School of Physical Sciences (SPS)

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School of Physical Sciences (SPS)

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Start date: 2023Has files: Yes

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    Mathematical model and analysis of the soil-transmitted helminth infections with optimal control
    (Springer Science and Business Media LLC, 2024-02) Festus Abiodun Oguntolu; Olumuyiwa James Peter; Abubakar Yusuf; B. I. Omede; G. Bolarin; T. A. Ayoola
    Soil-transmitted helminth diseases are highly prevalent in impoverished regions and pose a significant health burden on the global population. These diseases are primarily transmitted through the contamination of soil with human faces containing parasite eggs. This study presents a novel deterministic mathematical model to comprehensively investigate the dynamics of helminth infection transmission through the soil. The mathematical model exhibits two equilibrium points: the diseases-free equilibrium point (DFE) and the endemic equilibrium point (EEP). The DFE is proven to be locally and globally asymptotically stable when the basic reproduction number is less than one, indicating the potential for disease eradication. Conversely, the EEP is locally asymptotically stable when the basic reproduction number exceeds unity, representing a persistent endemic state. To explore effective intervention strategies for controlling the spread of these infections, optimal control theory is applied. The study incorporates two time-varying control variables derived from sensitivity analysis: the rate of hygiene consciousness in the susceptible class and the rate of hygiene consciousness in the infectious class. Numerical simulations demonstrate that implementing optimal control strategies can successfully curb and mitigate soil-transmitted helminth infections. Overall, this research highlights the importance of proactive and targeted interventions, emphasizing the significance of hygiene education and awareness campaigns. By implementing optimal control measures based on the proposed strategies, the burden of soil-transmitted helminth diseases can be significantly reduced, improving public health in affected regions.
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    Surface Modification and Functionalization of Ceramic Composites.
    (Elsevier, 2023) Okeke, I. S; Obodo, R. M; Eze, C. N.; Orji, M. P; Agwu, K. K; Ubachukwu, A. A; Ezema, F. I
    Materials with high dielectric constants are essential in the control and advancement of electronics and electrical power systems. The dielectric properties of materials majorly include dielectric constants (ꜫo) and loss tangent (tan ẟ), and for a material to be considered a very good dielectric material, it needs greater ꜫo, lower tan ẟ and reduced leakage current (J). Inorganic mixed transition oxides (MTMOS) ceramics composites have shown huge potential than the transition metal oxide because they constitute two or more metal elements with different expansion coefficients that give rise to synergistic effects. MTMOs ceramics composites are mostly found with spinel structure such as normal spinel structure (NSS) and inverse spinel structure (IVS). Several synthesis techniques have been used in formulation of MTMOs ceramic composites. Their dielectric properties have been modified considerately by altering its morphology, use of modifying agent, and high calcination temperatures. In this chapter, we summarized MTMOs major structure type synthesis technique that have been successfully used in preparation of MTMOs, the dielectric properties of MTMOs and basis of surface modification in MTMOs as well as its effect in the dielectric properties.
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    The Role of Local Dyes in Dye-Doped Stannates and Titanates for Enhancement f Solar Energy Capture
    (FUDMA Journal of Sciences, 2025) Eze, C. N.
    Local dyes play a crucial role in enhancing solar energy capture in dye-doped stannates and titanates by acting as light-harvesting agents, boosting the efficiency of dye-sensitized solar cells (DSSCs). These dyes, when adsorbed onto the surfaces of porous semiconductor materials like TiO2, absorb incoming sunlight and then inject electrons into the semiconductor, initiating an electron transfer process that generates electricity. This process is similar to how plants capture sunlight in photosynthesis. Stannates and titanates, such as TiO2, ZnTiO3, BaSnO3 etc provide a porous surface for dye adsorption and act as the conductive material for electron transport. Their nanostructured surfaces increase the surface area available for dye adsorption, enhancing light capture.
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    Modeling prevalence of meningitis control strategies through evaluating with available data on meningitis cases reported in Nigeria
    (Springer Science and Business Media LLC, 2025-05-14) O.J. Peter; F.A. Oguntolu; N. Nyerere; A. El-Mesady
    Meningitis is a major public health concern, especially in developing nations, due to its devastating consequences for human health. Although modeling studies have examined disease transmission dynamics, little attention has been paid to how control strategies affect the behavior of different population groups, including carriers, symptomatic individuals, hospitalized patients, and those in intensive care. This study proposes a computational framework that compares the effectiveness of vaccination of people at risk of the disease versus treating symptomatic infected persons. The basic reproduction number is used to evaluate the equilibrium points. Assess the precision of the proposed model’s illustration to data. We fit the meningitis model using the information at our disposal on meningitis cases reported in Nigeria from the first week of January to the last week of December 2023; this was obtained from the Nigerian Center for Disease Control (NCDC) database. We also performed a sensitivity analysis using a normalized forward sensitivity index to see which parameters had significant effects on the effective reproduction number. The results of both analytical techniques and numerical simulations reveal that recruitment rate, vaccination, progression from carrier to symptomatic stages, and disease-induced death all significantly reduce the incidence and prevalence of meningitis in the community. The study findings could be used to inform decisions about meningitis control initiatives.
