Scholarly work in the Department of Physics with Electronics

Permanent URI for this collection

https://repository.crawforduniversity.edu.ng/handle/123456789/224

Browse

Browsing Scholarly work in the Department of Physics with Electronics by Author "Onaiwu Kingsley Nosakhare"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Effect Of Coulomb Interactions on The Amplitude Of Persistent Currents In One Dimensional Disordered Mesoscopic Metallic Rings
    (arXiv preprint, 2021) Onaiwu Kingsley Nosakhare; Okanigbuan Robinson O; Ehika S
    Persistent current is a small but perpetual electric current that flows in metallic rings in the absence of any applied source. We compute the persistent currents of one-dimensional disordered metallic rings of interacting electrons in the presence of impurity on lattices up to 8-sites at half-filling and also away from half-filling using the Lanczos algorithm. For the case of half-filling, we observe that both interaction and disorder suppress the amplitude of the persistent currents by localizing the electrons. However, in the presence of disorder and away from half-filling, the Coulomb interaction is observed to enhance the persistent current. Furthermore, in the half-filled case, there is a transition from metal to insulator as U is increased significantly. In addition, shifting away from half-filling, the system is observed to remain in the metallic state irrespective of the value of the Coulomb repulsion (U). The observations are quite in agreement with the results from other techniques.
  • Thumbnail Image
    Item
    Evaluation of Lateritic Soil Using 2-D Electrical Resistivity Methods at Alapoti, Southwestern Nigeria
    (Global Journal of Pure and Applied Sciences, 2021-04) Onaiwu Kingsley Nosakhare; Akinnawo Olumide Olufemi; Adeola Adewole John; Usifo Abel Giwa
    A 2-D resistivity survey was carried out in Alapoti, Ogun State, a sedimentary terrain of South-western Nigeria. This area lies between longitude 0060 34′0″N and 0060 40′0″N and latitude 00302′0″E and 00306′0″E. The wenner alpha electrode configuration was engaged through out in this study. Ten profiles were covered; five in the north-south direction, and the other five in the west-east direction. To obtain a good 2-D picture of the subsurface, the coverage of the measurements must be 2-D as well. The distance between adjacent traverse is 25 metres. The data from each 2-D survey line was inverted independently with RES2DINV to give 2-D cross-sections with averages of 4.8 iteration and RMS error of 8.15%. A contoured pseudosection conveys a qualitative two- dimensional resistivity variation with depth within the subsurface. The inversed model resistivity sections created models for the subsurface resistivity using an iterative smoothness constrained least square inversion and are interpreted to generate the subsurface geologic characteristics. Results from 2-D inversed resistivity section showed that the second layer with resistivity value of about 200 m to 600 m and thickness of about 4.0m is composed of lateritic clay. The third layer is made up of moderate laterite having a thickness of about 3.0m and apparent resistivity ranging from 600 m to 1,000 m, while the fourth layer of apparent resistivity value 1,000 m to 1,500 m is laterite but rich in sand and it is located at a deep of about 12.0m.
  • Thumbnail Image
    Item
    Ground State Properties Of The One-Dimensional Hubbard Model: Symmetry Projected Variational Wave Function Approach
    (arXiv preprint, 2021) Onaiwu Kingsley Nosakhare; Okanigbuan Robinson O
    We use the C4v symmetry group of the 4*site Hubbard model to construct a ground state variational wave function of two- and four interacting electrons. In the limit U 0, ground state energies of the two- and four interacting electrons system is of the order *4t. The variational wave function of the four interacting electrons obtained using the B1 irreducible representation is valid for on-site Coulomb repulsion, while the one obtained using the A1 representation is valid for negative values of the Coulomb interaction. The system exhibits antiferromagnetic correlations.
  • Thumbnail Image
    Item
    Hamiltonian Complete Number of Some Variants Of Caterpillar Graphs
    (arXiv preprint, 2025-04) Onaiwu Kingsley Nosakhare; Adefokun Tayo Charles; Ajayi Deborah Olayide; Ogundipe Opeoluwa Lawrence
    A graph G is said to be Hamiltonian if it contains a spanning cycle. In this work, we investigate the Hamiltonian completeness of certain classes of caterpillar graphs, which are trees with a central path to which all other vertices are adjacent. For a non-Hamiltonian graph G, the Hamiltonian complete number H(G) is the minimum number of edges that must be added to G to make it Hamiltonian. We focus on both regular and irregular caterpillar graphs, deriving explicit formulas for H(G) in various cases. Specifically, we show that for a regular caterpillar graph Gn(k) where each vertex on the central path is adjacent to k leaves, H(Gn(k)) = n(k−1). We also explore irregular caterpillar graphs, where the number of leaves adjacent to each vertex on the central path varies, and provide bounds for H(G) in these cases. Our results contribute to the understanding of Hamiltonian properties in tree-like structures and have potential applications in network design and optimization.