Ahmed Eid - Academia.edu (original) (raw)
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The equipment used in standardization must be adjusted in order that both the receiver amplifier ... more The equipment used in standardization must be adjusted in order that both the receiver amplifier and video display are linear over the range of distance and flaw size to be used. The failure to do that would result in different block-to-block response ratios because of the measurements depending on the scope reading or attenuator setting. In this paper, using two sets of steel reference blocks (area-amplitude and distance-amplitude) to modified method to verify the linearity of the system of instruments used in the ultrasonic inspection. This method depends on the response from reference blocks with different hole diameters at constant gain and ratio between the figures slope at different gains. The linearity of the ultrasonic instruments can be measured with high precision. The results can be used effectively for determining resolution and sensitivity capabilities.
In this paper, using two sets of reference steel blocks (area-amplitude and distance-amplitude) t... more In this paper, using two sets of reference steel blocks (area-amplitude and distance-amplitude) to investigate a modified method to verify the linearity of the system of instruments used in the ultrasonic inspection. The mechanical and physical properties of the material of the blocks before and after heat treatment are measured. The ultrasonic longitudinal and transverse velocities are measured in the blocks and the elastic parameters of the blocks are calculated. The attenuation of the ultrasonic wave at the centers of the blocks as a function of the metal distance in the distance-amplitude and the area amplitude as a function of the hole diameter for steel reference blocks with frequency 10 MHz using the immersion technique at a constant gain has been investigated. According to the experimental results, this study can significantly improve the detection accuracy of reference steel blocks, and will serve as a reference for assessing engineers.
The effect of aging, type and concentration of filler (Alumina trihydrate (ATH) and silica (SiO 2... more The effect of aging, type and concentration of filler (Alumina trihydrate (ATH) and silica (SiO 2 )) on the mechanical and electrical properties of polyester composite as a high voltage insulating materials, were investigated by means of ultrasonic and electrical techniques. Ultrasonic wave velocities (both longitudinal and shear) were measured at frequencies of 4 MHz at room temperature. Results of density, ultrasonic wave velocities, mechanical properties and electrical loss showed the improvement of the polymer composite network with aging and type of filler. This behavior may be due to the change in cross-link density and average stretching force of bonds with aging.
Three polyethylene/clay formulations (3%, 7% and 10%) were prepared by ultrasonic technique of po... more Three polyethylene/clay formulations (3%, 7% and 10%) were prepared by ultrasonic technique of polyethylene (PE) and montmorillonite organically modifi ed with imidazolium salt (OMC) in toluene as solvent. The prepared PE/OMC nanocomposites were characterised by colour measurement and atomic force microscopy (AFM). An intercalated, mixed intercalated-exfoliated and delaminated structure in PE/OMC nanocomposites with different OMC content were found. The thermal stability and fl ammability of PE/clay nanocomposites were measured by thermogravimetric analysis (TGA) and cone calorimetry. By adding 3, 7 and 10 phr organoclay, the peak heat release rate of the nanocomposite was reduced by 34.5, 45.4 and 50.5% respectively. Further studies indicated that the improvement of fl ammability performance was due to the formation of a clay enriched protective char during combustion.
In the present study, pulse echo overlap method (PEO) has been used as a non-destructive techniqu... more In the present study, pulse echo overlap method (PEO) has been used as a non-destructive technique for evaluating the mechanical properties of Al/SiC nanocomposites. The nano-sized AI/SiC powders were prepared by mechanical alloying method. The particle size and microstructures of the milled powders were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) techniques. Al/SiC powders containing different amounts of nano-size SiC particles (0, 5 and 10 vol.%) were subsequently cold-pressed and sintered to produce bulk composite samples. The polycrystalline bulk modulus K, Young's modulus E, shear modulus G, Poisson ratio t and hardness H of Al/SiC composites are gained by PEO method. The results showed an increase in the hardness value from 3.8 to 6.6 GPa and a decrease in Al crystallite size from 175.6 to 90.8 nm with increasing SiC content. Besides, Young's modulus of Al/10SiC sample was measured to be 97.1 GPa, which is much higher than that for pure Al (72.6 GPa). Poisson's ratio results indicate that its value decreases with increasing the elastic moduli and ultrasonic wave velocities of Al/SiC composites. The Pugh ratio showed the ductility behavior of all Al/SiC samples, while Poisson's ratio showed slightly decrease in the ionic contribution with increasing the volume fraction of SiC nanoparticles in metal matrix composites MMCs. Microstructural analysis revealed that the origin of change in mechanical properties is attributed to the decrease in interparticle spacing and increase in the grain boundary area, which provides more obstacles for dislocation pile up in the adjacent grains.
