School of Physical Sciences (SPS)

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School of Physical Sciences (SPS)

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    Mathematical model for the dynamics of COVID-19 Pandemic Incorporating Isolation and Non-Linear Recovery Rate
    (ISEP Porto-Portugal, 2024-06-22) N. I. Akinwande; T. T. Ashezua; S. A. Somma; O. N. Abdurrahman; F. A. Oguntolu; O. M. Adetutu; R. I. Gweryina; R. O. Olayiwola; T. P. Adajime; F. A. Kuta; S. Abdulrahman; A. I. Enagi; G. A. Bolarin; M. D. Shehua; A. Usman.
    COVID-19 has in recent times created a major health concern in both developed and developing parts of the world. In this wise, there is every need to theoretically explore ways that will provide some insights into curtailing the spread of the disease in the population. In this paper, we present a population model for COVID-19 pandemic incorporating isolation and nonlinear recovery rate. The reproduction number was obtained using the next generation method. The disease-free equilibrium (DFE) of the model (1) was found to be locally and globally asymptotically stable whenever the associated reproduction number is less than unity. Results from the sensitivity analysis of the model, using the reproduction number, RC show that the top parameters that largely drive the dynamics of COVID-19 in the population are COVID-19 transmission rate and the proportion of individuals progressing to the class of reported symptomatic infectious individuals. Numerical simulations of the model shows that increasing the recovery rate of infected patients in the population will lead to an initial decrease in the number of hospitalized patients before subsequent increase. The reason for this could be attributed to the number of unreported symptomatic infectious individuals who are progressing to reported symptomatic infectious stage of infection for immediate isolation.
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    HARVESTING RENEWABLE ENERGY FOR A SUSTAINABLE FUTURE USING QUANTUM DOT TECHNOLOGY
    (13th annual and international hybrid conference of the renewable and alternative energy of nigeria, 2025-03) Ikeri, H.I; Ndubueze, D. N; Eze, C. N.; Achuka, E. I; Nwagbara, O.; Onuabuchi, V. C
    This paper explores the role of quantum dots in revolutionizing renewable energy technologies, addressing challenges such as stability and environmental impact. Renewable energy is essential for a sustainable future and advancements in nanotechnology have opened new possibilities for efficient energy harvesting. The result obtained indicates that quantum dots (QDs), display tunable electronic properties, discrete electronic state and high photon absorption efficiency. The novel properties allow for new design architectures such as immediate band, multiple exciton generation and multiple junction solar cell technologies. These mechanics have shown to derive quantitative gains in the solar to electricity conversion efficiency to surpass the Shockley and Quisser limit imposed on conventional cells. By integrating QD-based systems with solar photovoltaics and next generation batteries would paves the way for more efficient and sustainable energy solutions.
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    A STUDY OF CHEMICALLY DEPOSITED OXIDE- BASED TERNARY THIN FILM OF ZINC TITANATE (ZnTiO3) DOPED WITH NATURAL DYES AND THEIR POTENTIAL PHOTOVOLTAIC APPLICATIONS.
    (journal of nano and material science research, 2025) Eze, C. N.
    The ternary metal oxide thin film of ZnTiO3 doped with three different natural dyes were synthesized on glass substrate via solution growth (SG) at room temperature. Chemical baths were used which contained Zinc Sulphate (ZnSO4.7H2O), Sodium Hydroxide (NaOH), Titanium Chloride (TiCl3), distilled water and calibrated drops per bath of organic dyes: Lawsonia inermis, Beta vulgaries and Jatropha curcas respectively. Each deposit which was set at a temperature of 80 0C lasted for 1 h and each deposit was annealed at 400 0C for 1 h. These deposited nano thin films were characterized for their structural, morphological, optical properties, elemental composition and electronic (chemical) structure and presence of functional groups by means of X-ray diffraction (XRD), Scanning Electron Microscope (SEM), UV-VIS spectrophotometer, Energy Dispersive X-ray Fluoroscopy (EDXRF) and photoluminescence Fourier Transform Infrared Radiation Spectroscopy (FTIR). Polycrystalline thin films were evidenced which marked porosity offered them maximum surface area for dye loading which is critical for photosensitization in dye sensitized solar cells (DSSCs). Such doping presented band gaps of doped ZnTiO3 from 1.84 eV to 3.45 eV depending on dopants applied as against undoped film band gap that was 3.55 eV. The FTIR results showed good photophysical, carboxylate and modification properties of the dyes which helps in sunlight harvesting, anchoring and surface structure modification of the films. The dye influenced the optical properties of the samples and in particular, the reduction of the energy band gap, Eg from an increase in absorption coefficient α, giving high absorbance A, low extinction coefficient k, low reflectance R, which inferred its potential applications in solar energy devices when used in construction, poultry houses, solar cells and DSSCs.
