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Abbas, Mohamed,Torati, Sri Ramulu,Rao, B. Parvatheeswara,Abdel-Hamed, M.O.,Kim, CheolGi Elsevier 2015 JOURNAL OF ALLOYS AND COMPOUNDS Vol.644 No.-
<P><B>Abstract</B></P> <P>Monodisperse Mn<I> <SUB>x</SUB> </I>Zn<SUB>1−</SUB> <I> <SUB>x</SUB> </I>Fe<SUB>2</SUB>O<SUB>4</SUB> (<I>x</I> =0.2, 0.5 and 0.8) nanoparticles have been synthesized using two different routes namely sonochemical and polyol methods, and the shape and size along with physiochemical properties of the nanoparticles were compared in detail. In both the routes, the synthesis was performed in a single reaction without the use of any surfactant and deoxygenated conditions. The reaction kinetics and surface adsorption characteristics of nanoparticles were observed by thermogravimetric analysis and Fourier transform infrared spectroscopy measurements. X-ray diffraction patterns confirmed the formation of a pure ferrite phase with cubic spinel structure, and the patterns further clearly indicate that the sonochemical method produces highly crystalline particles without any post calcination reaction, comparing with the polyol process. Transmission electron microscopy results reveal that the nanoparticles synthesized by polyol method are mostly aggregated and spherical in nature whereas the nanoparticles produced by sonochemical method are monodisperse large particles with cubic like shapes. The overall studies demonstrated that the sonochemical method is facile, reliable, rapid and very attractive for the aqueous synthesis of highly crystalline and high magnetic moment (84.5emu/g) monodisperse superparamagnetic Mn–Zn ferrite nanoparticles which considered as potential materials for various applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Mn–Zn ferrite NPs were synthesized by two different methods are polyol and sonochemical. </LI> <LI> The sonochemical method produced NPs with high crystallinity than polyol method. </LI> <LI> The ferrite samples synthesized by sonochemical method showed high magnetization values and superparamagnetic properties. </LI> <LI> XRD, TEM, EDS, TGA, FTIR, and VSM techniques used to characterize the samples. </LI> </UL> </P>
Mohamed I. Abbas 장전수학회 2022 Advanced Studies in Contemporary Mathematics Vol.32 No.2
In this paper, we study the controllability of generalized proportional- Caputo fractional differential equations (GPC-FDE). The main key in this investigation is the Krasnoselskii’s fixed point theorem.
Mohamed Abbas,김철기,Md. Nazrul Islam,B. Parvatheeswara Rao,M.O. Abdel-Hamed 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.31 No.-
In this study, we demonstrated a novel and facile chemical approach for synthesis of monodispersemaghemite (g-Fe2O3) nanoparticles. Compared to the reported works for synthesis of maghemitenanoparticles which require the use of much amount of surfactant and complicated procedures, wecould develop here an approach in which we did not use any surfactant or deoxygenated condition andfurther the synthesis process was also completed in a single reaction. X-ray diffraction analysis of thesample confirms single phase fully crystalline spinel structure. Transmission electron microscopyimages reveal that the shape of the synthesized maghemite nanoparticles is a mix of spherical and cubewith chain-like patterns and the average particles size is of 25 nm. The obtained maghemite (g-Fe2O3)nanoparticles showed high magnetic moment of 65 emu/g with superparamagnetic properties. Owing tothe high moment, mono disperse superparamagnetic nature of the sample, the synthesized maghemitenanoparticles are useful for biomedical applications.
Enhanced CNC Machines Capabilities by Adding Circular Patterns Cycle
Adel Taha Mohamed Abbas 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
Holes in multiple circular patterns exist in several recent industrial parts such as antennas, heat exchanger support plates, condensers, boilerplates, trammel screens and separators. There is a lot of difficulty in preparing CNC programs using conventional programming or canned cycle programming. This study illustrates an effort to establish a practical common algorithm allowing the drilling of holes arranged in multiple circular patterns. The programmed algorithm can easily be adapted to any modern CNC unit to create a user cycle or subroutine. To test the capabilities of this algorithm, two case studies were developed. The first used the Numeripth800-B CNC unit equipped with a horizontal Orion-500 machining center, and the second case study was developed using the Sinumeric 840-D equipped with a vertical Emco machining center. A number of samples were produced successfully. The new algorithm shows high efficiency in the part program establishment and offers the advantage of decreasing the encoding errors.
Seismic pounding effects on adjacent buildings in series with different alignment configurations
Shehata E. Abdel Raheem,Mohamed Y.M. Fooly,Aly G.A. Abdel Shafy,Yousef A. Abbas,Mohamed Omar,Mohamed M.S. Abdel Latif,Sayed Mahmoud 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.3
Numerous urban seismic vulnerability studies have recognized pounding as one of the main risks due to the restricted separation distance between neighboring structures. The pounding effects on the adjacent buildings could extend from slight non-structural to serious structural damage that could even head to a total collapse of buildings. Therefore, an assessment of the seismic pounding hazard to the adjacent buildings is superficial in future building code calibrations. Thus, this study targets are to draw useful recommendations and set up guidelines for potential pounding damage evaluation for code calibration through a numerical simulation approach for the evaluation of the pounding risks on adjacent buildings. A numerical simulation is formulated to estimate the seismic pounding effects on the seismic response demands of adjacent buildings for different design parameters that include: number of stories, separation distances; alignment configurations, and then compared with nominal model without pounding. Based on the obtained results, it has been concluded that the severity of the pounding effects depends on the dynamic characteristics of the adjacent buildings and the input excitation characteristics, and whether the building is exposed to one or two-sided impacts. Seismic pounding among adjacent buildings produces greater acceleration and shear force response demands at different story levels compared to the no pounding case response demands.
Abbas H. Mohammed,Nildem Tayşi 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.62 No.5
During their life span, post-tensioned concrete structures may be exposed to thermal loads. Therefore, there has been a growing interest in research on the advanced analysis and design of post-tensioned concrete slabs subjected to thermal loads. This paper investigates the structural behaviour of post-tensioned one-way spanning concrete slabs. A nonlinear finite element model for the analysis of post- tensioned unbonded and bonded concrete slabs at elevated temperatures was developed. The interface between the tendon and surrounding concrete was also modelled, allowing the tendon to retain its profile shape during the deformation of the slab. The load-deflection behaviour, load-force behaviour in the tendon, and the failure modes are presented. The numerical analysis was conducted by the finite element ANSYS software and was carried out on two different one-way concrete slabs chosen from literature. A parametric study was conducted to investigate the effect of several selected parameters on the overall behavior of post-tensioned one-way concrete slab. These parameters include the effect of tendon bonding, the effect of thermal loading and the effect of tendon profile. Comparison between uniform thermal loading and non-uniform thermal loading showed that restrained post tensioned slab with bottom surface hotter has smaller failure load capacity.