Al Jīzah, Egypt
Al Jīzah, Egypt

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Kamel B.M.,National Research Center of Egypt | Mohamed A.,Akhbar El Yom Academy | El Sherbiny M.,Cairo University | Abed K.A.,National Research Center of Egypt | Abd-Rabou M.,Cairo University
Journal of Dispersion Science and Technology | Year: 2017

The addition of graphene nanosheets (GNSs) in lubricating grease could significantly reduce the interfacial friction and improve the load-bearing capacity of the parts. Therefore, it has been considered as having great potential as lubricant additives. In this study, we synthesized GNSs that are prepared by a modified Hummer method, and investigated the effect of GNS with different concentration (0.5%, 1%, 2%, 3%, and 4 wt%) on the tribological properties of the calcium grease. The friction and wear experiments were performed using a four-ball tribometer. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to examine the GNS and the friction mechanisms. Results indicate that the friction reduction ability and anti-wear property of the base grease can be improved with the addition of GNS. It was also found that the friction reduction decreases by 61%, and the wear scar diameter (WSD) decreases by 45%, and the extreme-pressure (EP) properties increased 60% at 3 wt% GNS. It is clear that the GNS in grease easily forms protective deposited films to prevent the rubbing surfaces from coming into direct contact, thereby improving the entire tribological behavior of the grease. © 2017 Taylor & Francis.


Gharib T.F.,Ain Shams University | Fouad M.M.,Akhbar El Yom Academy | Aref M.M.,Ain Shams University
Advanced Techniques in Computing Sciences and Software Engineering | Year: 2010

Text mining refers generally to the process of extracting interesting information and knowledge from unstructured text. This area is growing rapidly mainly because of the strong need for analysing the huge and large amount of textual data that reside on internal file systems and the Web. Text document clustering provides an effective navigation mechanism to organize this large amount of data by grouping their documents into a small number of meaningful classes. In this paper we proposed a fuzzy text document clustering approach using WordNet lexical categories and Fuzzy c-Means algorithm. Some experiments are performed to compare efficiency of the proposed approach with the recently reported approaches. Experimental results show that Fuzzy clustering leads to great performance results. Fuzzy c-means algorithm overcomes other classical clustering algorithms like k-means and bisecting k-means in both clustering quality and running time efficiency. © Springer Science+Business Media B.V. 2010.


Seddeek M.A.,Qassim University | Seddeek M.A.,Akhbar EL Yom Academy | Odda S.N.,Helwan University | Abdelmeguid M.S.,Ain Shams University
Journal of Aerospace Engineering | Year: 2016

An analytical study is presented for the effects of chemical reaction and mass transfer on the free convective flow of a viscous and incompressible fluid past a vertical isothermal cone surface. The derived fundamental equations on the assumption of small magnetic Reynolds number are solved. A comparison between the analytical and numerical solution has been included in the analysis. The effects of buoyancy parameter, chemical reaction parameter, and Schmidt number on the flow field are discussed through graphs. © 2015 American Society of Civil Engineers.


Khalil W.,Akhbar El Yom Academy | Mohamed A.,Akhbar El Yom Academy | Bayoumi M.,Al - Azhar University of Egypt | Osman T.A.,Cairo University
Fullerenes Nanotubes and Carbon Nanostructures | Year: 2016

