Bakry M.,Gazan University |
Mousa M.O.,Minia University |
Ali W.Y.,Taif University
Materialwissenschaft und Werkstofftechnik | Year: 2013
In the present work, friction material composites were proposed to be used as automotive friction materials. The composites were reinforced by agricultural fibres of corn, palm, and sugar bars. The conventional friction materials based on asbestos cause serious lung diseases and being cancerous potential. The aim of the present work is to replace them by the proposed composites because they are environmentally friendly friction material for brake lining and clutch facings. Agricultural wastes of sugar bars, corn and palms fibres were prepared to obtain fibres of length less than 5 mm. The fibre materials were mixed by carbon, barium sulfate, silica, metallic powders and phenol formaldehyde. The proposed composites were pressed in the die at 105°C temperature. The produced specimens were subjected to machining processes to obtain the cylindrical form of 8 mm diameter. Experiments were carried out using test rig designed and manufactured to measure both friction and wear. It consists of a rotating hollow flat disc made of carbon steel, with an outside diameter of 250 mm and 16 mm thickness. The experiments investigated the effect of agriculture fibre wastes (corn, sugar bars, and palms fibres) on friction coefficient and wear. Wear mechanisms of the proposed composites were characterized by scanning electronic microscopy. The tribological properties of the proposed composites materials were compared to three commercial brake linings. Based on the experimental results it was found that, addition of agriculture fibre wastes (corn, sugar bars, and palms fibres) to composites materials increased friction coefficient and decreased wear. Friction coefficient slightly increased, while wear drastically decreased with increasing fibres content. The maximum friction value (0.58) was obtained by composites containing 30 wt.% iron and 25 wt.% sugar bar fibres. The corn fibres were more compatible with aluminum powder where it gave the highest friction coefficient and relatively lower wear compared to other composites. Wear resistance of the tested composites containing bunches and aluminum represented the lowest values among composites containing corn and bunches fibres. The lowest wear values were observed for composites containing 25 wt.% corn fibres and 30 wt.% aluminum and composites containing 20-25 wt.% sugar bar fibres. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Ateto M.S.,South Valley University |
Ateto M.S.,Gazan University
International Journal of Quantum Information | Year: 2015
Entanglement dynamics of two identical non-interacting atoms (qubits) coupled individually with simultaneous classical and quantum fields are studied. The cavity field is filled with a nonlinear Kerr medium and initially prepared in a coherent state. The atoms are initially set up as a Bell-like pure state (BS). We present an approach for diagonalization of time-dependent nonlinear Hamiltonian of the system exactly. Connection between the change in the degree of entanglement and tomography of field state in phase space are also illustrated and interpreted. We demonstrate the possibility of atom-atom (qubit-qubit) entanglement optimization by suitably choosing initial interaction settings. Overall, we show that both classical driving amplitude and detuning as well as Kerr media and initial atomic states acts as the control parameters for the qubit-qubit entanglement. By adjusting of these parameters, accurately, entanglement can be enhanced noticeably and high degree of steady periodical entanglement can be generated. Moreover, starting with initial atomic BSs in presence of classical driving suppresses coherences randomness and considerably accompanied with (for specific values of detuning) slight decrease in their amplitudes. Furthermore, the addition of cross Kerr term suppresses degree of entanglement noticeably, where entanglement creation and enhancement could just be possible if cross Kerr effect is moved out from interaction. Our present approach promises the great advantage of being suitable for large quantum systems of various kinds of nonlinearities. © 2015 World Scientific Publishing Company.