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    On the verification of existence of backward bifurcation for a mathematical model of cholera dynamics
    (African Journals Online, 2023-09-12) A. A. Ayoade; O. J. Peter; F. A. Oguntolu; C.Y. Ishola; S. Amadiegwu
    A cholera transmission model, which incorporates preventive measures, is studied qualitatively. The stability results together with the center manifold theory are used to investigate the existence of backward bifurcation for the model. The epidemiological consequence of backward bifurcation is that the disease may still persist in the population even when the classical requirement of the reproductive number being less than one is satisfied.
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    Mathematical Model of COVID-19 Pandemic with Double Dose Vaccination
    (Springer Science and Business Media LLC, 2023-03-06) Olumuyiwa James Peter; Hasan S. Panigoro; Afeez Abidemi; Mayowa M. Ojo; Festus Abiodun Oguntolu
    This paper is concerned with the formulation and analysis of an epidemic model of COVID-19 governed by an eight-dimensional system of ordinary differential equations, by taking into account the first dose and the second dose of vaccinated individuals in the population. The developed model is analyzed and the threshold quantity known as the control reproduction number is obtained. We investigate the equilibrium stability of the system, and the COVID-free equilibrium is said to be locally asymptotically stable when the control reproduction number is less than unity, and unstable otherwise. Using the least-squares method, the model is calibrated based on the cumulative number of COVID-19 reported cases and available information about the mass vaccine administration in Malaysia between the 24th of February 2021 and February 2022. Following the model fitting and estimation of the parameter values, a global sensitivity analysis was performed by using the Partial Rank Correlation Coefficient (PRCC) to determine the most influential parameters on the threshold quantities. The result shows that the effective transmission rate, the rate of first vaccine dose, the second dose vaccination rate and the recovery rate due to the second dose of vaccination are the most influential of all the model parameters. We further investigate the impact of these parameters by performing a numerical simulation on the developed COVID-19 model. The result of the study shows that adhering to the preventive measures has a huge impact on reducing the spread of the disease in the population. Particularly, an increase in both the first and second dose vaccination rates reduces the number of infected individuals, thus reducing the disease burden in the population.
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    Modelling the impacts of media campaign and double dose vaccination in controlling COVID-19 in Nigeria
    (Elsevier BV, 2023-10) N.I. Akinwande; S.A. Somma; R.O. Olayiwola; T.T. Ashezua; R.I. Gweryina; F.A. Oguntolu; O.N. Abdurahman; F.S. Kaduna; T.P. Adajime; F.A. Kuta; S. Abdulrahman; A.I. Enagi; G.A. Bolarin; M.D. Shehu; A. Usman
    Corona virus disease (COVID-19) is a lethal disease that poses public health challenge in both developed and developing countries of the world. Owing to the recent ongoing clinical use of COVID-19 vaccines and non-compliance to COVID-19 health protocols, this study presents a deterministic model with an optimal control problem for assessing the community-level impact of media campaign and double-dose vaccination on the transmission and control of COVID-19. Detailed analysis of the model shows that, using the Lyapunov function theory and the theory of centre manifold, the dynamics of the model is determined essentially by the control reproduction number (Rmv). Consequently, the model undergoes the phenomenon of forward bifurcation in the absence of the double dose vaccination effects, where the global disease-free equilibrium is obtained whenever Rmv≤1. Numerical simulations of the model using data relevant to the transmission dynamics of the disease in Nigeria, show that, certain values of the basic reproduction number ((R0≥7)) may not prevent the spread of the pandemic even if 100% media compliance is achieved. Nevertheless, with assumed 75% (at R0=4)) media efficacy of double dose vaccination, the community herd immunity to the disease can be attained. Furthermore, Pontryagin's maximum principle was used for the analysis of the optimized model by which necessary conditions for optimal controls were obtained. In addition, the optimal simulation results reveal that, for situations where the cost of implementing the controls (media campaign and double dose vaccination) considered in this study is low, allocating resources to media campaign-only strategy is more effective than allocating them to a first-dose vaccination strategy. More so, as expected, the combined media campaign-double dose vaccination strategy yields a higher population-level impact than the media campaign-only strategy, double-dose vaccination strategy or media campaign-first dose vaccination strategy.
