Browsing by Author "Muhammad, S."

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    Modification of the Exterior and Interior Solution of Einstein’s g22 Field Equation for a Homogeneous Spherical Massive Bodies whose Fields Differ in Radial Size, Polar Angle, and Time
    (Department of Physics, Nasarawa State University Keffi, 2021-08-16) Rilwan, Usman; Maisalatee, A.U.; Ogwu, E.I.; Okara, O.G.; Muhammad, S.; Ubaidullah, A.; Abdulrahman, H.
    In general theory of relativity, Einstein’s field equations relate the geometry of space-time with the distribution of matter within it. These equations were first published by Einstein in the form of a tensor equation which related the local space-time curvature with the local energy and momentum within this space-time. In this article, Einstein’s geometrical field equations interior and exterior to astrophysically real or hypothetical distribution of mass within a spherical geometry were constructed and solved for field whose gravitational potential varies with time, radial distance and polar angle. The exterior solution was obtained using power series. The metric tensors and the solution of the Einstein’s exterior field equations used in this work has only one arbitrary function f(t,r,θ) , and thus put the Einstein’s geometrical theory of gravitation on the same bases with the Newton’s dynamical theory of gravitation. The gravitational scalar potential f(t,r,θ) obtained in this research work to the order of co, c-2 , contains Newton dynamical gravitational scalar potential and post Newtonian additional terms much importance as it can be applied to the study of rotating bodies such as stars. The interior solution was obtained using weak field and slow-motion approximation. The obtained result converges to Newton’s dynamical scalar potential with additional time factor not found in the well-known Newton’s dynamical theory of gravitation which is a profound discovery with the dependency on three arbitrary functions. Our result obeyed the equivalence principle of Physics.
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    PROPOSED THERMAL MODEL OF SILICON-ON-INSULATOR (SOI) INTEGRATED CIRCUITS
    (Department of physics, Nasarawa State Univesity Keffi, 2018-10-13) Loko, A.Z.; Anyanninuola, O.S.; Muhammad, S.
    The Silicon-on-insulator (SOI) metal oxide semiconductor field effect transistor (MOSFET) structure with a layer of buried silicon oxide added to isolate the device body and the silicon substrate can significantly cut down source and drain depletion capacitances and can reduce the effect of short channel. Though, the low thermal conductivity of the buried oxide (BOX) can cause local heating, changed electrical properties, altered heat flow down interconnects, and failure of thermal devices. The current thermal models that are presently used in simulation of a circuit to account for thermal effects do not accurately capture the heat flow in the devices. However, accurate models rely on large network circuits or arithmetic simulations which does not execute speedily enough for large scale integrated circuit (LSIC) simulation. The drive of this research work is to advance a method that is efficient balance between accuracy, adaptability and speed and can be used in large scale simulation. The approach will integrate efficient SOI device thermal model and communicate thermal model into integrated circuit (IC) simulation, and will offer accurate, effective and efficient electro-thermal simulation tool for large scale SOI integrated circuit structure.