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ON SOLUTIONS OF VOLTERRA-FREDHOLM INTEGRAL EQUATIONS
Thabet, A.A.,Alim, A.Hadi Department of Mathematics 1989 Kyungpook mathematical journal Vol.29 No.2
The existence and uniqueness of solutions of nonlinear Volterra-Fred-holm integral equations of the more general type are investigated. The main tool employed in our analysis is the method of successive approximation based on the general idea of T.Wazewski.
Thabet Abouzeid A.,Badawi Mohamed S. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.10
NaI(Tl) scintillation materials are considered to be one of many materials that are used exclusively for gray detection and spectroscopy. The gamma-ray spectrometer is not an easy-to-use device, and the accuracy of the numerical values must be carefully checked based on the rules of the calibration technique. Therefore, accurate information about the detection system and its effectiveness is of greater importance. The purpose of this study is to estimate, using an analytical-numerical formula (ANF), the purely geometric solid angle, geometric efficiency, and total efficiency of a cylindrical NaI(Tl) g-ray detector with a side-through hole. This type of detector is ideal for scanning fuel rods and pipelines, as well as for performing radio-immunoassays. The study included the calculation of the complex solid angle, in combination with the use of various points like gamma sources, located axially and non-axially inside the through detector side hole, which can be applied in a hypothetical method for calibrating the facility. An extended g-ray energy range, the detector, source dimensions, “source-to-detector” geometry inside the side-through hole, path lengths of g-quanta photons crossing the facility, besides the photon average path length inside the detector medium itself, were studied and considered. This study is very important for an expanded future article where the radioactive point source can be replaced by a volume source located inside the side-trough hole of the detector, or by a radioactive pipeline passing through the well. The results provide a good and useful approach to a new generation of detectors that can be used for lowlevel radiation that needs to be measured efficiently.
Thabet, Abouzeid A.,Hamzawy, A.,Badawi, Mohamed S. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6
The geometrical efficiency of a source-to-detector configuration is considered to be necessary in the calculation of the full energy peak efficiency, especially for NaI(Tl) and HPGe gamma-ray spectroscopy detectors. The geometrical efficiency depends on the solid angle subtended by the radioactive sources and the detector surfaces. The present work is basically concerned to establish a new mathematical approach for calculating the solid angle and geometrical efficiency, based on conversion of the geometrical solid angle of a non-axial radioactive point source with respect to a circular surface of the detector to a new equivalent geometry. The equivalent geometry consists of an axial radioactive point source with respect to an arbitrary elliptical surface that lies between the radioactive point source and the circular surface of the detector. This expression was extended to include coaxial radioactive circular disk source. The results were compared with a number of published data to explain how significant this work is in the efficiency calibration procedure for the γ-ray detection systems, especially in case of using isotropic radiating γ-ray sources in the form of point and disk shapes.
Incidence of factors of risks in the self-regulation as prevention of the tobacco in adolescents
Thabet, Hassan Haithem,Mendez, Leonardo Rodriguez,Ugando, Maira Quintana,Alvarez, Jesus Cuellar Korea FoodHealth Convergence Association 2018 식품보건융합연구 (KJFHC) Vol.4 No.2
Background: the self-regulating in adolescent's smokers as prevention is one of the lines of the work team in the consultation of Ceasing Tobacco. Objective: to identify the factors of risks that impact in the self-regulation to prevent the tobacco in adolescents. The investigation embraced one period from March 2017 to September 2018. Method: a descriptive study of traverse court was used. Registered to 31 students for sampling intentional non probabilistic, of an universe of 50 adolescent students. It was used empiric methods; clinical histories, interviews structured and the questionnaire. Conclusion: the female sex prevailed, where 54,8 % between the 12 to 19 years of age. Results: the incidence the factors of risks that impact in the self-regulation to prevent the tobacco in adolescents are the group contagion with 54,7 %, family problems for a 29,0 % and situational depression with 16,1 %, where it is necessary the self-regulation that should have the adolescents in the life.