This study examined the tribological properties of two lubricating oils, mobil gear 627 and paraffinic mineral oils, with multi-walled carbon nanotubes (MWCNTs) nanoparticles used as additives with various concentrations (0.1, 0.5, 1, and 2 wt.%). The friction and wear experiments were performed using a four ball tribotester. The samples were tested for their anti-wear, load carrying capacity, and friction coefficients according to ASTM D-2783, ASTM D-2596, and ASTM D-5183 standards. The experimental results show that the addition of MWCNTs to base oils exhibit good friction reduction and anti-wear properties. The wear test results show a decreased wear by 68% and 39% in the case of MWCNTs-based mineral oil as compared with base mobil gear 627 and paraffinic mineral oils, respectively. Furthermore, the friction reduction results show a decrease of friction about 57% and 49% in the case of MWCNTs-based mineral oil as compared with base mobil gear 627 and paraffinic mineral oils, respectively. The weld load of the base oil containing 1% MWCNTs was found to be 400 kgf and 125 kgf as compared with base mobil gear 627 and paraffinic mineral oils, respectively, which got welded at 200 kgf and 100 kgf. The morphologies and typical element distribution of the worn surfaces were characterized by scanning electron microscope (SEM) and energy-dispersive X-ray (EDX). The SEM micrographs and EDX chemical analysis confirm the formation of a tribolayer composed of the elements from the nanoparticles. © 2016 Taylor & Francis Group, LLC.


Elshalakany A.B.,Akhbar El Yom Academy | Elshalakany A.B.,Cairo University | Osman T.A.,Cairo University | Khattab A.,Cairo University | And 2 more authors.
Journal of Nanomaterials | Year: 2014

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. © 2014 Abou Bakr Elshalakany et al.


Kamel B.M.,National Research Center of Egypt | Mohamed A.,Akhbar El Yom Academy | El Sherbiny M.,Cairo University | Abed K.A.,National Research Center of Egypt
Industrial Lubrication and Tribology | Year: 2016

Purpose - The purpose of this paper is to fabricate composite nanogrease for tribological applications. Multi-walled carbon nanotubes (MWCNTs) with a size 10 nm average diameter and 5 μm in length were used as additives to calcium grease. Design/methodology/approach - The tribological four-ball machine was used to evaluate calcium grease with carbon nanotubes (CNTs) as an additive. The interaction between CNT and calcium grease (nanogrease) were studied by transmission electron microscopy and X-ray diffraction. Findings - MWCNTs composite nanogrease was manufactured for tribological applications. The effectiveness of the fabricated grease in improving the tribological performance at different concentrations and under different loads was tested. The results are summarized as follows. CNT nanoparticle additive dispersed in calcium grease significantly improve its anti-wear performance, reducing friction, increasing load-carrying capacity and extreme pressure (EP) property. The friction is reduced by about 50 per cent, the wear scar diameter (WSD) decreased to 32 per cent and the EP properties increases about 38 per cent, with only 3 wt.%. The modified grease with CNTs additives of 3 wt.% showed the most favorable results. Energy dispersive x-ray (EDX) analysis shows that C was present on the worn scar surface, with atomic concentration of about 22 per cent. The presence of C suggests that a lubricating film is likely formed because of the presence of CNTs and very likely prevented the steel-to-steel direct contact. Originality/value - The results indicated that a 3 wt.% of MWCNT nanogrease is an excellent antiwear, with EP and low friction coefficient. It was also found that the friction coefficient was reduced to about 50 per cent, the WSD decreased by about 32 per cent and the EP properties increased about 38 per cent. The mating surfaces were investigated with scanning electron microscopy and EDX. The results show that a boundary film mainly composed of CNTs, Cr and Fe was formed on the rubbed surfaces. © Emerald Group Publishing Limited.


Elshalakany A.B.,Akhbar El Yom Academy | Elshalakany A.B.,Cairo University | Ali S.,Akhbar El Yom Academy | Ali S.,Cairo University | And 3 more authors.
International Journal of Advanced Manufacturing Technology | Year: 2016

