from 39 ${\rm pm}/^{\circ}{\rm C}$ at room temperature to 63 ${\rm pm}/^{\circ}{\rm C}$ at 250$^{\circ}{\rm C}$.
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Background A pandemic outbreak of severe acute respiratory syndrome coronavirus 2 (COVID 19) inci... more Background A pandemic outbreak of severe acute respiratory syndrome coronavirus 2 (COVID 19) incidence data are largely available online. Until August 17, COVID 19 has hit more than 22 million individuals all over the globe. So, it is urged to get clear information about the prevalence of the virus. Therefore, one can manipulate easily a suitable mathematical model to fit these published data. Methods We propose a mathematical model that considers the total population, in 25 countries, either infected by COVID-19 or confined (safe) during the period from November 17, 2019, to August 17, 2020. The model considers the total population as a complex number; the imaginary part is the number of infected individuals and the real part is the number of confined individuals. This classification combined with mathematical treatments leads to a transmission dynamics of the virus to be as wave-like motion. The virus can hit any country either by one wave or by successive waves (up to eleven wave...
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Journal of Applied Polymer Science
The influence of polymer on the structure, optical, electrical, and thermal properties of nanosca... more The influence of polymer on the structure, optical, electrical, and thermal properties of nanoscale fillers is a crucial clue to introduce these novel nanocomposites to service life applications. In the present work, different compositions of cadmium‐doped zinc oxide (Cd xZn1−x O) nanopowders, x = 0.1, 0.3, and 0.5, with a uniform particle size of around 8 nm have been synthesized. A fixed amount, 1 wt %, of the prepared nanopowders was blended with aryl poly ether ether ketone (PEEK) by solution mixing to prepare PEEK/Cd xZn1−x O nanocomposite films. The structure and morphology of Cd xZn1−x O nanopowders and PEEK/Cd xZn1−x O nanocomposite films have been characterized using transmission electron microscopy and X‐ray diffraction. The results showed that the particle size of nanoscale filler decreases from 10 nm to 5–7 nm when mixed with PEEK and these nanocomposites have amorphous structure. The thermogravitational analysis results show that a small amount of Cd xZn1−x O nanopowder...
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American Journal of Scientific and Industrial Research, 2013
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International Journal of Nanoparticles, 2009
... J. Nanoparticles, Vol. 2, Nos. 1/2/3/4/5/6, pp.490–496. Biographical notes: S. Abdalla is an ... more ... J. Nanoparticles, Vol. 2, Nos. 1/2/3/4/5/6, pp.490–496. Biographical notes: S. Abdalla is an Associate Professor of Medical Physics in the Division of Medical Physics at King Abdulaziz University, Kingdom of Saudi Arabia. He ...
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Temperature dependencies of the optical Kerr effect have been studied for a series of four analog... more Temperature dependencies of the optical Kerr effect have been studied for a series of four analogous diols (of which three contained a heteroatom). The molar Kerr constant was found to increase with temperature below the room temperature and decrease above. The magnitude and ...
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Nonlinear Optics Quantum Optics
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Physical Chemistry Chemical Physics, 2000
Systematic measurements of optically induced birefringence in the series of homologous polyoxyeth... more Systematic measurements of optically induced birefringence in the series of homologous polyoxyethylenediols have been carried out. Macroscopic and microscopic parameters of the molecular liquids studied, such as viscosity, molecular Kerr constant and effective optical anisotropy, have ...
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Ceramics International, 2015
ABSTRACT Here, we report, for the first time, syntheses of ferromagnetic transparent conducting e... more ABSTRACT Here, we report, for the first time, syntheses of ferromagnetic transparent conducting electrodes based on Ce1−xCuxO2 (0.01<x<0.17). These electrodes were synthesized using an ethylene glycol modified sol-gel spin coating technique. To assess the properties of the transparent conducting electrodes, we studied the influence of the amount of the Cu dopant on the structural, optical, electrical and magnetic properties of the CeO2 films. The films were characterized using X-ray powder diffraction, scanning electron microscopy combined with energy dispersive spectroscopy, atomic force microscopy, electrical and magnetic measurements. The data obtained demonstrate that the structure and composition govern the performance characteristics of these films as transparent electrodes. An efficient ferromagnetic transparent conducting electrode with the high transparency (87%), low sheet resistance (0.8 Ω/cm2) and the high magnetic moment (1.63 µB/Cu) was obtained by doping CeO2 with 9 at.% of Cu ions.
