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Madīnat Sittah Uktūbar, Egypt

Yousef S.,Akhbar Elyom Academy | Osman T.A.,Cairo University | Abdalla A.H.,Cairo University | Zohdy G.A.,Cairo University
JOM | Year: 2014

Although the applications of nanotechnologies are increasing, there remains a significant barrier between nanotechnology and machine element applications. This work aims to remove this barrier by blending carbon nanotubes (CNT) with common types of acetal polymer gears (spur, helical, bevel and worm). This was done by using adhesive oil (paraffin) during injection molding to synthesize a flange and short bars containing 0.02% CNT by weight. The flanges and short bars were machined using hobbing and milling machines to produce nanocomposite polymer gears. Some defects that surfaced in previous work, such as the appearance of bubbles and unmelted pellets during the injection process, were avoided to produce an excellent dispersion of CNT in the acetal. The wear resistances of the gears were measured by using a TS universal test rig using constant parameters for all of the gears that were fabricated. The tests were run at a speed of 1420 rpm and a torque of 4 Nm. The results showed that the wear resistances of the CNT/acetal gears were increased due to the addition of CNT, especially the helical, bevel and worm gears. © 2014 The Minerals, Metals & Materials Society Source

Elkaramany E.M.A.,Cairo University | Abo El-Hadeed F.G.,Cairo University | Ahmed A.S.S.,Akhbar Elyom Academy
Journal of Electromagnetic Waves and Applications | Year: 2014

Two-dimensional circuit is used to determine the resonant frequencies of the arbitrarily shaped, single-layer microstrip patch antennas. This circuit is based on the long transmission line model in the frequency domain. Derivation, analysis, and treatment of boundaries are given. Simple matrix form is obtained and the problem is reduced to an eigenvalue problem which is solved to get the required solution. The resonant frequencies of the resulting circuit are the required resonant frequencies of the patch antenna. Numerical results are given and are compared with the available analytical and experimental results reported by others. © 2014 Taylor & Francis. Source

Visco A.,Messina University | Yousef S.,Messina University | Yousef S.,Akhbar Elyom Academy | Galtieri G.,Messina University | And 3 more authors.
JOM | Year: 2016

Ultra-high molecular weight polyethylene (UHMWPE) is a very attractive polymer employed as a high performance material. For its high viscosity, dispersion of fillers is considered a critical point in UHMWPE nanocomposites preparation process. Currently, paraffin oil (PO) is used extensively to overcome this issue in an assisted melt-mixing process. In this work, we have prepared nanocomposites based on UHMWPE, carbon nanofiller (CNF) and PO mixed by different mixing methods: magnetic stirring, ball milling (BM), ultrasonic and Mini-Lab extruder (EX). The aim of this work was to check the effect of the dispersion method on the mechanical and thermal features of UHMWPE/CNF nano composites in order to obtain a material with improved mechanical and physical properties. The samples were characterized by calorimetric, density, mechanical tensile and rheological analyses. Experimental results highlighted that the nanocomposites produced by EX and BM exhibits the best dispersion, good filler matrix interaction and had significantly improved mechanical properties compared to pure UHMWPE. For instance, for the BM method, the yield strength improved to 18.6 MPa (+96%), the yield strain improved by 60%, while stress at break improved by 13%. In summary, the EX improved the stiffness while the BM produced better ductility, melting temperature and the crystalline degree of the nanocomposites. © 2016 The Minerals, Metals & Materials Society Source

Yousef S.,Akhbar Elyom Academy | Khattab A.,Cairo University | Osman T.A.,Cairo University | Zaki M.,Akhbar Elyom Academy
Proceedings of the 2012 1st International Conference on Innovative Engineering Systems, ICIES 2012 | Year: 2012

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. © 2012 IEEE. Source

Yousef S.,Akhbar Elyom Academy | Osman T.A.,Cairo University | Khattab M.,Cairo University | Bahr A.A.,Cairo University | Youssef A.M.,Cairo University
Advances in Tribology | Year: 2015

This work aims to study the wear characterization of common types of acetal polymer gears (spur, helical, bevel, and worm) using a new TS universal test rig, in order to obtain reliable results and as a reference when compared with acetal nanocomposite gears later. The TS universal test rig consists of three different units that are connected by a main driver shaft and a pair of constantly meshing metal spur gears, which transfer power to the bevel and worm test units. The first unit is used to test the bevel gears, the second unit is used to test the spur and helical gears, and the third unit is used to test the worm gears. The loading mechanism is similarly designed to block the brake mechanism. Hobbing and milling machines were used to machine an injection-moulded polymer flanges and produce the tested gears. All gear pairs, except the worm gear, have identical gear ratios. The experiments were performed at speed 1420 rpm and the torque was 4 Nm. The results showed that the wear rates (in the form of weight loss) of spur gears were consistent with the previous results and the other gear types had larger wear rates. © 2015 Samy Yousef et al. Source

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