Cold-rolled low carbon steel sheets of thicknesses ranging from 0.8 to 2 mm were sheets welded together to form a single part before the formability tests. In this study, the formability of the tailor-welded blanks (TWBs) was evaluated in terms of three measures which are limited dome height (LDH), forming limit diagram (FLD), and minimum major strain. In addition to the mechanical properties, the welded specimens were analyzed experimentally under the effect of thickness ratios. The influence of welding orientation and its relation with the rolling direction on formability and mechanical properties were also studied. The mechanical properties of the welded specimens were investigated by tensile testing and micro-hardness measurements. The metallographic studies were investigated using optical microscope and scanning electron microscope (SEM). The experimental findings in this study showed that the higher the thickness ratio of the TWBs, the lower the forming limits curve level and the lower formability. The minimum major strain was clearly inversely proportional to the thickness ratio of the TWBs. On the other hand, the results of uniaxial tests clearly illustrated that there was no significant difference between the tensile strengths of the TWBs and base metal. The micro-hardness measurements indicated that the hardness in the weld bead increased by about 55 % of the base metal. © 2016 Springer-Verlag London


Mohamed A.,Akhbar El Yom Academy | Mohamed A.,Cairo University | Osman T.A.,Cairo University | Khattab A.,Cairo University | Zaki M.,Cairo University
Journal of Tribology | Year: 2015

Carbon nanotubes (CNTs) with 10 nm average diameter and 5 lm in length were synthesized by electric arc discharge. The morphology and structure of CNTs were characterized by high resolution transmission electron microscopy (HRTEM) and X-ray powder diffraction. The tribological properties of CNTs as an additive on lithium grease were evaluated with a four ball tester. The results show that the grease with CNTs exhibit good performance in antiwear (AW) and decrease the wear scare diameter (WSD) about 63%, decrease friction reduction about 81.5%, and increase the extreme pressure (EP) properties and load carrying capacity about 52% with only 1% wt. of CNTs added to lithium grease. The action mechanism was estimated through analysis of the worn surface with a scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results indicate that a boundary film mainly composed of CNTs, Cr, iron oxide, and other organic compounds was formed on the worn surface during the friction process. Copyright © 2015 by ASME.


Moustafa M.M.A.,Akhbar El Yom Academy
International Conference on Advanced Communication Technology, ICACT | Year: 2010

Digital Video Broadcasting for Handheld Terminals (DVB-H) standard uses Orthogonal Frequency-Division Multiplexing (OFDM) technique which exhibits some major drawbacks, namely; the sensitivity to Doppler shift, the sensitivity to frequency synchronization and the high Peak to Average Power Ratio (PAPR). This paper proposes using OFDMNariable Spreading Factor (VSF)-Code Division Multiple Access (CDMA) for DVB-H transmission. Simulation results show a Bit Error Rate (BER) performance enhancement of the proposal over the OFDM based traditional transmission. The drawbacks of the proposal are the requirements for a higher RF bandwidth and the relative higher complexity overhead.


Kamel B.M.,National Research Center of Egypt | Mohamed A.,Akhbar El Yom Academy | El Sherbiny M.,Cairo University | Abed K.A.,National Research Center of Egypt
Fullerenes Nanotubes and Carbon Nanostructures | Year: 2016

Recently, nanofluids attract considerable interest for enhanced rheological behavior and thermal performance. The aim of this research is to study the influence of additives Multi-Walled Carbon Nanotubes (MWCNTs) on the rheological behavior and its structure, thermal conductivity, and the influence of shear thinning rate on oil separation at different temperatures for calcium grease. Various concentrations of MWCNTs (0.5, 1, 2, 3, and 4%) have been added to the grease to obtain the best percentages that improve the properties of nanofluid. The microstructure of MWCNTs and nanofluid were examined by X-ray diffraction (XRD), Transmission Electron Microscope (TEM), and Scanning Electron Microscope (SEM). These experimental investigations were evaluated with a Brookfield programmable Rheometer DV-III ULTRA. The results indicated that the optimum concentration of MWCNTs was 3%, and the dropping point increasing about 11%. The rheological behaviors of the nanofluids show that the grease with various concentrations of MWCNTs demonstrates non Newtonian behaviors and the results indicated that the shear stress, apparent viscosity and thermal conductivity increase with the increase of volume concentration of MWCNTs to 65%, 52%, and% 56, respectively. © 2016 Taylor & Francis Group, LLC.

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