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    Optical Properties of PbSe, PbS, and PbTe Semiconductor Quantum Dots and their Applications
    (2025-08) Ikeri, H.I; Harry, S.T; Achuka, E.I; Eze, C. N.; Asielue, O.K; Ndubueze, N.D
    Abstract - Optical properties of PbSe, PbS, and PbTe semiconductors in confinement regimes have been studied using the Brus equation. The results indicate that QDs exhibit size-dependent optical behavior and, hence, tunable bandgaps and emission wavelengths as a consequence of quantum confinement. As the QD size decreases, the absorption edge and emission peak are blue-shifted for all three materials. It is found that PbSe QDs display significant quantum confinement even at larger sizes. Due to its relatively large exciton Bohr radius (~46 nm), as the size decreases from 10 nm to 2 nm, the bandgap increases from 0.27 eV to over 1 eV, shifting absorption and emission into the near-infrared (NIR), leading to applications into NIR photodetectors, solar cells, and biomedical imaging. Also, PbS QDs exhibit significant quantum confinement effects at smaller sizes due to their smaller exciton Bohr radius (~20 nm) compared to PbSe. The bandgap increases from 0.41 eV to around 1.5 eV as the size decreases from 10 nm to 2 nm, shifting absorption and emission from the NIR into the visible range. This is utilized in solar cells, visible to NIR photodetectors and LEDs. Furthermore, PbTe QDs also exhibit pronounced quantum confinement effects because of their relatively large exciton Bohr radius (~46 nm). The bandgap increases from 0.32 eV to around 1 eV as the size decreases from 10 nm to 2 nm, shifting absorption and emission into the NIR and Mid-Infrared (MIR) regions, making them excellent materials for infrared detectors, thermoelectric and MIR applications. Among the semiconductor materials studied, PbS QD typically exhibits the largest increase in bandgap with decreasing size, making them suitable for applications requiring larger bandgap tunability, followed by PbSe and PbTe. These different optical characteristics are due to their unique electronic properties and exciton Bohr radii.
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    Mathematical Analysis of the Transmission Dynamics of Hepatitis B Virus
    (Springer Science and Business Media LLC, 2025-05-15) F.A. Oguntolu; O.J. Peter; D. Aldila; G. B. Balogun; O. P. Ogunmola; B. I. Omede
    Hepatitis B is a life-threatening hepatic illness induced by the Hepatitis B virus (HBV). This is a major worldwide health issue, especially in low- and middle-income nations in Africa and the Western Pacific, where prevalence rates are the greatest. Nevertheless, the existence of an efficacious vaccination, Hepatitis B persists in inflicting significant morbidity and death owing to a deficiency of awareness regarding the illness. Thus, we developed a deterministic mathematical model to elucidate the transmission dynamics of Hepatitis B, integrating elements such as vertical transmission, re-infection, and environmental viral concentration. The study starts with the calculation of the basic reproduction number and the assessment of the local stability of the disease-free equilibrium employing the Routh-Hurwitz criteria. A comprehensive examination of the model indicates that the model may experience backward bifurcation phenomena under some specific conditions. This trait presents considerable challenges in the proper management of Hepatitis B infection among the population. Assuming no re-infection of Hepatitis B post-recovery, the disease-free equilibrium point is globally asymptotically stable when the basic reproduction number is less than or equal to one. The sensitivity analysis of the basic reproduction number was conducted to assess the influence of each fundamental parameter in the model that contributes to disease transmission. Utilizing the optimal control theory to effectively curb the spread of Hepatitis B, we incorporated two time-varying control strategies, namely the prevention of susceptible individuals from acquiring HBV (through safe sex practice, regular washing of hands, and using protective hand gloves when handling blood, body fluid and semen) and the sensitization on individuals on personal hygiene, sterilization and proper disposal of medical and dental equipment like syringes in order to reduce the shedding of HBV in the environment. The numerical simulations indicated that Hepatitis B infection may be effectively managed and mitigated within the community if both control measures are correctly implemented.