ADS-Bsec: A novel framework to secure ADS-B
Thabet Kacem,Alexandre Barreto,Duminda Wijesekera,Paulo Costa 한국통신학회 2017 ICT Express Vol.3 No.4
The Automatic Dependent Surveillance Broadcast (ADS-B) protocol can be used as a complement to Radar-based Air Traffic Control (ATC), or as a replacement in areas where the latter is impractical. However, ADS-B messages do not include any integrity or authenticity thus they can be easily tampered using inexpensive hardware and open source software. Modifying ADS-B message format is infeasible because it would render the already large implemented base obsolete. This paper proposes ADS-Bsec, which addresses the ADS-B limitations while being compatible with the installed base. ADS-Bsec provides the missing integrity and authenticity into ADS-B packets using a key management infrastructure without altering the existing packet format. This paper also argues for including the proposed framework as a component of the NextGen infrastructure based on our experience in prototyping efforts using cognitive radios, cryptography and multilateration together with existing radar-based ATC systems.
Hajer Thabet,Mounir Ayadi,Frédéric Rotella 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.6
This paper is devoted to an experimental comparison between two different methods of ultra-local modelcontrol. The concept of the first proposed technique is based on the linear system resolution technique to estimatethe ultra-local model parameters. The second proposed method is based on the linear adaptive observer whichallows the joint estimation of state and unknown system parameters. The closed-loop control is implemented via anadaptive PID controller. In order to show the efficiency of these two control strategies, experimental validations arecarried out on a two-tank system. The experimental results show the effectiveness and robustness of the proposedcontrollers.
Ahmed Thabet,Nourhan Salem 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.3
Nanoparticles distribution techniques inside electrical insulation materials is an essential technology for improving electric and dielectric behavior and maintaining the reliability of industrial applications. In this paper, it has been investigated on dielectric strength of polyvinyl chloride nanocomposites materials based on distribution of individual and multiple nanoparticles techniques under uniform and non-uniform electric fields. It has been succeeded to enhance and control the dielectric strength based on the arrangement of multiple nanoparticles inside polyvinyl chloride materials under uniform and nonuniform applied electric fi elds. Moreover, optimal types and concentrations of individual and multiple nanoparticles have been specified for dielectric strength degradation under variant thermal conditions (20–80 °C). Trends of using individual and multiple nanoparticles have been depicted the industrial features against traditional industrial materials.
Ahmed Thabet,M. Fouad 한국전기전자재료학회 2022 Transactions on Electrical and Electronic Material Vol.23 No.2
Formulation of voids and impurities inside the power cable insulation may be found based on fabrication or installation processes that lead to the formation of high electrical stress and collapse of the insulation material of the power cable with cable aging. In this research, it has been investigated on possibility of nanoparticles for developing polyvinyl chloride that is used in power cable fabrication. Therefore, new polyvinyl chloride (PVC) nanocomposites have been fabricated and experimentally tested under high voltage tester. In this paper, it has been investigated on the effect of nanoparticles on electrostatic field distribution inside three-core power cables insulation in presence of air, water and copper impurities with different shapes (rectangle, circle and ellipse). Finite element method has been used to calculate the electrostatic field distribution in power cable insulation. This research success to design innovative patterns of polyvinyl chloride insulation materials for enhancing the electrical stress according to type and concentration of nanoparticles. Also, a comparative study of partial discharges in three-core power cables has been investigated on conventional PVC structure material and new nanocomposites industrial materials.
Controlling on Attraction Forces of Water Droplets on Surfaces of Polypropylene Nanocomposites
Ahmed Thabet Mohamed,Khaled Ebnalwaled Abdelfattah Ahmed 한국전기전자재료학회 2018 Transactions on Electrical and Electronic Material Vol.19 No.5
In this work, Sol gel method was used to prepare polypropylene nanocomposites; some diff erent types of the nanoparticles(clay, ZnO, SiO 2 and TiO 2 ) and diff erent concentration (1, 5 and 10 wt%) were used to control on the attraction forces of waterdroplets on surfaces of polypropylene nanocomposites. The prepared polypropylene nanocomposites were characterized byFTIR, SEM, dielectric constant, contact angle, wetting energy, spreading coeffi cient and work of adhesion measurements. Experimental results deduced that clay and ZnO nanoparticles reduce the dielectric constant of polypropylene, while SiO 2and TiO 2 increase this value. It has been reported that the wettability of the prepared nanocomposites is reduced by increasingcertain nanoparticles ratio, which indicate the ability of the obtained nanocomposites for packaging and battery casesapplications.