Browsing by Author "Khalil, Mohamed"

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    Chebyshev Pseudospectral Approximation for Solving Higher-Order Boundary Value Problems
    (NSP, 1/25/2021) El-kady, Mamdouh; Khalil, Mohamed
    In this paper, a Chebyshev Pseudospectral differentiation matrix is used to construct an approximate solution for higher-order boundary value problems. The algorithm developed approximates the numerical solution and their higher-order derivatives of sixth-order and fourth-order boundary value problems. The numerical results are compared with both the exact solution and the results of other methods. It is demonstrated that our algorithm is of high precision and efficiency.
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    Occupational exposure to staff during endoscopic retrograde cholangiopancreatography in Sudan
    (Oxford University Press, 2011) Sulieman, A; Elzaki, M; Khalil, Mohamed
    Endoscopic retrograde cholangiopancreatography (ERCP) procedure is an invasive technique that requires fluoroscopic and radiographic exposure. The purpose of this study was to determine the occupational dose of ionising radiation at three gastroenterology departments (Fedial, Soba and Ibn seena hospitals) in Khartoum, Sudan. The radiation dose was measured during 55 therapeutic ERCP procedures. Thermoluminescence dosemeters were used. The mean radiation dose for the first operator was 0.27 mGy for the eye lens, 0.21 for the thyroid, 0.32 for the chest, 0.17 for the hand and 0.22 for the leg. The mean radiation dose for the second operator was 0.21 mGy for the hand and 0.20 mGy for the chest, while the mean radiation dose for the nurse was 0.44 mGy for the hand and 0.19 for the chest. The radiation dose received by the staff in these hospitals was found to be higher than most of the values in the literature. The radiation absorbed dose received by the different organs is relatively low. Additional studies need to be conducted for radiation dose optimisation.
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    On a Fractional Variable-Order Model of MERS-CoV
    (Natural Sciences Publishing, 2023-04) Khalil, Mohamed; Arafa, Anas; Sayed, Amaal
    In this paper, a non-integer variable-order epidemiological model is presented to study the human-to-human transmission of Middle East respiratory syndrome coronavirus (MERS-CoV) pandemic in two areas. In the presented SISImodel, the human population is divided into two compartments; susceptible and infectious compartments. The impact of the memory which changes with time in the sense of Caputo’s derivative of fractional variable-order is studied through the numerical solutions of the proposed model. The numerical solutions are obtained via predictor corrector method. Moreover, the equilibrium points and stability of the model are illustrated. © 2023 NSP Natural Sciences Publishing