Browsing by Author "Mukalazi, Herbert"

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Couple-stress nanofluid flow comprised of titanium alloy subject to Hall current and Joule heating effects: Numerical investigation
(AIP Advances, 2024-11-01) Jubair, Sidra; Ali, Bilal; Rafique, Khadija; Ansari, Mushtaq Ahmad; Mahmood, Zafar; Kumar, Abhinav; Mukalazi, Herbert; Alqahtani, Haifa
Nanofluid flowoverarotating disk has several applications in engineering and industrial sectors, such as in cooling systems, heat exchangers, aerospace systems, and renewable energy systems. In the current analysis, the couple stress nanofluid flow over a rotating disk is reported. The nanofluid consists of ethylene glycol and titanium aluminum vanadium (Ti6Al4V) nanoparticles (NPs). The unique properties of Ti6Al4V-NPs, such as biocompatibility, high strength, high boiling point (1604–1660○C), and high corrosion resistance, make them more suitable for automobile industries. For the heat and mass transfer, the Cattaneo–Christov concept is introduced. In addition, the fluid flow is subjected to magnetic field, Hall current, thermal radiation, and Joule heating. The modeled equations are restructured into the dimensionless system of ordinary differential equations (ODEs) by using the similarity approach. The system of ODEs is further numerically solved through a MATLABpackagebased on the finite difference method (BVP4c). The results are presented in figures. It has been observed that the energy and curves of the nanofluid decline with the influence of thermal and solutal time relaxation parameters, respectively.
Discussing the epidemiology of COVID-19 model with the effective numerical scheme
(Scientific Reports, 2025-07-17) Aljohani, Abeer; Mustafa, Shahbaz; Shan, Ali Khan; Alhushaybari, Abdullah; Mukalazi, Herbert
COVID-19 is a contagion that’s container lead to lung difficulties such as pneumonia and, in the greatest severe circumstances, serious respirational disease. In response to these challenges, the present research proposes and analyses an SEIQR model with a nonlinear recovery and incidence rate. The appearance aimed at fundamental threshold quantity (R0) is established, which is critical to the stability of disease-free and endemic equilibria. A non-standard Finite difference (NSFD) Scheme is developed and for the model, and the denominator function is select so that the proposed structure maintains solution boundedness. It is demonstrated that the NSFD scheme is not dependent on the step size produces superior outcomes in totally admirations. The Jacobian approach is employed to establish the local stability of the disease free equilibrium, while Schur-Cohn conditions are used for the endemic equilibrium point in the the discrete NSFD scheme. The Enastu Criterion and the Lyapunov Function are used to demonstrate the global stability of the disease free and endemic equilibria. Numerical simulation are also presented to discuss the benefits of the NSFD scheme and to validate the theoretical conclusions. Calculated simulations show that the NSFD method preserves the important aspects of the continuous model. As a result, they generate estimates that align consistently with the model’s solutions.
Exploring the wave’s structures to the nonlinear coupled system arising in surface geometry
(Scientific Reports, 2025-04-04) Farooq, Khizar; Hussain, Ejaz; Younas, Usman; Mukalazi, Herbert; Khalaf, Tamer M.; Mutlib, Abdul; Syed, Asif Ali Shah
This manuscript deals with the Heisenberg ferromagnet-type integrable Akbota equation (AE), which refers to a set of differential equations that are integrable and linked together, and they possess solitary waves. AE is a basic gear for investigating nonlinear dynamics in the fields of optics, magnetism, and differential geometry of curves and surfaces. It is extensively used to represent optical solitons in nonlinear optical fibers, which are crucial for fiber-optic communication owing to their capacity to maintain form across considerable distances. The dynamical behavior of AE is explored by constructing accurate closed-form traveling wave solutions. For this purpose, the Kumar-Malik method, the new Kudryashov method, and the Riccati equation method are utilized. The resulting solutions consist of trigonometric, hyperbolic, and rational functions. By employing these methodologies, precise analytical remedies for soliton waves are derived, which include kink, bright, and dark solitons. To get a better understanding of the physical aspects of these solutions, we depict them via several visual representations. 3D-surface graphs, 2D-line graphs, and contour and density plots, in addition to theoretical derivations.