Farag H.K.,National Research Center of Egypt |
Hegab K.H.,National Research Center of Egypt |
Hegab K.H.,Gazan University |
Zein El Abedin S.,National Research Center of Egypt |
Zein El Abedin S.,Clausthal University of Technology
Journal of Materials Science | Year: 2011
Zirconia and mixed zirconia/titania were synthesized in two different ionic liquids, namely, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) amide ([BMP]TFSA) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide ([EMIm]TFSA) using sol-gel methods. The synthesized oxides were characterized by means of X-ray diffraction, scanning electron microscopy with energy dispersive X-ray (SEM-EDX)), thermogravimetric and differential thermal analyses (TGA-DTA). The results show that the as-synthesized ZrO 2 powders obtained either in [BMP]TFSA or in [EMIm]TFSA show amorphous behaviour, and calcination at 500 °C yields t-ZrO 2 which is subject to further phase transformation to m-ZrO 2 at 1000 °C. The type of the ionic liquid influences the morphology of the synthesized zirconia as the sample obtained from [BMP]TFSA showed a porous morphology with very fine particles in the nanometer regime, whereas micro-rods were obtained from [EMIm]TFSA. ZrO 2-TiO 2 nanorods with an average diameter of about 100 nm were synthesized in [EMIm]TFSA. The presence of zirconia in the mixed oxides stabilizes the anatase phase and elevates the temperature at which the phase transformation to rutile occurs. © 2011 Springer Science+Business Media, LLC.
Abdel-Wahab B.F.,National Research Center of Egypt |
Mohamed H.A.,National Research Center of Egypt |
Khidre R.E.,Gazan University |
Khidre R.E.,National Research Center of Egypt |
El-Mansy M.F.,Marquette University
Journal of Heterocyclic Chemistry | Year: 2015
Published data on the methods of preparation of different azoles linked directly to oxadiazoles are described systematically. This review is divided into classes based on the number of heteroatoms in the azoles connected to oxadiazole ring, and the subtitles are divided according to the type of oxadiazoles isomer. © 2014 HeteroCorporation.
Khedr A.M.,Tanta University |
Abou-Sekkina M.M.,Tanta University |
El-Metwaly F.G.,Tanta University |
El-Metwaly F.G.,Gazan University
Journal of Electronic Materials | Year: 2013
Spinel lithium manganese oxide and a series of Sm/LiMn2O 4 spinels with different Sm additive contents (x = 0.02%, 0.05%) were prepared for the first time via a coprecipitation method for rechargeable lithium-ion batteries. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive analysis of x-rays (EDAX), infrared (IR), and electron spin resonance spectral studies as well as various electrochemical measurements were used to examine the structural and electrochemical characteristics of LiMn2-x Smx O4 (x = 0.00%, 0.02%, 0.05%). XRD and SEM studies confirmed the nano materials size for all prepared spinels. From cyclic voltammetry studies, in terms of peak splitting, electrochemical active surface area, and intensity of the peaks, the LiMn1.98Sm 0.02O4 sample possesses better electrochemical performance compared with the LiMn1.95Sm0.05O4 sample. Hence, limited addition of a rare-earth dopant is preferable to obtain better efficiency. Direct-current (DC) electrical conductivity measurements indicated that these samples are semiconducting and their activation energies decrease with increasing rare-earth Sm3+ content. © 2013 TMS.
Abou El-Soud N.H.,National Research Center of Egypt |
El-Lithy N.A.,National Research Center of Egypt |
El-Saeed G.,National Research Center of Egypt |
Wahby M.S.,National Research Center of Egypt |
And 3 more authors.
Journal of Applied Pharmaceutical Science | Year: 2014
Aim of the study was to assess the renoprotective effect of Carum carvi essential oil. Thirty male albino rats were divided into three groups: normal control (group A), diabetic positive control (group B), and experimental (group C) receiving Carum carvi oil as a renoprotective agent at 10 mg/kg of body weights orally. Group B and C rats received STZ (60 mg/kg) for induction of diabetes. Rats with fasting blood glucose levels over 200mg/dl were considered diabetic. Blood samples were collected on the 22 th day for the determination of glutathione peroxidase and glucose. Kidneys were also extracted for examination. Carum carvi oil was analysed using the GC and GC/MS analysis. The major components of caraway essential oil were Carvone (70.1%) followed by γ - Terpinene (12.6%) and Limonene (5.5%) in addition to some minor compounds including Linalool (0.7%), Thymol (0.5%), γ -Cadinene (0.5%), α- Farnesene (0.4%), δ- Cadinene (0.4%). The diabetic group rats showed an increase in the serum level of glucose, and decrease in glutathione peroxidase. 10 mg/kg body weight dose of Carum carvi oil significantly corrected these parameters. The morphological examination of group B rats kidneys showed glomerular and tubular degeneration with massive cellular infiltration, hemorrhage in interstitial tissue and deformed renal tissue architecture. Whereas the kidney rats in group C showed marked improvement with minor pathological changes. Conclusion: Carum carvi oil showed renoprotection against diabetic nephropathy. This could be contributed to Carum carvi constituents, especially carvone, γ-Terpinene and Limonene which have strong anti-oxidant activity. © 2014 Neveen H. Abou El-Soud et al.