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    Estimating the Heat Flow, Geothermal Gradient and Radiogenic Heat within the Young Granites of Jos Plateau North Central Nigeria
    (University of Tehran Press, 2024-02) Adetona, A. A; Rafiu, A. A; Aliyu, B. Sh; John, M. K; Kwaghhua, I. F
    Both aeromagnetic and radiometric data were used to evaluate the Curie point depth and radiogenic heat production (RHP) of the young granitic regions of the Jos Plateau. An area of 55 by 110 square kilometers is bounded by latitude 9°30' to 10°00' N and longitude 8°30' to 9°30' E in central Nigeria. The magnetic data was subjected to spectral analysis to obtain the Curie depth, which was subsequently used to evaluate the geothermal gradient and heat flow for the area. Also, the concentration of radioelements (potassium, thorium and uranium) and the average density of the in-situ rock were used to estimate the radiogenic heat production at each point where the Curie point was evaluated. The heat flow in the study area ranges from 10 to 165.5 mW/m2 with an average value of 111.00 mW/m2. The regions with anomalous heat flow of 165.5 mW/m2 are located around Bowon Dodo, Dan Tsofo, Kadunu, Gimi, Kaura and Zankan in plateau state. The geothermal gradient values range from 5 to 68 °C/Km with an average of 26.16 °C/Km. The radiometric data analysis resulted in radiogenic heat values ranging from 0.4 µWm3 to 6 µW/m3 with an average radiogenic heat value of 3.36 µW/m3. Both analyses revealed that regions such as Ataka, Gimi, Jimjim and Pari could be investigated for geothermal energy potential. The high concentration of uranium, thorium and potassium associated with the study area is likely due to the weathering of the in-situ granitic basement rocks.
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    Integrated Geophysical Investigation for Potential Gold Mineralised Zone within Lower Part of Zuru Schist Belts, NW Nigeria
    (Nigerian Institute of Physics, 2024) Augie, A. I; Salako, K. A; Rafiu, A. A; Jimoh, M. O
    The study began with a reconnaissance survey that used high-resolution aeromagnetic data of the study area to identify suitable structure zones with the potential to trap mineral resources within the context of the gold exploration target. The findings of magnetic studies were followed up with detailed investigations using 2D electrical resistivity tomography (ERT) and induced polorisation (IP) techniques to reveal further details about gold mineral zones and other lithological boundaries. The airborne magnetic data of sheet 118_Yelwa was obtained from the NGSA; these datasets were processed and analyzed using Oasis Montaj's first vertical derivative (FVD) and center for exploration targeting (CET) techniques. Results of FVD and CET grid anomalies show that regions of major magnetic structures (lineaments) are associated with granite gneiss, migmatitic augen gneiss, and medium to coarse-grained biotite when compared to the geological settings of the area. The zones of major structures obtained in this study coincided with previous magnetic studies of the area, located in the eastern parts of Ngaski, Yauri (Yelwa), Shanga, Agwara, as well as Magama's northwest region. Some of the regions for lineament (in the eastern part of Ngaski/Yauri) were investigated further with 2D ERT and IP detailed geophysical methods in a dipole-dipole configuration. The results of geoelectric techniques along profiles 1, 2, and 3 identified the major gold mineralisation potential zones, which were labeled A1, A2, and A3. These regions have low/high resistivity (1.6 to 459 Ωm/1889 to 7773 Ωm) and chargeability signatures (≥ 20 msec), and could thus be interpreted as potential target zones for metallic mineral exploration, particularly gold mineralisation. The regions are located in the northern Mararraba and southwest of the Jinsani areas of Kebbi State. The results of integrated geophysical methods have produced updated structural features of the regions, as well as a database containing precise locations, lateral lengths, thicknesses, and depths for prospective gold mineralisation zones. This database could assist the miner/explorer in locating the potential zone of gold mineralisation.