The equipment used in standardization must be adjusted in order that both the receiver amplifier ... more The equipment used in standardization must be adjusted in order that both the receiver amplifier and video display are linear over the range of distance and flaw size to be used. The failure to do that would result in different block-to-block response ratios because of the measurements depending on the scope reading or attenuator setting. In this paper, using two sets of steel reference blocks (area-amplitude and distance-amplitude) to modified method to verify the linearity of the system of instruments used in the ultrasonic inspection. This method depends on the response from reference blocks with different hole diameters at constant gain and ratio between the figures slope at different gains. The linearity of the ultrasonic instruments can be measured with high precision. The results can be used effectively for determining resolution and sensitivity capabilities.
In this paper, using two sets of reference steel blocks (area-amplitude and distance-amplitude) t... more In this paper, using two sets of reference steel blocks (area-amplitude and distance-amplitude) to investigate a modified method to verify the linearity of the system of instruments used in the ultrasonic inspection. The mechanical and physical properties of the material of the blocks before and after heat treatment are measured. The ultrasonic longitudinal and transverse velocities are measured in the blocks and the elastic parameters of the blocks are calculated. The attenuation of the ultrasonic wave at the centers of the blocks as a function of the metal distance in the distance-amplitude and the area amplitude as a function of the hole diameter for steel reference blocks with frequency 10 MHz using the immersion technique at a constant gain has been investigated. According to the experimental results, this study can significantly improve the detection accuracy of reference steel blocks, and will serve as a reference for assessing engineers.
The effect of aging, type and concentration of filler (Alumina trihydrate (ATH) and silica (SiO 2... more The effect of aging, type and concentration of filler (Alumina trihydrate (ATH) and silica (SiO 2 )) on the mechanical and electrical properties of polyester composite as a high voltage insulating materials, were investigated by means of ultrasonic and electrical techniques. Ultrasonic wave velocities (both longitudinal and shear) were measured at frequencies of 4 MHz at room temperature. Results of density, ultrasonic wave velocities, mechanical properties and electrical loss showed the improvement of the polymer composite network with aging and type of filler. This behavior may be due to the change in cross-link density and average stretching force of bonds with aging.
Three polyethylene/clay formulations (3%, 7% and 10%) were prepared by ultrasonic technique of po... more Three polyethylene/clay formulations (3%, 7% and 10%) were prepared by ultrasonic technique of polyethylene (PE) and montmorillonite organically modifi ed with imidazolium salt (OMC) in toluene as solvent. The prepared PE/OMC nanocomposites were characterised by colour measurement and atomic force microscopy (AFM). An intercalated, mixed intercalated-exfoliated and delaminated structure in PE/OMC nanocomposites with different OMC content were found. The thermal stability and fl ammability of PE/clay nanocomposites were measured by thermogravimetric analysis (TGA) and cone calorimetry. By adding 3, 7 and 10 phr organoclay, the peak heat release rate of the nanocomposite was reduced by 34.5, 45.4 and 50.5% respectively. Further studies indicated that the improvement of fl ammability performance was due to the formation of a clay enriched protective char during combustion.
In the present study, pulse echo overlap method (PEO) has been used as a non-destructive techniqu... more In the present study, pulse echo overlap method (PEO) has been used as a non-destructive technique for evaluating the mechanical properties of Al/SiC nanocomposites. The nano-sized AI/SiC powders were prepared by mechanical alloying method. The particle size and microstructures of the milled powders were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) techniques. Al/SiC powders containing different amounts of nano-size SiC particles (0, 5 and 10 vol.%) were subsequently cold-pressed and sintered to produce bulk composite samples. The polycrystalline bulk modulus K, Young's modulus E, shear modulus G, Poisson ratio t and hardness H of Al/SiC composites are gained by PEO method. The results showed an increase in the hardness value from 3.8 to 6.6 GPa and a decrease in Al crystallite size from 175.6 to 90.8 nm with increasing SiC content. Besides, Young's modulus of Al/10SiC sample was measured to be 97.1 GPa, which is much higher than that for pure Al (72.6 GPa). Poisson's ratio results indicate that its value decreases with increasing the elastic moduli and ultrasonic wave velocities of Al/SiC composites. The Pugh ratio showed the ductility behavior of all Al/SiC samples, while Poisson's ratio showed slightly decrease in the ionic contribution with increasing the volume fraction of SiC nanoparticles in metal matrix composites MMCs. Microstructural analysis revealed that the origin of change in mechanical properties is attributed to the decrease in interparticle spacing and increase in the grain boundary area, which provides more obstacles for dislocation pile up in the adjacent grains.