Forecasting the thermal degradation depending on the kinetics of dracaena Draco lignocellulosic fibers using an artificial neural network
(Journal of Natural Fibers;Taylor &Francis, 2025-07-17) Hadou, Abdelwaheb; Belaadi, Ahmed; Ghernaout, Djamel; Mukalazi, Herbert
In order to forecast the thermal degradation of Dracaena draco plant fibers (DDFs) using thermogravimetric analysis (TGA) at heating rates ranging from 5 to 30°C/min, this study employed artificial neural networks (ANNs). Hemicellulose, cellulose, and lignin break-down were represented by the three different degradation stages that were seen. The enhanced ANN27 model successfully captured pyrolysis behavior and degradation patterns, achieving a high prediction accuracy (R2 = 0.99966). The model performed well at lower heating rates (5 and 10°C/min), but because of bias and heteroscedasticity, adjustments are required at higher rates (15–30°C/min). In contrast to the experimental averages of 131.244 kJ/mol, 109.269 kJ/mol, and 131.694 kJ/mol, respectively, kinetic analysis showed that the ANN27-predicted activation energies (Ea) were 133.420 kJ/mol (KAS), 53.692 kJ/mol (FWO), and 133.784 kJ/mol (STR). Without requiring a lot of testing, our ANN method provides insights into DDF thermal behavior and optimizes processing settings by properly forecasting degradation curves
Quality evaluation and predictive analysis of drilled holes in jute/ palm/polyester hybrid bio-composites using CMM and ANN techniques
(Journal of Natural Fibers, 2025-04-26) Amroune, Salah; Elhadi, Abdelmalek; Slamani, Mohamed; Arslane, Mustapha; Belaadi, Ahmed; Abdullah, Mahmood M. S.; Al-Lohedan, Hamad A.; Bidi, Tarek; Mukalazi, Herbert; Al-Khawlani, Amar
In this study, the evaluation of 75 holes drilled in a hybrid bio-composite jute/palm/polyester plate and controlled by a coordinate measuring machine (CMM) is essential to ensure the quality, dimensional precision, and geometric conformity of the plate. This rigorous process is necessary to meet industrial standards for circularity and cylindricity, which are essential criteria for high-performance applications. Additionally, the integration of artificial neural network (ANN) techniques has revolutionized this approach by enabling precise predictions of key parameters such as delamination, circularity, and cylindricity. In this study, the ANN was trained with 52 samples (70%), while 8 samples (10%) were used for validation and 15 others (20%) for testing at different stages. The results show the influence of feed rate on the delamination factor (Fd) (R2 = 0.98), circularity error (R2 = 0.99), and cylindricity error (R2 = 0.98). This predictive approach significantly improves the reliability and efficiency of the evaluation process.
Stability analysis of a nonlinear malaria transmission epidemic model using an effective numerical scheme
(Scientific Reports, 2024-07-29) Jian, Jun He; Abeer, Aljohani; Shahbaz, Mustafa; Ali, Shokri; Khalsaraei, Mohammad Mehdizadeh; Mukalazi, Herbert
Malaria is a fever condition that results from Plasmodium parasites, which are transferred to humans by the attacks of infected female Anopheles mosquitos. The deterministic compartmental model was examined using stability theory of differential equations. The reproduction number was obtained to be asymptotically stable conditions for the disease-free, and the endemic equilibria were determined. More so, the qualitatively evaluated model incorporates time-dependent variable controls which was aimed at reducing the proliferation of malaria disease. The reproduction number R (o) was determined to be an asymptotically stable condition for disease free and endemic equilibria. In this paper, we used various schemes such as Runge–Kutta order 4 (RK-4) and non-standard finite difference (NSFD). All of the schemes produce different results, but the most appropriate scheme is NSFD. This is true for all step sizes. Various criteria are used in the NSFD scheme to assess the local and global stability of disease-free and endemic equilibrium points. The Routh–Hurwitz condition is used to validate the local stability and Lyapunov stability theorem is used to prove the global asymptotic stability. Global asymptotic stability is proven for the disease-free equilibrium when R0 ≤ 1. The endemic equilibrium is investigated for stability when R0 ≥ 1. All of the aforementioned schemes and their effects are also numerically demonstrated. The comparative analysis demonstrates that NSFD is superior in every way for the analysis of deterministic epidemic models. The theoretical effects and numerical simulations provided in this text may be used to predict the spread of infectious diseases.