Abdel-Wahab B.F.,King Abdulaziz University |
Khidre R.E.,Gazan University |
Khidre R.E.,National Research Center of Egypt |
Farahat A.A.,Mansoura University
Arkivoc | Year: 2011
This review deals with synthesis and reactions of pyrazole-3(4)- carbaldehydes as well as their biological activity. The data on the methods of synthesis, chemical reactions,and biological activity of these heterocycles published over the last years are reviewed here for the first time. © ARKAT-USA, Inc.
Ghaly M.Y.,Gazan University |
Al-Maghrabi M.N.N.,King Abdulaziz University |
Ismail E.,Gazan University |
Ali M.E.M.,National Research Center of Egypt
Desalination and Water Treatment | Year: 2015
Abstract: The Advanced oxidation processes sunlight/photocatalyst is common for remediation treatments. During the oxidation processes, organic matter decomposed into smaller compounds, which affect the characteristics of the treated effluent. In the present work, two types of commercial TiO2 (TiO2 P-25 Degussa and commercial TiO2 (A)) were supported on small glass spirals. The photooxidation of natural organic matters (NOMs) over immobilized TiO2 using parabolic solar collector was investigated. The effects of addition of H2O2 as electron acceptor and pH values were also investigated. The degradation of NOMs was followed up by analysis of total organic carbon (TOC) and UV absorbance at 254 nm (A254). It was found that NOMs were completely removed over immobilized TiO2 on glass spirals under sunlight irradiation after 120 min. Also, approximately 77% of TOC was reduced from groundwater. Upon obtained results, solar energy could be used for photocatalytic degradation of NOMs in ground and surface waters and therewith lighten the process of preparing them to the potable water. © 2014 Balaban Desalination Publications. All rights reserved.
Khalil H.M.,Gazan University
Arabian Journal of Geosciences | Year: 2012
The stratigraphy of the Farasan Islands (Pliocene- Pleistocene deposits) is established on the basis of a detailed study of six stratigraphic sections described and sampled in the field. Detailed examinations involve the microfacies analyses and identification of macrofossils makes it possible to determine two new informal formations, namely, from the base to the top: Esbah formation of Pliocene age and Farasan formation of Pleistocene age. The detected microfacies types of the studied samples are only carbonate facies and include five major types: mudstone, wackestone, packstone, floatstone and boundstone. No grains of quartz sand or igneous mineral were found in the islands. The nomenclature of the biostratigraphic units established in the present work is not intended to define world-wide zonal standards. It is only used to subdivide the sequence into biostratigraphic zones according to 137 macrofaunal species (78 bivalves, 56 gastropods and three echinoids). These biozones, namely: Lithophaga teres zone (Early Pliocene), Clypeaster reticulates-Laganum depressum zone and Chesapecten madisonius-Noetia limula interval zone are assigned to the Late Pliocene; meanwhile, Noetia limuli-Anadara ovalis interval zone and A. ovalis range zone are assigned to the Pleistocene age. The affinity of the Pliocene-Pleistocene fauna recorded from the Farasan Islands increase with time towards the Indo-Pacific realm. The identified bivalves and gastropods are dominated by the Indo-Pacific forms suggesting the connection of the Red Sea rift with the open Indian Ocean via the Gulf of Aden and Bab El Mandab in the latest Miocene and Early Pliocene. © Saudi Society for Geosciences 2011.