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Polymer Composites, 2012
ABSTRACT The interest to ferrite nanoparticles (NPs) is thriving because of their unique applicat... more ABSTRACT The interest to ferrite nanoparticles (NPs) is thriving because of their unique applications in life industry. Doping of rubber composites by nanoparticles results in a novel characteristics which is not exist either in the ferrite or rubber alone. In this study, zinc ferrite NPs have been synthesized via sol–gel technique. These nanoferrites embedded into acrylonitrile butadiene rubber (NBR) at different concentrations. The morphology and structure of zinc ferrite and zinc ferrite NPs doped NBR were investigated using X-ray diffraction and transmission electron microscopy. The influence of zinc ferrite NPs loading on the thermal stability showed that the zinc ferrite enhanced the thermal stability and reduced the rate of thermal degradation of rubber nanocomposites. The effect of zinc ferrite NPs on the mechanical properties of NBR showed that the hardness, tear strength, and tensile stress are improved. The magnetic measurements of these nanocomposites showed that the saturation magnetization is enhanced as the concentration of zinc ferrite NPs increased into NBR nanocomposites. The EPR spectra of zinc ferrite NPs doped NBR indicated that the increase in zinc ferrite NPs content resulted in an increase in the g-factor and line width. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
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Sensors and Actuators B: Chemical, 2014
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Solid State Communications, 2014
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Polymer Composites, 2013
ABSTRACT The development of nano-metal oxide materials with unique optoelectronic properties such... more ABSTRACT The development of nano-metal oxide materials with unique optoelectronic properties such as highly solar energy absorption and generation of dense amount of electrons is one of the hottest topics now days. The incorporation of these nanomaterials into polymers results in an improvement of the properties of these polymers. Therefore, the understanding of their electronic properties is an essential demand to introduce these nanocomposites into service life. In this work, Yttrium barium copper oxide (YBCO) nanopowders with a uniform particle size of around 11 nm was prepared, sintered, and blended with polyvinyl alcohol (PVA) by casting technique. The characteristics of the structure and morphology of PVA/YBCO nanocomposite films are studied using X-ray diffraction and transmission electron microscopy. The influence of YBCO nanoparticles on the thermal stability of PVA showed that the YBCO enhanced the thermal stability and reduced the rate of thermal degradation of PVA nanocomposites. Current–voltage behavior of PVA/YBCO nanocomposite films was measured at different temperatures. An explanation for the charge carrier concentration in the conduction band with the calculation of the barrier height, activation energy, and conversion and their dependence on temperature and applied field is presented.
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Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, Jan 24, 2014
Nanocrystalline Zn(1-x)Cu(x)O thin films (x=0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized ... more Nanocrystalline Zn(1-x)Cu(x)O thin films (x=0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by sol-gel dip-coating technique on a quartz substrate. These films were annealed at 350°C for 2 h. The X-ray diffraction showed a hexagonal crystal structure with high intensity peak for the (002) reflection plane indicating preferential growth along the c-axis of the crystal lattice. The peak position related to the (002) peak was shifted as a result of the copper ion incorporation, confirming the interstitial substitution of the zinc ions by the copper ions. This interstitial substitution leads to a decrease of an average crystallite size and lattice constants and an increase of the micro-strain up to 2 at.% of the copper amount. The surface morphology was explored by scanning electron microscopy which confirmed the homogenous distribution of nanoparticles in the deposited films along the quartz substrates. The energy dispersion X-ray spectroscopy revealed absence of impurities in the...
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Superlattices and Microstructures, 2013
ABSTRACT Highly crystalline GaSe thin film was synthesized by electrochemical deposition techniqu... more ABSTRACT Highly crystalline GaSe thin film was synthesized by electrochemical deposition technique on a silicon substrate. The X-ray diffractions showed a hexagonal crystal structure with preferential orientation along (0 0 4) plane. The scanning electron microscopy confirmed the homogenous distribution of deposited GaSe film along the silicon substrate. The high resolution electron microscopy showed that the GaSe nanoparticles have mean diameter of 23 nm. The energy dispersion X-ray spectroscopy revealed a high purity of the as-deposited film. The junction characteristics of GaSe/n-Si diode were investigated. The current-voltage characteristics of the GaSe/n-Si were investigated in the temperature range 23-120 °C. The I-V characteristics exhibit non-linearity indicating Schottky contact at the GaSe and n-Si interface. It was noticed the increase of current under the impact of light. Various device parameters such as series resistance, ideality factor and barrier height were estimated. The effect of temperature on the values of junction parameters was analyzed.
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Physical Chemistry Chemical Physics, 2000
Systematic measurements of optically induced birefringence in the series of homologous polyoxyeth... more Systematic measurements of optically induced birefringence in the series of homologous polyoxyethylenediols have been carried out. Macroscopic and microscopic parameters of the molecular liquids studied, such as viscosity, molecular Kerr constant and effective optical anisotropy, have ...
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Journal of Applied Polymer Science, 2012
ABSTRACT The influence of polymer on the structure, optical, electrical, and thermal properties o... more ABSTRACT The influence of polymer on the structure, optical, electrical, and thermal properties of nanoscale fillers is a crucial clue to introduce these novel nanocomposites to service life applications. In the present work, different compositions of cadmium-doped zinc oxide (CdxZn1−xO) nanopowders, x = 0.1, 0.3, and 0.5, with a uniform particle size of around 8 nm have been synthesized. A fixed amount, 1 wt %, of the prepared nanopowders was blended with aryl poly ether ether ketone (PEEK) by solution mixing to prepare PEEK/CdxZn1−xO nanocomposite films. The structure and morphology of CdxZn1−xO nanopowders and PEEK/CdxZn1−xO nanocomposite films have been characterized using transmission electron microscopy and X-ray diffraction. The results showed that the particle size of nanoscale filler decreases from 10 nm to 5–7 nm when mixed with PEEK and these nanocomposites have amorphous structure. The thermogravitational analysis results show that a small amount of CdxZn1−xO nanopowders (1 wt %) without surface modification can greatly improve the thermal stability of PEEK. The UV–vis spectra showed that there is absorption peak at 284 nm due to interband π−π* electronic transition. This absorption peak gets shifted toward the longer wavelength region as the concentration of cadmium ions increase in the PEEK matrix. This red shift results in a decrease of the band energy gap. The electrical conductivity of PEEK/CdxZn1−xO nanocomposite films was increased as the cadmium ion increases. The results showed that PEEK/CdxZn1−xO nanocomposite films can be used in thermostat and/or fire alarm devices. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
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Papers by waleed shirbeeny