Browsing by Author "Zaki, M."
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Item Effects of Increasing Electrodes on CNTs Yield Synthesized by Using Arc-Discharge Technique(Hindawi Publishing Corporation, 2013) Yousef, Samy; Khattab, A.; Osman, T. A.; Zaki, M.A new design of fully automatic system was built up to produce multiwalled carbon nanotube (MWCNT) using arc discharge technique in deionized water and extra pure graphite multiple electrodes (99.9% pure). The goal of the experimental research is to determine the yield of CNT in two different cases: (a) single plasma electrodes and (b) multiplasma electrodes, particularly 10 electrodes. The experiments were performed at constant parameters (75 A, 238 V). The obtained CNT was examined by scanning electron microscope (SEM), transmission electron microscope (HRTEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that the produced CNT is of type MWCNT, with a diameter of 5 nm, when using multiplasma electrodes and 13 nm when using single plasma electrodes. The yield of MWCNT was found to be 320% higher in case of comparing multielectrodes to that of single plasma electrodes. Under the experimental test conditions, a yield of 0.6 g/hr soot containing 40% by mass nanotube was obtained in case of single plasma electrodes and above 60% in case of multiplasma electrodes.Item Fully automatic system for producing carbon nanotubes (CNTs) by using arc-discharge technique multi electrodes(IEEE, 2012) Yousef, Samy; Khattab, A.; Osman, T. A.; Zaki, M.The production and industrial applications of carbon nanotubes (CNT) are recently the main concern of research in nanotechnology. CNT exhibit unique properties which have valuable commercial applications ranging from electronics to chemical processes. The main goal of the present paper is to develop the complete design of fully automatic system for producing carbon nanotubes (CNTs) by using deionized water and extra pure graphite multiple electrodes (99.9% pure). The advantage of the designed system is the increase yield of Carbon Nanotubes CNTs within the experimental limitations, through the increase of the number of cathodes and anodes and by using automatic feeding system for the electrodes, considering techniques at lower costs. The results of these experiments were examined by scanning electron microscope (HRSEM) and transmission electron microscope (HRTEM). The results show that the produced CNTs are multi-wall carbon nanotubes with average diameter of 25nm.Item Improved mechanical and tribological properties of A356 reinforced by MWCNTs(Taylor & Francis, 2018) El Shalakany, Abou Bakr; M. Kamel, Bahaa; Khattab, A.; Osman, T. A.; Azzam, B.; Zaki, M.The objective of this paper is to investigate the effect of Multi-Walled Carbon Nanotubes (MWCNTs) content on microstructure and dry sliding wear behavior of hypo-eutectic A356Al–Si alloy Metal Matrix Nano-Composites (MMNCs). Composites containing 0.5, 1.5, and 2.5 wt.% MWCNTs were prepared by rheocasting technique followed by squeeze casting. Characterization of nanocomposites was done by scanning electron microscopy (SEM) equipped with energy dispersive X-ray analysis (EDX), dry sliding wear tests were performed in a pin-on-disk wear tester against a steel disk at various speeds and normal loads. Results revealed that a decrease in both wear rate and friction coefficient of the nanocomposites considerably with the increase of MWCNT’s content. The formation of the hard compact transfer layer on the pin surface nanocomposites assisted in increasing the wear resistance of these materials. It is that the transfer layer which was formed under an applied load of 20 N can act as a protective layer and help in reducing the wear rate. The results indicate the nano composites could be used in light-weight applications where moderate strength and wear properties are needed.Item Influence Of Nano Grease Composite On Rheological Behaviour(Journal of Engineering Research and Applications, 2013) Mohamed, Alaa; Khattab, A.; Osman, T.A.; Zaki, M.The aim of this work is to study the rheological behaviors of carbon nanotubes (CNTs) as an additive on lithium grease at different concentrations. The results indicated that the optimum concentrations of the CNTs was 2 %. These experimental investigations were evaluated with a HAAKE Rheovisco RV20, Penetrometer and Measurement of the dropping point. The results indicated that the shear stress and apparent viscosity increase with the increase of CNTs concentration, penetration and consistency not effect of base grease, and the dropping point increasing about 25%. The microstructure of CNTs and lithium grease was examined by high resolution