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    Integrated Geophysical Investigation using Aero-radiometric and Electrical Methods for Potential Gold mineralization within Yauri/Zuru Schist Belts, Kebbi State NW Nigeria
    (Unierasidad Naciona de Colombia, 2024) Abdulrahaman Idris Augie; Kazeem Adeyinka Salako; Andy Anderson Bery; Adewuyi Abdulwaheed Rafiu; Mufutau Owolabi Jimoh
    This study used aero-radiometric, 2D electrical resistivity tomography (ERT), and induced polarization (IP) methods to delineate gold mineralization potential. The study also confirmed and followed-up on regions with major structural features identified in previous aeromagnetic studies in the area. A half-degree airborne radiometric data of sheet 118_ Yelwa from the NGSA, which contains three radioelements (%K, eTh, and eU) were used in this study. These datasets were processed and analyzed with Oasis Montaj Grid Math expression builder to obtain the %K_ratio_eTh and Ternary grid anomalies. The results identified zones E and F as hydrothermally altered regions that may harbour gold mineralization. These findings were consistent with the regions of major structural features identified in previous aeromagnetic studies in the area. The zones were located in the eastern parts of Ngaski, Yauri (Yelwa), Shanga, and Agwara, as well as Magama’s northwest region. However, zone F1 (the eastern portion of Ngaski/Yauri) has been further investigated using 2ERT and IP detailed geophysical methods in a dipole-dipole configuration. The results of geoelectric techniques along profiles 1, 2, and 3 identified the major gold mineralization potential zones, which were labeled A1, A, and C. These regions have low/high resistivity and chargeability signatures, and could thus be interpreted as potential target zones for metallic mineral exploration, particularly gold mineralization. The regions are located in the northern part of Mararraba and southwest of the Jinsani areas of Kebbi State.
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    Mathematical analysis of a novel fractional order vaccination model for Tuberculosis incorporating susceptible class with underlying ailment
    (International Journal of Modelling and Simulation (Taylor & Francis), 2024-07-10) El-Mesady, A.; Peter, Olumuyiwa James; Omame, Andrew; Oguntolu, Festus Abiodun
    Tuberculosis (TB) is a communicable, airborne infection caused by the bacillus Mycobacterium tuberculosis. Pulmonary tuberculosis (PTB) is the most common presentation, although infection can spread anywhere to cause extra-pulmonary tuberculosis (EPTB). In this paper, a novel fractional order mathematical model is designed for the transmission dynamics of tuberculosis. Uninfected vulnerable individuals are categorized into the following: susceptible with underline ailment and susceptible without underline ailment. The research seeks to qualitatively and quantitatively analyze the proposed model and suggests comprehensive intervention measures for the control of tuberculosis among individuals with underline ailment. Some of the major highlights from the numerical investigation points out that TB vaccination is key to reducing the spread of TB among individuals with underline ailment. Furthermore, efforts to step down the spread of TB through awareness campaigns could significantly reduce the burden of the disease among individuals with co-morbidity.
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    Mathematical model on the transmission dynamics of leptospirosis in human and animal population with optimal control strategies using real statistical data
    (Springer Science and Business Media LLC, 2024-12-07) Festus Abiodun Oguntolu; Olumuyiwa James Peter; Benjamin Idoko Omede; Ghaniyyat Bolanle Balogun; Tawakalt Abosede Ayoola
    Leptospirosis poses a significant public health challenge, with a growing incidence in both human and animal populations. The complex interplay between reservoir hosts, environmental factors, and human activities complicates efforts to curb the spread of the disease. Consequently, this paper presents a deterministic mathematical model for the transmission dynamics of leptospirosis within the intertwined human and animal populations. A comprehensive examination of the model revealed that the disease-free equilibrium is globally asymptotically stable when the basic reproduction number is below one. Utilizing center manifold theory, we demonstrated that the Leptospirosis model displays forward bifurcation. Consequently, the epidemiological significance of this forward bifurcation suggests that eradicating leptospirosis from the community is feasible, provided the reproduction number remains below one. We conducted a sensitivity analysis on the basic reproduction number of Leptospirosis to identify parameters that contribute positively to the disease’s spread. Furthermore, We validated our Leptospirosis model by fitting it with confirmed cases reported in Kerala State, India, covering the period from January 2021 to December 2022. This calibration process ensures the model’s accuracy and reliability in reflecting real-world epidemiological dynamics within the specified region and timeframe. In addition, we enhanced the Leptospirosis model by incorporating three time-dependent control measures. These controls encompass the vaccination of animals, environmental sanitation, and preventive actions such as using hand gloves and goggles when handling animals, as well as wearing rubber boots during periods of flooding or heavy rainfall. Results obtained from numerical simulations indicate that implementing the vaccination of animals as a standalone control strategy has no discernible effect on the number of infected humans or the bacteria population. However, when the three time-dependent control measures are combined, there is a substantial and meaningful impact on reducing the number of infected humans, infected animals, and the overall bacteria population within a relatively short timeframe. This underscores the effectiveness of the integrated approach in mitigating the spread of leptospirosis across both human and animal populations.