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    Modeling tuberculosis dynamics with vaccination and treatment strategies
    (Elsevier BV, 2025-03-19) Olumuyiwa James Peter; Dipo Aldila; Tawakalt Abosede Ayoola; Ghaniyyat Bolanle Balogun; Festus Abiodun Oguntolu
    Tuberculosis (TB) remains a leading cause of morbidity and mortality worldwide, worsened by the emergence of drug-resistant strains. The implementation of vaccination and observed treatment still becomes the most popular intervention in many countries. This study develops a mathematical model to analyze TB dynamics by considering the impact of integrated intervention vaccination and treatment strategy, and also taking into account the possibility of treatment failure and drug–resistant. The model constructed by dividing the population into six compartments: susceptible S, vaccinated V, latent L, active TB (I), drug-resistant TB Dr, and recovered R. Through a mathematical analysis of the dynamical properties of the proposed model, we demonstrated that the disease-free equilibrium point is always locally asymptotically stable when the basic reproduction number is less than one and unstable when it exceeds one. Moreover, the endemic equilibrium point is shown to exist uniquely only when the basic reproduction number is greater than one, and once it exists, it is always locally stable. For better visualization of the stability properties, we perform continuation simulations to generate a bifurcation diagram of our model, utilizing various bifurcation parameters. The Partial Rank Correlation Coefficient (PRCC) approach is used to carry out sensitivity analyses to determine the most sensitive parameters to the disease control. Simulation results show that increased vaccination rates efficiently reduce the susceptible population to increase the vaccinated population, decreasing disease transmission and lowering the burden of active and drug-resistant tuberculosis. Recovery rates after second-line treatment have a substantial impact on the dynamics of drug-resistant tuberculosis. Higher recovery rates result in faster rises in the recovered population and improved disease control. The findings emphasize the need for integrated measures, such as vaccination campaigns and enhanced treatment procedures, to reduce tuberculosis incidence, minimize drug resistance, and improve public health outcomes. These findings lay the groundwork for enhancing tuberculosis control programs, especially in countries with limited resources.
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    EFFECT OF ELECTRON TRANSPORT LAYERS, INTERFACE DEFECT DENSITY AND WORKING TEMPERATURE ON PEROVSKITE SOLAR CELLS USING SCAPS 1-D SOFTWARE
    (EAST EUROPEAN JOURNAL OF PHYSICS. 1. 332-341 (2024), 2023-12-30) YUSUF Abubakar Sadiq; A.M. Ramalan; A.A. Abubakar; I.K. Mohammed
    Perovskite solar cells have garnered significant attention from solar cell researchers due to their potential for achieving high efficiency, primarily attributed to their exceptional Electron Transport layer (ETL). One of the key elements of perovskite solar cells for transporting electrons to generate current is the ETL material. Moreover, there is a promising avenue for enhancing stability and reducing fabrication costs by substituting the transport layer. In this study, TiO2 and SnO2 were used as ETL materials in the architecture of perovskite solar cells for a comparative analysis between two devices featuring distinct structures: TiO2/CH3NH3PbI 3 /Spiro- OMeTAD and SnO 2/CH3NH3PbI 3/Spiro-OMeTAD. To evaluate the performance of each electron transport layer (ETL), the SCAPS 1D tool was employed. The investigation involved varying the thickness of the electron transport layers, interface defect density and working temperature, allowing for a comprehensive assessment of key parameters such as voltage at open circuit (Voc), short circuit current density (Jsc), fill factor (FF), and overall efficiency (PCE%). Remarkably, when employing SnO2 as the ETL, the achieved efficiency stands at 10.10 %. In contrast, utilizing TiO2 as the ETL yields a slightly higher efficiency of 12.84%. These findings underline the nuanced influence of transport layer materials on the overall performance of perovskite solar cells
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    Effect of Al Dope with ZnO Electron Transport Layer in Perovskite Solar Cells Using SCAPs 1-D Simulation
    (Nigerian Journal of Physics (NJP)ISSN online: 3027-0936ISSN print: 1595-0611, 2024-06-01) YUSUF Abubakar Sadiq; Ramalan, A. M; Abubakar, A. A; Mohammed,I.K; Ibrahim, S. O; Adamu, F. E; Ahmadu, U; Isah, K. U
    Perovskite solar cells have shown exceptional performance and significant advancements in solar cell efficiency. For perovskite solar cells to conduct electrons and generate current, one of the key components is the substance known as the electron transport layer (ETL). Using the SCAPS 1D modelling program, ZnO: Al was used in this instance as the ETL material in a perovskite solar cell. Because of its interaction with the perovskite material, the ZnO: Al ETL demonstrated high cell efficiency. The performance of the ZnO: Al-doped-based solar cell achieved a PCE as high as 23.5%. In the meanwhile, the greatest cell performance in terms of enhancing the charge transport mechanism and raising cell efficiency was shown by perovskite solar cells doping the ETL with Al and having the right layer thickness. Thus, throughout the manufacturing process, the parameters used in this study may serve as a guide.