transmission electron microscope (HRTEM) and transmission electron microscope (TEM).Item Microstructure and Mechanical Properties of MWCNTs Reinforced A356 Aluminum Alloys Cast Nanocomposites Fabricated by Using a Combination of Rheocasting and Squeeze Casting Techniques(Hindawi Publishing Corporation, 2014) Elshalakany, Abou Bakr; Osman, T. A.; Khattab, A.; Azzam, B.; Zaki, M.A356 hypoeutectic aluminum-silicon alloys matrix composites reinforced by different contents of multiwalled carbon nanotubes (MWCNTs) were fabricated using a combination of rheocasting and squeeze casting techniques. A novel approach by adding MWCNTs into A356 aluminum alloy matrix with CNTs has been performed. This method is significant in debundling and preventing flotation of the CNTs within the molten alloy. The microstructures of nanocomposites and the interface between the aluminum alloy matrix and the MWCNTs were examined by using an optical microscopy (OM) and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analysis (EDX). This method remarkably facilitated a uniform dispersion of nanotubes within A356 aluminum alloy matrix as well as a refinement of grain size. In addition, the effects of weight fraction (0.5, 1.0, 1.5, 2.0, and 2.5 wt%) of the CNT-blended matrix on mechanical properties were evaluated. The results have indicated that a significant improvement in ultimate tensile strength and elongation percentage of nanocomposite occurred at the optimal amount of 1.5 wt% MWCNTs which represents an increase in their values by a ratio of about 50% and 280%, respectively, compared to their corresponding values of monolithic alloy. Hardness of the samples was also significantly increased by the addition of CNTs.Item Total hip performance under magnetic field(Elsevier, 2004) Zaki, M.; Aljinaidi, A.A.; Hamed, M.Recently, there is an increasing demand for the utilization of magnetic fields in bioengineering applications. Beneficial uses of the magnetic field have been revealed in the excitation of muscles, nerves, heart valves, for fixation of dental prosthetic, for cancer therapy, etc. However, no attention has been concern with the artificial implant joint materials. Therefore, the present work aims to elucidate the tribological behavior of artificial joint materials under the effect of a medium strength magnetic field. Experimental investigation was carried out on a designed hip simulator in which the variations in friction and wear were evaluated under the influence of a medium strength magnetic field. A “JRI Modular Muller Standard-Total Hip” was used with high alumina ceramic head and UHMWPE socket. The tests were conducted under both dry and lubricated sliding using saline solution. The simulator duplicates the physiological loading and motion cycles during normal human walking. The presence of magnetic field of 270 G strength resulted in high beneficial reductions in friction and wear, which can extend the implant life. The results has revealed that the smooth polymer transfer to the alumina; plays a dominant role in dictating the frictional and wear behaviors and leads to reductions in both. Two action mechanisms dominate the sliding process: adhesive at the beginning of sliding and abrasive at further periods of sliding.Item Wear Characterization of Carbon Nanotubes Reinforced Polymer Gears(IEEE, 2013) Yousef, Samy; Khattab, Ahmed; Zaki, M.; Osman, T. A.In last decade, polymeric gears have found wide applications in industrial fields. This is due to their advantages like noise reduction, self-lubricating features, weight reduction, cost savings as well as lower tribological characteristics in term of friction and wear. The main objective of this paper is to study the wear behavior of spur gears that makes polymer blended by carbon nanotubes (CNTs) (acetal). This was made by using appropriate adhesive oil (Paraffin) during injection moulding practice to produce thick flanges with diameter 134 mm and thickness 29 mm. The CNTs were produced by a fully automatic system using arc-discharge technique multi-electrodes. The synthesizing CNT/acetal flanges contain 1% CNTs by weight. The flanges were machined using CNC milling machine to produce spur gears. The dispersion of CNTs in polymer were examined by scanning electron microscope. The experiments were performed at a running speed of 1420 r/min and at torques of 13 and 16 N·m. In addition, the mechanical properties of CNT/acetal have been tested. The results showed that the wear resistances of the CNTs/acetal spur gears increased with the addition of CNT. The strength, Young's modulus and stiffness also increased while the hardness was not affected by the addition of CNT.